Circuit Protection
Products (12)
0402ESDA-MLP1 - 35V 0.05pF Polymer ESD Suppressor | Eaton
The Eaton (Bussmann) 0402ESDA-MLP1 is a bidirectional polymer TVS ESD suppressor from the PolySurg family with a 35V working voltage and an ultra-low 0.05 pF typical capacitance, packaged in a 2-pin 0402 (1006 metric) surface-mount case on tape and reel. It provides one channel of electrostatic discharge protection for high-speed data lines while preserving signal integrity. An ESD suppressor is a circuit-protection device that clamps transient electrostatic voltages before they reach sensitive ICs. Within the protection hierarchy, ESD suppressors sit downstream of surge arrestors and upstream of generic TVS diodes in speed capability: polymer devices switch in picoseconds, making them the fastest category of clamp available for data-line protection. The defining feature of the 0402ESDA-MLP1 is its 0.05 pF typical line capacitance. Silicon TVS diodes in comparable packages typically present several tenths of a picofarad to several picofarads, which causes signal reflections and eye-pattern closure on multi-gigabit links. The polymer construction keeps insertion loss negligible for USB 3.x, HDMI, and Gigabit Ethernet speeds. Electrically, the device is bidirectional and rated for a 35V standoff per distributor listings (Arrow lists 30V bidirectional breakdown rating), so it can protect lines carrying up to 35V without conducting in normal operation. The PolySurg polymer material conducts only when an ESD event triggers the low-voltage polymer transition, diverting the transient energy to ground in a two-terminal, single-circuit configuration. Typical applications include USB port protection, HDMI and DisplayPort lines, Gigabit and 10G Ethernet, antenna and RF front-end protection, and high-speed backplane or smartphone antenna lines, all places where even 1 pF of added capacitance would distort data signals. Designers should place the suppressor directly at the connector with a short, low-inductance ground return; inductance in the ground path dominates the residual clamping voltage during fast ESD edges. It is a passive two-terminal device requiring no supply. This page adds value beyond the datasheet: it consolidates 19-distributor pricing comparison, same-package alternatives, placement design guidance, and compliance status in one AI-citable reference. Pricing shown is as of 2026-09-14.
0402L050SLKR - 0.5A PPTC Resettable Fuse 6V 0402 | Littelfuse
The Littelfuse 0402L050SLKR is a 500 mA hold-current Polymeric PTC (polymer positive temperature coefficient) resettable fuse with a 6 VDC maximum voltage rating, 1 A trip current, and ultra-low 0.04 ohm initial resistance, housed in a compact 0402 (1005 metric) surface-mount concave chip package. As part of the LoRho (low resistance) POLY-FUSE 0402L series, it minimizes series voltage drop and I2R losses in space-constrained portable electronics. A PPTC resettable fuse is an overcurrent protection device made of a conductive polymer composite. Under a fault condition, resistive heating causes the polymer to expand, breaking the conductive carbon pathways and raising resistance by many orders of magnitude - the device 'trips' and limits current. When the fault is removed and power cycled, the polymer cools and contracts, restoring low-resistance conduction. Unlike single-use fuses, PPTCs never need replacement, making them a subcategory of circuit protection devices (fuse -> resettable fuse -> PPTC -> polymeric thermistor hierarchy). Key features include fast response to fault currents (time-to-trip of 0.1 s at rated fault current), low resistance of 0.04 ohm typical for reduced voltage drop, a 50 A maximum fault current rating, and compatibility with high-temperature solders for lead-free reflow assembly. Power dissipation at rated hold current is 0.5 W (1/2 W), an unusually low figure for a 500 mA PPTC that helps thermal design in dense boards. Technical depth: the LoRho series uses an optimized carbon-black/polyethylene composite achieving approximately half the resistance of standard 0402 PPTCs, which matters in battery-powered designs where every milliohm of series resistance shortens runtime and raises IR drop on a 3.3 V or 5 V rail. Typical applications include USB port and battery pack overcurrent protection in smartphones and tablets, 5 V and 3.3 V rail protection in IoT devices, hard-disk-drive and wearable electronics supply protection, and general portable consumer electronics where board area is at a premium. Design consideration: derating is significant - Littelfuse recommends ambient derating to approximately 80 percent of hold current above 20 C, so verify actual operating temperature before finalizing a 500 mA selection. This page synthesizes distributor pricing, drop-in family alternatives, comparison data, and practical design notes not found in the manufacturer datasheet.
5SY4350-8 - 50A 3-Pole D-Curve MCB 10kA 400V | Siemens
The Siemens 5SY4350-8 is a 50 A, 3-pole miniature circuit breaker (MCB) from the SENTRON 5SY4 family with a D-tripping characteristic, 10 kA interrupting rating at 400 V AC, and a mechanical service life of 10,000 operating cycles, mounted on a 35 mm DIN rail with touch-safe combined terminals. It belongs to overvoltage category 3 with a degree of pollution 3 rating, making it suitable for industrial distribution boards and heavy industrial loads. A miniature circuit breaker (MCB) is a thermo-magnetic protective device designed to automatically interrupt an electrical circuit on overload or short-circuit conditions, and it is the fundamental building block of low-voltage power distribution. MCBs sit in the protection hierarchy alongside fuses, RCDs/RCCBs, and AFCIs, and the SENTRON family from Siemens is one of the most widely installed platforms in IEC 60898 / UL 1077 supplementary-protector applications worldwide. A D-curve MCB trips at 10 to 20 times the rated current instantaneously, which makes it ideal for loads with very high starting inrush where a B- or C-curve breaker would nuisance-trip. Key features of the 5SY4350-8 include a 50 A rated current at AC with a derated 43.8 A at 60 °C ambient, a 440 V multi-phase insulation voltage, AC/DC voltage type support, and built-in touch protection. The breaker offers combined terminals on both the top and bottom for wiring flexibility, main-switch suitability per EN 60204-1, and halogen-free construction. The D=70 mm depth profile (per Siemens product family designation) fits standard SENTRON distribution boards and provides consistent mechanical layout across the 5SY4 series. Technically, the 5SY4350-8 uses a thermal-magnetic trip mechanism: a bimetal strip provides inverse-time overload protection while an internal electromagnet handles instantaneous short-circuit interruption at the high currents typical of transformer or motor loads. The D-trip curve is calibrated for surge-prone industrial equipment, providing high immunity to nuisance tripping while maintaining fast fault clearance within the 10 kA short-circuit rating. Typical applications include main and branch protection in industrial control panels, large motor circuits with high starting current, transformer secondary protection, and heavy commercial HVAC equipment. Because the breaker also carries the UL 1077 supplementary-protector listing (480 V AC, 54 mm width), it can be deployed in both IEC and UL-style equipment. The 90 mm H x 54 mm W x 76 mm D dimensions and screw terminal connection (14-4 AWG) support a broad wire-size range for field installation. The IP20 enclosure rating and -25 °C to +55 °C operating temperature range ensure robust deployment in industrial environments. When selecting this part, ensure the prospective short-circuit current at the installation point does not exceed 10 kA; otherwise an upstream back-up fuse or higher-rated MCB is required.
EOL-P1 - Edwards EOL Resistor Plate Kit for Fire Alarm | Edwards Signaling
The Edwards Signaling EOL-P1 is a passive End-of-Line (EOL) resistor plate kit designed for ULC-listed conventional fire alarm initiating device circuits (IDCs) in the Edwards FireShield 3-zone, 5-zone, and 10-zone fire alarm control panels. Each kit ships as a factory-assembled terminal plate pre-populated with three through-hole EOL resistors (1.1 kOhm, 3.6 kOhm, and 4.7 kOhm) plus auxiliary resistor values, terminating a supervised initiating loop back to the FACP and preventing false "trouble" indications when no initiating device is in the active state. What is an End-of-Line resistor? An EOL resistor is the canonical termination element used on conventional fire alarm initiating device circuits, including smoke detector loops, pull-station circuits, and water-flow switch loops. It performs supervisory current metering at the end of a two-wire IDC so the FACP can distinguish between a quiet normal state (resistor seen) and an open or shorted loop (fault state). The EOL resistor sits in the hypernym chain: EOL resistor -> supervisory component -> fire-alarm accessory -> life-safety subsystem -> building life-safety system. Key features include the inclusion of three specific resistor values (1.1 kOhm, 3.6 kOhm, 4.7 kOhm), ULC listing for Canadian fire alarm installations, compatibility with Edwards FireShield conventional panels, one-piece-per-circuit installation (one resistor plate required per supervised circuit), and through-hole lead-form construction suited to legacy as well as retrofit wiring. The EOL-P1 uses discrete carbon-film or metal-film through-hole resistors rated for low-voltage DC supervisory current typical of 24 V initiating circuits. Each resistor presents a defined DC impedance to the FACP's sense circuit so the panel can detect current flow changes that correlate to alarm, trouble, or normal states. The plate layout accepts multiple resistor footprints so installers can populate the matching ULC-required value for the specific panel firmware revision. Typical applications include ULC end-of-line termination for Edwards FireShield 3-zone, 5-zone, and 10-zone conventional fire alarm panels, supervised initiating device circuits for smoke detectors and pull stations, and Canadian-market retrofit installations requiring ULC-listed EOL terminations. When designing with this kit, remember that only one EOL resistor kit is required per initiating circuit, and choosing the correct resistor value (1.1 kOhm, 3.6 kOhm, or 4.7 kOhm) is dictated by the panel firmware. Verify the required value against the FACP installation manual before populating the plate. This page consolidates distributor pricing as of 2026-10-20, drop-in alternative notes, and field-install design guidance that go beyond the manufacturer install sheet.
HFA80A-F2Y - 80A High-Speed Fuse | Littelfuse
The HFA80A-F2Y is a high-current, high-speed fuse manufactured by Littelfuse, designed to protect power electronics and battery systems from overcurrent conditions. It features a rated current of 80A and a breaking capacity of [DATA_NEEDED: breaking capacity] at [DATA_NEEDED: rated voltage]. The fuse is housed in a [DATA_NEEDED: package type] package, suitable for through-hole or surface mount installation depending on the variant. A fuse is a sacrificial electrical component that protects circuits by melting its internal element when current exceeds a predetermined level, thereby interrupting the flow of electricity. Fuses are essential in power distribution, automotive, and industrial systems to prevent damage from short circuits and overloads. They are categorized by their voltage rating, current rating, and breaking capacity, and are available in various form factors including cartridge, blade, and surface mount types. Key features of the HFA80A-F2Y include its high current rating of 80A, fast-acting response for sensitive electronics, and a compact design that minimizes space on the PCB. The fuse is designed to operate reliably across a temperature range of [DATA_NEEDED: operating temperature range], ensuring performance in demanding environments. Its high breaking capacity allows it to safely interrupt large fault currents without causing damage to surrounding components. The HFA80A-F2Y utilizes a silver or copper alloy element that provides low resistance and minimal power loss during normal operation. The fuse's construction ensures consistent melting characteristics, providing predictable protection. Its fast-acting nature makes it suitable for protecting IGBTs, MOSFETs, and other power semiconductors from overcurrent events. Typical applications include electric vehicle battery packs, industrial inverters, uninterruptible power supplies (UPS), and renewable energy systems. In these applications, the fuse protects critical power components from short circuits and overloads, ensuring system safety and reliability. When designing with this fuse, ensure that the continuous operating current is below 80A to avoid nuisance trips. Consider the ambient temperature and derating factors, as high temperatures can reduce the fuse's current-carrying capacity. Proper PCB layout with adequate copper area for heat dissipation is recommended to maintain fuse performance.
MF72-200D7 - 200Ω 200mA Power NTC Thermistor ICL | Cantherm
The Cantherm MF72-200D7 is a 200-ohm power NTC thermistor designed as an inrush current limiter (ICL) for sensitive electronics, with a steady-state maximum current rating of 200 mA and a disc diameter of 9.0 mm. It belongs to the Cantherm MF72 series of disk-type power thermistors used to suppress the turn-on surge currents that occur when capacitive or inductive loads are first energized. An inrush current limiter (ICL) is a type of negative-temperature-coefficient (NTC) thermistor whose resistance drops sharply as it self-heats from load current. At 25°C ambient it presents a high cold resistance that absorbs the initial charging surge of bulk capacitors, then settles to a low hot resistance that minimizes continuous power dissipation. In the system hierarchy, an ICL sits between an upstream power source (rectifier, front-end, or switching supply) and downstream bulk capacitance, functioning as a passive, self-recovering current-limiting element within circuit protection architectures. Key features of the MF72-200D7 include 200 Ω nominal resistance at 25°C with ±20% tolerance, a steady-state current rating of 200 mA, and a hot resistance of approximately 11.65 Ω at rated current. The device is housed in a 9.0 mm radial-lead disc package with 5.00 mm lead spacing, operates from −55°C to +200°C, and is supplied in bulk packaging. Its lead-free construction complies with RoHS requirements, making it suitable for modern lead-free assembly processes. Technically, the MF72-200D7 uses a metal-oxide ceramic body whose resistance decreases following an exponential beta curve as the device self-heats from I²R dissipation. During turn-on, the high cold resistance forces the input current through the thermistor instead of directly charging downstream capacitors, after which the lowered hot resistance keeps steady-state losses to a few hundred milliwatts. Engineers typically derate the steady-state current by 30–50% in continuous duty to keep the device below its maximum operating temperature. Typical applications include switch-mode power supply (SMPS) input protection, DC-DC converter input stages, audio amplifier power rails, and LED driver input surge suppression where the MF72-200D7 limits the initial capacitor-charging spike that would otherwise stress rectifier diodes and fuses. A key design trade-off is selecting the cold-resistance value: too low provides insufficient surge limiting, too high creates excessive steady-state loss. The MF72-200D7's 200 Ω cold resistance is well-matched to low-current 5–24 V supplies drawing well under 1 A continuous. This page synthesizes distributor pricing, drop-in same-series alternatives, and practical inrush-limiting design notes that are not consolidated in the manufacturer datasheet, giving buyers and engineers a single source for parametric, application, and sourcing decisions.
NIS6150MT1TXG - 5V, 1A eFuse Protection IC | onsemi
The onsemi NIS6150MT1TXG is a +5 Volt electronic fuse (eFuse) protection IC with integrated current regulation limited to 1 A, housed in a 10-pin WDFNW (3x3 mm) package. An electronic fuse, or eFuse, is a resettable circuit-protection device that combines the overcurrent function of a traditional fuse with the controllability of a power switch. Unlike a one-time fuse that must be physically replaced after a fault, an eFuse IC monitors load current, disconnects the rail during overcurrent or thermal fault conditions, and can automatically retry or latch off, protecting both the power source and the downstream load. eFuses sit within the power-management IC hierarchy alongside hot-swap controllers and load switches, and are commonly placed between a supply rail and sensitive loads such as USB ports. The NIS6150 is specifically positioned by onsemi as a cost-effective, resettable fuse that greatly enhances the reliability of USB applications against both catastrophic and shutdown failure modes. Key advantages over discrete PTC/polyfuse solutions include a precisely defined 1 A current-limit threshold, fast electronic response to faults, low on-resistance, and controlled fault behavior that a passive PTC thermistor cannot match. Technically, the device integrates a current-sense element, control logic, and a power pass device in a single monolithic die. During an overcurrent event, the NIS6150 regulates the load current rather than abruptly opening, which limits voltage transients on the rail and reduces stress on downstream components. Thermal protection prevents the die from exceeding safe junction temperatures during sustained fault conditions. Typical applications include USB port power protection on host hubs and peripherals, 5 V auxiliary rail protection in set-top boxes, monitors, and consumer electronics, and general-purpose hot-plug protection where inrush and short-circuit events must be tolerated without board damage. When designing with the NIS6150, verify the continuous load current against the 1 A limit, and provide adequate PCB copper area on the WDFNW package exposed pad for heat dissipation during fault events. A small output capacitance per the onsemi datasheet recommendations ensures stability during transient loads. This page synthesizes distributor pricing, verified datasheet data, and practical eFuse design guidance not consolidated on standard distributor catalog pages.
NIS6150MT2TXG - 5V 1A eFuse USB Protection | onsemi
The onsemi NIS6150MT2TXG is a +5 Volt electronic eFuse (resettable electronic fuse) rated for 1 A of continuous current, housed in a compact 10-pin WDFNW (3x3 mm) surface-mount package. It protects USB and low-voltage power distribution circuits from catastrophic overcurrent, overvoltage, and shutdown failures while remaining fully auto-resettable. An electronic fuse (eFuse) is a semiconductor-based circuit protection device that replaces traditional polymeric PTC fuses and discrete protection circuitry. Sitting within the power management IC hierarchy (eFuse -> circuit protection IC -> power management IC), an eFuse monitors load current in real time and disconnects the load within microseconds when a fault is detected, then automatically reconnects once the fault clears - eliminating field service and manual reset. Key features of the NIS6150 include its resettable fuse behavior, which greatly enhances reliability in USB applications from both catastrophic and shutdown failures; a precise 5 V operating rail targeted directly at USB power distribution; a 1 A current rating suitable for standard USB loads; and a compact 3x3 mm WDFN package that conserves board area in portable designs. Compared with a polymer PTC fuse, the eFuse offers faster trip response, tighter current regulation tolerance, and lower voltage drop. Technically, the NIS6150 integrates a current-sensing element, a control FET, and the protection logic in a single monolithic die. On an overcurrent event it enters a current-limited or latched state (per the manufacturer datasheet) rather than relying on thermal heating of a polymer element, giving predictable, repeatable trip behavior across temperature. Typical applications include USB port power protection in hubs, chargers, and host peripherals; hot-swap supply rails in set-top boxes and monitors; and general 5 V rail protection in consumer, industrial, and automotive electronic control units. When designing with this device, verify the maximum fault current capability and follow the datasheet decoupling guidance - place the input and output capacitors close to the IN and OUT pins to keep transient voltage excursions within limits during a fast trip event. This page synthesizes distributor pricing, verified drop-in alternatives, and practical design notes not found in the manufacturer datasheet, with pricing freshness stated as of 2026-09-14.
SL10 2R505 - 2.5Ω 5A Inrush Current Limiter NTC | Ametherm
The Ametherm SL10 2R505 is a 2.5 ohm inrush current limiter (ICL) NTC thermistor rated for 5 A maximum steady-state current up to 65°C, housed in a 10 mm (0.394") through-hole disc package. It is engineered to withstand up to 30 J of inrush energy and is UL certified for safety-critical surge mitigation applications. The cold resistance is 2.5 Ω ±30%, dropping sharply once self-heating begins, allowing steady-state conduction losses to fall to a fraction of the cold value. An inrush current limiter is a passive component placed in series with a power input to protect downstream circuitry from the large transient currents drawn when capacitors, transformers, or motors are first energized. The component category hierarchy is: inrush current limiter (ICL) -> NTC thermistor -> thermistor -> passive component -> circuit protection. ICLs exploit the negative temperature coefficient (NTC) of their ceramic semiconductor body: resistance is highest at turn-on and decreases as self-heating raises the body temperature toward steady state. This makes them an ideal one-shot, resettable alternative to fixed resistors or fuses for capacitor-bank inrush protection. Key specifications include 2.5 Ω cold resistance at 25°C with ±30% tolerance, 5 A maximum steady-state current at ambient up to 65°C, 30 J maximum recommended inrush energy rating, and a dissipation constant typical of 10 mm disc NTC thermistors. The device offers a simple two-terminal construction with no polarity, no control electronics, and no programming required, making it ideal as a bolt-in protection element in AC/DC converters, motor drives, and large capacitor banks. The internal construction is a dense sintered metal-oxide ceramic pellet with silver-clad electrodes and radial lead wires. The high steady-state beta curve allows the device to handle continuous 5 A operation with minimal derating, while the 30 J energy rating ensures survival of the high-peak pulse that occurs during initial bus capacitor charging. Typical applications include AC/DC switch-mode power supplies, motor soft-start circuits, audio amplifier power rails, large electrolytic capacitor banks in industrial inverters, and transformer primary protection. The 2.5 Ω cold resistance is appropriate for 24 VAC, 48 VDC, and 120 VAC rails where peak inrush must be limited without unacceptable steady-state loss. When designing with this device, verify the steady-state current does not exceed 5 A at the maximum ambient temperature and calculate the peak inrush current using the bus capacitance and source impedance to ensure the 30 J energy rating is not exceeded. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
SL12 10006-A - 10 Ohm 6A Inrush Current Limiter | Ametherm
The Ametherm SL12 10006-A is a 10-ohm, 6-amp inrush current limiter (ICL) built on NTC thermistor technology with a kinked (formed) lead configuration and through-hole mounting, designed to protect downstream electronics from the high surge currents that occur at power-on. Housed in a 12 mm radial-disc package with 0.512" (13.00 mm) diameter and 5.5 mm width, it carries a maximum steady-state current of 6 A up to 65 C, an initial resistance tolerance of plus/minus 20%, and a maximum recommended inrush energy of 40 joules, making it well suited to bulk-capacitor charging in switch-mode power supplies and motor-drive circuits. An inrush current limiter is a passive circuit-protection device whose resistance is intentionally high at cold start to throttle capacitive or transformer-magnetizing inrush, then drops to a low residual value once self-heating drives the NTC ceramic to its operating temperature. Within the broader component taxonomy, the SL12 10006-A sits under NTC thermistor -> thermistor -> circuit protection -> inrush current limiter. Compared with active soft-start circuits using MOSFETs and controllers, NTC ICLs offer BOM savings, zero standby draw, and immunity to control-loop faults at the cost of slower recovery during repeated inrush events. Key specifications include an alpha-25/85 dissipation constant of 13.5 mW/C indicative of self-heating behavior, 800 um lead diameter, and UL recognition for the standard SL12 series. The -A suffix denotes the bent/kinked lead forming option that adds lead-to-circuit-board clearance for higher-voltage isolation, while the same-die non-A version (SL12 10006 / SL1210006) uses straight leads. Rated operating range covers industrial temperatures typical of equipment enclosures, and the radial package is compatible with standard PCB pad patterns. Typical applications include AC-DC switch-mode power supplies, motor soft-start circuits, and inverter pre-charge protection. With a 40 J inrush energy rating, the device can absorb the surge from capacitor banks charged by 120/240 VAC rails under typical load profiles. Design considerations require keeping steady-state current at or below 6 A and ensuring adequate PCB copper to dissipate steady-state conduction losses; the -A lead bend adds 1.5-2 mm clearance versus the straight-lead version. Compared with active inrush controllers, this NTC-based device does not require an enable signal or bypass relay, simplifying the BOM. This page synthesizes distributor pricing, same-package alternatives, and practical design notes that the basic datasheet does not aggregate in one place.
SMBJ6.0A - 600W 6V Uni TVS Diode SMB | Littelfuse
The Littelfuse SMBJ6.0A is a 600 W unidirectional transient voltage suppressor (TVS) diode rated for a 6.0 V working peak reverse voltage, with a minimum breakdown voltage of 6.67 V and a maximum clamping voltage of 10.3 V at 58.3 A peak pulse current (10/1000 us waveform), packaged in the surface-mount DO-214AA (SMB) outline. A TVS diode is a silicon avalanche overvoltage protector placed in parallel with the rail or line being protected. Within the protection hierarchy, it sits alongside ESD arrays and gas discharge tubes as a circuit-protection component: it clamps fast transient events in nanoseconds, absorbing surge energy that would otherwise destroy downstream ICs, MOSFETs, and signal-line interfaces. The SMBJ family is the 600 W surface-mount tier between the smaller SMAJ (400 W) and larger SMCJ (1500 W) families. Key features of the SMBJ6.0A include 600 W peak pulse power capability at the 10/1000 us double-exponential waveform, low in-line capacitance and an avalanche-mode response time typically below 1.0 picosecond, a tight 5% tolerance on standoff voltage, and a low-profile DO-214AA package compatible with automated pick-and-place assembly and 260 C reflow profiles. Technically, the device uses a large-junction silicon die biased below its avalanche breakdown of 6.67 V minimum during normal operation, conducting only leakage current. During a transient, the junction avalanches within nanoseconds and dissipates the surge energy as heat, holding the rail below the 10.3 V maximum clamp. Per manufacturer datasheets, the SMBJ series is qualified against IEC 61000-4-2 ESD and MIL STD 883 method 3015, plus IEC 61000-4-4 and IEC 61000-4-5 burst and surge events. Typical applications include 5 V and 3.3 V power-rail protection in industrial supplies, automotive module secondary protection, and transient clamping on signal lines and inductive-load-switching circuits where lightning-induced or switching transients threaten ICs and MOSFETs. Design consideration: place the TVS close to the connector or transient entry point with a short, wide low-inductance return path to ground; also verify that the worst-case clamp voltage (10.3 V) remains below the absolute maximum rating of the protected device. This page synthesizes distributor pricing, drop-in alternatives from multiple manufacturers, and practical design notes not found in the manufacturer datasheet.
TPS1689 - 9-80V 20A Stackable eFuse PMBus | Texas Instruments
The Texas Instruments TPS1689 is a 9V to 80V, 20A stackable integrated hot-swap eFuse (electronic fuse) with PMBus digital telemetry, providing high-current circuit protection and power management with an integrated 3.5mOhm (typ) power FET and a 92V absolute maximum rating. An eFuse is an electronic circuit protection device that guards against overloads, short circuits, and excessive inrush current. Unlike traditional one-time fuses, eFuses are resettable and offer programmable current limits, making them essential for hot-swap applications where boards are inserted into live backplanes. The TPS1689 belongs to the hot-swap controller / integrated eFuse family within the broader power management IC hierarchy. Key features include a PMBus interface for telemetry, control, and configuration, enabling real-time monitoring of voltage, current, and temperature. The integrated FET with RON of 3.65mOhm typ (3.5mOhm in newer datasheet revisions) minimizes conduction losses at 20A. Stackable operation allows multiple TPS1689x devices to be paralleled for higher current, with IMON pins tied together to report total current. The output withstands negative transient voltages up to -5V. Technically, the integrated power FET eliminates external FET driving complexity of discrete hot-swap controllers, while PMBus-programmable current limits, slew rates, and fault responses provide design flexibility. Multiple protection modes cover overcurrent, overvoltage, undervoltage, and thermal shutdown, improving system-level reliability in power distribution trees. Typical applications include 48V backplane hot-swap power, server and datacenter power distribution, telecom equipment, and industrial automation. The 9V-80V operating range fits 48V rails with transient headroom up to the 92V absolute maximum rating. Design with the TPS1689 requires attention to thermal management: PCB copper area and thermal vias are essential at 20A continuous load. Configure PMBus registers so current-limit and fault-response settings match the application protection requirements.