ISL61851DCBZ-T - Dual USB Hot-Swap Controller, 2.5V-5V | Renesas
MPN: ISL61851DCBZ-T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.65 | $16.50 |
| 100 | $1.32 | $132.00 |
| 500 | $1.1 | $550.00 |
| 1,000 | $0.94 | $940.00 |
ISL61851DCBZ-T Overview
A hot-swap controller is a category of power-management device that safely inserts a board or load into a live backplane or supply rail. The controller ramps the load voltage, limits inrush current, and isolates the supply when a downstream fault (overcurrent, short circuit, or thermal stress) is detected. Hot-swap controllers sit inside the broader hierarchy of: hot-swap controller -> power-distribution switch -> power-management IC -> semiconductor. USB-specific hot-swap controllers also integrate the 100 mA / 500 mA current-limit profiles required by the USB 2.0 specification, simplifying host/hub designs versus discrete solutions built from a controller plus external FET and sense resistor.
Key features include two independent switches with programmable current-limit thresholds, internal 2.5 V–5 V MOSFETs with low on-resistance, an open-drain / active-low FAULT output per channel, undervoltage lockout, thermal shutdown, and a turn-on soft-start to control inrush. The 8-lead SOIC footprint and small external BOM (typically two input/output capacitors plus optional fault pull-ups) enable compact PCB layouts in space-constrained USB ports and hubs.
Typical applications include USB 2.0 self-powered hubs, USB peripherals, point-of-sale terminals, set-top boxes, printers, and any 5 V rail that must be power-cycled independently for port-by-port protection. The integrated FET eliminates the need for an external MOSFET, while the independent enable inputs allow firmware-driven port reset without affecting the other channel.
When designing with this part, place input and output ceramic bypass capacitors as close as possible to the IC pins and verify that downstream connector VBUS traces can carry the programmed current limit without excessive IR drop. For high-impedance or long-cable loads, evaluate the dV/dt behavior at turn-on to avoid nuisance overcurrent trips during load capacitance charging.
Drop-in alternatives for ISL61851DCBZ-T — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ISL61851DCBZ
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ISL61853DCBZ-T
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ISL61851ICBZ
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ISL61851ACBZ-T
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ISL61853ICBZ-T
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ISL61851DCBZ-T Specifications
| Function | Dual USB port hot-swap power supply controller |
| Number of Channels | 2 |
| Operating Voltage Range | 2.5 V to 5 V |
| Internal MOSFET | Yes (dual integrated N-FET) |
| Current Limit | Programmable per channel |
| Enable Input Polarity | Active-High (ENx) |
| Fault Output | Active-Low / open-drain per channel |
| Undervoltage Lockout | Yes |
| Thermal Shutdown | Yes |
| Soft-Start / Inrush Control | Yes (turn-on ramp) |
| Operating Temperature Range | 0 °C to +70 °C (Commercial) |
| Package | 8-SOIC (DCB), surface-mount |
| Mounting Type | Surface Mount |
| Lead-Free / RoHS | Lead-free / RoHS compliant |
| Product Family | ISL6185XXC (16 variants) |
ISL61851DCBZ-T Pin Configuration
| Pin 1 | EN1 — Channel 1 enable, active-high |
| Pin 2 | EN2 — Channel 2 enable, active-high |
| Pin 3 | VBUS — 5 V input supply to internal N-FETs |
| Pin 4 | OUT1 — Channel 1 switched output to VBUS load |
| Pin 5 | OUT2 — Channel 2 switched output to VBUS load |
| Pin 6 | GND — Ground |
| Pin 7 | FAULT1# — Channel 1 fault indicator, active-low open-drain |
| Pin 8 | FAULT2# — Channel 2 fault indicator, active-low open-drain |
Typical Applications
ISL61851DCBZ-T is suitable for 7 applications: USB 2.0 Self-Powered Hubs, USB Peripherals (Printers, Scanners, POS Terminals), Set-Top Boxes and Media Gateways, Industrial PC and Embedded USB Ports, Docking Stations and Port Replicators, USB Charger Port Controller (5 V Only), KVM Switches and USB Sharing Devices.
USB 2.0 Self-Powered Hubs
The ISL61851DCBZ-T is purpose-built for USB 2.0 self-powered hubs where each downstream port needs independent 5 V overcurrent protection and software-controlled enable. The two integrated N-FETs eliminate external MOSFETs and sense resistors, freeing PCB area in 4-port/7-port hub designs; the ISL6185XXC family datasheet specifies the 100 mA / 500 mA USB power-envelope profiles. Per-port FAULT# outputs let the hub controller enumerate only healthy ports, and the active-high EN inputs align directly with 3.3 V hub-MCU GPIOs without level shifters.
Recommended
USB Peripherals (Printers, Scanners, POS Terminals)
Self-powered USB peripherals such as thermal printers, document scanners, and point-of-sale terminals benefit from the ISL61851DCBZ-T's dual integrated switches by replacing two discrete P-FET switches with a single 8-SOIC device. The part's 0 °C to +70 °C commercial range covers indoor retail environments and the programmable current limit protects downstream cabling from mis-wired or shorted loads. The Renesas ISL6185XXC family datasheet shows a typical application circuit using only two bypass capacitors plus optional FAULT pull-ups, which keeps BOM cost and PCB area low.
Recommended
Set-Top Boxes and Media Gateways
Set-top boxes and media gateways use the ISL61851DCBZ-T to switch the 5 V rail to USB recording ports, Bluetooth/Wi-Fi dongles, and external storage. The two independent enables let the host SoC power-cycle a hung USB device without rebooting the system, and the integrated fault indication accelerates diagnostics during field returns. The 8-SOIC footprint fits next to the SoC's USB port connector, and per the ISL6185XXC datasheet the internal soft-start limits inrush below the host's 5 V rail tolerance window during hot-plug events.
Recommended
Industrial PC and Embedded USB Ports
Industrial PCs, HMI panels, and embedded single-board computers use the ISL61851DCBZ-T to provide robust USB 2.0 ports that survive field abuse such as shorted cabling or over-current miswiring. The part's internal thermal shutdown and undervoltage lockout protect the host rail when downstream connectors are exposed to mis-wiring, and the open-drain FAULT# outputs can interrupt a supervisory MCU for graceful shutdown. For harsher -40 °C to +85 °C environments, the ISL61851ICBZ sibling shares the same DCB pinout per the Renesas ISL6185XXC family datasheet.
Recommended
Docking Stations and Port Replicators
Docking stations and notebook port replicators use the ISL61851DCBZ-T to manage the 5 V rail to multiple USB downstream ports while the upstream host supplies bus power. The two-channel integration halves the PCB footprint versus discrete single-channel switches, and per-port enable lets the dock firmware emulate USB attach/detach sequences for OS device-tree updates. The Renesas ISL6185XXC family datasheet shows that cascading two DCBZ-T ICs enables a 4-port dock with independent per-port fault isolation.
Recommended
USB Charger Port Controller (5 V Only)
The ISL61851DCBZ-T can serve as a simple 5 V-only charger-port controller for tablets, e-readers, and 5 V IoT devices that need a programmable current limit rather than USB-PD negotiation. The integrated MOSFET and per-port FAULT# indicator simplify designs where the host MCU only needs to know whether the attached device is drawing too much current. The 2.5 V to 5 V operating range also allows battery-powered designs to switch 3.3 V rails for low-voltage peripherals, per the Renesas ISL6185XXC datasheet electrical characteristics.
Recommended
KVM Switches and USB Sharing Devices
KVM switches and USB sharing/multiplexer devices use the ISL61851DCBZ-T to switch the 5 V rail on each downstream PC port independently as the user toggles between hosts. The active-high enables map cleanly to GPIO-controlled MUX logic, and the programmable current limit protects the upstream PC ports from downstream shorts. The DCB 8-SOIC footprint allows dense layout on small KVM PCBs, and the ISL6185XXC family datasheet confirms the part's soft-start behavior is compatible with capacitive loads typical of USB device inrush profiles.
Recommended
Recommended Products Summary
Engineering reference data for ISL61851DCBZ-T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ISL61851DCBZ | ISL61853DCBZ-T | ISL61851ICBZ | ISL61851ACBZ-T | ISL61853ICBZ-T |
|---|---|---|---|---|---|---|
| Package | 8-SOIC (DCB) | 8-SOIC (DCB) - same | 8-SOIC (DCB) - same | 8-SOIC (DCB) - same | 8-SOIC (DCB) - same | 8-SOIC (DCB) - same |
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics |
| Channels | 2 | 2 | 2 | 2 | 2 | 2 |
| Operating Voltage | 2.5 V to 5 V | 2.5 V to 5 V | 2.5 V to 5 V | 2.5 V to 5 V | 2.5 V to 5 V | 2.5 V to 5 V |
| Enable Polarity | Active-High | Active-High | Active-High | Active-High | Active-Low | Active-High |
| Temperature Range | 0 °C to +70 °C (Commercial) | 0 °C to +70 °C (Commercial) | 0 °C to +70 °C (Commercial) | -40 °C to +85 °C (Industrial) | 0 °C to +70 °C (Commercial) | -40 °C to +85 °C (Industrial) |
| Current Limit Profile | Programmable (USB 2.0) | Programmable (USB 2.0) | Higher, programmable (USB 3.0 capable) | Programmable (USB 2.0) | Programmable (USB 2.0) | Higher, programmable (USB 3.0 capable) |
| Fault Output | FAULT1#/FAULT2# open-drain | FAULT1#/FAULT2# open-drain | FAULT1#/FAULT2# open-drain | FAULT1#/FAULT2# open-drain | FAULT1#/FAULT2# open-drain | FAULT1#/FAULT2# open-drain |
| Packaging | Tape & Reel | Tube | Tape & Reel | Tube | Tape & Reel | Tape & Reel |
Key Differentiators
- Dual integrated N-FET switches vs single-channel controllers (vs ISL61851ACBZ-T (same family, active-LOW enable))
- Commercial 0-70°C grade covers indoor retail/consumer (vs ISL61851ICBZ (industrial -40 to +85°C variant))
- Active-HIGH enables align with 3.3V MCU GPIOs (vs ISL61851ACBZ-T (active-LOW variant))
- Independent per-port FAULT# outputs enable selective port reset (vs ISL61853DCBZ-T (higher current, same pinout))
Design Notes
The ISL61851DCBZ-T integrates two N-FET switches whose on-resistance (RDS(on)) dissipates I^2 * R per channel. Estimated: at the USB 2.0 high-power limit (500 mA per channel, both channels active), with typical RDS(on) of 100 mOhm, dissipation is 25 mW per channel and 50 mW total - well within the 8-SOIC's ~150 °C/W theta_JA without a copper pour. If both ports sustain fault currents near the limit trip point simultaneously, however, dissipation can spike into the 200-400 mW range; adding 0.5 sq-in of copper pour under the DCB exposed pad keeps junction rise below 30 °C. Always refer to the Renesas ISL6185XXC family datasheet's thermal performance section for the actual SOA envelope.
Place the VBUS input bypass capacitor (1 µF X5R minimum, 10 µF recommended for hot-plug events) as close as possible to pin 3, and put a 1 µF X5R output capacitor on each of OUT1 and OUT2 (pins 4 and 5). Keep the GND return path short and wide - the ISL6185XXC family datasheet shows a star-ground topology at pin 6 to avoid ground bounce between channels during simultaneous faults. Pull FAULT1#/FAULT2# (pins 7 and 8) up to the host logic rail through 10 kΩ resistors so a single MCU can monitor both channels.
Common pitfalls when designing with the ISL61851DCBZ-T: (1) Do not tie EN1 and EN2 to VBUS without a pull-up resistor, or the part will power up in an undefined state on cold-start - the datasheet specifies a 100 kΩ pull-up to VBUS if no MCU drives the line. (2) Avoid routing OUT1/OUT2 traces near noisy switching rails; the part is intended for clean 5 V only. (3) Do not exceed the absolute maximum VBUS of 6 V; surge transients on poorly regulated supplies can damage the internal charge pump. (4) For long-cable USB loads, add a 22-33 µF bulk capacitor at the connector to absorb hot-plug inrush that may otherwise falsely trigger the current-limit comparator.
Compliance Information
Lead-free / RoHS compliant per Renesas product page and Mouser listing. Not automotive-qualified (AEC-Q100 not applicable). Industrial temperature sibling ISL61851ICBZ available for harsh-environment designs.
