LM5008AMM/NOPB - 100V 350mA Buck Regulator | Texas Instruments
MPN: LM5008AMM/NOPB ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.95 | $2.95 |
| 10 | $2.62 | $26.20 |
| 100 | $2.31 | $231.00 |
| 500 | $2.07 | $1,035.00 |
| 1,000 | $1.86 | $1,860.00 |
LM5008AMM/NOPB Overview
A buck regulator (also called a step-down switching regulator or step-down converter) is a switch-mode DC-DC converter that produces a lower regulated DC output voltage from a higher DC input voltage with high efficiency by rapidly switching an internal power MOSFET and storing energy in an external inductor and capacitor. Within the broader power management hierarchy, a buck regulator sits under switching regulators -> DC-DC converters -> power management ICs (PMICs) -> semiconductors. The constant on-time (COT) control architecture eliminates the need for external loop compensation, simplifies design, and provides excellent line and load transient response.
Key features of the LM5008AMM/NOPB include an integrated 100-V N-channel buck switch, internal startup regulator, ultra-fast transient response with no loop compensation required, an adjustable output from 2.5 V to 75 V, and a 350-mA continuous load capability. On-time varies inversely with input voltage (feed-forward), giving near-constant ripple at varying line. The device also incorporates cycle-by-cycle current limit, thermal shutdown, and an enable/UVLO pin for input-side monitoring and sequencing. The 8-pin VSSOP package keeps outboard supplies below 1 square inch of PCB area, while a thermally enhanced 8-pin WSON variant (LM5008AMWC/NOPB) is offered for higher-power designs.
Typical applications include 24-V/48-V industrial bus regulation, telecom secondary-side point-of-load conversion, HVAC and appliance subsystems, battery-powered equipment down-conversion, and bias supplies for gate drivers. The wide 6 V–95 V input tolerance tolerates 24-V industrial transients and 48-V telecom rails without front-end protection.
When designing with the LM5008AMM/NOPB, select the on-time programming resistor (RT) using the RT = (VIN × 6.15 ns × (VOUT/1.235 V)) / (1 µs × 1 µF) approximation from the datasheet, and place the bootstrap capacitor and feedback divider as close to the IC as practical.
This page consolidates distributor pricing, same-package alternatives, comparison data and engineering notes that supplement the manufacturer datasheet.
Drop-in alternatives for LM5008AMM/NOPB — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with LM5008AMM/NOPB (same form factor and footprint) — differing in Package, Topology.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LM5008MM/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LM5008AMMX/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LM5009MM/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LM5013QDMTRQ1
✅ Drop-In📋 Reference alternative (not in catalog)
TPS5430DDAR
✅ Drop-In✓ In Stock
$1.19 / Unit
View Datasheet →LM5008AMM/NOPB Maximum Ratings & Electrical Characteristics
| Topology | Buck (Step-Down), Non-Synchronous |
| Input Voltage Range (LM5008A) | 6 V to 95 V |
| Integrated Switch Voltage Rating | 100 V (N-channel MOSFET) |
| Output Voltage Range | 2.5 V to 75 V (adjustable) |
| Continuous Output Current | 350 mA |
| Switching Control | Constant On-Time (COT) |
| Feedback Reference Voltage | 1.235 V |
| Operating Temperature Range | -40 C to +125 C |
| Package | VSSOP-8 (DGK), 3.0 mm body width |
| Pins | 8 |
| Mounting Type | Surface Mount |
| MSL Level | 1 (per TI VSSOP DGK package) |
| Enable / UVLO Pin | Yes (EN/UVLO, with internal pull-up) |
| Internal Soft Start | No (COT architecture) |
| Loop Compensation | Not Required (COT) |
| Synchronous Rectifier | No (external diode required) |
| RoHS Status | Compliant |
LM5008AMM/NOPB Pin Configuration
| Pin 1 | RT — On-time programming resistor; sets buck switch on-time |
| Pin 2 | EN/UVLO — Enable / undervoltage lockout input with internal pull-up |
| Pin 3 | VIN — Input supply voltage (6 V to 95 V, 100-V transient) |
| Pin 4 | GND — Power and analog ground return |
| Pin 5 | SW — Buck switch node to external inductor and Schottky diode |
| Pin 6 | BST — Bootstrap capacitor for high-side gate drive |
| Pin 7 | VCC — Internal LDO output for gate drive and control circuits |
| Pin 8 | FB — Feedback input; connects to VOUT resistor divider |
Typical Applications
LM5008AMM/NOPB is suitable for 6 applications: Industrial 24-V / 48-V Bus Regulation, Telecom 48-V Point-of-Load Conversion, Bias Supply for Gate Drivers and Optocouplers, Battery-Powered Equipment Down-Conversion, HVAC and Appliance Subsystems, E-Meter and Smart Energy Sub-Circuits.
Industrial 24-V / 48-V Bus Regulation
The LM5008AMM/NOPB fits 24-V and 48-V industrial bus rails because its 6 V–95 V input range (LM5008A revision) directly tolerates 24-V industrial transients and 48-V telecom rails without front-end protection. The internal 100-V N-channel MOSFET gives 5 V of headroom above the 95-V continuous maximum, a critical margin for 48-V telecom surge events. Its constant on-time (COT) control eliminates the compensation network, reducing the BOM to one inductor, one Schottky diode, an input capacitor and a bootstrap cap - a sub-$0.30 power stage for 350-mA industrial loads like sensor bias, low-power PLC I/O, and HVAC controllers. Compared to a linear regulator at the same node, the switching topology cuts dissipation from ~5 W to ~0.3 W at 24 V to 5 V / 350 mA.
Recommended
Telecom 48-V Point-of-Load Conversion
The LM5008AMM/NOPB is well-suited to telecom secondary-side 48-V point-of-load conversion, where the 95-V upper input limit and integrated 100-V switch tolerate the 50-V typical operating point with margin for ringing transients. Its COT architecture yields ultra-fast transient response, important when feeding DSP cores, FPGA auxiliary rails and opto-isolator bias from a 48-V backplane. At 48 V to 5 V / 350 mA, the LM5008AMM/NOPB hits ~85% efficiency with a small 47-uH inductor and a 100-V Schottky diode - enough for low-power telecom cards and line cards. Designers reuse the same BOM across 24-V and 48-V product variants simply by re-selecting RT.
Recommended
Bias Supply for Gate Drivers and Optocouplers
The LM5008AMM/NOPB is ideal for generating the 12-V to 24-V bias rail needed by IGBT/MOSFET gate drivers and high-side optocouplers in motor-drive and solar applications. The 100-V input rating lets it pull directly from the rectified 60-V to 80-V PFC output or the rectified 48-V telecom bus without an intermediate pre-regulator, and the 350-mA continuous output is sufficient for 4-8 gate-drive channels. The internal VCC LDO derived from VIN powers housekeeping; the EN/UVLO pin doubles as input undervoltage lockout for safe sequencing. A 47-uH/220-uF LC filter plus a 100-V Schottky keep ripple under 1% at full load, important for clean gate thresholds.
Recommended
Battery-Powered Equipment Down-Conversion
The LM5008AMM/NOPB can drop a multi-cell Li-ion battery stack (24-V to 36-V nominal) down to 12-V or 5-V rails for portable industrial test equipment, e-bike controllers, and medical cart electronics. The 6-V minimum VIN (LM5008A) supports low-battery cut-off to 6 V, maximizing usable capacity. At 24-V to 5-V / 350-mA, the regulator hits ~85% efficiency and stays below 100 mA no-load thanks to the shutdown mode. The COT control delivers clean ripple-free output, important for downstream ADCs that digitize sensor signals in portable diagnostic equipment.
Recommended
HVAC and Appliance Subsystems
The LM5008AMM/NOPB fits HVAC and appliance subsystems where 24-VAC rectified DC (typically 24-V to 36-V DC) powers sensors, displays and microcontrollers. Its 95-V input tolerance absorbs rectified mains transients without additional protection; the integrated 100-V switch eliminates the need for an external high-voltage FET. White-goods designers benefit from the COT topology's ultra-fast transient behavior when downstream microcontrollers wake up at high di/dt loads. The 8-pin VSSOP-8 footprint keeps the power stage under 50 mm^2 of board real estate, important for compact thermostat and control-panel PCBs.
Recommended
E-Meter and Smart Energy Sub-Circuits
The LM5008AMM/NOPB works well inside e-meters and smart energy sub-circuits, deriving 3.3-V and 5-V logic rails for metering MCUs and communication ICs from the rectified 48-V to 80-V AC mains tap. The 95-V maximum input handles the worst-case rectified 60-V RMS mains with margin, while the 6-V minimum input supports wide-line-fail detection. At 48 V to 3.3 V / 100 mA, the regulator hits ~80% efficiency and stays inside 60 C junction rise even on a 2-layer board, making it ideal for the thermal-constrained, sealed enclosures typical of utility-grade meters.
Recommended
Recommended Products Summary
Engineering reference data for LM5008AMM/NOPB — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM5008MM/NOPB | LM5008AMMX/NOPB | LM5009MM/NOPB |
|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | VSSOP-8 (DGK) | VSSOP-8 (DGK) - same | VSSOP-8 (DGK) - same | VSSOP-8 (DGK) - same |
| Input Voltage Range | 6 V to 95 V (LM5008A) | 9 V to 95 V (LM5008 non-A) | 6 V to 95 V (LM5008A) | 6 V to 95 V |
| Continuous Output Current | 350 mA | 350 mA | 350 mA | 350 mA |
| Switch Internal Voltage | 100 V (N-FET) | 100 V | 100 V | 100 V |
| Feedback Reference Voltage | 1.235 V | 1.235 V | 1.235 V | 0.8 V |
| Control Topology | Constant On-Time (COT) | COT | COT | COT |
| Minimum Input Voltage (LM5008A vs LM5008) | 6 V (A revision) | 9 V (non-A) | 6 V | 6 V |
Key Differentiators
- Wide 6-V to 95-V input (LM5008A revision) eliminates the 9-V startup barrier of the original LM5008 (vs LM5008MM/NOPB)
- COT control eliminates compensation network (vs TPS5430DDA)
- Ultra-fast transient response with feed-forward on-time (vs LM5009MM/NOPB)
Design Notes
Do not assume the LM5008A revision supports 6 V minimum VIN - confirm by ordering code suffix. The 'A' in LM5008A is the A silicon revision (6 V minimum); the LM5008 (no A) starts at 9 V minimum. At VIN below the minimum, the internal VCC LDO may not regulate and the BST part may undercharge, causing high-side drive failure. Always check the device mark vs the datasheet to confirm the silicon revision before PCB build.
Keep the buck switch loop (VIN -> SW -> diode -> ground) physically small to minimize EMI. Place the input ceramic capacitor as close as possible to the VIN and GND pins, and the bootstrap capacitor (typically 100 nF) directly between BST and SW. Use a wide, short trace for the SW connection - this trace carries 350 mA pulsed at up to ~1 MHz effective frequency with significant di/dt. Route the FB trace away from the SW node to avoid noise injection into the feedback path.
Estimated at VIN = 95 V, VOUT = 5 V, IOUT = 350 mA: switching losses dominate and dissipation in the VSSOP-8 (DGK) package (theta-JA ~53 C/W on JEDEC 4-layer board) can raise junction temperature by ~50 C above ambient. At VIN = 24 V the same 5 V/350 mA node runs at ~85% efficiency with ~280 mW dissipation and < 15 C rise. For continuous high-voltage operation in sealed enclosures, choose the WSON-8 (DPR) variant LM5008AMWC/NOPB with theta-JA around 35 C/W.
Place the feedback divider (RFBT/RFBB) within 5 mm of the FB pin and ground the bottom of the divider to a quiet analog ground island. The RT resistor should connect to a quiet VIN node (not the SW node) to avoid on-time jitter. The exposed thermal pad of the WSON variant (LM5008AMWC/NOPB) must be soldered to a continuous ground pour for thermal dissipation and electrical reference.
Compliance Information
RoHS compliant per TI product page. Lead-free N/O (Matte Sn) finish. Not AEC-Q100 qualified in VSSOP-8 DGK variant; LM5008 family AEC-Q100 parts exist in other TI packages. Halogen-free per TI material content disclosure.
