Texas Instruments LM5101BSDX/NOPB

Overview

LM5101BSDX/NOPB from Texas Instruments is a 2-A peak-output, TTL-input high-voltage dual gate driver for synchronous buck and half-bridge topologies. It independently drives high-side (HO) and low-side (LO) N-channel MOSFETs with bootstrap-supplied high-side operation up to 100 V HS-to-VSS, 118 V HB-to-VSS, and fast 22–56 ns propagation delays. Used in industrial DC/DC converters requiring robust level shifting and UVLO protection.

For engineers reviewing the LM5101BSDX/NOPB datasheet, LM5101BSDX/NOPB pinout, LM5101BSDX/NOPB application, or LM5101BSDX/NOPB equivalent, key selection criteria include TTL input thresholds (1.3–2.3 V), 2-A peak sink/source capability, SO PowerPAD-8 package thermal performance (RθJA = 40°C/W), and independent HI/LI logic control with matched delay (≤10 ns).

Technical Context

The LM5101BSDX/NOPB integrates a high-voltage bootstrap diode (VDH ≤ 1 V @ 100 mA) and a robust level shifter enabling clean, low-power switching transitions from logic-level inputs to the floating high-side driver referenced to HS. Its UVLO circuitry independently monitors VDD (6.0–7.4 V threshold) and HB–HS (5.7–7.1 V threshold) to prevent shoot-through during under-voltage conditions.

It operates in two functional modes: normal mode (HI/LI-controlled HO/LO outputs per truth table) and UVLO mode (both outputs forced low until supply thresholds are met). The device supports 50 V/ns maximum HS slew rate and requires external 0.1 µF bootstrap capacitor placed adjacent to HB/HS pins for reliable high-side bias generation.

Key Specifications

Pinout & Package

LM5101BSDX/NOPB uses the SO PowerPAD-8 package (3.90 mm × 4.89 mm) with exposed thermal pad soldered to PCB ground plane for enhanced thermal dissipation (RθJA = 40°C/W, RθJC(bot) = 4.4°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage dual gate driver applications.

Compared with LM5101ASD/NOPB and UCC27211D, LM5101BSDX/NOPB uniquely balances TTL compatibility, 2-A drive, integrated bootstrap diode, dual UVLO, and SO PowerPAD thermal efficiency - making it optimal for industrial 48-V–100-V buck/half-bridge designs requiring reliability and layout simplicity.

Availability

LM5101BSDX/NOPB is available at Aetrix Electronics and suitable for industrial DC/DC converters, motor drive half-bridges, and telecom power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM5101BSDX/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader delivering analog and embedded processing solutions, with deep expertise in power management ICs and high-reliability industrial components.

The LM5100/LM5101 family was designed specifically for high-efficiency, high-voltage switching power stages - targeting synchronous buck, half-bridge, and active-clamp topologies in industrial, telecom, and automotive power systems.

FAQ

What is the recommended bootstrap capacitor value for LM5101BSDX/NOPB?

The LM5101BSDX/NOPB datasheet recommends a 0.1-µF ceramic capacitor placed directly between HB and HS pins. This value ensures sufficient charge replenishment at typical switching frequencies (100–500 kHz) while minimizing ESR-induced voltage droop. Larger values (e.g., 1 µF) may be used for very high duty cycles or high-frequency operation, but must remain low-ESL and located within 2 mm of the IC pins to maintain stability.

Does LM5101BSDX/NOPB require an external bootstrap diode?

No. The LM5101BSDX/NOPB integrates a high-voltage bootstrap diode (anode to VDD, cathode to HB) with 100-mA rated forward current and 37-ns reverse recovery. External diodes are unnecessary and discouraged, as they add parasitic inductance and degrade high-frequency performance. The internal diode supports efficient capacitor charging across the full operating temperature range (–40°C to 125°C).

How does the UVLO function on the HB rail affect LM5101BSDX/NOPB operation?

The HB–HS UVLO (rising threshold 5.7–7.1 V) disables only the high-side output (HO) if bootstrap voltage falls below threshold - preserving low-side functionality and enabling controlled shutdown. This prevents unintended high-side turn-on during startup or fault conditions. The 0.4-V hysteresis ensures stable re-enablement once HB–HS recovers, avoiding oscillation near the trip point.

Can LM5101BSDX/NOPB drive both MOSFETs simultaneously in a synchronous buck?

No. The LM5101BSDX/NOPB does not include built-in shoot-through protection or interlock logic. Simultaneous HI = LI = H results in both HO and LO driven high - causing direct shoot-through if HS and VSS are shorted through external FETs. Safe operation requires external PWM controller logic or gate timing circuitry to enforce non-overlapping drive signals with adequate dead time.

What is the maximum allowable HS node slew rate for reliable LM5101BSDX/NOPB operation?

The LM5101BSDX/NOPB specifies a maximum HS slew rate of 50 V/ns in Recommended Operating Conditions. Exceeding this rate risks false triggering of the level shifter or premature UVLO activation due to capacitive coupling. Layout best practices - including minimized HS trace length, symmetric routing, and local ground plane - are essential to maintain slew rates within specification across temperature and load variations.