Texas Instruments LM5109BQNGTRQ1

Overview

LM5109BQNGTRQ1 from Texas Instruments is an AEC-Q100 Grade 1 qualified high-voltage half-bridge gate driver IC designed to independently control high-side and low-side N-channel MOSFETs in automotive synchronous buck and half-bridge power converters. It delivers 1-A peak sink/source output current per channel, supports bootstrap supply voltages up to 108 V DC, and features TTL/CMOS-compatible inputs with 30 ns typical propagation delay and ≤2 ns matching between channels.

For engineers reviewing the LM5109BQNGTRQ1 datasheet, LM5109BQNGTRQ1 pinout, LM5109BQNGTRQ1 application, or LM5109BQNGTRQ1 equivalent, this page provides verified technical context, validated pin functions, confirmed automotive-grade UVLO thresholds (6.7 V VDD rising, 6.6 V HB–HS rising), real-world thermal metrics (RθJA = 42.3°C/W), and two rigorously cross-checked alternative gate drivers for half-bridge topologies.

Technical Context

The LM5109BQNGTRQ1 integrates a robust level-shift circuit enabling clean, high-speed signal translation from ground-referenced logic inputs (HI/LI) to the floating high-side driver referenced to the HS node. Its dual independent outputs drive gates with matched 32 ns turn-on and 30 ns turn-off delays across –40°C to +125°C junction temperature.

Under-voltage lockout operates separately on VDD (6.7 V rising threshold, 0.5 V hysteresis) and HB–HS (6.6 V rising threshold, 0.4 V hysteresis), ensuring safe startup and fault isolation. The WSON-8 package includes an exposed thermal pad soldered to PCB ground for enhanced heat dissipation (RθJB = 19.3°C/W).

Key Specifications

Pinout & Package

The LM5109BQNGTRQ1 is housed in a thermally enhanced 4.00 mm × 4.00 mm WSON-8 package with an exposed thermal pad on the bottom surface, requiring direct solder connection to PCB ground plane for optimal thermal performance (RθJB = 19.3°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC27211QDRQ1 and IRS2007MTRPBF, the LM5109BQNGTRQ1 uniquely balances AEC-Q100 Grade 1 qualification, 108-V HB rating, and ≤2-ns HO/LO delay matching-making it the only option qualified for safety-critical automotive DC-DC converters requiring simultaneous high voltage, high precision, and automotive reliability.

Availability

LM5109BQNGTRQ1 is available at Aetrix Electronics and suitable for automotive power conversion, industrial half-bridge inverters, and electric power steering systems requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LM5109BQNGTRQ1 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 specializing in analog and embedded processing technologies, with decades of experience in automotive-grade power management ICs.

The LM5109B-Q1 product line was engineered specifically for AEC-Q100-compliant high-voltage gate driving in automotive powertrain and body electronics, emphasizing robustness, timing precision, and thermal resilience in compact WSON packaging.

FAQ

What is the maximum allowable HS node voltage for LM5109BQNGTRQ1?

The LM5109BQNGTRQ1 specifies HS to VSS absolute maximum rating of –5 V to +90 V. During normal operation, HS is clamped by the body diode of the low-side MOSFET and typically remains ≥ –1 V. However, transient negative excursions are permitted down to VDD – 15 V - for example, if VDD = 10 V, HS may dip to –5 V without damage. This transient tolerance is explicitly defined in Section 6.1 Absolute Maximum Ratings and Figure 7.4 of the datasheet.

Does LM5109BQNGTRQ1 support 3.3-V logic inputs directly?

Yes, LM5109BQNGTRQ1 supports 3.3-V logic inputs directly. Its HI and LI pins feature TTL/CMOS-compatible thresholds: VIH(min) = 0.8 V and VIH(max) = 2.2 V at full temperature range (–40°C to +125°C), and VIL(min) = 1.8 V at 25°C dropping to 0.8 V at extremes. A 3.3-V microcontroller output comfortably exceeds the 2.2-V high-threshold ceiling, ensuring reliable logic recognition without external level shifters.

What is the recommended bootstrap capacitor value for LM5109BQNGTRQ1?

The datasheet recommends a minimum 100-nF ceramic (X7R) bootstrap capacitor placed directly between HB and HS pins. This value assumes 500-kHz switching, 17-nC MOSFET gate charge, and 10-V VDD. For higher gate charge or lower VDD, Equation 3 in Section 8.2.2.1 calculates CBoot ≥ (QG × DMax + IHBS × TSW) / ΔVHB, where ΔVHB is the allowable drop below the 6.6-V UVLO threshold. Real-world designs typically use 220–470 nF for margin against leakage and duty-cycle variation.

How does the UVLO behavior differ between VDD and HB–HS rails in LM5109BQNGTRQ1?

In LM5109BQNGTRQ1, VDD UVLO (6.7 V rising, 0.5 V hysteresis) disables both HO and LO outputs until satisfied. HB–HS UVLO (6.6 V rising, 0.4 V hysteresis) only disables HO while LO remains fully functional - enabling asymmetric operation during bootstrap charging phases. This independent monitoring prevents high-side misfiring without compromising low-side control, a key safety feature in half-bridge configurations where bootstrap recharge occurs during low-side conduction.

Is the LM5109BQNGTRQ1 pinout compatible with LM5109BQDRQ1?

No, LM5109BQNGTRQ1 and LM5109BQDRQ1 are not pin-compatible. LM5109BQNGTRQ1 uses the WSON-8 (NGT) package with pin 1 = VDD, pin 2 = HI, pin 3 = LI, pin 4 = VSS, pin 5 = LO, pin 6 = HS, pin 7 = HO, pin 8 = HB. LM5109BQDRQ1 uses the SOIC-8 (D) package with different pin mapping: pin 1 = HI, pin 2 = VDD, pin 3 = LI, pin 4 = VSS, pin 5 = LO, pin 6 = HO, pin 7 = HS, pin 8 = HB. PCB layout and schematic symbols must be redesigned for substitution.