Texas Instruments LM74501QDDFRQ1

Overview

LM74501QDDFRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive reverse battery protection controller that operates with an external N-channel MOSFET to provide low-loss input polarity protection across 3.2 V–65 V supply range, withstands –18 V reverse voltage, integrates gate discharge timer for ISO7637-2 Pulse 1 compliance without TVS diode, and features battery voltage monitoring via SW pin - deployed in body control modules and ADAS domain controllers.

For engineers reviewing the LM74501QDDFRQ1 datasheet, LM74501QDDFRQ1 pinout, LM74501QDDFRQ1 application, or LM74501QDDFRQ1 equivalent, key selection considerations include cold-crank operation down to 3.2 V, TVS-less transient immunity per ISO7637-2 Pulse 1, integrated V_DS clamp at 20 V (EN = low), 1 µA shutdown current, and SOT-23-8 package compatibility with space-constrained automotive PCB layouts.

Technical Context

The LM74501QDDFRQ1 implements a charge-pump-driven gate control architecture for external N-FETs, enabling full enhancement down to 3.2 V input while maintaining <1 µA shutdown IQ. Its gate discharge timer uses an internal 30 kΩ discharge resistor and external CT capacitor to sustain conduction during ISO7637-2 Pulse 1 transients, eliminating need for TVS diodes when loads tolerate reverse current.

It integrates dual protection functions: V_DS clamping at 20 V (typ) during EN = low to limit FET stress under inductive kickback, and battery voltage monitoring via SW pin with internal switch disconnecting resistor divider leakage in shutdown mode - both critical for automotive BCM and infotainment power domains requiring robust cold-crank and transient resilience.

Key Specifications

Pinout & Package

Package: 8-pin SOT-23 (DDF), 2.90 mm × 1.60 mm footprint - optimized for high-density automotive PCBs with thermal resistance R_θJA = 133.8 °C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar reverse battery protection applications.

Compared with LM74501QDDFRQ1, LM74700QDBVRQ1 offers lower cold-crank voltage but omits V_DS clamp and battery monitoring, while TPS26600PWPR adds current limiting at the cost of higher quiescent current and loss of TVS-less transient capability - making LM74501QDDFRQ1 optimal for space-constrained, low-IQ automotive systems needing integrated diagnostics and robust pulse immunity.

Availability

LM74501QDDFRQ1 is available at Aetrix Electronics and suitable for body electronics, ADAS domain controllers, and digital cockpit systems requiring stable component supply, AEC-Q100 qualified assurance, and long-term automotive lifecycle support.

Supply support for LM74501QDDFRQ1 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 automotive-grade power management ICs and functional safety-compliant design.

The LM74501QDDFRQ1 belongs to TI's automotive reverse polarity protection controller product line, engineered specifically to replace P-FET solutions with smaller, more efficient N-FET-based architectures while meeting ISO7637-2 transient immunity and cold-crank requirements.

FAQ

What is the minimum input voltage at which LM74501QDDFRQ1 maintains full N-FET enhancement?

The LM74501QDDFRQ1 maintains full N-FET enhancement down to 3.2 V input voltage, verified across –40°C to +125°C ambient temperature. This enables reliable operation during severe cold-crank conditions where battery voltage drops below 4 V - a key advantage over P-FET alternatives whose R_DS(on) increases sharply below 4 V. The LM74501QDDFRQ1 achieves this via its regulated charge pump delivering ≥12 V gate drive even at 3.2 V SOURCE.

How does LM74501QDDFRQ1 achieve TVS-less operation during ISO7637-2 Pulse 1 events?

The LM74501QDDFRQ1 achieves TVS-less ISO7637-2 Pulse 1 compliance using its integrated gate discharge timer, which sustains external N-FET conduction via an internal 30 kΩ discharge resistor and external CT capacitor. This keeps the FET on during the transient's negative voltage phase, allowing reverse current to flow back to the battery instead of developing destructive voltage spikes - provided the load (e.g., H-bridge motor driver) can safely handle short-duration reverse current.

What is the purpose of the SW pin on LM74501QDDFRQ1, and how is it used?

The SW pin on LM74501QDDFRQ1 enables battery voltage monitoring by connecting an external resistor divider from SW to GND. When EN = high, an internal switch connects SW to SOURCE, allowing accurate voltage scaling. When EN = low, the switch opens, eliminating divider leakage current - critical for ultra-low-power automotive sleep modes. This integrated function replaces discrete monitoring circuitry, reducing BOM count and PCB area in BCM and infotainment applications.

Does LM74501QDDFRQ1 provide reverse current blocking capability?

No, the LM74501QDDFRQ1 does not provide reverse current blocking. It is designed for input reverse polarity protection only and assumes downstream loads (e.g., motor drivers, H-bridges) can tolerate or safely conduct reverse current during transients like ISO7637-2 Pulse 1. This architecture enables TVS-less operation but excludes use cases requiring bidirectional blocking - such as protecting sensitive supplies from backfeeding. For those, a separate ideal diode or OR-ing controller is required alongside LM74501QDDFRQ1.

What is the V_DS clamp behavior of LM74501QDDFRQ1, and when is it active?

The LM74501QDDFRQ1 activates its V_DS clamp (20 V typical) only when EN = low and the voltage difference between DRAIN and SOURCE exceeds the clamp threshold. This protects the external N-FET during inductive load turn-off (e.g., motor braking) or if the gate discharge timer expires prematurely. The clamp is inactive during normal conduction (EN = high), preserving low R_DS(on) performance. It serves as a secondary safeguard complementing the primary gate discharge timer function.