Texas Instruments LM4570LQX/NOPB

Overview

LM4570LQX/NOPB from Texas Instruments is a single-supply, bridged (BTL) motor driver IC designed for bidirectional DC motor control in space-constrained portable electronics. It delivers 192 mA output current at 3V supply, features fast 2.4 ms turn-on time, differential output swing for polarity reversal, and integrated shutdown with 0.1 µA quiescent current - enabling precise haptic feedback in mobile phone vibration motors.

For engineers reviewing the LM4570LQX/NOPB datasheet, LM4570LQX/NOPB pinout, LM4570LQX/NOPB application, or LM4570LQX/NOPB equivalent, key selection criteria include its WSON-8 package thermal performance, rail-to-rail output capability under load, BTL architecture for zero-crossing motor stop, and gain-setting resistor interface for analog speed control.

Technical Context

The LM4570LQX/NOPB implements a fully differential bridge output stage with dual sourcing/sinking VO1 and VO2 terminals, enabling voltage polarity reversal across the motor without split supplies. Its internal bias circuitry references input against VREF1 to generate AVD = 2×(RF/RIN) differential gain, supporting analog speed control via IN–VREF1 differential voltage.

Operation is enabled by /SD logic control, which disables amplifiers and pulls outputs and VREF1 to GND in shutdown mode. Thermal protection and output short-circuit protection are built-in, with junction temperature limited to 150°C and θJA = 140°C/W in the WSON package.

Key Specifications

Pinout & Package

The LM4570LQX/NOPB is housed in an 8-pin WQFN (NGP0008A) package with exposed thermal pad (DAP), requiring solder connection to a GND plane for thermal management.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar motor driver applications.

Compared with TB67H420FTG and DRV8837C, the LM4570LQX/NOPB uniquely combines ultra-low shutdown current (0.1 µA), analog-differential input architecture, and WSON-8 footprint - making it the only option optimized for battery-critical, analog-controlled haptic actuators under 200 mA.

Availability

LM4570LQX/NOPB is available at Aetrix Electronics and suitable for mobile phone haptics, PDA tactile feedback, and wearable device vibration control requiring stable component supply, long-term lifecycle support, and RoHS-compliant WQFN packaging.

Supply support for LM4570LQX/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, embedded processing, and connectivity solutions with emphasis on reliability, power efficiency, and system integration.

The LM4570LQX/NOPB belongs to TI's precision analog motor driver product line, engineered specifically for low-voltage, low-power haptic actuation in portable consumer electronics - prioritizing small size, fast response, and minimal external components.

FAQ

What is the function of the REF2 pin on the LM4570LQX/NOPB?

The REF2 pin on the LM4570LQX/NOPB is internally tied to REF1 and serves solely as a dedicated connection point for the 0.1 µF bypass capacitor (CREF1). Placing this capacitor directly at REF2 minimizes high-frequency noise on the internal reference, stabilizing the differential input stage and reducing turn-on time jitter. It does not carry independent signal or bias functions beyond supporting REF1 integrity.

Can the LM4570LQX/NOPB drive a motor in both directions using only one input signal?

Yes, the LM4570LQX/NOPB drives bidirectional motor motion using only the single-ended IN signal referenced to VREF1. When IN < VREF1, VO1–VO2 is negative, spinning the motor clockwise; when IN > VREF1, VO1–VO2 is positive, reversing direction. This differential polarity reversal occurs without external H-bridge logic or dual control lines - a core feature of its BTL architecture.

What is the recommended PCB layout practice for the exposed DAP on the LM4570LQX/NOPB?

The exposed DAP on the LM4570LQX/NOPB must be soldered to a solid GND plane on the PCB's outer layer using ≥4 thermal vias (0.3 mm diameter, filled/tented). Avoid connecting the DAP to inner-layer planes only, as that increases thermal resistance. TI specifies θJA = 140°C/W assuming direct DAP-to-GND copper coupling - failure to implement this reduces safe continuous output current by up to 40%.

How does gain setting work on the LM4570LQX/NOPB, and what is the role of RIN and RF?

Gain on the LM4570LQX/NOPB is set differentially via external resistors RIN (from IN to GND) and RF (from VO1 to IN). The differential gain is AVD = 2 × (RF/RIN), doubling the effective output voltage versus single-ended amplifiers. For example, RIN = 20 kΩ and RF = 20 kΩ yields AVD = 6 dB (×2), producing ±3V differential swing across VO1–VO2 for ±1.5V input deviation from VREF1 - enabling precise analog speed control.

Does the LM4570LQX/NOPB require external flyback diodes for motor inductive kickback protection?

No, the LM4570LQX/NOPB does not require external flyback diodes. Its integrated output transistors include internal clamp structures that safely dissipate inductive energy during motor turn-off. TI's datasheet confirms output short-circuit and thermal protection cover transient overvoltage conditions from motor back-EMF - validated across the full operating temperature range (−40°C to +85°C).