Diodes Incorporated AM4961GSTR-G1

Overview

AM4961GSTR-G1 from Diodes Incorporated is a single-phase full-wave brushless DC motor driver IC with integrated PWM speed control, Hall bias generation, and FG/RD status outputs. It delivers 1.0 A output current, operates from 3.5–16 V supply, and supports speed regulation via VPWM/VMIN analog inputs. Used in CPU cooler fans and compact BLDC systems requiring thermal shutdown, lock protection, and minimal-speed setup.

For engineers reviewing the AM4961GSTR-G1 datasheet, AM4961GSTR-G1 pinout, AM4961GSTR-G1 application, or AM4961GSTR-G1 equivalent, this page provides verified package mapping (HTSSOP-14), functional pin roles, real-world motor control timing behavior, and validated alternative drivers for fan and small BLDC applications.

Technical Context

The AM4961 integrates a dual-output pre-driver stage with complementary high-side/low-side MOSFET control logic, Hall sensor interface with ±20 mV hysteresis, and an internal 25 kHz oscillator (COSC=100 pF). Its VMIN/VPWM dual-input architecture enables both fixed-minimum-speed and variable-duty PWM modes.

It features open-collector FG (phase-change-based tachometer) and RD (rotation-detect) outputs, a 1.25 V Hall bias regulator (HB), and CT capacitor-based lock detection with 10 μA typical charge/discharge current ratio of 10:1. Thermal shutdown activates at junction temperature >150°C.

Key Specifications

Pinout & Package

AM4961GSTR-G1 is supplied in HTSSOP-14 package (6.55 × 4.50 mm, 0.65 mm pitch), optimized for thermal dissipation in fan modules. Pin 14 is GND (control ground); Pin 1 is OUT2; Pin 16 is not present - this variant uses the 14-pin configuration per ordering code "GHTR-G1".

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar single-phase BLDC motor driver applications.

Compared with A4962KLPTR-T and DRV10983DGQR, AM4961GSTR-G1 uniquely balances Hall-integrated simplicity, dual diagnostic outputs, and thermal robustness for cost-sensitive, space-constrained single-phase fan applications - making it irreplaceable where Hall sensor reuse and FG/RD hardware monitoring are mandatory.

Availability

AM4961GSTR-G1 is available at Aetrix Electronics and suitable for CPU cooler fan control, industrial sensor enclosure cooling, automotive cabin blower modules, and portable appliance BLDC drives requiring stable component supply across extended temperature ranges (–30°C to +90°C).

Supply support for AM4961GSTR-G1 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.

The AM4961 belongs to Diodes' Motor Driver product line, engineered specifically for compact, Hall-sensored BLDC fan control in computing, industrial, and automotive thermal management systems - emphasizing integration, reliability, and ease of system-level validation.

FAQ

What is the function of the CT pin on AM4961GSTR-G1?

The CT pin connects to an external capacitor that sets the lock detection timeout period. Internal charge/discharge currents (1.5–2.85 μA charge, 0.14–0.285 μA discharge) create a ramp voltage; when rotation stops, CT voltage crosses thresholds to trigger lock protection and automatic restart after a user-defined delay determined by capacitor value.

Can AM4961GSTR-G1 drive a motor without a Hall sensor?

No - the AM4961 requires a 3-wire Hall sensor for commutation timing. Its HIN+ and HIN− inputs are designed for differential Hall output signals with ≥0.2 V amplitude and ±20 mV hysteresis. It does not support sensorless (BEMF) operation, and omitting the Hall sensor will prevent proper phase switching and cause motor stall or erratic behavior.

How does the VMIN pin affect motor speed control?

The VMIN pin sets the minimum duty cycle applied to the motor windings. When VPWM voltage exceeds VMIN, speed is controlled by VMIN - establishing a guaranteed lowest RPM. If VMIN is unused, it must be tied to VPWM to fix minimum duty at 10%, preventing unintended zero-speed operation during low PWM signals.

What is the difference between GND and PGND pins on AM4961GSTR-G1?

GND is the reference for control circuitry (logic, Hall inputs, FG/RD outputs); PGND is the return path for high-current motor drive outputs (OUT1/OUT2). Separating them prevents switching noise from corrupting Hall signals or PWM references - layout best practice requires routing PGND directly to bulk capacitor and keeping GND traces short and isolated from power loops.