Description

The AM4964 is highly integrated feature rich single phase Brushless Direct Current (BLDC) full wave motor driver with combined PWM and temperature speed control function for fans, blowers and extractors.

For system flexibility, the motor speed can be controlled by an external PWM signal and temperature sensed by Thermal resister at the same time. Based on external input PWM and temperature signals, the AM4964 adjusts the output PWM duty cycle. If the input PWM duty is constant, the output PWM duty varies with temperature sensed by Thermal resister sensor between the low and high temperature corners. If the temperature signal is constant, the output duty varies with the external input PWM duty. The low and high temperature corners and the output PWM duty gap between these temperature corners are adjustable

To help protect the motor coil, the AM4964 provides a rotor lock protection which shuts down the output if rotor lock is detected. The device automatically re-starts when the rotor lock is removed.

AM4964 provides a tachometer output Frequency Generator (FG). The FG output is the magnetic change frequency.

The AM4964 is available in TSSOP-20EP package.

Feature(s)

Flexible Speed Control Options
- Combined PWM+Thermistor Speed Control
- PWM Speed Control
- DC Voltage Speed Control
Adjustable Low and High Temperature Corners
Full Speed When Thermal Resistor is Shorted
Adjustable Output Duty Gap between High and Low Temperature when 100% PWM Input
Built-in oscillator – No external capacitor
Built-in Minimal Speed Setup Circuit
Alpha Slope Adjustable
Rotation Speed Indicator (FG)
Built-in Temperature Control Circuit
Built-in Thermal Shutdown Circuit
Lock Protection and Auto-restart
Totally Lead-free & Fully RoHS Compliant
Halogen and Antimony Free. “Green” Device

Application(s)

CPU Cooler Fan in PC
Brushless DC Motor Driver

Specifications & Technical Documents

Product Parameters

Average OutputDrive Current (mA)	-
Frequency Generator (FG) and Rotation Detect	FG
Hall Bias Voltage (V)	1.07
Lock Detect, Shut-Down and Auto Start	Yes
Minimum Speed Setting	Yes
Operating Ambient Temperature (°C)	-30 to 90
Operating Voltage (V)	3.5 to 16
Other Protection Features	Thermal Shutdown
Peak Output Current (mA)	1000
Reference Voltage Output (V)	-
Speed Control	PWM +Temp or VDD and Slope Adjust
Speed Control Slope Adjust	Yes
SupplyCurrent (mA)	8

Technical Documents

Recommended Soldering Techniques

TN1.pdf

Purchase & Availability

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Product Change Notices (PCNs)

A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

PCN #	Issue Date	Implementation Date	Subject
PCN-2770	2025-10-30	2025-10-30	Add Fab Site Code, Country of Diffusion (COD) and Assembly Site Origin (ASO) on Product and Shipping Labels for all Diodes Products
PCN-2672	2024-03-11	2024-09-07	Device End of Life (EOL)

AM4964 (NRND)