IRDM982 Series

3 www.irf.com

© 2015 International Rectifier

April 8, 2015

Introduction

IRDM982-025MB, IRDM982-035MB are the complete PM motor controller including six power

MOSFET, high voltage integrated circuit, high precision analog circuit and digital control

algorithm. There are three products depending on power rating of internal high voltage MOSFET

listed below:

1) IRDM982-025MB – employs six MOSFET 500V 2A and 600V high voltage IC

2) IRDM982-035MB – employs six MOSFET 500V 3A and 600V high voltage IC

All two products are packaged in the 12 x 12 PQFN package and designed to dissipate the power

loss through a mating PCB without an external heatsink. All two products contain exactly same

control algorithm and analog functions. The controller implements a Hall sensor based control

algorithm for 3-phase sinusoidal permanent magnet motor fan applications. The control also

employs high efficiency PM motor control algorithm based on a quadratic load curve stored in

internal ROM. 16 possible curves are selectable.

All devices have an on-chip voltage regulator to derive the 3.3V, required by the digital logic, from

the 15V (VCC) supply. The 3.3VDC regulated voltage pin is available externally for connection to

Hall-effect sensors. The IC provides low power standby (less than 7mW) mode of operation that

3.3V power is cut off when VSP (Voltage Input) becomes less than 1.15V to provide further power

efficient operation.

An integrated A/D Converter is used to acquire EFF load curve selection, temperature (internal

temp sensing), and the VSP input that sets the voltage applied to the motor.

An internal temperature sensor is interfaced to the ADC and resulting digital conversion data is

used to control the dynamic overcurrent setpoints as well as max overtemperature limit.

The protection functions include a supply under-voltage lockout (3.3V and 15VDC), over-speed

protection, over-temperature limit and Over-current limitation protections. The reset circuitry

includes a Power-On reset block and a reset input.

All devices do not require any programming. Default coefficients and system parameters are

stored in internal ROM. The EFF input pin, used to adapt to specific motor and load to improve

efficiency, can be used by means of two resistor pairs to choose one of 16 pre-stored load curves

in ROM. DIR is a digital input pins which specify the motor direction command (CW or CCW).

All devices have an on-chip PLL to generate internal clocks. The PLL requires an external low

frequency reference clock (32,768 Hz). The clock can be provided through an RC network

connected to CLKIN and XTAL pins.

The IRDM982-025MB, IRDM982-035MB integrate high and low side gate drivers for applications

up to 500V, it includes integrated Bootstrap FET that emulate bootstrap diode function and six

power MOSFETs. The simplified block diagram is shown in Figure 1 in terms of hardware

elements.