ACT4921QI

Rev 1.0, 18-Jan-2018

www.active-semi.com

Copyright © 2018 Active-Semi, Inc.

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CMI OPTIONS

This section provides the basic default configuration settings for each available ACT4921 CMI option.

CMI 301: ACT4921QI301

CMI 301 is designed for standard 3.3V input applications. CMI 301 default settings are appropriate for most typical

applications. It operates with a buck switching frequency of 1.125MHz to provide an optimal tradeoff between overall

size and efficiency. Table 10 shows the default register settings.

Table 10: CMI 301 Default Register Settings

Function

Value

Register

Register Settings

Storage Voltage

28V

0x0Dh

BST_VSET[4:0] = 10111

Boost Current Limit

950mA

0x0Dh

BST_CLIM[1:0] = 10

Buck Switching Frequency

1125kHz

0x10h

BK_FREQ[1:0] = 01

Buck Peak Current Limit

6A

0x0Fh

BKILIM_OPT = 1

Buck Undervoltage Threshold

80%

0x0Fh

BKUV[1:0] = 10

Input Voltage Overvoltage Reference

0.82V

0x0Eh

VINS_OV_REF[2:0] = 001

Health Monitor Time

32ms

0x0Bh

HMON_TSET[3:0] = 0100

Health Monitor Threshold

95%

0x0Ch

HMON_THR[3:0] = 0000

Startup Delay

1ms

0x0Ch

EN_STARTDLY[2:0] = 001

Latch Supplement Mode

Yes

0x0Ch

EN_LATCH_SPLMNT = 1

Blocking FET Control

Pin Enabled

0x0Bh

EN_ENB_REG = 0

0x5Ah

n/a

n/a

CMI Identification

0x00h

0x2Ah

CMI_ID[7:0] = 0x00h

I2C Address

The CMI 301 7-bit I2C address is 0x5Ah. This results in 0xB4h for a write address and 0xB5h for a read address.

CMI Identification

The CMI 301 CMI identification (register 0x2Ah) = 0x00h. This register can be used to distinguish between different CMI

versions.