Datasheet

Table Of Contents

LM63

SNAS190E –SEPTEMBER 2002–REVISED MAY 2013

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Table 5. Fan Control Registers (continued)

ADDRESS READ/ POR

BITS NAME DESCRIPTION

HEX WRITE VALUE

HEX

FAN PWM FREQUENCY REGISTER

7:5 000 These bits are unused and always set to 0

The PWM Frequency = PWM_Clock / 2n, where PWM_Clock = 360 kHz

PWM

or 1.4 kHz (per the PWM Clock Select bit in Register 4A), and n = value

4D R/W

Frequency

of the register.

4:0 10111

Note: n = 0 is mapped to n = 1. See the APPLICATION NOTES section

at the end of this datasheet.

HEX

PWM VALUE REGISTER

7:6 00 These bits are unused and always set to 0

If PWM Program (register 4A, bit 5) = 0 this register is read only and

reflects the LM63’s current PWM value from the Lookup Table.

Read

If PWM Program (register 4A, bit 5) = 1, this register is read/write and the

(Write only PWM

desired PWM value is written directly to this register, instead of from the

if reg 4A Value

5:0 000000

Lookup Table, for direct fan speed control.

bit 5 = 1.)

This register will read 0 during the Spin-Up cycle.

See the APPLICATION NOTES section at the end of this datasheet for

more information regarding the PWM Value and Duty Cycle in %.

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