Datasheet

LTC3883/LTC3883-1
69
3883fa
For more information www.linear.com/LTC3883
Bit[3] Setting this bit to a 1 starts the patent pending inductor DCR auto calibration to determine the DCR of the
inductor. This will update the value of IOUT_CAL_GAIN using the READ_IIN, READ_IOUT, and DUTY_CYCLE values.
IOUT_CAL_GAIN is adjusted so that READ_IOUT • DUTY_CYCLE = READ_IIN. The auto calibration procedure will only
complete successfully if the following conditions are met.
1) The PWM is enabled
2) DUTY_CYCLE is at least 3%
3) READ_IIN is at least 10mA
4) The calibrated IOUT_CAL_GAIN is within ±30% of the uncalibrated IOUT_CAL_GAIN
If any of the above conditions are not met, bit 0 of the STATUS_CML command will be set, and the value of IOUT_
CAL_GAIN will not be changed. Bit[3] must then be reset to a 0 by the user. A STORE_USER_ALL command must be
issued to store the updated IOUT_CAL_GAIN value into NVM.
Bit[1:0] determine the PWM mode of operation.
This command has one data byte.
MFR_PWM_CONFIG_LTC3883
The MFR_PWM_CONFIG_LTC 3883 command sets the switching frequency and phase offset with respect to the falling
edge of the SYNC signal. The part must be in the OFF
state to process this command. The RUN pin must be low or
the part must be commanded off. If the part is in the RUN state and this command is written, the command will be
ignored and a BUSY fault will be asserted. Bit 6 of this command affects the loop gain of the PWM output which may
require modifications to the external compensation network.
BIT MEANING
7 Reserved, set to 0.
6 If V
OUT
RANGE = 1, the maximum output voltage is 2.75V.
If RANGE = 0, the maximum output voltage is 5.5V.
5 Reserved
4 Share Clock Enable : If this bit is 1, the SHARE_CLK pin
will not be released until V
IN
> VIN_ON. The SHARE_CLK
pin will be pulled low when V
IN
< VIN_OFF. If this bit is
0, the SHARE_CLK pin will not be pulled low when VIN <
VIN_OFF except for the initial application of VIN.
3 Reserved, set to 0
BIT [2:0] Phase Offset
000b 0
001b 90
010b 180
011b 270
100b 60
101b 120
110b 240
111b 300
This command has one data byte.
PMBus COMMAND DETAILS