LTC3883 Datasheet, PDF (70/112 Pages) Linear Technology – Single Phase Step-Down DC/DC Controller with Digital Power System Management

LTC3883/LTC3883-1
PMBus Command Details
FREQUENCY_SWITCH
The FREQUENCY_SWITCH command sets the switching frequency, in kHz, of a PMBus device.
Supported Frequencies:
VALUE [15:0]
RESULTING FREQUENCY (TYP)
0x0000
External Oscillator
0xF3E8
250kHz
0xFABC
350kHz
0xFB52
425kHz
0xFBE8
500kHz
0x023F
575kHz
0x028A
650kHz
0x02EE
750kHz
0x03E8
1000kHz
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. When the part is commanded off and the frequency is changed, a PLL_UNLOCK status may be detected as
the PLL locks onto the new frequency.
This command has two data bytes and is formatted in Linear_5s_11s format.
Voltage
Input Voltage and Limits
COMMAND NAME
CMD CODE DESCRIPTION
VIN_OV_FAULT_ LIMIT
0x55 Input supply overvoltage fault limit.
VIN_UV_WARN_LIMIT
0x58 Input supply undervoltage warning limit.
VIN_ON
VIN_OFF
MFR_RVIN
0x35 Input voltage at which the unit should start power
conversion.
0x36 Input voltage at which the unit should stop power
conversion.
0xF7 The resistance value of the V_IN pin filter element in
milliohms
TYPE
R/W
Word
R/W
Word
R/W
Word
R/W
Word
R/W
Word
DATA
FORMAT
L11
L11
L11
L11
L11
UNITS
V
V
V
V
mΩ
DEFAULT
NVM VALUE
Y
15.5
0xD3E0
Y
6.3
0xCB26
Y
6.5
0xCB40
Y
6.0
0xCB00
Y
3000
0x12EE
VIN_OV_FAULT_LIMIT
The VIN_OV_FAULT_LIMIT command sets the value of the measured input voltage, in volts, that causes an input
overvoltage fault. The fault is detected with the A/D converter resulting in latency up to 120ms.
This command has two data bytes and is formatted in Linear_5s_11s format.
VIN_UV_WARN_LIMIT
The VIN_UV_WARN_LIMIT command sets the value of the input voltage that causes an input undervoltage warning.
The warning is detected with the A/D converter resulting in latency up to 120ms.
This command has two data bytes and is formatted in Linear_5s_11s format.
3883f
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