Linear ANALOG DEVICES LTM4680, Operation Manual, Page: 41 / 126

LTM4680
41
Rev. B
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OPERATION
Refer to Figure 7 for a legend.
Handshaking features are included to ensure robust system communication. Please refer to the PMBus Communication
and Command Processing subsection of the Applications Information section for further details.
SDA
SCL
t
HD(STA)
t
HD(DAT)
t
SU(STA)
t
SU(STO)
t
SU(DAT)
t
LOW
t
HD(SDA)
t
SP
t
BUF
START
CONDITION
STOP
CONDITION
REPEATED START
CONDITION
START
CONDITION
t
r
t
f
t
r
t
f
t
HIGH
4680 F06
Figure 6. PMBus Timing Diagram
Table 6. Abbreviations of Supported Data Formats
PMBus
ADI
TERMINOLOGY DEFINITION EXAMPLE TERMINOLOGY
SPECIFICATION
REFERENCE
L11 Linear Part II ¶7.1 Linear_5s_1s Floating point 16-bit data: value = Y • 2
N
,
where N = b[15:11] and Y = b[10:0], both
two’s compliment binary integers
b[15:0] = 0x9807 = 10011_000_0000_0111
value = 7 • 2
–13
= 854E-6
L16 Linear
VOUT_MODE
Part II ¶8.2 Linear_16u Floating point 16-bit data: value = Y • 2
–12
,
where Y = b[15:0], an unsigned integer
b[15:0] = 0x4C00 = 0100_1100_0000_0000
value = 19456 • 2
–12
= 4.75
CF DIRECT Part II ¶7.2 Varies 16-bit data with a custom format defined in
the detailed PMBus command description
Often an unsigned or two’s compliment
integer
Reg Register Bits Part II ¶10.3 Reg Per-bit meaning defined in detailed PMBus
command description
PMBus STATUS_BYTE command
ASC Text Characters Part II ¶22.2.1 ASCII ISO/IEC 8859-1 [A05] LTC (0x4C5443)