ltc2978 Linear Technology Corporation, ltc2978 Datasheet - Page 26

• Manufacturer Part Number: ltc2978
• Description: Octal Pmbus Power Supply Monitor And Controller With Eeprom
• Manufacturer: Linear Technology Corporation

VOUT_MODE
The data byte for the VOUT_MODE command is 8 bits
that consists of a three bit format and a five bit exponent.
The three bit format specifies PMBus linear mode for all
output voltage related commands. The five bit exponent
provides the exponent for the mantissa specified in the
data word. The LTC2978 device sets the format at the time
of manufacture. The five bit exponent is read only and is
set to a value of –13 decimal.
Output voltage related commands are calculated as fol-
lows except for odd numbered channels configured to
measure current:
where Voltage is the parameter of interest in volts.
V is a 16-bit unsigned binary integer for all voltages,
(e.g. Margin_high[15:0]);
N = Vout_mode_exponent, is a 5-bit two’s complementary
binary integer with a value hardwired to –13 decimal.
Vout_mode_parameter is read only.
Vout_mode_type is read only.
VOUT_MODE Data Contents
LTC2978
operaTion

BIT(S) SYMBOL
b[7:5]
b[4:0]
Voltage = V[15:0] • 2
Vout_mode_type
Vout_mode_parameter Linear mode exponent. 5-bit two’s
N
OPERATION
Reports linear mode. Hard wired to
3’b000.
complement integer. Hardwired to
‘h13 (–13 decimal).
Output Voltage Related Commands
VOUT_COMMAND, VOUT_MAX, VOUT_MARGIN_
HIGH, VOUT_MARGIN_LOW, VOUT_OV_FAULT_LIMIT,
VOUT_OV_WARN_LIMIT, VOUT_UV_WARN_LIMIT,
VOUT_UV_FAULT_LIMIT, POWER_GOOD_ON and
POWER_GOOD_OFF
These commands use the same format and provide various
servo, margining, and supervising limits for a channel’s
output voltage. When odd channels are configured to
measure current, the OV_WARN_LIMIT, UV_WARN_LIMIT,
OV_FAULT_LIMIT and UV_FAULT_LIMIT commands are
not supported.
Data Contents
b[15:0] Vout_command[15:0],
BIT(S)
SYMBOL
Vout_max[15:0],
Vout_margin_high[15:0],
Vout_margin_low[15:0],
Vout_ov_fault_limit[15:0],
Vout_ov_warn_limit[15:0],
Vout_uv_warn_limit[15:0],
Vout_uv_fault_limit[15:0],
Power_good_on[15:0],
Power_good_off[15:0]
OPERATION
These commands relate to
output voltage. The data uses
the linear mode format as
defined by VOUT_MODE:
V(Symbol) = Y • 2
Y = b[15:0] is an unsigned
integer and N = Vout_mode_
parameter is a 5-bit two’s
complement exponent that’s
hardwired to –13 decimal.
Units: V
N
where
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