Datasheet

LTC3880/LTC3880-1
9
3880fc
For more information www.linear.com/LTC3880
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. (Note 2) V
IN
= 12V, V
RUN0,1
= 3.3V, f
SYNC
= 500kHz (externally
driven) unless otherwise specified.
ELECTRICAL CHARACTERISTICS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3880/LTC3880-1 are tested under pulsed load conditions
such that T
J
≈ T
A
. The LTC3880E/LTC3880E-1 are guaranteed to meet
performance specifications from 0°C to 85°C. Specifications over the
–40°C to 105°C operating junction temperature range are assured by
design, characterization and correlation with statistical process controls.
The LTC3880I/LTC388I-1 are guaranteed over the full –40°C to 125°C
operating junction temperature range. T
J
is calculated from the ambient
temperature T
A
and power dissipation P
D
according to the following
formula:
T
J
= T
A
+ (P
D
• θ
JA
)
The maximum ambient temperature consistent with these specifications
is determined by specific operating conditions in conjunction with board
layout, the rated package thermal impedance and other environmental
factors.
Note 3: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified.
Note 4: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels.
Note 5: The data format in PMBus is 5 bits exponent (signed) and 11 bits
mantissa (signed). This limits the output resolution to 10 bits though the
internal ADC is 16 bits and the calculations use 32-bit words.
Note 6: The data conversion is done in round robin fashion. All inputs
signals are continuously converted for a typical latency of 100ms.
Note 7: The IOUT_CAL_GAIN = 1.0mΩ and MFR_IOUT_CAL_GAIN_TC =
0.0. Value as read from READ_IOUT in amperes.
Note 8: Part tested with PWM disabled. Evaluation in application
demonstrates capability. TUE (%) = ADC Gain Error (%) + 100 • [Zero
Code Offset + ADC Linearity Error]/Actual Value.
Note 9: All V
OUT
commands assume the ADC is used to auto-zero the
output to achieve the stated accuracy. LTC3880 is tested in a feedback loop
that servos V
OUT
to a specified value.
Note 10: The maximum V
OUT
voltage is 5.5V.
Note 11: The maximum V
IN
voltage is 28V.
Note 12: When V
IN
< 6V, INTV
CC
must be tied to V
IN
.
Note 13: EEPROM endurance and retention are guaranteed by design,
characterization and correlation with statistical process controls. The
minimum retention specification applies for devices whose EEPROM
has been cycled less than the minimum endurance specification. The
RESTORE_USER_ALL command (NVM read) is valid over the entire
operating junction temperature range.
Note 14: The LTC3880-1 quiescent current (I
Q
) equals the I
Q
of V
IN
plus
the I
Q
of EXTV
CC
.
Note 15: Guaranteed with a common mode voltage (V
OUT
) between 0V and
5.5V.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Digital Filtering of GPIO0, GPIO1
I
FLTG
Input Digital Filtering GPIO 3 µs
Digital Filtering of RUN0, RUN1
I
FLTG
Input Digital Filtering RUN 10 µs
PMBus Interface Timing Characteristics
f
SMB
Serial Bus Operating Frequency
l
10 400 kHz
t
BUF
Bus Free Time Between Stop and Start
l
1.3 µs
t
HD,STA
Hold time After Repeated Start Condition.
After this Period, the First Clock is Generated
l
0.6 µs
t
SU,STA
Repeated Start Condition Setup Time
l
0.6 µs
t
SU,STO
Stop Condition Setup Time
l
0.6 µs
t
HD,DAT
Data Hold Time
Receiving Data
Transmitting Data
l
l
0
0.3 0.9
µs
µs
t
SU,DAT
Data Setup Time
Receiving Data
l
0.1 µs
t
TIMEOUT_SMB
Stuck PMBus Timer Non-Block Reads
Stuck PMBus Timer Block Reads
Measured from the Last PMBus Start Event 32
150
ms
ms
t
LOW
Serial Clock Low Period
l
1.3 10000 µs
t
HIGH
Serial Clock High Period
l
0.6 µs