Datasheet

LTC3129-1
4
31291fa
For more information www.linear.com/LTC3129-1
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 LTC3129-1 is tested under pulsed load conditions such
that T
J
≈ T
A
. The LTC3129E-1 is guaranteed to meet specifications
from 0°C to 85°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3129I-1 is guaranteed over the full –40°C to 125°C operating junction
temperature range. The junction temperature (T
J
, in °C) is calculated from
the ambient temperature (T
A
, in °C) and power dissipation (P
D
, in watts)
according to the formula:
T
J
= T
A
+ (P
D
• θ
JA
),
where θ
JA
(in °C/W) is the package thermal impedance.
Note that the maximum ambient temperature consistent with these
specifications is determined by specific operating conditions in
conjunction with board layout, the rated thermal package thermal
resistance and other environmental factors.
PARAMETER CONDITIONS MIN TYP MAX UNITS
V
CC
UVLO Threshold (Rising)
l
2.1 2.25 2.42 V
V
CC
UVLO Hysteresis 60 mV
V
CC
Current Limit V
CC
= 0V
l
4 20 40 mA
V
CC
Back-Drive Voltage (Maximum)
l
5.5 V
V
CC
Input Current (Back-Driven) V
CC
= 5.5V (Switching) 2 4 mA
V
CC
Leakage to V
IN
if V
CC
>V
IN
V
CC
= 5.5V, V
IN
= 1.8V, Measured on V
IN
–27 µA
V
OUT
UV Threshold (Rising)
l
0.95 1.15 1.35 V
V
OUT
UV Hysteresis 150 mV
V
OUT
Current – Shutdown RUN = 0V, V
OUT
= 15V Including Switch Leakage 10 100 nA
V
OUT
Current – Sleep PWM = 0V, V
OUT
≥ V
REG
V
OUT
/27 µA
V
OUT
Current – Active PWM = V
CC
, V
OUT
= 15V (Note 4) 5 9 µA
PGOOD Threshold, Falling Referenced to Programmed V
OUT
Voltage –5.5 –7.5 –10 %
PGOOD Hysteresis Referenced to Programmed V
OUT
Voltage 2.5 %
PGOOD Voltage Low I
SINK
= 1mA 250 300 mV
PGOOD Leakage PGOOD = 15V 1 50 nA
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). Unless otherwise noted, V
IN
= 12V, V
OUT
= 5V.
Note 3: Specification is guaranteed by design and not 100% tested in
production.
Note 4: Current measurements are made when the output is not switching.
Note 5: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature
will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may result in device degradation or failure.
Note 6:
Failure to solder the exposed backside of the package to the PC
board ground plane will result in a much higher thermal resistance.
Note 7: Switch timing measurements are made in an open-loop test
configuration. Timing in the application may vary somewhat from these
values due to differences in the switch pin voltage during non-overlap
durations when switch pin voltage is influenced by the magnitude and
duration of the inductor current.
Note 8: Voltage transients on the switch pin(s) beyond the DC limits
specified in the Absolute Maximum Ratings are non-disruptive to normal
operation when using good layout practices as described elsewhere in the
data sheet and Application Notes and as seen on the product demo board.