Datasheet

LT3690
4
3690fa
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
IN
= 12V unless otherwise noted (Notes 3, 7).
PARAMETER CONDITIONS MIN TYP MAX UNITS
PG Threshold as Percentage of V
FB
V
FB
Rising 88 90 92 %
PG Hysteresis 12 mV
PG Sink Current V
PG
= 0.3V
l
100 500 µA
PG Leakage V
PG
= 5V 0.1 1 µA
Error Amplifier Transconductance 400 µA/V
Error Amp Voltage Gain 60 dB
V
C
Source Current –50 µA
V
C
Sink Current 50 µA
V
C
Pin to Switch Current Gain
Transconductance
4.6 A/V
V
C
Switching Threshold 0.7 V
V
C
Clamp Voltage 2.0 V
Programmable Switching Frequency R
T
= 10kΩ 1.32 1.5 1.68 MHz
R
T
= 24.9kΩ 660 750 840 kHz
R
T
= 180kΩ 122 138 154 kHz
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: Absolute maximum voltage at the EN, UVLO and V
IN
pins is 36V
for continuous operation. For non-repetitive 1 second transients while
T
J
< 125°C, the absolute maximum voltage is 60V.
Note 3: The LT3690E is guaranteed to meet performance specifications
from 0°C to 125°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
LT3690I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT3690H is
guaranteed over the full –40°C to
150°C operating junction temperature range. The LT3690MP is guaranteed
over the full –55°C to 150°C operating junction temperature range. High
junction temperatures degrade operating lifetime. Operating lifetime is
derated at junction temperatures greater than 125°C.
Note 4:
This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed the maximum operating junction temperature
when overtemperature protection is active. Continuous operation above
the specified maximum operating junction temperature may impair device
reliability.
Note 5: This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the switch.
Note 6: Current limit guaranteed by design and/or correlation to static test.
Slope compensation reduces current limit at higher duty cycles. Current
limit reduced when feedback voltage is below the reference voltage.
Note 7: The voltages are referred to GND and currents are assumed
positive, when the current flows into the pin. Negative magnitudes are
shown as maximum.