Datasheet

LT3692
4
3692fa
For more information www.linear.com/3692
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
VIN1/2
= 15V unless otherwise specified. (Note 3)
PARAMETER CONDITIONS MIN TYP MAX UNITS
RT/SYNC to CLKOUT Delay ( t
DRTSYNCH
) V
RT/SYNC
= 0V to 2V Rising Edge 300 ns
RT/SYNC to CLKOUT Delay ( t
DRTSYNCL
) V
RT/SYNC
= 2V to 0V Falling Edge 150 ns
SYNC Frequency Range 250 2000 kHz
SYNC Phase Angle Ch 1 to Ch 2 SYNC Frequency = 250kHz 180 Deg
Minimum Switch On-Time Ch 1/2 180 ns
Minimum Switch Off-Time Ch 1/2 200 ns
Minimum Boost for 100% DC Ch 1/2 (Note 10) 1.4 1.8 2.2 V
IND + V
OUT
Current Ch 1/2 V
VOUT1/2
= 0V
V
VOUT1/2
= 5V
1.5
0.5
5
5
µA
µA
ILIM1/2 Reference Current V
FB1/2
= 0.9V, V
ILIM
= 0.4V
l
10 12 14 µA
IND to V
OUT
Maximum Current Ch 1/2 V
ILIM1/2
= 0V, V
VOUT
= 1V (Note 11)
V
ILIM1/2
= 0V, V
VOUT
= 5V (Note 11)
V
ILIM1/2
= 0.5V, V
VOUT
= 1V (Note 11)
V
ILIM1/2
= 0.5V, V
VOUT
= 5V (Note 11)
V
ILIM1/2
= 1.5V, V
VOUT
= 1V (Note 11)
V
ILIM1/2
= 1.5V, V
VOUT
= 5V (Note 11)
l
l
1
1.25
1.6
1.8
3.8
3.8
1.8
2
2.6
2.8
4.8
4.8
2.6
2.75
3.6
3.8
5.8
5.8
A
A
A
A
A
A
Switch Leakage Current Ch 1/2 V
SW1/2
= 0V
l
1 5.0 µA
Switch Saturation Voltage Ch 1/2 I
SW1/2
= 500mA, V
BST1/2
= 18V
I
SW1/2
= 3A, V
BST1/2
= 18V
100
300
mV
mV
Boost Current Ch 1/2 I
SW1/2
= 500mA, V
BST1/2
= 18V
I
SW1/2
= 3A, V
BST1/2
= 18V
9
40
13
55
17
70
mA
mA
Minimum Boost Voltage Ch1/2 (Note 12) I
SW1/2
= 3A, V
BST1/2
= 18V 1.75 2.0 2.5 V
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 V
IN1/2
and SHDN1/2 pins is 60V for
nonrepetitive 1 second transients and 40V for continuous operation.
Note 3: The LT3692EUH 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
LT3692IUH is guaranteed over the full –40°C to 125°C operating junction
temperature range.
Note 4: The SHDN pins can be connected to V
IN
or driven by a logic-level
source with a series current limiting resistor.
Note 5: V
IN
undervoltage lockout is defined as the voltage which the V
IN
pin must exceed for operation. The threshold guarantees that internal bias
lines are regulated and switching frequency is constant. Actual minimum
input voltage to maintain a regulated output will depend upon output
voltage and load current. See Applications Information.
Note 6: V
IN
overvoltage lockout is defined as the voltage when exceeded
halts converter operation. See Applications Information.
Note 7: The T
J
output voltage represents the temperature at the center
of the die while dissipating quiescent power. Due to switch power
dissipation and temperature gradients across the die, the T
J
output
voltage measurement does not guarantee that absolute maximum junction
temperature will not be exceeded.
Note 8: An internal power on reset (POR) latch is set on the positive
transition of the SHDN1/2 pin through its threshold, thermal shutdown or
overvoltage lockout. The output of the latch activates current sources on
each SS pin which typically sink 400µA and discharge the SS capacitor.
The latch is reset when both SS pins are driven below the soft-start POR
threshold or the SHDN pin is taken below its threshold.
Note 9: The threshold is expressed as a percentage of the feedback
reference voltage for the channel.
Note 10: To enhance dropout operation, the output switch will be turned
off for the minimum off-time only when the voltage across the boost
capacitor drops below the minimum boost for 100% duty cycle threshold.
Note 11: The IND to V
OUT
maximum current is defined as the value of
current flowing from the IND pin to the V
OUT
pin which resets the switch
latch when the V
C
pin is at its high clamp.
Note 12: This is the minimum voltage across the boost capacitor needed
to guarantee full saturation of the internal power switch.