Datasheet

3
LT1737
1737fa
Note 1: Absolute Maximum Ratings are those values beyond which the life of
a device may be impaired.
Note 2: Component value range guaranteed by design.
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 14V, GATE open, V
C
= 1.4V unless otherwise noted.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Current Amplifier
V
C
Control Pin Threshold Duty Cycle = Min 0.90 1.12 1.25 V
● 0.80 1.35 V
V
ISENSE
Switch Current Limit Duty Cycle ≤ 30% 220 250 270 mV
Duty Cycle ≤ 30%
● 200 280 mV
Duty Cycle = 80% 220 mV
∆V
ISENSE
/∆V
C
0.30 mV
Timing
f Switching Frequency C
OSCAP
= 100pF 90 100 115 kHz
● 80 125 kHz
C
OSCAP
Oscillator Capacitor Value (Note 2) 33 200 pF
t
ON
Minimum Switch On Time R
tON
= 50k 200 ns
t
ED
Flyback Enable Delay Time R
ENDLY
= 50k 200 ns
t
EN
Minimum Flyback Enable Time R
MENAB
= 50k 200 ns
R
t
Timing Resistor Value (Note 2) 24 240 kΩ
Maximum Switch Duty Cycle ● 85 90 %
Load Compensation
Sense Offset Voltage 25mV
Current Gain Factor 0.80 0.95 1.05 mV
UVLO Function
V
UVLO
UVLO Pin Lockout Threshold ● 1.21 1.25 1.29 V
UVLO Pin Shutdown Threshold 0.75 V
● 0.4 0.95 V
I
UVLO
UVLO Pin Bias Current V
UVLO
= 1.2V –0.25 +0.1 + 0.25 µA
V
UVLO
= 1.3V –4.50 –3.5 – 2.50 µA
3V Output Function
V
REF
Reference Output Voltage I
LOAD
= 1mA ● 2.8 3.0 3.2 V
Output Impedance 10 Ω
Current Limit ● 815 mA