Datasheet

LT3761
3
3761f
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 24V, EN/UVLO = 24V, CTRL = 2V, PWM = 5V, unless otherwise noted.
elecTrical characTerisTics
PARAMETER CONDITIONS MIN TYP MAX UNITS
Error Amplifier
Full-Scale ISP/ISN Current Sense Threshold
(V
ISP-ISN
)
CTRL ≥ 1.2V, ISP = 48V
CTRL ≥ 1.2V, ISN = 0V
l
l
242
243
250
257
258
268
mV
mV
1/10th Scale ISP/ISN Current Sense Threshold
(V
ISP-ISN
)
CTRL = 0.2V, ISP = 48V
CTRL = 0.2V, ISN = 0V
l
l
21
20
25
28
30
36
mV
mV
Mid-Scale ISP/ISN Current Sense Threshold
(V
ISP-ISN
)
CTRL = 0.5V, ISP = 48V
CTRL = 0.5V, ISN = 0V
l
l
96
95
100
105
104
115
mV
mV
ISP/ISN Overcurrent Threshold 600 mV
ISP/ISN Current Sense Amplifier Input Common Mode
Range (V
ISN
)
0 80 V
ISP/ISN Input Bias Current High Side Sensing (Combined) PWM = 5V (Active), ISP = ISN = 48V
PWM = 0V (Standby), ISP = ISN = 48V
100
0.1
µA
µA
ISP/ISN Input Bias Current Low Side Sensing (Combined) PWM = 5V, ISP = ISN = 0V –230 µA
ISP/ISN Current Sense Amplifier g
m
(High Side Sensing) V
ISP-ISN
= 250mV, ISP = 48V 120 µS
ISP/ISN Current Sense Amplifier g
m
(Low Side Sensing) V
ISP-ISN
= 250mV, ISN = 0V 70 µS
CTRL Pin Range for Linear Current Sense Threshold
Adjustment
l
0 1.0 V
CTRL Input Bias Current Current Out of Pin 50 100 nA
V
C
Output Impedance 0.9V ≤ V
C
≤ 1.5V 15 MΩ
V
C
Standby Input Bias Current PWM = 0V –20 20 nA
FB Regulation Voltage (V
FB
) ISP = ISN = 48V, 0V
l
1.225 1.255 1.275 V
FB Amplifier g
m
FB = V
FB
, ISP = ISN = 48V 500 µS
FB Pin Input Bias Current Current Out of Pin, FB = V
FB
40 100 nA
FB Open LED Threshold OPENLED Falling, ISP Tied to ISN
l
V
FB
–
65mV
V
FB
–
50mV
V
FB
–
40mV
V
C/10 Inhibit for OPENLED Assertion (V
ISP-ISN
) FB = V
FB
, ISN = 48V, 0V 14 25 39 mV
FB Overvoltage Threshold PWMOUT Falling V
FB
+
50mV
V
FB
+
60mV
V
FB
+
70mV
V
V
C
Current Mode Gain (∆V
VC
/∆V
SENSE
)
4 V/V
Oscillator
Switching Frequency R
T
= 95.3kΩ
R
T
= 8.87kΩ
l
85
925
100
1000
115
1050
kHz
kHz
GATE Minimum Off-Time C
GATE
= 2200pF 160 ns
GATE Minimum On-Time C
GATE
= 2200pF 180 ns
Linear Regulator
INTV
CC
Regulation Voltage 10V ≤ V
IN
≤ 60V
l
7.6 7.85 8.05 V
INTV
CC
Maximum Operating Voltage 8.1 V
INTV
CC
Minimum Operating Voltage 4.5 V
Dropout (V
IN
– INTV
CC
) I
INTVCC
= –10mA, V
IN
= 7V 390 mV
INTV
CC
Undervoltage Lockout
l
3.9 4.1 4.4 V
INTV
CC
Current Limit INTV
CC
= 6V, 8V ≤ V
IN
≤ 60V 30 36 42 mA
INTV
CC
Current in Shutdown EN/UVLO = 0V, INTV
CC
= 8V 8 13 µA