LT3956 View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LT3956 Datasheet PDF : 20 Pages
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LT3956
Electrical Characteristics The l denotes the specifications which apply over the full operating temp-
erature range, otherwise specifications are at TA = 25°C. VIN = 24V, EN/UVLO = 24V, CTRL = 2V, PWM = 5V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP MAX UNITS
SW Pin Leakage
SW = 48V
5
10
µA
SW Pin Current Limit
l
3.3
3.9
4.6
A
SW Pin Voltage Drop
I(SW) = 2A
220
mV
SS Pull-Up Current
Current Out of Pin
8
10
13
µA
Error Amplifier
Full-Scale Current Sense Threshold ( V(ISP–ISN))
FB = 0V, ISP = 48V, CTRL ≥ 1.2V
l
240
250 257
mV
Current Sense Threshold at CTRL = 1V ( V(ISP–ISN))
CTRL = 1V, FB = 0V, ISP = 48V
l
217
225 231
mV
Current Sense Threshold at CTRL = 0.5V ( V(ISP–ISN))
Current Sense Threshold at CTRL = 0.1V ( V(ISP–ISN))
CTRL Range for Current Sense Threshold Adjustment
CTRL = 0.5V
CTRL = 0.1V, FB = 0V, ISP = 48V
l
96
100 103
mV
l
–2.5
0
4.5
mV
0
1.1
V
CTRL Input Bias Current
Current Out of Pin, CTRL = 0V
50
100
nA
Current Sense Amplifier Input Common Mode
Range ( VISN)
ISP/ISN Short-Circuit Threshold ( V(ISP–ISN))
ISN = 0V
2.9
80
V
300
335 370
mV
ISP/ISN Short-Circuit Fault Sensing Common Mode
Range ( VISN)
ISP/ISN Input Bias Current (Combined)
PWM = 5V (Active), ISP = ISN = 48V
PWM = 0V (Standby), ISP = ISN = 48V
0
3
V
80
µA
0
0.1
µA
LED Current Sense Amplifier gm
VC Output Impedance
VC Standby Input Bias Current
FB Regulation Voltage (VFB)
1V < VC < 2V
PWM = 0V
ISP = ISN = 0V, 48V
120
µS
15000
kΩ
–20
20
nA
l 1.220 1.250 1.270
V
1.232 1.250 1.265
V
FB Amplifier gm
FB = VFB, ISP = ISN
480
µS
FB Pin Input Bias Current
Current Out of Pin, FB = 1V
40
100
nA
FB Voltage Loop Active Threshold
VMODE Falling
VFB –
VFB – VFB –
V
65mV 50mV 40mV
FB Overvoltage Threshold
PWMOUT Falling
VFB + 50mV VFB + VFB +
V
60mV 80mV
Oscillator
Switching Frequency
SW Minimum Off-Time
RT = 100k
RT = 10k
l
90
100 125
kHz
925
1000 1050
kHz
170
ns
SW Minimum On-Time
200
ns
Linear Regulator
INTVCC Regulation Voltage
7
7.15
7.3
V
Dropout (VIN – INTVCC)
INTVCC Undervoltage Lockout
INTVCC Current Limit
IINTVCC = –10mA, VIN = 7V
1
V
l
4.1
4.4
V
14
17
25
mA
INTVCC Current in Shutdown
EN/UVLO = 0V, INTVCC = 7V
8
12
µA
3956f
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