LT3922
elecTrical characTerisTics The l denotes the sꢄecificltions which lꢄꢄuy over the fCuu oꢄerltinꢂ
temꢄerltCre rlnꢂe, otherwise sꢄecificltions lre lt TA = 25°ꢀ, VIN = 12V, VEN/UVLꢃ = 2V Cnuess otherwise noted.
PAꢁAMETEꢁ
ꢀꢃNDITIꢃNS
MIN
TYP
MAX
UNITS
Soft-Stlrt
SS Pin Charging Current
SS Pin Discharging Current
SS Lower Threshold
SS Higher Threshold
FlCut Detection
V
V
= 1V
= 2V
20
2
µA
µA
V
SS
SS
0.2
1.7
V
l
Open-Circuit Threshold (FB Rising)
Open-Circuit Falling Hysteresis
V
= V = 20V
1.117
1.140
50
1.163
V
mV
mV
mA
nA
ISP
ISN
LED Short-Circuit Threshold (V − V
)
ISN
V
V
V
= 20V
150
ISP
ISP
FAULT Pull-Down Current
FAULT Leakage Current
ꢃvervoutlꢂe Protection
FB Overvoltage Threshold (Rising)
FB Overvoltage Falling Hysteresis
LED ꢀCrrent Monitor
= 0.2V, V = 1.25V
0.8
FAULT
FAULT
FB
= 3V, V = 0.7V
−100
100
FB
l
1.240
1.266
22
1.292
V
mV
l
l
ISMON Voltage
V
V
− V = 100mV (100ꢀ), V = 24V
0.980
80
1.000
100
1.020
120
V
mV
ISP
ISP
ISN
ISP
− V = 10mV (10ꢀ), V = 24V
ISN
ISP
PWM Driver
PWMTG Gate Drive (V
– V
)
V
= 20V, V = 1.5V
PWM
9
10
1.4
0.2
11
V
V
OUT
PWMTG
OUT
PWM Threshold (Rising)
PWM Falling Hysteresis
PWM Pin Current
V
V
= 2V
−100
100
nA
PWM
PWM to PWMTG Propagation Delay
C
V
= 2.1nF (Connected from V
to PWMTG)
PWMTG
OUT
OUT
Turn-On
Turn-Off
= 20V
110
140
ns
ns
Internlu PWM Dimminꢂ
PWM Voltage for 100ꢀ PWM Dimming
PWM Voltage for 0ꢀ PWM Dimming
PWM Dimming Accuracy
R = 28.7k, V = 2V
2.00
V
V
P
REF
R = 28.7k, V = 2V
0.99
P
REF
R = 28.7k, V = 2V, V
= 1.1V
= 1.9V
7.5
89
10.5
92
13.5
95
ꢀ
ꢀ
P
REF
PWM
PWM
R = 28.7k, V = 2V, V
P
REF
PWM Dimming Frequency
RP Pin Current Limit
R = 28.7k, R = 45.3k, V
= 0V
= 0V
7.34
115
7.81
122
8.28
129
kHz
Hz
P
T
SYNC/SPRD
R = 332k, R = 45.3k, V
P
T
SYNC/SPRD
V
= 0V, Current Out of Pin
65
µA
RP
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.
LT3922I is guaranteed to meet performance specifications over the
−40°C to 125°C operating junction temperature range. The LT3922H is
guaranteed over the −40°C to 150°C operating junction temperature range.
Operating lifetime is derated at junction temperatures greater than 125°C.
Note 2: Do not apply a positive or negative voltage source to these pins,
otherwise permanent damage may occur.
Note 3: The LT3922E 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
Note 4: This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. The maximum
rated junction temperature will be exceeded when this protection is active.
Continuous operation above the specified absolute maximum operating
junction temperature may impair device reliability or permanently damage
the device.
3922f
4
For more information www.linear.com/LT3922
Linear Systems [ Linear Systems ]
