LT3922E-1/LT3922I-1 ............................ –40 to 125°C
LT3922H-1 ............................................. –40 to 150°C
Storage Temperature Range ......................–60 to 150°C
28 27 26 25 24 23
SW 1
BST 2
INTV
CC
3
V
IN
4
EN/UVLO 5
OVLO 6
V
REF
7
CTRL 8
UFD PACKAGE
28-LEAD (4mm
×
5mm) PLASTIC QFN
θ
JA
= 25°C/W (AS MEASURED ON DEMO BOARD DC2247A),
θ
JC
= 3.4°C/W
EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT3922EUFD-1#PBF
LT3922IUFD-1#PBF
LT3922HUFD-1#PBF
TAPE AND REEL
LT3922EUFD-1#TRPBF
LT3922IUFD-1#TRPBF
LT3922HUFD-1#TRPBF
PART MARKING*
39221
39221
39221
PACKAGE DESCRIPTION
28-Lead (4mm × 5mm) Plastic QFN
28-Lead (4mm × 5mm) Plastic QFN
28-Lead (4mm × 5mm) Plastic QFN
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
Consult ADI Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Tape and reel specifications.
Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix.
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
IN
= 12V, V
EN/UVLO
= 2V unless otherwise noted.
PARAMETER
Input Voltage Range
V
IN
Pin Quiescent Current
EN/UVLO Threshold (Falling)
EN/UVLO Rising Hysteresis
EN/UVLO Pin Current
Input OVLO Threshold (Rising)
Input OVLO Falling Hysteresis
OVLO Pin Current
V
OVLO
= 1.0V
–100
V
EN/UVLO
= 1.2V
1.145
V
EN/UVLO
= 1.5V, Not Switching
V
EN/UVLO
= 0.1V, Shutdown
1.260
CONDITIONS
MIN
2.8
2.9
1.330
25
2
1.205
50
100
1.265
TYP
MAX
36
4
1
1.400
UNITS
V
mA
µA
V
mV
µA
V
mV
nA
ELECTRICAL CHARACTERISTICS
Rev 0
2
For more information
www.analog.com
LT3922-1
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
IN
= 12V, V
EN/UVLO
= 2V unless otherwise noted.
PARAMETER
Reference
V
REF
Voltage
V
REF
Pin Current Limit
LED Current Regulation
CTRL-Off Threshold (Falling)
CTRL-Off Rising Hysteresis
CTRL Pin Current
Sense Voltage (V
ISP
−V
ISN
)
(Analog Input)
ISP Pin Current
ISN Pin Current
Current Error Amplifier Transconductance
Duty Cycle Control of LED Current
Sense Voltage (V
ISP
−V
ISN
)
(Duty Cycle Input)
CTRL Pulse Input High (V
IH
)
CTRL Pulse Input Low (V
IL
)
CTRL Pulse Input Frequency Range
Voltage Regulation
FB Regulation Voltage
FB Pin Current
Voltage Error Amplifier Transconductance
INTV
CC
Regulator
INTV
CC
Voltage
INTV
CC
Pin Current Limit
Power Stage
Peak Current Limit
Bottom Switch Minimum Off-Time
Bottom Switch On-Resistance
Top Switch On-Resistance
Oscillator
Programmed Switching Frequency (f
SW
)
Spread Spectrum Frequency Range
RT Pin Current Limit
SYNC/SPRD Threshold (Rising)
SYNC/SPRD Falling Hysteresis
SYNC/SPRD Pin Current
V
SYNC/SPRD
= 5V
−100
R
T
= 45.3k, V
SYNC/SPRD
= 0V
R
T
= 499k, V
SYNC/SPRD
= 0V
R
T
= 45.3k, V
SYNC/SPRD
= 3V
R
T
= 499k, V
SYNC/SPRD
= 3V
V
RT
= 0V, Current Out of Pin
l
l
l
ELECTRICAL CHARACTERISTICS
CONDITIONS
I
VREF
= 0µA
I
VREF
= 500µA
MIN
l
TYP
2
2
3.2
MAX
2.03
2.015
UNITS
V
V
mA
1.97
1.985
V
REF
= 0V, Current Out of Pin
200
−100
l
l
l
210
15
220
100
mV
mV
nA
mV
mV
mV
µA
µA
µA/V
V
CTRL
= 2V
V
CTRL
= 2V (100%), V
ISP
= 24V
V
CTRL
= 0.75V (50%), V
ISP
= 24V
V
CTRL
= 0.3V (5%), V
ISP
= 24V
V
ISP
= 24.1V, V
ISN
= 24V, V
CTRL
= 2V
V
ISP
= 24.1V, V
ISN
= 24V , V
CTRL
= 2V
V
ISP
= 24V
CTRL Duty = 75% (100%), V
ISP
= 24V
CTRL Duty = 37.5% (50%), V
ISP
= 24V
CTRL Duty = 15% (5%), V
ISP
= 24V
98
48.5
4
100
50
5
75
75
140
102
51.5
6
99
49
4
1.6
100
50
5
101
51
6
0.4
mV
mV
mV
V
V
kHz
V
nA
µA/V
10
V
CTRL
= 2V
FB in Regulation
l
200
1.200
1000
1.225
100
1.175
−100
2.7
V
INTVCC
= 0V, Current Out of Pin
V
IN
= 3V
l
3
20
3.3
V
mA
2.3
15
2.55
25
140
155
2.8
35
A
ns
mΩ
mΩ
1880
175
1880
175
2000
200
2120
245
2650
306
kHz
kHz
kHz
kHz
µA
V
V
nA
75
1.4
0.2
100
1.5
Rev 0
For more information
www.analog.com
3
LT3922-1
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
IN
= 12V, V
EN/UVLO
= 2V unless otherwise noted.
PARAMETER
Soft-Start
SS Pin Charging Current
SS Pin Discharging Current
SS Lower Threshold
SS Higher Threshold
Fault Detection
Open-Circuit Threshold (FB Rising)
Open-Circuit Falling Hysteresis
LED Short-Circuit Threshold (V
ISP
− V
ISN
)
FAULT
Pull-Down Current
FAULT
Leakage Current
Overvoltage Protection
FB Overvoltage Threshold (Rising)
FB Overvoltage Falling Hysteresis
LED Current Monitor
ISMON Voltage
PWM Driver
PWMTG Gate Drive (V
OUT
– V
PWMTG
)
PWM Threshold (Rising)
PWM Falling Hysteresis
PWM Pin Current
PWM to PWMTG Propagation Delay
Turn-On
Turn-Off
Internal PWM Dimming
PWM Voltage for 100% PWM Dimming
PWM Voltage for 0% PWM Dimming
PWM Dimming Accuracy
PWM Dimming Frequency
RP Pin Current Limit
R
P
= 28.7k, V
REF
= 2V
R
P
= 28.7k, V
REF
= 2V
R
P
= 28.7k, V
REF
= 2V, V
PWM
= 1.1V
R
P
= 28.7k, V
REF
= 2V, V
PWM
= 1.9V
R
P
= 28.7k, R
T
= 45.3k, V
SYNC/SPRD
= 0V
R
P
= 332k, R
T
= 45.3k, V
SYNC/SPRD
= 0V
V
RP
= 0V, Current Out of Pin
7.5
89
7.34
115
10.5
92
7.81
122
65
2.00
0.99
13.5
95
8.28
129
V
V
%
%
kHz
Hz
µA
V
PWM
= 2V
C
PWMTG
= 2.1nF (Connected from V
OUT
to PWMTG)
V
OUT
= 20V
−100
110
140
V
OUT
= 20V, V
PWM
= 1.5V
9
10
1.4
0.2
100
11
V
V
V
nA
ns
ns
V
ISP
− V
ISN
= 100mV (100%), V
ISP
= 24V
V
ISP
− V
ISN
= 10mV (10%), V
ISP
= 24V
l
l
l
ELECTRICAL CHARACTERISTICS
CONDITIONS
V
SS
= 1V
V
SS
= 2V
MIN
TYP
20
2
0.2
1.7
MAX
UNITS
µA
µA
V
V
V
ISP
= V
ISN
= 20V
V
ISP
= 20V
V
FAULT
= 0.2V, V
FB
= 1.25V
V
FAULT
= 3V, V
FB
= 0.7V
l
1.117
1.140
50
150
1.163
V
mV
mV
mA
0.8
−100
1.240
1.266
22
0.980
80
1.000
100
1.020
120
100
1.292
nA
V
mV
V
mV
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:
Do not apply a positive or negative voltage source to these pins,
otherwise permanent damage may occur.
Note 3:
The LT3922E-1 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
LT3922I-1 is guaranteed to meet performance specifications over the
−40°C to 125°C operating junction temperature range. The LT3922H-1 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 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
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