LT3922
Typical perForMance characTerisTics VIN = 12V, TA = 25°C, u nless otherwise noted.
FB OPENLED Threshold
VISP – VISN SHORTLED Threshold
Power Switch On-Resistance
1.20
1.15
1.10
1.05
1.00
0.95
0.90
180
170
160
150
140
130
120
350
300
250
200
150
100
50
RISING
FALLING
TOP SWITCH
BOTTOM SWITCH
0
–45 –20
5
30 55 80 105 130 155
–45 –20
5
30 55 80 105 130 155
–45 –20
5
30 55 80 105 130 155
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
3922 G28
3922 G29
3922 G30
Efficiency vs VIN
Efficiency vs ILED
Regu lated FB Voltage
100
98
96
94
92
90
88
86
84
82
80
100
98
96
94
92
90
88
86
84
82
80
1.23
1.22
1.21
1.20
1.19
1.18
I
= 400mA
V
SW
= 12V
= 2MHz
LED
IN
11 LEDs (V
~ 33V)
f
OUT
6 LED (V
~ 18V)
~ 27V)
~ 36V)
OUT
OUT
OUT
9 LED (V
f
= 400kHz
= 2MHz
SW
12 LED (V
f
SW
6
8
10 12 14 16 18 20 22 24 26 28 30
(V)
0
200
400
600
800
1000
–45 –20
5
30 55 80 105 130 155
V
I
(mA)
LED
TEMPERATURE (°C)
IN
3922 G31
3922 G32
3922 G33
PWMTG ON Voltage
PWM Driver Propagation Delay
FB OVLO Threshold
12
11
10
9
200
160
120
80
1.33
1.30
1.27
1.24
1.21
1.18
RISING
FALLING
TURN OFF
TURN ON
8
C
= 2.2nF (C0G type)
PWMTG
7
40
–45 –20
5
30 55 80 105 130 155
–45 –20
5
30 55 80 105 130 155
–45 –20
5
30 55 80 105 130 155
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
3922 G34
3922 G36
3922 G35
3922f
8
For more information www.linear.com/LT3922
Linear Systems [ Linear Systems ]
