LT3477EUF#TRPBF Linear Technology, LT3477EUF#TRPBF Datasheet - Page 13

• Manufacturer Part Number: LT3477EUF#TRPBF
• Description: IC LED DRVR HP CONST CURR 20-QFN
• Manufacturer: Linear Technology
• Type: High Power, Constant Currentr

Specifications of LT3477EUF#TRPBF

• Constant Current: Yes
• Constant Voltage: Yes
• Topology: Flyback, PWM, SEPIC, Step-Down (Buck), Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: General Purpose
• Type - Secondary: White LED
• Frequency: 200kHz ~ 3.5MHz
• Voltage - Supply: 2.5 V ~ 25 V
• Mounting Type: Surface Mount
• Package / Case: 20-QFN
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 3A
• Internal Switch(s): Yes
• Efficiency: 93%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -

APPLICATIONS INFORMATION
C1: NIPPON NTS40X5R1H225M
C2: TAIYO YUDEN GMK316BJ105ML
C3: TAIYO YUDEN LMK316BJ335KL
L1: TOKO D53LC (PN# A915AY-100M)
D1: ZETEX ZLLS400
D2: DIODES INC 1N4148
NMOS1, NM0S2: ZETEX 2N7002
PMOS: SILICONIX Si2303BDS
LED1 TO LED6: LUMILEDS LXHL-BW02
5V
0
100Hz
PWM
Figure 8a. 32V to 6 White LEDs: Buck Mode With PWM Dimming
100k
3.3V
V
500mA/DIV
500mA/DIV
PV
IN
32V
D2
IN
5V/DIV
PWM
I
LED
I
L
PV
6 LEDs
300mA
Figure 8b. PWM Dimming Waveforms
2.2μF
C3
3.3μF
C
33nF
IN
SS
C1
= 32V
NMOS1
C
0.1μF
C
SS
PWM FREQUENCY = 100Hz
BUCK MODE
I
V
I
I
SHDN
V
SP1
ADJ1
ADJ2
IN
C
I
2ms/DIV
SN1
LT3477
300mA
GND
PMOS
•
•
•
SW
R
0.33Ω
L1
10μH
3477 F08a
V
SENSE
I
I
FBN
FBP
SP2
SN2
REF
R
T
LED1
LED6
3477 F08b
1k
6.81k
1μF
C2
D1
NMOS2
1k
PWM
280k
10k
LT3477
13
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