LT1937 LINER [Linear Technology], LT1937 Datasheet - Page 7

• Manufacturer Part Number: LT1937
• Description: 20mA LED Driver and OLED Driver with Integrated Schottky in 3mm x 2mm DFN
• Manufacturer: LINER [Linear Technology]

BLOCK DIAGRAM
PIN FUNCTIONS
V
Place a bypass capacitor from this pin to GND. See the
Applications Information section.
CAP2 (Pin 8): Output of the OLED Driver. This pin is
connected to the cathode of the internal Schottky diode.
Place a bypass capacitor from this pin to GND.
SW2 (Pin 9): Switch Pin. This is the collector of the in-
ternal NPN power switch. Minimize the metal trace area
connected to this pin to minimize EMI.
V
passed.
10 F
C3
OUT2
IN
2.21M
R
FB2
(Pin 10): Input Supply Pin. Must be locally by-
C2
0.47 F
(Pin 7): Drain of Output Disconnect PMOS.
8
7
CAP2
V
OUT2
DISCONNECT
CONTROL
CONTROL
SHUNT
Q2
9
4
SW2
GND2
DRIVER
182k
10 F
L2
A5
CONTROL
SWITCH
+
+
–
FB2
6
5
C
4.7 F
CTRL2
IN
START-UP
CONTROL
VREF
10
V
IN
SW1 (Pin 11): Switch Pin. Connect the inductor of the
white LED driver at this pin. Minimize metal trace area at
this pin to minimize EMI.
CAP1 (Pin 12): Output of the White LED Driver. This pin is
connected to the cathode of the internal Schottky. Connect
the output capacitor to this pin and the sense resistor from
this pin to the LED1 pin.
Exposed Pad (Pin 13): Ground. The Exposed Pad must
be soldered to the PCB.
OSCILLATOR
GENERATOR
–
+
2.3MHz
RAMP
A2
COMPARATOR
R
C
C
15 F
C
L1
R
A1
S
–
+
+
Q
CTRL1 GND1
DRIVER
A3
2
+
–
SW1
11
3
Q1
R
OVERVOLTAGE
PROTECTION
A4
+
–
CAP1
LED1
LT3498
3498 BD
12
1
R
10
SENSE1
1 F
C1
7
3498f