CAT32EKT Datasheet, PDF (2/11 Pages) ON Semiconductor – CMOS White LED Driver

CAT32
Typical Application Circuit
VIN
2.7 V
to
4.2 V
C1
4.7 mF
L₁ 6.8 mH
D1
6
1
VIN
SW
PWM
DIMMING
CONTROL
TSOT−23 Pin Numbers
CAT32
5
SHDN
3
LED
RSET
4
R_SET
1.50 kW
GND
2
15 mA
C1: Taiyo Yuden JMK212BJ475
C2: Taiyo Yuden EMK212BJ105
D1: Zetez ZHCS400
L1: Sumida CLQ4D106R8
(Panasonic ELJEA6R8)
C2
1 mF
Figure 1. Li−Ion Driver for Four High−Brightness White LEDs
Table 1. PIN DESCRIPTION
Pin Number
SOT23
Pin Number
TDFN
1
8
2
5
3
6
4
4
5
3
6
2
−
1
Name
SW
GND
LED
RSET
SHDN
VIN
Power
Ground
Function
Switch pin. This is the drain of the internal power switch. For minimum EMI, min-
imize the trace area connected to this pin.
Ground pin. Connect pin 2 to ground.
LED (cathode) connection pin.
RESET pin. A resistor connected from pin 4 to ground sets the LED current. This
pin is also used to dim the LEDs.
Shutdown pin.
Input supply pin. This pin should be bypassed with a capacitor to ground. A
4.7 mF capacitor mounted close to the pin is recommended.
Power Ground
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