CAT37 Datasheet, PDF (2/11 Pages) Catalyst Semiconductor – CMOS White LED Driver Boost Converter

CAT37
Typical Application Circuit
VIN
3 V to 5 V
L1 6.8 mH D1
C1
1 mF
5
1
VIN
SW
ON _OFF
CAT37
4
SHDN
GND
2
3
FB
C2
1 mF
15 mA
C1: Taiyo Yuden JMK212BJ475
C2: Taiyo Yuden EMK212BJ105
L1: Panasonic ELJEA6R8 or equivalent
R₁
6.34 W
Figure 1. Driver for Four High−Brightness White LEDs
Table 1. PIN DESCRIPTION
Pin Number
Name
Function
1
SW
Switch pin. This is the drain of the internal power switch. For minimum EMI, minimize the trace area
connected to this pin.
2
GND
Ground pin. Connect pin 2 to ground.
3
FB
LED (cathode) connection pin.
4
SHDN Shutdown pin.
5
VIN
Input supply pin. This pin should be bypassed with a capacitor to ground. A 1 mF capacitor mounted
close to the pin is recommended.
Table 2. ABSOLUTE MAXIMUM RATINGS
Parameter
Rating
Unit
V_IN, FB, SHDN voltage
SW voltage
8
V
20
V
Storage Temperature Range
−65 to +160
°C
Junction Temperature
125
°C
Lead Soldering Temperature (10 secs)
300
°C
ESD Rating – Human Body Model
2000
V
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
Table 3. RECOMMENDED OPERATING CONDITIONS
Parameter
V_IN
Ambient Temperature Range
Inductor L1
Input Capacitor C1
Output Capacitor C2
I_LED with 1 to 4 LEDs in series
NOTE: Typical application circuit with external components is shown above.
Range
Unit
2.5 to 7
V
−40 to +85
°C
6.8 ± 20% typical
mH
1.0 ± 20% typical
mF
1.0 ± 20% typical
mF
0 to 20
mA
http://onsemi.com
2