0.5A Step-Down Switching Regulator
TC2574
Feedback
7.0 – 40V
Unregulated
DC Input
+VIN
CIN
22µF
1
TC2574
2
Sig 4
GND
Output
L1
330µH
5.0V Regulated
Output 0.5A Load
D1 COUT
220µF
+
5
7
PWR 3 ON/OFF
GND
Figure 1. Block Diagram and Typical Application: Fixed Output Versions
Test CIrcuit and Layout Guidelines
1
TC2574
Fixed Output
4
PWR 2
GND
Sig 3
GND
Output
7
ON/OFF
D1
1N5819
L1
330µH
VIN
5
7.0 – 40V
Unregulated
DC Input
+ C
IN
22µF
VOUT
COUT
220µF
+
Load
CIN
COUT
D1
L1
R2
- 22µF, 60V, Aluminum Electrolytic
- 220µF, 25V, Aluminum Electrolytic
- Schottky, 1N5819
- 2.0k,0.1%
- 6.12k, 0.1%
Adjustable Output Voltage Versions
1
TC2574
Adjustable
4
+
CIN
22µF
PWR 2
GND
Sig 3
GND
Output
7
ON/OFF
+
D1
1N5819
COUT
220µF
L1
330µH
VIN
5
7.0 – 40V
Unregulated
DC Input
VOUT
5.0V
R2
6.12k Load
R2
6.12k
VOUT = VREF
R1= R2
(
1.0 + R2
R1
)
(
VOUT - 1.0
)
VREF
Where VREF = 1.23V, R1
between 1.0kΩ and 5.0kΩ
Figure 2. Test Circuit and Layout Guidelines
TC2574-1 1/6/00
5
TELCOM [ TELCOM SEMICONDUCTOR, INC ]
