GM7230_13 Datasheet, PDF (7/11 Pages) Gamma Microelectronics Inc. – 150KHz, 3A STEP DOWN VOLTAGE SWITCHING REGULATORS

GM7230
150KHz, 3A STEP DOWN VOLTAGE
SWITCHING REGULATORS
Test Circuit and Layout Guidelines
Careful layout is important with any switching regulators. Rapidly switching currents associated with
wiring inductance generate voltage transients which can cause problems. To minimize inductance
and ground loops, the lengths of the leads indicated by heavy lines in Figure 1&2 below should be
kept as short as possible. Single point grounding (as indicated or ground plane construction should
be used for best results. When using the Adjustable version, place the programming resistors as
close as possible to GM7230, to keep the sensitive feedback wiring short.
1
VIN
VIN
Unregulatedd
DC Input
CIN
100μF
4
GM7230-x.x
3
5
Feedback _L1
68μH
2
VOUT
D1
GND
ON/OFF
VOUT
COUT
L
680μF ^O
A
D
Figure 1 Fixed Ouput Votlage Versions
CIN = 470μF, Aluminum Electrolytic
COUT = 220μF, 25V, Aluminum Electrolytic
D1 = Schottky, 5A/40V
L1 = 68μH
1
VIN
VIN
Unregulatedd
DC Input
CIN
100μF
GM7230-A
3
GND
4
Feedback
2
L1
68μH
5
VOUT
ON/OFF
D1
COUT
680μF
VOUT
R2 _L
O
A
R1 _D
Figure 2 Adjustable Ouput Votlage Versions
CIN = 470μF, Aluminum Electrolytic
COUT = 220μF, 25V, Aluminum Electrolytic
D1 = Schottky, 5A/40V
L1 = 68μH
VOUT = VREF (1 + R2/R1)
7