GM7130-12TA5R GAMMA [Gamma Microelectronics Inc.], GM7130-12TA5R Datasheet - Page 10

• Manufacturer Part Number: GM7130-12TA5R
• Description: 3A STEP-DOWN VOLTAGE SWITCHING REGULATORS
• Manufacturer: GAMMA [Gamma Microelectronics Inc.]

10
Typical Performance Characteristics
150
100
Inductor
90
80
70
60
50
45
40
35
30
25
20
Current
0.3
1A/ div
40
20
15
10
8
7
6
5
E • T = (V
0.3 0.4 0.5 0.6 0.8
MICROELECTRONICS
0.4 0.5 0.6 0.7 0.8 1.0
Figure 14. GM7130 -3.3
A
MAXIMUM LOAD CURRENT(A)
Figure 17. GM7130 - ADJ
MAXIMUM LOAD CURRENT(A)
IN
Figure 12. Switching Waveforms
- V
OUT
)
1
V
A
V
OUT
1.5
IN
2
•
1.5
F(in kHz)
2.5
1,000
2..0 2.5 3.0
3
40
35
30
25
20
18
16
15
14
0.3
3A STEP-DOWN VOLTAGE SWITCHING REGULATORS
0.4 0.5 0.6 0.70.8 1.0
Input
Output : 5V @3A
MAXIMUM LOAD CURRENT(A)
Figure 15. GM7130 - 12
PROCEDURE(Adjustable Output Voltage Versions)
Given:
V
V (Max) = Maximum Input Voltage
I
F = Switching Frequency (Fixed at 52 kHz)
1. Programming Output Voltage(Selecting R1 and R2, as shown in Figure 12.
And Figure 13.
Use the following formula to select the appropriate resistor values.
R can be between 1k and 5k. (For best temperature coefficient and stability
with time, use 1% metal film resistors)
EXAMPLE (Adjustable Output Voltage Versions)
Given:
V
V (Max) = 25V
I
F = 52kHz
1. Programming Output Voltage (Selecting R1 and R2)
R = 1k (8.13 - 1) = 7.13k, closest 1% value is 7.15k
Power Management
680µH
LOAD
LOAD
OUT
IN
OUT
IN
: 12V
1
2
Change
Voltage
Current
Output
(Max) = Maximum Load Current
(Max) =3A
= Regulated Output Voltage
= 10V
Load
470µH
V
V
R = R (
OUT
OUT
2
330µH
220µH
1.5
= V
150µH
= 1.23 (1+
Figure 13. Load Transient Response
1
REF
2.0 2.5 3.0
V
V
100µH
OUT
REF
R2 = R1 (
68µH
( 1+
3A
10mA
-1) = 1k (
R2
R1
R2
R1
)
)
V
V
OUT
REF
Select R1 = 1k
40
20
15
12
10
where V
9
8
7
0.3 0.4 0.5 0.60.8
1.23V
10V
-1)
MAXIMUM LOAD CURRENT(A)
Figure 16. GM7130 -5.0
-1)
REF
= 1.23V
GM7130
1 1.2 1.5
1kHz
100mv/ div
2
2.5 3