MAX1638 Datasheet, PDF (5/16 Pages) Maxim Integrated Products – High-Speed Step-Down Controller with Synchronous Rectification for CPU Power

High-Speed Step-Down Controller with
Synchronous Rectification for CPU Power
__________________________________________Typical Operating Characteristics
(T_A = +25°C, using the MAX1638 evaluation kit, unless otherwise noted.)
LOAD-TRANSIENT RESPONSE
WITHOUT GLITCHCATCHER (C_OUT = 880µF)
LOAD-TRANSIENT RESPONSE
WITHOUT GLITCHCATCHER (C_OUT = 440µF)
LOAD-TRANSIENT RESPONSE
WITH GLITCHCATCHER
A
B
10µs/div
V_IN = 5V, V_OUT = 2.0V, LOAD = 14A, 3A/µs
A: V_OUT, 50mV/div, AC COUPLED
B: INDUCTOR CURRENT, 10A/div
FOLDBACK CURRENT LIMIT
A
A
B
10µs/div
V_IN = 5V, V_OUT = 2.0V, LOAD = 14A, 3A/µs
A: V_OUT, 100mV/div, AC COUPLED
B: INDUCTOR CURRENT, 10A/div
START-UP WAVEFORMS
A
B
C
D
10µs/div
C_OUT = 440µF, V_IN = 5V, V_OUT = 2.0V, LOAD = 14A, 30A/µs
A: V_OUT, 100mV/div,
C: NDRV, 5V/div
AC COUPLED
D: INDUCTOR CURRENT,
B: PDRV, 5V/div
10A/div
SWITCHING WAVEFORMS
A
B
A
C
B
B
0
10µs/div
V_O = 2.0V NOMINAL
A: V_OUT = 0.5V/div
B: INDUCTOR CURRENT, 5A/div
400µs/div
A: V_OUT = 0.5V/div
B: INDUCTOR CURRENT, 5A/div
1µs/div
V_IN = 5V, V_OUT = 2.5V, LOAD = 5A
A: LX, 5V/div
C: INDUCTOR CURRENT,
B: V_OUT, 20mV/div, AC COUPLED 5A/div
EFFICIENCY vs. OUTPUT CURRENT
100
V_OUT = 3.5V
90
80
70
V_OUT = 1.3V
60
V_OUT = 2.0V
50
40
REFERENCE VOLTAGE
vs. OUTPUT CURRENT
5.094
4.594
4.094
SINKING
CURRENT
3.594
3.094
2.594
2.094
1.594
SOURCING
CURRENT
MAXIMUM DUTY CYCLE
vs. SWITCHING FREQUENCY
100
95
90
85
80
75
70
65
60
55
30
0.1
1.094
1
10
100
0.001
0.01
0.1
1
10
OUTPUT CURRENT (A)
OUTPUT CURRENT (mA)
50
0 200 400 600 800 1000 1200
SWITCHING FREQUENCY (kHz)
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