Rainbow Electronics MAX8715 - Manual (Page 6)

500mA
20mA
CH1 = LOAD CURRENT, 500mA/div
CH2 = OUTPUT VOLTAGE, AC-COUPLED, 200mV/div
CH3 = INDUCTOR CURRENT, 1A/div
V
OUT = 5V, f OSC = 640kHz, C OUT = 47 µF + 0.1µF
100 µs/div
MAX1790 LOAD-TRANSIENT RESPONSE
MAX1790 toc10
CH1
CH2
CH3
R COMP = 62k Ω
C COMP = 820pF
C COMP2 = 56pF
100 µs/div
MAX1790 STARTUP WAVEFORM
WITHOUT SOFT-START
MAX1790 toc11
CH1
CH2
CH3
CH1 = SHDN, 5V/div
CH2 = OUTPUT VOLTAGE, 5V/div
CH3 = INDUCTOR CURRENT, 1A/div
V
IN = 3.3V, V OUT = 12V, I OUT = 10mA, f OSC = 640kHz
NO SOFT-START CAPACITOR, C OUT = 33 µF
1ms/div
STARTUP WAVEFORM
WITH SOFT-START
MAX1790 toc12
CH1
CH2
CH3
CH1 = SHDN, 5V/div
CH2 = OUTPUT VOLTAGE, 5V/div
CH3 = INDUCTOR CURRENT, 200mA/div
V
OUT = 12V, I OUT = 10mA, f OSC = 640kHz,
C SS = 0.027 µF, C
OUT = 33 µF
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V
IN
= 3.3V, f
OSC
= 640kHz, T
A
= +25°C, unless otherwise noted.)
200mA
10mA
CH1
0
CH2
CH3
CH1 = LOAD CURRENT, 200mA/div
CH2 = OUTPUT VOLTAGE, AC-COUPLED, 100mV/div
CH3 = INDUCTOR CURRENT, 500mA/div
V
IN = 3.3V, V OUT = 9.0V
f OSC = 1.2MHz, L = 6.8 µH, C
OUT = 3 x 3.3 µF
40 µs/div
MAX8715 LOAD-TRANSIENT RESPONSE
MAX1790 toc07
R COMP = 82k Ω
C COMP = 750pF
C COMP2 = 10pF
1A
40mA
CH1
CH2
CH3
CH1 = LOAD CURRENT, 1A/div
CH2 = OUTPUT VOLTAGE, AC-COUPLED, 100mV/div
CH3 = INDUCTOR CURRENT, 500mA/div
V
IN = 3.3V, V OUT = 9.0V
f OSC = 1.2MHz, L = 6.8 µH, C
OUT = 3 x 3.3 µF
10 µs/div
MAX8715
PULSED LOAD-TRANSIENT RESPONSE
MAX1790 toc08
200mA
10mA
CH1
CH2
CH3
CH1 = LOAD CURRENT, 100mA/div
CH2 = OUTPUT VOLTAGE, AC-COUPLED, 200mV/div
CH3 = INDUCTOR CURRENT, 1A/div
V
IN = 3V
V OUT = 12V, f OSC = 640kHz, C OUT = 33 µF + 0.1µF
100 µs/div
MAX1790 LOAD-TRANSIENT RESPONSE
MAX1790 toc09 R COMP = 120k Ω
C COMP = 1200pF
C COMP2 = 56pF
MAX1790/MAX8715
Low-Noise Step-Up DC-DC Converters
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