Rainbow Electronics MAX1688 - Manual (Page 5)

MAX1687/MAX1688
Step-Up DC-DC Converters with
Precise, Adaptive Current Limit for GSM
_______________________________________________________________________________________ 5
Typical Operating Characteristics (continued)
( V IN = +3.3V, V OUT = 5V, V LIM = 1V, Figures 6b and 7, T A = +25°C, unless otherwise noted. )
500mA/div
500mA/div
200mV/div
V OUT
1ms/div
I LX
I LOAD
MAX1688
SWITCHING WAVEFORMS
(GSM PULSED LOAD 1A, R CHG = 40.2k Ω )
MAX1687/88 toc11
R CHL = 40.2k Ω , L = 10 µ H
200mA/div
0A
V LIM = 1V
V LIM = 0
2 µ s/div
I LX
I LX
INDUCTOR CURRENT
MAX1687/88 toc13
200mA/div
1V/div
I BATTERY
V ON
10 µ s/div
MAX1687/88 toc15
V ON vs. BATTERY CURRENT
2V/div
1V/div
V ON
V OUT
5ms/div
MAX1687/88 toc14
POWER-UP WAVEFORM
(R LOAD = 15 Ω C OUT = 2000 µ F)
500mA/div
500mA/div
200mV/div
V OUT
1ms/div
I LX
I LOAD
MAX1688
SWITCHING WAVEFORMS
(GSM PULSED LOAD 1A, R CHG = 18k Ω )
MAX1687/88 toc12
R CHG = 18k Ω , L = 10 µ H
500mA/div
100mV/div
V OUT
500 µ s/div
I LX
SWITCHING WAVEFORMS
(FIXED I LOAD = 300mA)
MAX1687/88 toc10a