Rainbow Electronics MAX849 - Manual (Page 7)

MAX848/MAX849
1-Cell to 3-Cell, High-Power,
Low-Noise, Step-Up DC-DC Converters
_______________________________________________________________________________________ 7
Typical Operating Characteristics (continued)
(T A = +25°C, unless otherwise noted.)
V IN = 3.6V, V OUT = 5V, C OUT = 440 µ F
A = V OUT RIPPLE, 200mV/div, AC COUPLED
B = LOAD CURRENT, 100mA TO 1A, 0.5A/div,
PULSE WIDTH = 577
µ s
MAX849
GSM LOAD-TRANSIENT RESPONSE
A
5V
0A
B
1ms/div
MAX848/9 TOC-14
V IN = 1.2V, V OUT = 3.3V, C OUT = 440 µ F
A = V OUT RIPPLE, 200mV/div, AC COUPLED
B = LOAD CURRENT, 50mA TO 400mA, 0.2A/div,
PULSE WIDTH = 416
µ s
MAX849
DECT LOAD-TRANSIENT RESPONSE
A
B
3.3V
0A
2ms/div
MAX848/9 TOC-15
2.7
0.1k 1k 10k 100k 1M
MAX849 NOISE SPECTRUM
(V
OUT
= 3.3V, V
IN
= 1.2V, R
LOAD
= 50 Ω )
0
MAX848/9 TOC-16
FREQUENCY (Hz)
NOISE (mV
RMS
)
380
280
-40 100
MAX849 INTERNAL OSCILLATOR
FREQUENCY vs. TEMPERATURE
360
MAX848/9 TOC-17
TEMPERATURE (°C)
INTERNAL OSC. FREQUENCY (kHz)
20
320
300
-20 0 60
340
40 80
V OUT = 5V
V OUT = 3.3V
1.2
2.5 3.5 3.0 4.0 5.5 5.0
MAX849 PEAK INDUCTOR CURRENT
vs. OUTPUT VOLTAGE
1.4
1.8
2.0
MAX848/9 TOC-18
OUTPUT VOLTAGE (V)
PEAK INDUCTOR CURRENT (A)
4.5
1.6
1.3
1.7
1.5