1- to 3-Cell, High-Current, Low-Noise,
Step-Up DC-DC Converters with Linear Regulator
MAX1705/MAX1706
____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 2, T
A
= +25°C, unless otherwise noted.)
MAX1705
LINE-TRANSIENT RESPONSE
MAX1705/6 TOC15
MAX1705
LOAD-TRANSIENT RESPONSE
MAX1705/6 TOC16
MAX1705
POWER-ON DELAY
(PWM MODE)
MAX1705/6 TOC17
3V
2.5V
A
A
B
C
A
3.3V
B
B
D
200µs/div
I
OUT
= 0mA, V
OUT
= 3.3V
A = V
IN
, 1.5V TO 2.0V, 200mV/div
B = V
OUT,
10mV/div, 3.3V DC OFFSET
200µs/div
V
IN
= 1.2V, V
OUT
= 3.3V
A = V
OUT
, 50mV/div, 3.3V DC OFFSET
B = I
OUT
, 0mA TO 200mA, 200mA/div
200µs/div
V
IN
= 1.2V, LOAD = 1kΩ
A = ONA, 2V/div
B = V
LDO
, 2V/div
C = V
OUT
, 2V/div
D = INDUCTOR CURRENT, 500mA/div
0mA
MAX1705
PWM SWITCHING WAVEFORMS
MAX1705/6 TOC18
MAX1705
PFM SWITCHING WAVEFORMS
MAX1705/6 TOC19
MAX1705
LINEAR-REGULATOR
OUTPUT NOISE
DC TO 500kHz
0mA
MAX1705/6 TOC20
A
B
1A
A
0V
B
0V
V
OUT
C
V
OUT
C
V
LDO
D
V
LDO
D
V
LDO
2µs/div
V
IN
= 1.2V, V
OUT
= 4.5V, V
LDO
= 3.3V, I
LDO
= 40mA
A = INDUCTOR CURRENT, 500mA/div
B = LX VOLTAGE, 5V/div
C = V
OUT
RIPPLE, 50mV/div AC COUPLED
D = V
LDO
RIPPLE, 5mV/div AC COUPLED
C5 = 0.33µF
1ms/div
V
LDO
IS AC COUPLED, 1mv/div
I
LDO
= 200mA
C5 = 0.33µF
1µs/div
V
IN
= 1.2V, V
OUT
= 4.5V, V
LDO
= 3.3V, I
LDO
= 200mA
A = INDUCTOR CURRENT, 500mA/div
B = LX VOLTAGE, 5V/div
C = V
OUT
RIPPLE, 50m/div AC COUPLED
D = V
LDO
RIPPLE, 5m/div AC COUPLED
C5 = 0.33µF
8
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MAXIM [ MAXIM INTEGRATED PRODUCTS ]
