Rainbow Electronics MAX1557 - Manual (Page 7)

MAX1556/MAX1557
16µA I Q , 1.2A PWM DC-DC
Step-Down Converters
_______________________________________________________________________________________ 7
LX
SS
ON
OFF SHDN
GND
INPUT
2.6V TO 5.5V
VOLTAGE
SELECT
OUTPUT
0.75V TO V
IN
PGND
C1
10 µF
C4
0.47 µF
R1
100 Ω
C2
22 µF
C3
1000pF
L1
3.3 µH
OUT
INP
IN
1.2A
D1
D2
MAX1556
Figure 2. MAX1556 Typical Application Circuit
Figure 1. Functional Diagram
LX
SS
ON
OFF SHDN
GND
INPUT
2.6V TO 5.5V
VOLTAGE
SELECT
OUTPUT
0.75V TO V IN
PGND
C4
10 µF
C5
22 µF
C6
1000pF
L2
4.7 µH
OUT
INP
IN
600mA
D1
D2
MAX1557
Figure 3. MAX1557 Typical Application Circuit
PWM
COMPARATOR
ERROR
AMPLIFIER
CURRENT-LIMIT
COMPARATOR
0.675V
CURRENT
SENSE
SLOPE
COMP
CLOCK
1MHz
INP
LX
PGND
SS
GND
PWM
AUTO SKIP
CONTROL
SKIP-OVER
ENTER SKIP/
SR OFF
V CS
ZERO-CROSS
DETECT
SHORT-CIRCUIT
PROTECTION
REFERENCE
1.25V
OUT
D1
D2
SHDN
IN
BIAS
OUTPUT
VOLTAGE
SELECTOR
MAX1556
MAX1557