el7531 Intersil Corporation, el7531 Datasheet - Page 3

• Manufacturer Part Number: el7531
• Description: Monolithic 1a Step-down Regulator With Low Quiescent Current
• Manufacturer: Intersil Corporation

SYNC
Pin Descriptions
Block Diagram
3.3V
EN
PIN NUMBER
+
–
10
1
2
3
4
5
6
7
8
9
470pF
10µF
C4
100Ω
0.1µF
100K
124K
V
V
FB
SYNC
EN
SGND
PIN NAME
DD
O
SGND
PGND
SYNC
VDD
VIN
PG
VO
EN
LX
FB
5M
REFERENCE
BANDGAP
CLOCK
START
SOFT-
3
+
10pF
-
Negative supply for the controller stage
Negative supply for the power stage
Inductor drive pin; high current digital output with average voltage equal to the regulator output voltage
Positive supply for the power stage
Power supply for the controller stage
SYNC input pin; when connected to HI, regulator runs at forced PWM mode; when connected to Low, auto
PFM/PWM mode; when connected to external sync signal, at external PWM frequency up to 12MHz
Enable
Power-Good open drain output
Output voltage sense
output
Voltage feedback input; connected to an external resistor divider between V
COMPENSATION
GENERATOR
VOLTAGE
LOCKOUT
UNDER-
POWER
GOOD
RAMP
PWM
EL7531
TEMPERATURE
COMPARATOR
COMPARATOR
CONTROL
ON-TIME
SENSE
+
PWM
PFM
+
PWM
-
-
PIN FUNCTION
CONTROL
LOGIC
INDUCTOR SHORT
SYNCHRONOUS
P-DRIVER
CURRENT
N-DRIVER
RECTIFIER
SENSE
+
+
-
-
O
PGND
and SGND for variable
V
PG
LX
IN
1.8µH
10µF
July 13, 2006
FN7428.9
100K
1.8V
0 TO 1A
PG