ncp1509 ON Semiconductor, ncp1509 Datasheet - Page 2

• Manufacturer Part Number: ncp1509
• Description: Up To 500 Ma, 1 Mhz, High Efficiency Synchronous Step-down Dc-dc Converter In Dfn Package
• Manufacturer: ON Semiconductor

GNDA
PIN FUNCTION DESCRIPTION
Number
SHD
CB0
CB1
FB
Pin
10
1
2
3
4
5
6
7
8
9
6
1
7
8
9
GNDA
GNDP
Name
VCCP
VCCA
SYNC
SHD
CB0
CB1
REFERENCE
LX
FB
COMPENSATION
AND SOFT
BANDGAP
ENABLE
DETECT
SELECT
LOGIC
START
RAMP
Power Output
Analog GND
Analog Input
Analog Input
Analog Input
Analog Input
Analog Input
Power GND
Power Input
Power Input
Type
SHUTDOWN
THERMAL
−
+
−
CMP
+
−
CMP
+
Figure 3. Simplified Block Diagram
OA
Ground connection for the Analog Section of the IC. This is the GND for the FB, SYNC,
CB0, CB1, PG and ENABLE pins.
Ground connection for the N−FET Power Stage.
Connection from Power MOSFETs to the Inductor.
Power Supply Input for the Switching P−FET.
Power Supply Input for the Analog Section of the IC.
Feedback voltage from the output of the power supply.
V
V
Enable for Switching Regulator. This pin is active high to turn on the NCP1509. This pin
contains an internal pulldown resistor.
Synchronization input for the PWM converter. If a clock signal is present, the converter
uses the rising edge for the turn on of the PFET. If this pin is low, the converter is in Low
Iq Pulse mode. If this pin is high, the converter uses the internal oscillator for the PWM
mode. This pin has an internal pulldown resistor to force the operation into the Pulse
mode.
out
out
Selection Pin. This pin contains a pulldown resistor.
Selection Pin. This pin contains a pullup resistor.
PWM
OVP
PM
http://onsemi.com
CMP
+
−
ISENS
2
CONTROL
(PWM,PM)
BLOCK
MODE SELECTION
ILIM
CMP
+
−
Description
SENFET
ZCL
TIMING BLOCK
TIMING BLOCK
SYNC DETECT
SYNC DETECT
SWITCHING
SWITCHING
DVR
CONTROL
CONTROL
DAMPING
DAMPING
AND
AND
CMP
DVR
ISENS
−
+
Q1
Q2
10
5
4
3
6
2
VCCA
VCCP
GNDP
SYNC
FB
LX