ncp1536 ON Semiconductor, ncp1536 Datasheet - Page 2

• Manufacturer Part Number: ncp1536
• Description: 3.0 A, Step-down Switching Regulator
• Manufacturer: ON Semiconductor

PIN FUNCTION DESCRIPTION
Pin
1
2
3
4
5
DC Input
Feedback
R1
R2
ON/OFF
Symbol
Output
C
GND
in
V
in
Feedback
This pin is the positive input supply for the NCP1536 step−down switching regulator. In order to minimize voltage
transients and to supply the switching currents needed by the regulator, a suitable input bypass capacitor must be
present (C
This is the emitter of the internal switch. The saturation voltage V
be kept in mind that the PCB area connected to this pin should be kept to a minimum in order to minimize coupling to
sensitive circuitry.
Circuit ground pin. See the information about the printed circuit board layout.
This pin is the direct input of the error amplifier and the resistor network R2, R1 is connected externally to allow pro-
gramming of the output voltage.
It allows the switching regulator circuit to be shut down using logic level signals, thus dropping the total input supply
current to approximately 80 mA. The threshold voltage is typically 1.4 V. Applying a voltage above this value (up to
+V
will be in the “on” condition.
in
+V
) shuts the regulator off. If the voltage applied to this pin is lower than 1.4 V or if this pin is left open, the regulator
1
4
in
in
in Figure 1).
Band−Gap
Reference
Representative Block Diagram and Typical Application
1.235 V
Fixed Gain
Error Amplifier
18 kHz
Freq
Shift
This device contains 162 active transistors.
Oscillator
52 kHz
Comparator
3.1 V Internal
Figure 1. Block Diagram
Regulator
http://onsemi.com
NCP1536
Description (Refer to Figure 1)
Reset
Latch
2
Current
Limit
ON/OFF
Shutdown
Driver
Thermal
sat
1.0 Amp
Switch
of this output switch is typically 1.5 V. It should
ON/OFF
Output
GND
5
2
3
D1
L1
C
out
Load
V
out