CMPWR280TO datasheet(3/11 Pages) ONSEMI

3 / 11 page

CMPWR280

http://onsemi.com

PACKAGE / PINOUT DIAGRAM

Top View

5−Pin TO−263

CMPWR280TO/TN

VOUT

DRIVE

VSBY

VCC

GND

Table 1. PIN DESCRIPTIONS

Pin(s)

Name

Description

VSBY

VSBY is the standby 5 V supply power source, which is only selected on when VCC < VCCDES. If VSBY is

selected, the regulator can deliver a maximum of 375 mA load current. Whenever VSBY exceeds both VCC

and VOUT, it will be used to provide all the internal bias currents and any necessary regulator current.

VCC

VCC is the primary 5 V power supply for the internal regulator. Whenever VCC exceeds VCCSEL (4.5 V), the

internal regulator (up to 1500 mA) will be enabled and deliver a fixed 3.3 V at VOUT. When VCC falls below

VCCDES (4.1 V typically) the regulator will be disabled.

Internal loading on this pin is typically 1.5 mA when the regulator is enabled, which reduces to 0.2 mA

whenever the regulator is disabled. If VCC falls below either the VSBY or VOUT voltage, the loading on VCC will

reduce to only a few microamperes.

During a VCC power up sequence, there will be an effective step increase in VCC line current when the

regulator is enabled. The amplitude of this step increase will depend on the dc load current and any current

required for charging/discharging the load capacitance. This line current transient will cause a voltage

disturbance at the VCC pin proportional to the effective power supply source impedance being delivered to the

VCC input.

To prevent chatter during Select and Deselect transitions, a built−in hysteresis voltage of 400 mV has been

incorporated. It is recommended that the power supply connected to the VCC input should have a source

impedance of less than 0.15 W to minimize the chatter during the enabling/disabling of the regulator.

GND

GND is the negative reference for all voltages. The current that flows in the ground connection is very low

(typically 2.0 mA) and has minimal variation over all load conditions.

VOUT

VOUT is the regulator output voltage connection used to power the load. An output capacitor of ten

microfarads is used to provide the necessary phase compensation, thereby preventing oscillation. The

capacitor also helps to minimize the peak output disturbance during power supply changeover.

When both VCC and VSBY falls below VOUT, then VOUT will be used to provide the necessary quiescent

current for the internal reference circuits. This ensures excellent start−up characteristics for the regulator.

DRIVE

Drive is an active LOW logic output intended to be used as the control signal for driving an external

P−channel MOSFET switch whenever the regulator is disabled. This will allow the voltage at VOUT to be

powered from an auxiliary supply voltage (3.3 V).

The Drive pin is pulled HIGH to VCC whenever the regulator is enabled, thus ensuring that the auxiliary supply

remains isolated during normal regulator operation.

SPECIFICATIONS

Table 2. STANDARD OPERATING CONDITIONS

Parameter

Rating

Units

VCC, VSBY Input Voltage

4.75 to 5.25

Ambient Operating Temperature Range

0 to +70

C

CEXT

10 10%

CMPWR280TO 数据表(PDF) 3 Page - ON Semiconductor

CMPWR280TO 数据表(HTML) 3 Page - ON Semiconductor

Html Pages

1 2 3 4 5 6 7 8 9 10 11

数据表下载