Nuvoton
500mA Linear Regulator
NCT3705U Series
NCT3705U
-Table of Content-
1.
2.
3.
4.
5.
6.
GENERAL DESCRIPTION .............................................................................................................. 1
FEATURES ...................................................................................................................................... 1
BLOCK DIAGRAM ........................................................................................................................... 2
PIN CONFIGURATION AND TYPICAL APPLICATION CIRCUIT .................................................. 4
PIN DESCRIPTION.......................................................................................................................... 5
FUNCTIONAL DESCRIPTION ........................................................................................................ 6
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
7.
OUTPUT VOLTAGE AND DROPOUT VOLTAGE ................................................................... 6
NOISE ....................................................................................................................................... 6
PSRR ........................................................................................................................................ 6
LOAD REGULATION CONSIDERATION ................................................................................ 7
CURRENT LIMIT PROTECTION ............................................................................................. 8
V
IN
& V
OUT
CAPACITOR SELECTION ...................................................................................... 8
OVER TEMPERATURE PROTECTION................................................................................... 8
LAYOUT NOTE......................................................................................................................... 9
THERMAL CONSIDERATION.................................................................................................. 9
ELECTRICAL CHARACTERISTIC ................................................................................................ 10
7.1
7.2
7.3
7.4
ABSOLUTE MAXIMUM RATINGS ......................................................................................... 10
THERMAL INFORMATION .................................................................................................... 11
RECOMMENDED OPERATING CONDITIONS..................................................................... 11
ELECTRICAL CHARACTERISTICS....................................................................................... 11
8.
9.
10.
11.
12.
TYPICAL OPERATING WAVEFORMS ......................................................................................... 13
PACKAGE DIMENSION ................................................................................................................ 17
TAPING SPECIFICATION.......................................................................................................... 17
ORDERING INFORMATION ...................................................................................................... 18
TOP MARKING SPECIFICATION.............................................................................................. 18
REVISION HISTORY ................................................................................................................. 19
-I-
Publication Date: Dec., 2008
Revision A1
NCT3705U
1.
GENERAL DESCRIPTION
The NCT3705U is a low supply current and low dropout linear regulator which provides
500mA power for battery-powered application such as notebook computers, cellular phones,
and handheld devices. An over current protection and an over-temperature protection circuit
were built-in the chip to prevent current and thermal overload. Featured low noise, high PSRR
and low dropout make it ideal for audio codec and handheld devices. It comes in a space
saving SOT-23-5 package and suitable for handheld applications.
The NCT3705U has two versions for different operation circuits. In fixed mode, the SET pin is
connected to ground. The output voltage is a preset value. There is no external component
required. When an output other than the preset value is needed, two external resistors should
be used as an output voltage divider and operates in adjustable mode. The output voltage can
be adjusted by the resistor ratio and regulates from 1.25V to 5.0V.
2. FEATURES
2.1.
General
Guaranteed 500mA Output Current
Low Ground Current 90uA @ No Load (Typical)
70dB PSRR @ 10mA, 100Hz
Low Dropout Voltage 145mV @ 150mA (V
OUT
= 5V)
Low Output Noise 28u Vrms @ 1mA with Bypass Capacitor
Excellent Load Regulation & Line Regulation
Short Circuit Protection & Over Current Protection
Over Temperature Protection
Stable with Low ESR Capacitor
0℃ to 70℃ Ambient Operating Temperature Range
2.2.
Package
SOT23-5 Green Package (Lead Free and Halogen Free)
-1-
Publication Date: Dec., 2008
Revision A1
WindowsCE
