US1206/1207/1208/1209

2-3

Rev. 1.1

6/26/00

Pin DescRIPTIONS

Pin DescRIPTIONS

PIN DESCRIPTION

A resistor divider from this pin to the Vout pin and ground sets

the output voltage.

An open collector output that switches low when the output

voltage drops about 4% below its expected regulated voltage.

The output of the regulator .A minimum of 2.2uF capacitor

must be connected from this pin to ground.

Ground pin. This pin must be connected to the lowest poten-

tial in the system & all other pins must be at higher potential

with respect to this pin.

Enable pin. A low signal or left open on this pin shuts down the

output.This pin must be tied HI or to Vin for normal operation.

The input pin of the regulator. Typically a large storage

capacitor is connected from this pin to ground to insure that

the input voltage does not sag below the minimumdrop out

voltage during the load transient response. This pin must al-

ways be 0.6V higher than Vout in order for thedevice to regu-

late properly.

APPLICATION INFORMATION

APPLICATION INFORMATION

Stability

The US120X series of regulators require the use of an

output capacitor as part of the frequency compensation

in order to make the regulator stable. A minimum of

2.2uF capacitance and the ESR in the range of 0.5 to 2

ohm insures the stability of the system.

Part Number

Output

Voltage

US1206-18

1.8V

US1206-25

2.5V

US1206-33

3.3V

US1207-18

1.8V

US1207-25

2.5V

US1207-33

3.3V

US1208

1.24V

US1209

1.24V

Table 1- Output voltage v.s. part number

Note 1 : Low duty cycle pulse testing with Kelvin con-

nections are required in order to maintain accurate data.

Note 2 : Drop-out voltage is defined as the minimum

differential voltage between Vin and Vout required to main-

tain regulation at Vout. It is measured when the output

voltage drops 1% below its nominal value.

US1207,1208

SYM

TEST CONDITION

MIN

TYP

MAX

UNITS

Ground Current-S.D Activated

Iqsd

Enable=0V

0.01

1

uA

Enable pin input LO voltage

Venl

Regulator OFF (Note 4)

0.8

V

Enable pin input HI voltage

Venh

Regulator ON (Note 4)

2

V

Enable pin input LO current

Venl=0V to 0.8V (Note 4)

0.1

2

uA

Enable pin input HI current

Venh=2V to Vin (Note 4)

100

600

uA

US1207,1209

Flag Output Threshold Voltage Vthfg

3.8

%Vo

Flag Output Hysterises Voltage Vhys

Output Ramping Up

0.8

%Vo

Flag Output Saturation Voltage Vfsat

Io=5mA

400

mV

Io=500uA

230

mV

Note 3 : Ground current is the the regulator quiescent

current plus the pass transistor current. The total cur-

rent from the supply is the sum of the load current plus

the ground pin current.

Note 4 : The specification applies for the junction tem-

perature of 0 to +125

°C.

PIN SYMBOL

Adj

US1208,1209

Flag

US1208

Vout

All devices

GND

All devices

Enable

US1207,1209

Vin

All devices