ST778 datasheet(3/11 Pages) STMICROELECTRONICS

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ST777/778/779

3/11

ELECTRICAL CHARACTERISTICS (VIN=2.5V, CI = 22µF, CO=100µF, SHDN and ILIM connected to IN,

AGND connected to PGND, TA=0 to 85°C, unless otherwise specified. Typical values are referred at

TA=25°C)

Note 1: Output in regulation, VOUT =VOUT (nominal) ± 4%.

Note 2: At hight VIN to VOUT differentials, the maximum load current is limited by the maximum allowable power dissipation in the package.

Note 3: Start-up guaranteed under these load conditions.

Note 4: Minimum value is production tested. Maximum value is guaranteed by design and is not production tested.

Note 5: In the ST779 supply current depends on the resistor divider used to set the output voltage.

Note 6: VOUT is set to a target value of +5V by 0.1% external feedback resistors. VOUT is measured to be 5V±2.5% to guarantee the error

comparator trip point.

Symbol

Parameter

Test Conditions

Min.

Typ.

Max.

Unit

VSTART

Start up Voltage

ILOAD < 10mA, TA = 25°C (Note 1)

VIN(MAX)

Maximum Input Voltage

(Note 1,2)

Output Voltage ST777 779

(set to 5V), (Note 3)

ILOAD≤ 30mA, VIN = 1.1V to 5V or

ILOAD≤ 80mA, VIN = 1.8V to 5V or

ILOAD≤ 130mA, VIN = 2.4V to 5V

4.8

5.0

5.2

Output Voltage ST778

(Note 3)

SEL=0V

ILOAD≤ 50mA,VIN =1.1V to 3.3V or

ILOAD≤ 210mA,VIN =1.8V to 3.3V or

ILOAD≤ 300mA,VIN =2.4V to 3.3V

3.17

3.30

3.43

SEL=OPEN

ILOAD≤ 30mA, VIN =1.1V to 3V or

ILOAD≤ 210mA, VIN =1.8V to 3V or

ILOAD≤ 300mA, VIN =2.4V to 3V

2.88

3.00

3.12

Output Voltage Range

ST779

(Note 4)

2.7

6.5

IIN

No Load Supply Current

ILOAD = 0 mA, (Switch ON) (Note 5)

270

µA

ISHDN

Shutdown Supply Current

SHDN=0V, (Switch OFF)

µA

IIN SHDN

Shutdown Input Current

SHDN = 0 to VIN

100

SHDN =VIN to 5V

µA

Efficiency

ILOAD=100mA

VIH

Shutdown Input Threshold

VIN=1V to 6V

VIN/2 + 0.25

ILIM

Current Limit

1.0

ILIM TEMPCO Current Limit Temperature

Coefficient

-0.3

%/°C

tOFFMIN

Minimum Switch Off Time

1.2

µs

tONMAX

Maximum Switch ON Time

VIN=2.5V

4.5

VIN=1.8V

6.5

VIN=1V

VCESAT NPN Switch saturation Voltage

ISW=400mA

0.25

ISW=600mA

0.33

ISW=1000mA

0.5

VCESAT NPN Rectifier Forward Drop

ISW=400mA

0.18

ISW=600mA

0.22

ISW=1000mA

0.4

VFB

Error Comparator Trip Point ST779, over operating input

voltage (Note 6)

1.23

±2%

IFB

FB Pin Bias Current

ST779, VFB=1.3V

ILX

Switch Off Leakage Current

0.1

µA

Rectifier Off Leakage

Current

0.1

µA

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