Rev. 1.00

3

April 19, 2012

HT7939A

Absolute Maximum Ratings

InputVoltage,FBVoltage,EN............................6.0V

SWVoltage...........................................................36V

OVPVoltage.........................................................36V

OperatingTemperatureRange.......... -40°Cto+85°C

StorageTemperatureRange............ -55°Cto+150°C

MaximumJunctionTemperature..................... 150°C

Note:Thesearestressratingsonly.StressesexceedingtherangespecifiedunderAbsoluteMaximumRatingsmay

causesubstantialdamagetothedevice.Functionaloperationofthisdeviceatotherconditionsbeyondthose

listedinthespecificationisnotimpliedandprolongedexposuretoextremeconditionsmayaffectdevice

reliability.

Electrical Characteristics

Symbol

Parameter

Test Conditions

Min.

Typ.

Max.

Unit

Input Supply Voltage and Current

Input Voltage

―

2.6

―

5.5

V

UVLO

Under Voltage Lockout

―

1.8

2.1

2.4

V

Supply Current

Switching

―

1.0

5.0

mA

VEN= 0

―

0.1

1.0

μA

Error Amplifier

Feedback Voltage

―

190

200

210

mV

V

Line Regulation

―

1.0

―

%

Power Switch

Switching Frequency

Measured at SW Pin

0.8

1.2

1.6

MHz

DC

Maximum Duty Cycle

85

90

―

%

SW ON Resistance

―

―

0.5

―

Ω

Switch Leakage Current

―

―

0.1

1.0

μA

Enable

EN Voltage High

―

2.0

―

―

V

EN Voltage Low

―

―

―

0.8

V

Dimming Clock Rate

Duty= 5%~100%

100

―

200

kHz

OVP and OCP

OVP Threshold

No Load, for 39A-1 Marking

15.8

17.6

19.4

V

No Load, for 39A-2 Marking

28.8

32.0

35.2

V

N-channel MOSFET Current limit

―

―

1200

―

mA

Thermal Shutdown

Thermal Shutdown Threshold

―

―

150

―

°C

Thermal Shutdown Hysteresis

―

―

25

―

°C

temperaturerangeareassuredbydesign,characterization.