ASM8P18S42 / ASM8P18S42ER

ASM8P1843 / ASM8P18S43ER

June 2005

ASM8P18S44ER / ASM8P18S45ER

rev 0.6

Voltage Mode PWM Controller with EMI Reduction

3 of 11

Notice: The information in this document is subject to change without notice.

Application Information

Spread Spectrum Deviation

The deviation can be determined by selecting the proper

selection)

PWM Frequency

The PWM frequency can be determined by selecting the

Start-up Current

ASM8P18xx allows a substantial reduction in the start up

current. Low start up current allows high resistance, lower

wattage start-up resistor, to supply controller start up

power.

Under Voltage Lockout (UVLO)

When the power supply voltage is below the start up

threshold voltage, internal circuitry puts the output into low

impedance state and sets the output to zero.

Thermal Shutdown

The output of ASM8P18xx goes down to zero when the

junction temperature of the device rises above 155°C. The

device automatically resumes operation when temperature

drops to 126°C. This protects the device from thermal

breakdown.

Overload and under current protection

ASM8P18xx provides Cycle by cycle current limit and pulls

peak voltage of 1V, with a delay to output of 125 nS

maximum.

At no load condition when the device senses the peak

200mS, the oscillator enters in to cycle skip mode. Normal

more than three cycles. Details of cycle skip for different

options are provided in the Electrical Characteristics table.

Absolute Maximum Ratings

Symbol

Parameter

Min

Max

Units

Supply Voltage

30

V

Supply Current

TBD*

mA

Maximum Output Current

1

A

Current Sense Inputs and feedback

5

V

Reference Voltage

6

V

Oscillator Voltage

4

V

Output Voltage

30

V

Operation Junction Temperature

-45

150

°C

Storage Temperature

-65

150

°C

Lead Soldering Temperature (10 Seconds)

300

°C

Static Discharge Voltage MIL-STD-883

2

KV

*Maximum output voltage = 30V