FAN4810EVAL

PRODUCT SPECIFICATION

2

REV. 1.0.2 6/17/04

Figure 1. FAN4810 Evaluation Board Test Results

Test Conditions: 500 Watt load on output at 25ºC

Equipment Used: Voltech Digital Single-Phase Power

Analyzer Model PM100, 500W Electronic load.

Power Ratings

Figure 2. Output Power vs. Line Voltage

The FAN4810 Evaluation Board is designed to provide up to

500W output with an input of 90VAC. Due to thermal limita-

tions the actual output with no fan is limited to

≤400W at

inputs below 115VAC, and up to 40ºC ambient. Figure 2

displays the maximum power vs. line voltage with no fan.

Above 115VAC input the maximum output power is 500W.

The unit will safely provide 500W at 90 VAC input with

adequate fan cooling. Note that even though the FAN4810

Evaluation board can achieve 500 Watts with additional fan

cooling, the heatsinks utilized are not optimal for use with

a fan.

Layout Considerations

The FAN4810 Evaluation board contains high impedance,

low-level signals and low impedance, high level circuits;

consequently extra care is required in component placement,

grounding and PC trace routing. In order to shield low-level

circuits from the high level signals, control circuits were

placed in surface mount form on the bottom side of the

board. This allowed a return shield to be placed on the top-

side. Since the current sense for the FAN4810 is not differen-

tial, care must be taken to prevent a large di/dt from occur-

ring across the PCB trace joining the output cap (assumed to

be the reference return for the IC) to the current sense resis-

tor. Since the best reference for the IC is at the output cap

return potential (the most stable potential), the difference

between this potential and the current sense resistor return

potential must be kept to a minimum. This is done by star-

grounding all the 400V return connections to the output

capacitor, and/or maintaining very low inductive/resistive

paths from all power devices to the output capacitor return.

Some general layout guidelines:

A. Return the low side of the timing capacitor (C18)

directly to the IC ground pin.

B. Bypass the reference and supply voltage pins directly to

the IC ground pin with a 1 µF, low ESR/ESL capacitor.

C. Return all compensation components directly to the IC

ground pin, keeping the lead lengths as short as possible.

D. Make sure that low-level, noise free, returns do not share

return paths with high-level, or noisy, signals (e.g., gate

drive).

E.

Isolate and/or shield rapidly changing waveforms, such

as the drain of Q1 from sensitive, high impedance cir-

cuits, such as the timing capacitor, PFC current sense

input, error amplifier input/output, etc.

FAN4810 with 500 Watt Load

89

90

91

92

93

94

95

96

97

90

110

130

150

170

190

210

230

250

V line (RMS)

4

4.5

5

5.5

6

6.5

7

7.5

Efficiency

THD

115

Input (VAC)

110

105

100

95

90

85

400

420

440

460

480

500

Pout