YEV09T03 3A DC-DC POL Converter

Data Sheet

ZD-01968 Rev 1.1, 25-Mar-09

www.power-one.com

Page 8 of 10

where:

converter will be 0.591V.

Note that the trim resistor tolerance directly affects

the output voltage accuracy. It is recommended to

use ±0.1% trim resistors to meet the output voltage

setpoint accuracy specified in p. 4.2.

Table 1. Trim Resistor Values

Calculated

Standard Value of

0.1% Resistor, kΩ

0.8

5.65

5.62

1.2

1.94

1.93

1.5

1.3

1.30

1.8

0.98

0.976

2.5

0.62

0.619

3.3

0.44

0.437

5.0

0.27

0.267

6.3

ON/OFF (Pin 1)

The ON/OFF pin is used to turn the POL converter

ON or OFF remotely by a signal from a system

controller. For positive logic, the POL converter is

ON when the ON/OFF pin is at a logic high (2.4V

min) or left open. The POL converter is OFF when

the ON/OFF pin is at a logic low (0.4V max) or

connected to GND.

The ON/OFF pin should be controlled with an open

collector transistor as shown in Figure 13.

Figure 13. Circuit Configuration For ON/OFF Function

6.4

Protections

6.4.1

Input Undervoltage Lockout

The POL converter will shut down when the input

voltage drops below a predetermined voltage. It will

start automatically when the input voltage exceeds

the specified threshold.

6.4.2

Output Overcurrent Protection

The POL converter is protected against overcurrent

and short circuit conditions.

Upon sensing an

overcurrent condition, the POL converter will enter

hiccup mode of operation. Once the overload or

short circuit condition is removed, the POL converter

will automatically restart and Vout will return to its

nominal value.

7.

Characterization

7.1

Ripple and Noise

The output voltage ripple and input reflected ripple

current waveforms are measured using the test

setup shown in Figure 14.

Figure 14. Test Setup For Measuring Input Reflected-Ripple

Current And Output Voltage Ripple

8.

Safety

The YEV09T03 POL converters do not provide

isolation from input to output. The input devices

powering YEV09T03 must provide relevant isolation

requirements according to all IEC60950 based

standards. Nevertheless, if the system using the

converter needs to receive safety agency approval,

certain rules must be followed in the design of the

system.

In particular, all of the creepage and

clearance requirements of the end-use safety

requirements

must

be

observed.

These

requirements are included in UL60950 - CSA60950-

00 and EN60950, although specific applications may

have other or additional requirements.

The YEV09T03 POL converters have no internal

fuse.

If required, the external fuse needs to be

CONTROL

INPUT

VIN

GND

ON/OFF

VOUT

3

2

4

1

TRIM

5

Rload

INPUT

VOLTAGE

4.32kΩ

Internal

Enable

Circuit

YEV09T03

Vout

V source

22

F

ceramic

capacitor

1H

DC/DC

Converter

100 F

tantalum

+2x10F

ceramic

YEV09T03