Input:

Output:

Current:

Package:

35-75 V

1.5 V

100 A

Half-brick

Technical Specification

C

2

C

1

L

External

Input

Filter

Trim

I

load

C

load

R

trim-up

or

R

trim-down

ON/OFF

Electrolytic

Capacitor

APPLICATION CONSIDERATIONS

Input System Instability: This condition can occur because

any DC/DC converter appears incrementally as a negative

resistance load. A detailed application note titled “Input System

Instability” is available on the SynQor website which provides

an understanding of why this instability arises, and shows the

preferred solution for correcting it.

Application Circuits: Figure D below provides a typical circuit

diagram which details the input filtering and voltage trimming.

Input Filtering and External Capacitance: Figure E below

provides a diagram showing the internal input filter components.

This filter dramatically reduces input terminal ripple current, which

otherwise could exceed the rating of an external electrolytic input

capacitor. The recommended external input capacitance is speci-

fied in the “Input Characteristics” section. More detailed informa-

tion is available in the application note titled “EMI Characteristics”

on the SynQor website.

Startup Inhibit Period: The Startup Inhibit Period ensures that

the converter will remain off for approximately 200ms when it is

shut down for any reason. When an output short is present, this

generates a 5Hz “hiccup mode,” which prevents the converter

from overheating. In all, there are seven ways that the converter

can be shut down, initiating a Startup Inhibit Period:

• Input Under-Voltage Lockout

• Input Over-Voltage Shutdown (not present in Quarter-brick)

• Output Over-Voltage Protection

• Over Temperature Shutdown

• Current Limit

• Short Circuit Protection

• Turned off by the ON/OFF input

Figure F shows three turn-on scenarios, where a Startup Inhibit

the unit is disabled by the Input Under-Voltage Lockout feature.

When the input voltage rises above the UVL threshold, the Input

Under-Voltage Lockout is released, and a Startup Inhibit Period is

initiated. At the end of this delay, the ON/OFF pin is evaluated,

and since it is active, the unit turns on.

be enabled again until the Startup Inhibit Period has elapsed.

Period has elapsed, and the output turns on within the typical

Turn-On Time.

Figure D: Typical application circuit (negative logic unit, permanently enabled).

47µF

Product # PQ60015HPAA0

Phone 1-888-567-9596

www.synqor.com

Doc.# 005-2HP651K Rev. D

05\20\09

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