PQ60033ETL30 Datasheet, PDF (11/13 Pages) SynQor Worldwide Headquarters – Eighth-brick DC/DC Converter

Technical Specification
Input: 35-75 V
Output: 3.3 V
Current: 30 A
Package: Eighth-brick
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 cir-
cuit diagram which details the input filtering and voltage trim-
ming.
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 input
electrolytic capacitor. The recommended external input capaci-
tance is specified in the “Input Characteristics” section. More
detailed information is available in the application note titled
“EMI Characteristics” on the SynQor website.
Startup/Restart Inhibit Period: The Restart Inhibit Period
ensures that the converter will remain off for approximately
200ms once it is shut down. When an output short is present, this
generates a 5Hz "hiccup mode," which prevents the converter
from overheating. In all, there are five ways that the converter
can be shut down that initiate a Restart Inhibit Period:
• Input Under-Voltage Lockout
• Output Over-Voltage Protection
• Over Temperature Shutdown
• Current Limit
• Turned off by the ON/OFF input
Figure F shows four turn-on scenarios, where a Restart Inhibit
Period is initiated at t₁, t₂, and t₃:
A Startup Inhibit Period is initiated when the input voltage is
brought up from zero voltage during initial startup, beginning as
the input voltage reaches approximately 10V. At the end of the
Startup Inhibit Period (typically 10mS), if the ON/OFF pin has
been active for at least 1ms, and the input voltage is above the
Under-Voltage Lockout threshold, the output turns on with the
Typical Turn-On Time. This is shown at time t₀.
Vin(+)
Vout(+)
Electrolytic
Vsense(+)
Vin
External
Input
Capacitor
47µF
ON/OFF
R_trim-up
Trim
or
Filter
Vsense(^_)
R_trim-down C_load
I_load
Vin(^_)
Vout(^_)
Figure D: Typical application circuit (negative logic unit, permanently enabled).
L
Vin(+)
C
Vin(^_)
Figure E: Internal Input Filter Diagram (component values listed on the specifications page).
Product # PQ60033ETL30
Phone [phone]
www.synqor.com
Doc.# 005-2ET633F Rev. A
06/01/06
Page 11