Input:
Output:
35-75 V
1.8 V
Current:
Package:
40 A
Quarter-brick
Technical Specification
amount of the Over-Temperature Shutdown Restart Hysteresis
value.
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 web site
(www.synqor.com) which provides an understanding of why
this instability arises, and shows the preferred solution for cor-
recting 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 elec-
trolytic input capacitor. The recommended external input capac-
itance is specified in the “Input Characteristics” section. More
detailed information is available in the application note titled
“EMI Characteristics” on the SynQor website.
Vout(+)
Vin(+)
Vsense(+)
Electrolytic
Capacitor
External
Input
R
trim-up
or
47µF
Vin
Trim
ON/OFF
Filter
C
R
load
trim-down
Iload
_
Vsense( )
_
_
Vin( )
Vout( )
Figure D: Typical application circuit (negative logic unit, permanently enabled).
L
Vin(+)
C
C
2
1
_
Vin( )
Figure E: Internal Input Filter Diagram (component values listed on the specifications page).
Product # PQ60018QTA40
Phone 1-888-567-9596
www.synqor.com
Doc.# 005-2QT618C Rev. C
09/08/05
Page 11
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