pq30033qga25 SynQor Worldwide Headquarters, pq30033qga25 Datasheet - Page 12

• Manufacturer Part Number: pq30033qga25
• Description: Quarter-brick Dc/dc Converter
• Manufacturer: SynQor Worldwide Headquarters

Product # PQ30033QGA25
T
T
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.
echnical S
echnical S
V
in
pecification
pecification
Figure D: Typical application circuit (negative logic unit, permanently enabled).
Figure E: Internal Input Filter Diagram
External
Input
Filter
Phone [phone]
V
V
in(+)
in( _ )
Electrolytic
Capacitor
47µF
www.synqor.com
V
ON/OFF
V
L
in(+)
in( _ )
(component values listed on page 3)
V
V
sense(+)
Doc.# 005-2QG33LU Rev. B
sense( _ )
V
V
out(+)
out( _ )
Trim
C
P
R
P
R
trim-up
Current:
trim-down
Current:
ackage:
ackage:
Output:
Output:
or
Input:
Input:
.
C
load
4/28/05
18-60 V
3.3 V
25 A
Quarter-brick
18-60 V
3.3 V
25 A
Quarter-brick
I
load
Page 12