ꢀTO ꢃꢁRIꢁꢃ
15 WATT
DC/DC Converters
28 volt Input
not reCoMMenDeD For neW DesIGns
Features
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–55°C to +85° C operation
ꢀODꢁꢂꢃ
VDC Output
16 to 36 VDC input
50 V for 50 ms transient protection
Fully isolated
triple
+5 & ±12
+5 & ±15
Fixed frequency switching
Inhibit function
Indefinite short circuit protection
Up to 79% efficiency
ꢃize (max.): Non-flanged, case F4, 1.950 x 1.350 x 0.505 inches (49.53 x 34.29 x 12.83 mm)
Flanged, case J5, 2.720 x 1.350 x 0.505 inches (69.09 x 34.29 x 12.83 mm)
ꢃee cases F4 and J5 for dimensions.
Weight:
53 grams typical
ꢃcreening: ꢃtandard or ꢁꢃ. ꢃee screening table for more information.
Description
Interpoint’s ꢀTO ꢃeries™ of DC/DC converters delivers 15 watts of output
power with three output voltages and a choice of two input voltage ranges.
The ꢀTO ꢃeries converters are packaged in hermetically sealed metal
cases and operate at full load over a case temperature range of -55°C to
+85°C (measured at the base plate of the converter).
Features
An inhibit terminal, pin 8, provides shut-down and start-up control. Applying
a logic low (<0.8 V) will disable the output of the converter reducing input
current to 8 mA, typical. ꢂeaving the terminal unconnected or connecting it
to Vin will enable the converter. The inhibit pin has an open circuit voltage
of approximately 10 volts.
COnVerter Design
ꢃoft-start provides a controlled 20 milliseconds turn-on to minimize inrush
current and reduce overshoot at initial start-up or when inhibit is released.
The push-pull forward topology coupled with pulse-width modulation
minimizes output noise and maintains good regulation. Nominal switching
frequency is 250 kHz. Although an internal input filter reduces input ripple
current, for applications requiring conformance to ꢀIꢂ-ꢃTD-461C, Cꢁ03,
use the ꢀTO in conjunction with Interpoint’s Fꢀ-461 ꢁꢀI filter.
Internal current limiting circuitry protects all three outputs against short
circuits. When output power exceeds approximately 125% of maximum
output power, the output currents are limited. In addition, separate current
limiting circuitry protects each output individually.
Operating at maximum ratings may require removing self-generated heat.
To increase heat dissipation, heat conducting material can be used in
contact with the converter’s base plate. Interpoint’s Thermal ꢀounting Pad
(TꢀP), model TꢀP-002, is designed for use with the ꢀTO converter.
paCkaging
ꢀTOconvertersarepackagedinhermeticallysealedmetalcases.Thecases
are constructed of cold-
Positive
Input
1
rolled steel with a fused tin
2
finish. ꢀTO converters can
be purchased in a flanged
or non-flanged case. The
flanged option provides
increased heat dissipation
and also provides greater
stability when mechanically
secured.
+5 Vout
Pre-
Regulator
Error
Amp
Pulse
3
5
Output
Common
Width
Modulator
Short Circuit Amp
Pass Transistor
Positive
Auxiliary
Output
Input 10
Common
Linear
Regulator
8
Inhibit
7
Case Ground
Linear
Regulator
4
Negative
Auxiliary
Output
Pass Transistor
Figure 1: simpliFieD sChematiC
Crane Aerospace & Electronics
Electronics Group (Interpoint Brand)
PO Box 97005 • Redmond WA 98073-9705
Page 1 of 6
MTO Rev C 20100212
425.882.3100
• power@crane-eg.com
www.interpoint.com