MCOTS-C-28-12-HP Datasheet, PDF (11/13 Pages) SynQor Worldwide Headquarters – MILITARY COTS DC/DC CONVERTER

Technical Specification
MCOTS-C-28-12-HP
Output: _12V
Current: _16A
Startup Inhibit Period: The Startup Inhibit Period ensures that
the converter will remain off for approximately 200 ms when it is
shut down for any reason. When an output short is present, this
generates a 5 Hz “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
• Output Over-Voltage Protection
• Over Temperature Shutdown
• Current Limit
• Short Circuit Protection
• Turned off by the ON/OFF input
Figure E shows three turn-on scenarios, where a Startup Inhibit
Period is initiated at t₀, t₁, and t₂:
Before time t₀, when the input voltage is below the UVL threshold,
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.
At time t₁, the unit is disabled by the ON/OFF pin, and it cannot
be enabled again until the Startup Inhibit Period has elapsed.
When the ON/OFF pin goes high after t₂, the Startup Inhibit
Period has elapsed, and the output turns on within the typical
Turn-On Time.
Thermal Considerations: The maximum operating base-plate
temperature, T_B, is 100 ºC. As long as the user’s thermal system
keeps T_B < 100 ºC, the converter can deliver its full rated power.
A power derating curve can be calculated for any heatsink that is
attached to the base-plate of the converter. It is only necessary
to determine the thermal resistance, RTHBA, of the chosen heatsink
between the base-plate and the ambient air for a given airflow
rate. This information is usually available from the heatsink
vendor. The following formula can the be used to determine the
maximum power the converter can dissipate for a given thermal
condition if its base-plate is to be no higher than 100 ºC.
Pmax
diss
=
100
ºC
-
T_A
RTHBA
This value of power dissipation can then be used in conjunction
with the data shown in Figure 2 to determine the maximum load
current (and power) that the converter can deliver in the given
thermal condition.
For convenience, power derating curves for an encased converter
without a heatsink and with a typical heatsink are provided for
each output voltage.
Vin
Under-Voltage
Lockout Turn-
On Threshold
ON/OFF
(neg logic)
ON
OFF ON
OFF
ON
Vout
200ms
(typical start-up
inhibit period)
200ms
200ms
t₀
t₁
t₂
Figure E: Startup Inhibit Period (turn-on time not to scale)
9ms (typical
turn on time)
t
Product # MCOTS-C-28-12-HP Phone [phone]
www.synqor.com
Doc.# 005-0005279 Rev. 1
06/16/09
Page 11