Data Sheet
PIM300X Series; ATCA Board Power Input Modules
-38 to -75Vdc; 300W Input
April 2, 2008
internal current-limiting circuitry. The unit can endure
current overload conditions continuously or shutdown
due to thermal protection depending on operating
ambient temperature conditions. The unit will restart
automatically once the overload condition is removed.
Holdup Capacitor Charging Current
(72V_CAP)
The module employs a unique feature to charge and
recharge the external energy storage holdup/bulk
capacitors (C_HLDP) within seconds from the
application of power to a nominal voltage of 72Vdc
Input Under Voltage Lockout
(+3%/-5%) resulting in significant reduction in the real
estate on the board in order to comply with the
PICMG 3.0’s 0 volt/5msec transient requirements.
Since the 72V_CAP is also regulated, there is further
reduction in real estate board because now 80V
capacitors with higher capacitance can be used
instead of the >/= 100Vdc caps required in
conventional designs. The maximum rate of input
voltage change (dv/dt) shall not exceed 5V/ms when
the -72V_CAP output is switched on the -
At input voltages below the input under voltage
lockout threshold limit (VUVLO), the module operation is
disabled. The module will begin to operate at an input
voltage above the under voltage lockout turn-on
threshold(VUVHI). Please see the Electrical
Specifications Table for the specified trip points.
Transient Over Voltage Protection
The module incorporates a Transient Voltage
Suppressor. This feature helps protect the module
and the downstream DC/DC converters from input
voltage transients exceeding -75Vdc. The TVS is
rated for 1500W of Peak Pulse Power with the
Breakdown Voltage (VBR) of 77.8V to 86.0V.
48V_OUT/VRTN_OUT bus.
The holdup capacitors are switched on automatically
when there is a loss of power on both feeds A & B or
both feeds have dropped below –38V (typical).
Upon restoration of normal power on either or both
feeds, the holdup capacitors automatically go off line
and are recharged for the next power loss event.
Input Reverse Polarity Protection
Note 1: The holdup capacitors and the bleed resistor
are installed external to the module.
The module shall not be damaged from reverse
polarity connection in the event of miswiring of either
input feeds at the shelf input terminals.
Note 2: The PICMG 3.0’s requirements for the 0 Vdc
transient for 5ms is normally interpreted as the holdup
time requirement by many. In actuality, when one
considers the additional specification of 50V/ms fall
time and 12.5 V/ms rise time to and from the 0Vdc
condition, this leads to a 9.3ms of total hold up time
requirement when power is interrupted at -43Vdc. The
72V_CAP output provided by the module to charge
the bulk capacitors provides a tremendous advantage
over conventional designs in terms of real estate
requirements on the board with the added benefit of
the usage of 80V capacitor rating vs >/=100V.
Over Temperature Protection
To provide over temperature protection in a fault
condition, the unit will shutdown if any thermal sensor
reference point TOTP (identified in Figure 16), exceeds
the trip point of 125oC (+/- 5oC). The thermal
shutdown is not intended as a guarantee that the unit
will survive temperatures beyond its rating. The
module will automatically restart after it cools down.
During thermal design verification, it is recommended
that these temperatures be monitored by IR Thermal
imaging camera. In case thermocouples are used, the
thermocouple contacts should be attached as close
as possible to the thermal sensors (thermistors) on
the PWB but not directly on the thermistors
themselves. Attaching the contacts directly to the
thermocouple is not recommended as this will result
in false temperature measurements due to the heat
sink effect of the thermocouple wires.
The holdup time, Tholdup, is defined for power loss at -
43Vdc input and the C_HLDP maintaining -48V_OUT
bus to at least –36Vdc (which is the minimum
operating voltage of the downstream DC/DC bus
converter).
Note 3: Bleed Resistor (R_Bleed): Normally, the
bleed resistor is not required as there is sufficient
standby current drain within the module to bleed the
holdup capacitors from 75V to 60V in 1 second as
specified in the PICMG 3.0. Again, due to the
PIM300X’s unique design, the placement of the bleed
resistor results in significantly less power dissipation
compared with conventional designs where the bleed
resistor is sized for -75Vdc continuous maximum
voltage and -100V transients.
Management Power (MGMT_PWR)
•
•
•
The module provides up to 8W of 3.3V
(PIM300F) or 5.0V (PIM300A) of isolated
output power referred to LOGIC_GND.
The management power is available
automatically as soon as the input voltage
levels are within –36Vdc to –75Vdc.
Over Current Protection (- 48V_OUT Bus)
To provide protection in a fault (output overload or
short circuit) condition, the unit is equipped with
The output is short circuit and over voltage
protected with low ripple and noise.
LINEAGE POWER
15
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