Tyco Electronics Corp. 7
Data Sheet MC010-Series Power Modules:
December 1999 18 Vdc to 36 Vdc Input; 10 W
Design Considerations
Input Source Impedance
The power module should be connected to a low-ac-
impedance input source. Source impedances greater
than 12 µH can aff ect the stability of the pow er module.
When the source impedance exceeds 12 µH, mount a
33 µF electrolytic capacitor (ESR < 0.7 Ω at 100 kHz)
close to the module input pins. This is also recom-
mended to minimize reflected-ripple current as well as
conducted and radiated electromagnetic interference
(EMI).
Output V oltage Reversal
CAUTION: Applying a reverse voltage across the
module output forward biases an inter-
nal diode. Attempting to start the mod-
ule under this condition can damage
the module.
Safety Considerations
For safety-agency approval of the system in which the
power module is used, the power module must be
installed in compliance with the spacing and separation
requirements of the end-use safety agency standard,
i.e.,
UL
1950,
CSA
C22.2 No. 950-95, and VDE 0805
(EN60950, IEC950).
For the converter output to be considered meeting the
requirements of safety extra-low voltage (SELV), the
input must meet SELV requirements.
The power module has extra-low v oltage (ELV) outputs
when all inputs are ELV.
The input to these units is to be provided with a maxi-
mum 5 A normal-blow fuse in the ungrounded lead.
Feature Descriptions
Overcurrent Protection
To provide protection in a fault (output overload) condi-
tion, the unit is equipped with internal current-limiting
and can endure current limiting for an unlimited dura-
tion. At the point of current-limit inception, the unit
shifts from voltage control to current control. If the out-
put voltage is pulled very low during a severe fault, the
current-limit circuit can exhibit either foldback or tailout
characteristics (output current decrease or increase).
The unit operates normally once the output current is
brought back into its specified range.
Remote On/Off
(MC010A1, B1, C1, BK1, and CL1 only)
To turn the power module on and off, the user must
supply a switch to control the voltage between the
on/off terminal and the VI(–) terminal (Von/off). The
switch can be an open collector or equivalent (see Fig-
ure 5). A logic low is Von/off = 0 V to 1.2 V, during which
the module is on. The maximum Ion/off during a logic
low is 1 mA. The switch should maintain a logic-low
voltage while sinking 1 mA.
During a logic high, the maximum Von/off generated by
the power module is 18 V. The maximum allowable
leakage current of the switch at Von/off = 18 V is 50 µA.
Note: A PWB trace between the on/off terminal and the
VI(–) terminal can be used to override the remote
on/off.
Either the user-supplied switch or the override jumper
should be wired into the circuit via individual traces not
common with the VI(–) po wer current path. Connect the
switch or jumper at the power module terminals (see
Figure 5). Configuring the switch connection in this w ay
pre vents noise from falsely triggering the remote on/off.
8-598(C).a
Figure 5. Remote On/Off Wiring Configuration,
T op View
VI(+) VI(–) COMMON
CONNECTION
POINT
Von/off
+
–
Ion/off
REMOTE
ON/OFF