Vicor DC MegaPAC DC-DC Switcher User Manual

Rev. 3/04 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) [e-mail]

DC MegaPAC™
DC-DC Switcher

Operator’s Manual

and

“Quick Install” Instructions

www.mpwrs.com

Pg. 2 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Rev. 3/04

DC MegaPAC Operator’s Manual

DC MegaPAC™

DC-DC Switcher

DC MegaPAC “Quick Install” Instructions

Mounting the DC MegaPAC

* The DC MegaPAC can be mounted on any of four sides.
* Use #8-32 or M4 mounting screws. Maximum penetration should not exceed 0.15" (3,8mm).
* Maintain 2" (5,1cm) clearance at either end for airflow.

Output Connections

Power Connections

Installing ring lugs and/or bus bars on output studs:

* The upper stud is Positive and the lower stud is the Return.
* Remove outer nut. Do not remove or loosen inner nut.
* Place ring lug over output stud.
* Replace and tighten outer nut to a maximum torque of 45 lb-in.

Do Not Over-Tighten Nuts.

Installing power connectors on DualPACs (J1A and J1B):

* Use Molex mating receptacle #39-01-2060 with #39-00-0039 terminals

provided.
* Pins 1 and 4 are Positive, while pins 2 and 5 are the Return.
* Attach terminals to 18-24 AWG stranded wire using Molex tool #11-01-0197.

Sense Connections

Sense connections must always be made. Failure to connect Sense lines can
cause failure to the unit.

Sense Connector J2:

* Sense connections do not have to be made if the Local Sense option has been

ordered. (An “L” in the ConverterPAC part number means the Local Sense

option has been installed; e.g. M5V/40AL.)
* Use Molex mating receptacle #50-57-9403 with #16-02-0103 terminals pro-

vided.
* J2-2 is the +Sense and J2-3 is the -Sense.
* Attach terminals to 22-24 AWG twisted pair wire using Molex tool #11-01-

0208.

* Attach opposite ends of Sense lines to point where regulation is desired.

* Verify that Sense lines are not cross-connected before applying input

power.

Sense Connections on DualPACs:

* Sense connections do not have to be made if the Local Sense option has been

ordered. (An “L” in the ConverterPAC part number means the Local Sense

option has been installed; e.g. D5V/20AL-12V/4.2AL.)
* Sense connections are available on the J2 connector or the J1A and J1B con-

nectors. Either can be used.
* If using J2 connector, see instructions above for “Sense Connector J2.”
* Pin 3 is the +Sense and Pin 6 is the -Sense.
* Attach terminals to 18-24 AWG twisted pair wire using Molex tool #11-01-

0197.

* Verify that Sense lines are not cross-connected before applying input

power.

DualPAC Output Connector

Pin
1
2
3

1&4 +Vout
2&5 -Vout
3 +Sense
6 -Sense

4
5
6

J1A & J1B

Sense Connector

Pin

1

1 Trim Pin Access

2

2 +Sense

3

3 -Sense

J2

DualPAC Output Connector

Pin
1
2
3

1&4 +Vout
2&5 -Vout
3 +Sense
6 -Sense

4
5
6

J1A & J1B

DC MegaPAC Operator’s Manual

Rev. 3/04 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Pg. 3

Trim Pin Connection J2

* The Trim J2 connection should only be made if the Trim option has not

been installed. (A “T” or an “F” in the ConverterPAC part number
means the Trim option is installed; e.g. M5V/40AT.)

* Use Molex mating receptacle #50-57-9403 with #16-02-0103 terminals

provided.

* J2-1 provides Trim access.

DC OK (Power Good) Connection J3
* DC OK is only available as an option and is not always present.

* J3-4 is Vcc In , J3-3 is Power Good, J3-2 is Power Good inverted, and

J3-1 is Signal Ground.

* Use Molex mating receptacle #39-01-0043 with #39-00-0031 terminals

provided.

* Attach terminals to 22-28 AWG stranded wire using Molex tool

#57005-5000.

Input Connections

Input Power J9
* Input DC power is applied to solderless lugs on J9 using 2 AWG wire.
* Maximum torque is 25 lb-in.
* A fuse or circuit breaker is recommended in the input line.

Interface Connections J10

* Use 25 pin D-sub connector provided.
* J10-8 to 11 and J10-21 to 24 are Enable/Disable for slots 1-8.
* J10-16, 17 are Vcc, J10-12 and 15 are Signal Ground, J10-18 is AC

Power OK, and J10-5 is General Shutdown.

J10

Sense Connector

Pin

1

1 Trim Pin Access

2

2 +Sense

3

3 -Sense

J2

DC OK (Power Good)

J3

Pin

J3-4 Vcc

4
3

J3-3 Power Good

2

J3-2 Power Good Inverted

1

J3-1 Signal Ground

J10 INTERFACE CONNECTOR IDENTIFICATION
1 Signal Ground 14 No Connection
2 Signal Ground 15 Signal Ground
3 Overtemp. Warning 16 Vcc +5 volt, 300 mA
4 Analog Temperature 17 Vcc +5 volt, 300 mA
5 General Shutdown 18 Input Power OK
6 No Connection 19 Input Power Fail
7 No Connection 20 No Connection
8 Enable/Disable #8 21 Enable/Disable #7
9 Enable/Disable #6 22 Enable/Disable #5
10 Enable/Disable #4 23 Enable/Disable #3
11 Enable/Disable #2 24 Enable/Disable #1
12 Signal Ground 25 Gate Out Slot #8
13 Gate In Slot #1

1

14 15

2

3

16 17 18 19

5

7

6

20 21 22 23

8

9

10 111213

24 25

4

Amp 25 pin connector #746862-2
plug for flat ribbon cable. Mates with
housing Amp #747548-2 plus slide
latch or similar.

Pg. 4 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Rev. 3/04

DC MegaPAC Operator’s Manual

DC MegaPAC™
DC-DC Switcher

Overview

The DC MegaPAC DC-DC switcher allows users to instantly configure high efficiency power supplies. Although
small in size (3.4"H x 6.0"W x 11.7"L), (85,8mm x 153,4mm x 296,7mm), the DC MegaPAC provides up to
1600W of output power with up to 16 isolated outputs.

A complete power supply is configured by selecting and inserting up to eight slide-in output assemblies called
“ConverterPACs.” ConverterPACs incorporate one or two Vicor DC to DC converters and are available in a wide
array of outputs and power levels. The net result is a power supply that offers the advantages of a custom supply,
but is assembled from standard and modular building blocks.

The entire family of MegaPAC power supplies is completely user-configurable. If output requirements change, i.e.,
more power or a different output voltage is needed, upgrading is easy: simply unlock a single screw and replace
the slide-in ModuPAC assembly with one that has the desired rating. For additional flexibility, ModuPACs can be
connected in parallel to increase output power (booster ModuPACs), or in series for higher voltages. The driver is
to the left of the boosters when looking at the output end of the supply. A user-friendly interface provides control
and output sequencing capability, in addition to useful status indicators. Please consult our Applications
Engineering Department if you have other special requirements.

Standard Features

• DC Input: 12 Vdc (10-20 Vdc), 24 Vdc (18-36 Vdc), 36 Vdc (21-56 Vdc), 48 Vdc (36-76 Vdc), 72 Vdc (55-100
Vdc)

• Output Power: 1600W; 1-16 outputs

• Full power output to 45°C; half power to 65°C

• Soft start for limiting inrush current

• Conducted EMI meets BTR 2511

• Output Sequencing and General Shutdown (Consult Applications Engineering for automatic sequencing

circuitry.)

• Remote Sense capability and output overcurrent protection on all outputs

• Output overvoltage protection on most outputs

• Output overtemperature protection on all outputs

• Vin OK status signal

• Input over, under and reverse voltage protection

• Box-to-box paralleling capability

• Input temperature monitor, warning, and shutdown

• CE Mark, UL, CSA

Optional Features

• DC OK status signal

• Output voltage adjustment range with built-in potentiometer

• Reversed fan airflow direction

• Industrial-grade screening of output converters

• Hardwired Local Sense

Rev. 3/04 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Pg. 5

DC MegaPAC Operator’s Manual

Technical Description

The DC MegaPAC chassis consists of an EMI filter, cooling fan, customer interface and associated housekeeping circuits.
Input DC voltage (+VIN, -VIN, and GND) is applied to the input connectors. The input current is passed through an EMI
filter designed to meet conducted British Telecom specifications. At start-up, inrush current is limited by a thermistor. The
thermistor is shunted out shortly after initial power-up by a relay driven by a DC bus voltage sense circuit. The DC voltage
is then fed to the backplane. The backplane supplies power to a variety of ConverterPAC assemblies that provide the
desired low voltage, regulated outputs.

Voltage conversion in the output assemblies is achieved by Vicor's family of Zero-Current-Switching (ZCS) DC-DC con­verters. These are forward converters in which the main switching element switches at zero current. This patented topology
has a number of unique attributes: low switching losses; high frequency operation resulting in reduced size for magnetics
and capacitors; excellent line and load regulation; wide adjustment range for output; low EMI/RFI emission and high effi­ciencies.

At initial power-up, the DC MegaPAC outputs are disabled to limit the inrush current and to allow the DC bus potential to
charge to the operating level. A low-power flyback converter operating with PWM current-mode control converts the DC
bus into regulated low voltage to power the internal housekeeping circuits and DC cooling fan. When operating on 48 Vdc,
the internal housekeeping Vcc comes up within 3s after the application of input power. Once the input range is within speci­fication, the VIN OK signal asserts to a TTL "1" indicating the input power is OK, and allows the power outputs to be
enabled. The power outputs will be in regulation 500 ms after the Vin OK signal asserts to a TTL "1." An auxiliary Vcc out­put of 5 Vdc sourcing up to 0.3A is provided for peripheral use.

An output Enable/Disable function is provided by using an optocoupler to control the Gate In pins of the ConverterPAC
assemblies. If the Enable/Disable control pin is pulled low, the optocoupler turns on, pulling the Gate In pin low and dis­abling the ConverterPAC output. The nominal delay associated for an output to come up when measured from release of the
Enable/Disable pin is 5-10 ms. The General Shutdown function controls all outputs simultaneously and works in a similar
manner. If driven from an electromechanical switch or relay, a capacitor should be connected to eliminate the effects of
switch bounce.

There is no ride-through (holdup) time available with the DC MegaPAC.

Figure 1. DC MegaPAC Architecture

Pg. 6 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Rev. 3/04

DC MegaPAC Operator’s Manual

ConverterPAC Functional Description

ConverterPACs are the family of slide-in output assemblies used in MegaPAC power supplies.
ConverterPACs are interchangeable within a MegaPAC so they can be added, moved, or changed
as necessary. They are also interchangeable between different AC input MegaPAC chassis. A
ConverterPAC removed from a Mini MegaPAC could be used in a 3 Phase MegaPAC, for exam­ple. ConverterPACs can be selected with a variety of options and in voltages from 2 to 95 Vdc.

ModuPAC

The ModuPAC output assembly consists of a VI-200 DC to DC converter that converts the high
voltage bus to the desired regulated output voltage. Each ModuPAC can provide up to 200 watts
of power. Multiple ModuPACs can be paralleled in a driver-booster configuration to provide more
power. ModuPACs are fused with a PC-Tron, DC-rated, fast-acting fuse. Apassive LC filter is used
to reduce output ripple/noise down to 1% typical, and 2% maximum peak-to-peak from 10% to
100% of rated load. An optional DC Power Good signal, or output voltage Trim potentiometer can
be specified. The ModuPAC contains overvoltage protection (OVP), overcurrent protection (OCP),
and overtemperature protection (OTP). The OCP has automatic recovery when the overcurrent
condition is removed. The OVP and OTP are latching functions and require recycling of the AC
input power to restart.

DualPAC

This output assembly consists of two VI-J00 DC to DC converters that convert the high voltage
bus to the desired regulated output voltages. Each output on a DualPAC can provide up to 100
watts of power and is fused with a single PC-Tron, DC-rated, fast-acting fuse. A passive LC filter
is used to reduce output ripple/noise down to 1% typical, and 2% maximum peak-to-peak from
10% to 100% of rated load. An optional output voltage Trim potentiometer can be specified. DC
Power Good signal is not available. The DualPAC contains overcurrent protection, which recovers
automatically when the overcurrent condition is removed. Overvoltage and overtemperature

protection are not available.

JuniorPAC

The JuniorPAC consists of one VI-J00 DC to DC converter that converts the high voltage bus to
the desired regulated output voltage. JuniorPACs can provide up to 100 watts of output power and
are fused with a single PC-Tron, DC-rated, fast-acting fuse. A passive LC filter is used to reduce
output ripple/noise down to 1% typical, and 2% maximum peak-to-peak from 10% to 100% of
rated load. An optional DC Power Good signal or output voltage Trim potentiometer can be spec­ified. The JuniorPAC contains output overcurrent protection, which recovers automatically when
the overcurrent condition is removed. Overvoltage and overtemperature protection are not avail­able.

RAMPAC

This output assembly consists of a VI-J00 DC to DC converter with a Ripple Attenuator Module
(RAM) and is designed for applications requiring low output ripple/noise. The RAMPAC can
attenuate the ripple/noise down to 10 mV peak-to-peak over a 20 MHz bandwidth from 10% to
100% of rated load of the converter. Each RAMPAC can provide up to 100 watts of output power,
and outputs from 5V to 50V are available. An optional DC Power Good signal or output voltage
Trim potentiometer can be specified. The RAMPAC contains output overcurrent protection, which
recovers automatically when the overcurrent condition is removed. Overvoltage and overtempera­ture protection are not available.

Configuring and Reconfiguring MegaPACs

ConverterPACs can be easily added, replaced, or moved by sliding the assemblies in or out of a MegaPAC chassis.
Most ConverterPACs are driver ModuPACs and can be inserted into any available slot. For outputs greater than
200 watts, a driver ModuPAC and one or more booster ModuPACs will be used. Arrays of drivers and boosters

Figure 2. ModuPAC

Figure 3. DualPAC

Figure 4. JuniorPAC

Figure 5. RAMPAC

Rev. 3/04 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Pg. 7

DC MegaPAC Operator’s Manual

should be configured so all boosters are placed in the slots to the immediate right of the driver when looking at the
output end of the MegaPAC.

Prior to removing or installing ConverterPACs, you must remove power from the MegaPAC and wait 5 min­utes. Failure to do so can result in personal injury or damage to the supply.

Take standard ESD precautions when handling ConverterPACs.

Removing ConverterPACs

ConverterPACs can be removed by loosening the captive screw at the base. Once this screw has been loosened, the
ConverterPAC will slide out of the chassis. Once a ConverterPAC has been removed, the empty slot MUST be
filled with either another ConverterPAC or an airblock. If the slot is left empty, it will provide an airflow
escape, significantly degrade thermal performance, and can cause failure.

Installing ConverterPACs as Drivers

ConverterPACs can be installed in empty slots by simply sliding in the new ConverterPAC and securing the screw
at the base. Power and interface connections can be made after the ConverterPAC has been installed.

Installing Booster ModuPACs to Increase Output Power

ConverterPACs can be paralleled for more power. Additional power to an output is obtained by connecting one or
more boosters in parallel with a single driver. The driver can be placed in any open slot. All boosters should be
inserted in the slots to the immediate right of the driver as viewed from the output end of the MegaPAC. Figure 6
shows a driver placed in slot #1 and 3 boosters placed in slot #s 2 to 4. After inserting the driver and boosters, they
are paralleled using bus bars across the positive and negative output studs. Drivers should not be paralleled with
each other. For help in identifying boosters and drivers, refer to the section on MegaPAC Part Numbers.

Figure 6. Paralleling ConverterPACs

ConverterPAC Feature Summary

Conver

terPAC OVP OCP OTP RS LS PG TrimPot

ModuPAC Std Std Std Std Opt Opt Opt
DualPAC N/A Std N/A Std Opt N/A Opt
JuniorPAC N/A Std N/A Std Opt Opt Opt
RAMPAC N/A Std N/A Std Opt Opt Opt

OVP Overvoltage Protection (latching) RS Remote Sense
OCP Overcurrent Protection (auto-recovery) LS Local Sense
OTP Overtemperature Protection (latching) PG Power Good (DC OK)

Table 1. Summary of ConverterPAC Features

Pg. 8 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Rev. 3/04

DC MegaPAC Operator’s Manual

Interface Connections

Chassis Input Power Terminals (J9)

Input DC power is applied to solderless lugs J9, using a wire size of 2 AWG. J9-1 is the +DC Voltage IN connection, and
J9-3 is the -DC Voltage IN connection. The Earth Ground is accessed via J9-2, a size 10-32 self-locking PEM nut.
Maximum torque recommended is 25 lb-in. A fault clearing device, such as a fuse or circuit breaker at the power supply
input is strongly recommended. For an output of 1600 watts with operation on 48 Vdc (and low line operation of 42 volts),

a fast-blow fuse of 50 amps is recommended. Start-up inrush current is limited by a thermistor, and in most cases, will be
less than nominal line current during operation. Start-up inrush current can be calculated by I = MaxVin/10 (where Max
Vin is the maximum operating voltage. See Table 2.). Example: for a nominal 48V input, the maximum operating voltage
is 68; therefore, I = 68V/10 = 6.8 amps.

Note: A fault clearing device, such as a fuse or circuit breaker at the power supply input is required per safety agency con­ditions of acceptability.

Output Power Connections (+P, -P for Single Output, or J1A/J1B for Dual Outputs)

For single output ConverterPACs, these terminals are two 1/4-20 plated steel studs. The upper stud is positive with respect
to the lower stud. For dual output ConverterPACs, there is a 6-pin Molex connector for each output. J1A pins 1 and 4 are
the +Output, and J1A pins 2 and 5 are the -Output. Pins 3 and 6 are duplicates of the Remote Sense terminals present on
J2A and J2B. Use appropriate wire size rated to handle the full output current, including short circuit levels. Avoid large
current loops in output cables; run power and return cables next to one another to minimize inductive effects. All outputs
are isolated and can provide positive or negative outputs.

Output +/-Sense Connections (J2 for Single Output, or J2A/J2B for Dual Outputs)

Although all outputs are open-Sense protected, the +/-Sense terminals MUST

be connected to their respective outputs
before the DC MegaPAC is powered up. Regardless of the output polarity configured, the +Sense should always connect to
the +Power output. The -Sense connects to the -Power output. Sense connections are not required on booster
ConverterPACs, BatPACs, or if the Local Sense option is specified. Sense pins can be accessed on J1A/J1B or J2A/J2B on
dual output units.

Signal Ground (J10-1, 2, 12, 15)

Signal Ground (Connector Pin Identification on page 14) is an isolated ground reference for all J10 interfacing signals, and
can be used for ConverterPAC output status signals such as Power Good. This is not the same as Earth Ground on input
power connector J9.

Enable/Disable (J10-8 to J10-11, and J10-21 through 24)

The Enable/Disable control pins allow ConverterPAC outputs to be sequenced either on or off. For the DC MegaPAC,
J10-8 through 11 and J10-21 through 24 are the control pins for output positions 1 through 8. For DualPACs, both outputs
are sequenced. In parallel arrays, only the driver ConverterPAC need be controlled. The Enable/Disable pins should be
pulled low to less than 0.7V with respect to Signal Ground to disable the outputs. They will sink 10 mA maximum. These
pins should be open circuited or allowed to exceed 4.5V when enabled. Do not apply more than 6V to these inputs at any
time. If driven from an electromechanical switch or relay, a capacitor should be connected to eliminate the effects of
switch bounce.

Figure 7. Input Panel Connectors

+

–

DC

DC

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DC MegaPAC Operator’s Manual

General Shutdown /GSD (J10-5)

The GSD control pin on J10-5 allows simultaneous shutdown of all ConverterPAC outputs (see Connector Pin
Identification on page 14). This pin must be pulled down to less than 0.7V, and will sink 10 mA maximum to shut
down all outputs. The GSD pin should be open circuited or allowed to exceed 4.5V when not in use, or when the
outputs are to be enabled. Do not apply more than 6V to this input at any time. Normal open circuit voltage is 1.5
to 3V with respect to Signal Ground. If driven from an electromechanical switch or relay, a capacitor should be
connected to eliminate the effects of switch bounce.

Input Power OK (J10-18)

This is an active high TTL compatible signal and provides a status indication of the DC input power (see Table 2
and Connector Pin Identification on page 14). It is capable of sinking 20 mA maximum. This signal switches to a
TTL “1” when Vin is within its specified range.

Figure 9. Enable/Disable and General Shutdown

OPERATING RANGE VIN OK TRIGGER

Nominal Low High Low Line High Line

Code Vdc Line Line Cut Off Cut Off

0 12 volts 10 volts 20 volts 6V to 10V 20V to 23V
1 24 volts 21 volts 32 volts 16V to 21V 32V to 36V
W 24W volts 18 volts 36 volts 12V to 18V 36V to 41V
2 36 volts 21 volts 56 volts 11V to 21V 56V to 63V
3 48 volts 42 volts 60 volts 34V to 42V 60V to 68V
N 48W volts 36 volts 76 volts 23V to 36V 76V to 86V
4 72 volts 55 volts 100 volts 40V to 55V 100V to 111V*

*Do not apply greater than 100 volts to the input of the DC MegaPAC.

Table 2. Input Voltage Range & Vin OK Limits

J10 INTERFACE CONNECTOR IDENTIFICATION

Figure 8. Interface Connector

1 Signal Ground 14 No Connection
2 Signal Ground 15 Signal Ground
3 Overtemp. Warning 16 Vcc +5 volt, 300 mA
4 Analog Temperature 17 Vcc +5 volt, 300 mA
5 General Shutdown 18 Input Power OK
6 No Connection 19 Input Power Fail
7 No Connection 20 No Connection
8 Enable/Disable #8 21 Enable/Disable #7
9 Enable/Disable #6 22 Enable/Disable #5
10 Enable/Disable #4 23 Enable/Disable #3
11 Enable/Disable #2 24 Enable/Disable #1
12 Signal Ground 25 Gate Out Slot #8
13 Gate In Slot #1

1

14 15

2

3

16 17 18 19

5

7

6

20 21 22 23

8

9

10 111213

24 25

4

Amp 25 pin connector #746862-2
plug for flat ribbon cable. Mates with
housing Amp #747548-2 plus slide
latch or similar.

Pg. 10 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Rev. 3/04

DC MegaPAC Operator’s Manual

78M05

Auxiliary Vcc

9

0.1 µF
Signal Ground

J10

10

+5V/300 mA

Input Power Fail (J10-19)

The Input Power Fail signal on pin J10-19 is the inverse of the Input Power OK signal on J10-18, and goes to a TTL "0"
when the input DC power is OK. It is capable of sinking 20 mA maximum.

Overtemperature Warning (J10-3)

J10-3 is a signal that asserts a TTL level "1" if the air temperature exceeds the following factory set levels. The warning trip
point is 65°C to 76°C, typically, and recovery point is 60°C to 71°C, typically.

Overtemperature Shutdown

If the inlet ambient air temperature exceeds the following factory set levels, the outputs are disabled. The shutdown trip
point is 70°C to 81°C, typically, and recovery point is 40°C to 48°C, typically.

Analog Temperature Monitor (10-4)

This signal on J10-4, referenced to Signal Ground, provides an analog DC voltage output between 0V and 10V that repre­sents the air temperature of 0°C to 100°C, respectively, inside the power supply. The inlet air temperataure is monitored
close to the fan.

Gate IN/Gate OUT (J10-13, 25)

The Gate IN and Gate OUT signals are used for paralleling DC MegaPACs for power expansion. The Gate OUT signal,
J10-25, of the driver DC MegaPAC should be connected to the Gate IN, J10-13, of the Booster DC MegaPAC; J10 signal
ground of the driver DC MegaPAC also needs to be connected to J10 signal ground of the booster DC MegaPAC.

The driver DC MegaPAC (ModuPAC, slot #8) generates the Gate OUT signal and sends it to the booster DC MegaPAC
(ModuPAC, slot #1). Vicor's zero-current-switching booster technology provides for accurate, dynamic power sharing with­in arrays, without the need for trimming, module "matching" or external components.

Auxiliary Vcc +5V/0.3A (J10-16, 17)

The Vcc on J10-16 and J10-17 is an auxiliary 5V regulated power source (see Figure 10 and Connector Pin Identification
on page 14). It is +5 Vdc (± 5%) with respect to Signal Ground, and can supply 300 mA maximum. It is short-circuit-proof,
but if shorted, all outputs will shut down through the Enable/Disable circuitry. The Auxiliary Vcc typically powers user cir­cuitry or is used with the Power Good circuitry to provide a pull-up reference for the outputs of the DC Power Good circuit
on a ModuPAC. If used for this purpose, a Signal Ground on J10 must also be connected to the J3-1 Signal Ground pin of
the ModuPAC.

Power Good (J3-3)

The optional Power Good signal on J3-3 is referenced to Signal Ground on J3-1, and indicates the status of the output volt­age. This signal is asserted a TTL “1” when the output voltage is above 95% of nominal. It is a TTL “0” when the output
voltage is below 85% of nominal.

If the Trim option is also used, the Power Good trip points DO NOT track with the trimmed voltage. It is possible to trim
the output below the fixed setpoints of the Power Good circuit and cause a negative Power Good signal.

Power Good Inverted (J3-2)

This is the inverse of the Power Good signal and is referenced to Signal Ground on J3-1.

Figure 10. Auxiliary Vcc

J10

16

Auxiliary Vcc

17

Auxiliary Vcc

Signal Ground

15

78M05

+5V/300 mA

0.1 µF

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DC MegaPAC Operator’s Manual

Signal Ground (J3-1)

Signal Ground on J3-1 is an isolated secondary ground reference for J3 status signals. It is used to provide a refer­ence point for the Power Good circuitry and is not the same as Earth Ground on input power connector J9.

Vcc In (J3-4)

The Vcc In on J3-4 is an input that requires +5V either from the J10 Auxiliary Vcc, or from another source. Input
current to this pin is limited by an internal resistor to 3 mA. If the J10 Auxiliary Vcc is connected to Vcc In on J3­4, then at least one J10 Signal Ground must be connected to Signal Ground on J3-1.

+Sense/–Sense (J2-2 and J2-3)

The +Sense on J2-2 should be connected to the +Power Out, and the –Sense on J2-3 to the –Power Out terminal.
Do not reverse or leave the Sense pins open. Sense pins can be terminated locally at the output of the power sup­ply, in which case the power supply will provide regulation at the output terminals. The voltage appearing at the
load may drop slightly due to voltage drop in the power cables. If it is necessary to compensate for voltage drop
along the output power cables, this termination should be made close to the output load. Compensation of up to

0.5V (0.25V per lead) can be obtained. Use twisted pair 22-24 AWG wire for this purpose.

For DualPACs, the +Sense pins are available on connectors designated as J2A-2 and J2B-2 for outputs A and B,
respectively. –Sense pins are on J2A-3 and J2B-3, respectively. These pins are also duplicated on the power con­nectors J1A and J1B.

External Trim (J2-1)

Output voltage can be trimmed using an optional factory-installed Trim potentiometer or with the Trim pin (see
Figure 13). The Trim potentiometer is located on the ConverterPAC. If the Trim potentiometer has not been
ordered, the Trim pin must be used. When using the Trim pin, the Trim limits are determined by the DC/DC con­verter used on the ConverterPAC. Maximum Trim ranges are 10% above the nominal converter voltage and 50%
below the nominal converter voltage.

The Trim pin on J2 can be used to control the output voltage. It is referenced to the -Sense pin on J2 and can be
controlled by either a resistor network or an external voltage source. To increase an output voltage above its nomi­nal, it is necessary to increase the voltage at the Trim pin above the internal reference voltage (Vref). The reverse
is true to decrease an output voltage.

Figure 12. Sense Leads

Figure 11. Power Good and Vcc

Pg. 12 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Rev. 3/04

DC MegaPAC Operator’s Manual

Note: Converters are sometimes pretrimmed at the factory if a nonstandard output voltage is requested. Standard voltages
include 2V, 3.3V, 5V, 12V, 15V, 24V, 28V, and 48V. If using a nonstandard voltage, or if a ConverterPAC is ordered with a
Trim option, the resistor calculations will differ from those below. Please consult the factory for assistance.

OUTPUT MODULE V

ref

R

TH

VI-200/VI-J00 ≥3.3V 2.50V 10.0 kΩ
VI-200/VI-J00 <3.3V 0.97V 3.88kΩ

Table 3. Module Internal Reference Voltages and Thevenin Resistances.

Example:

±±

10% Trim adjust on a 12V nominal output.

Figure 13 shows a typical variable Trim circuit. Using a 10k trimpot (R7), the resistor values for R6 and R8 can be calculat­ed as follows:

V

1

= V

ref

+ 10% = 2.75V Given: V

ref

= 2.5V (see Table 3)

IR5= (2.75V - V

ref

)/RTH= (2.75V - 2.5V)/10kΩ = 25µA

Setting the bottom limit:

VR6= 2.5V - 10% = 2.25V

And since IR5= IR6= 25µA,

R6 = VR6/IR6= 2.25V/25µA = 90kΩσ

V2= V1+ VR6= 2.75V + 2.25V = 5V

IR7= V2/R7 = 5V/10kΩ = 500µA

IR8= IR7+ IR6= 525µA

VR8= (V

nom

+10%) - V2= 13.2V - 5V = 8.2V Given: V

nom

= 12V

R8 = VR8/IR8= 8.2V/525µA = 15.62kΩ

Using the above resistor combination, a 12V output can be trimmed externally up to 13.2V and down to 10.8V. For further
information on external trimming, refer to Chapter 5 of the Applications Manual or consult the factory for assistance.

CONSULT APPLICATIONS ENGINEERING WHEN TRIMMING OUTPUTS BELOW 5V.

Figure 13. External Trim

To Error
Amplifier

R5
10KW

2.5V
Bandgap

R1
10-300W

R2

R3

R4
20-200W

+P +Out

J2-2 +Sense

J2-1

R6 = 40k

J2-3 -Sense

-P -Out

(Remote Sense)

R8

R7 = 10k

Use 22-24 AWG Twisted Pair Wires

Load

DC MegaPAC Operator’s Manual

Rev. 3/04 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Pg. 13

Mechanical Considerations

The DC MegaPAC can be mounted on any of four surfaces using standard 8-32/M4 screws. The chassis comes
with four mounting points on each surface; maximum allowable torque is 20 lb-in. The maximum penetration is

0.15 in. (3,8mm).

When selecting a mounting location and orientation, the unit should be positioned so air flow is not restricted.
Maintain a 2” (5,1cm) minimum clearance at both ends of the DC MegaPAC and route all cables so airflow is not
obstructed. The standard unit draws air in at the fan side and exhausts air out the load side. If airflow ducting is
used, avoid sharp turns that could create back pressure. The fan moves approximately 30 CFM of air.

Avoid excessive bending of output power cables after they are connected to the DC MegaPAC. For high-current
inputs and outputs, use cable ties to support heavy cables, minimizing mechanical stress on output studs. Be care­ful not to short-out to neighboring output studs. The DC MegaPAC is supplied with serrated, flanged hex-nuts on
all output studs, so Loc-tite® or lock washers are not required. The maximum torque recommended on flanged
nuts is 45 lb-in. Never loosen the inner nut on a ConverterPAC. This nut supports the hardware inside the
ConverterPAC and is factory torqued.

Avoid applications in which the unit is exposed to excessive shock or vibration levels. In such applications, a
shock absorption mounting design is required.

MegaPAC Do’s and Don’ts

• Do not leave ConverterPAC Sense lines open. Always terminate them locally or at the load. Use twisted

pair 22-24 AWG wire.

• Always fill all output slots of the MegaPAC. If a slot is not filled with a ConverterPAC, it should be

filled with an airblock. Failure to do so can result in overheating and damage to the power supply.

• Do not unplug ConverterPACs while input power is applied. They are not designed for hot-plug appli­cations.

• Do not restrict airflow to the unit. The cooling fan draws air into the unit and forces it out at the output power
terminals.

• For power expansion use booster ConverterPACs. Viewing the unit from the output terminal side, always
insert boosters to the right side of the driver.

• Run the output (+/–) power cables next to each other to minimize inductance.

• Wait 5 minutes after shutting off power before inserting or removing ConverterPACs.

• Do not attempt to repair or modify the power supply in any manner other than the exchange of
ConverterPACs as described in this manual.

• Insert proper fault protection at power supply input terminals (i.e., a fuse).

• Use proper size wires to avoid overheating and excessive voltage drop.

• Never loosen the inner nut on a ConverterPAC.

• Verify output nuts are tight before powering up.

Pg. 14 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Rev. 3/04

DC MegaPAC Operator’s Manual

DC MegaPAC Mechanical Drawings

ModuPAC

JuniorPAC

RAMPAC

DualPAC

ConverterPAC Output and Connector Location and Connector Pin Identification

Molex #39-01-043 housing
using #39-00-0031 terminals
and 22-28 AWG stranded wire.
Use Molex tool #57005-5000.

Molex #39-01-2060 housing
with #39-00-0039 terminals and
18-24AWG stranded wire. Use
Molex tool #11-01-0197.

Molex #50-57-9403 housing,
using #16-02-0103 terminals and
22-24 AWG stranded wire. Use
Molex tool #11-01-0208.

Sense Connector

Pin

1
2
3

J2

1 Trim Pin Access
2 +Sense
3 -Sense

J10 INTERFACE CONNECTOR IDENTIFICATION
1 Signal Ground 14 No Connection
2 Signal Ground 15 Signal Ground
3 Overtemp. Warning 16 Vcc +5 volt, 300 mA
4 Analog Temperature 17 Vcc +5 volt, 300 mA
5 General Shutdown 18 Input Power OK
6 No Connection 19 Input Power Fail
7 No Connection 20 No Connection
8 Enable/Disable #8 21 Enable/Disable #7
9 Enable/Disable #6 22 Enable/Disable #5
10 Enable/Disable #4 23 Enable/Disable #3
11 Enable/Disable #2 24 Enable/Disable #1
12 Signal Ground 25 Gate Out Slot #8
13 Gate In Slot #1

DC OK (Power Good)

Pin

1

1 Vcc

2

2 Power Good

3
4

3 Power Good Inverted
4 Signal Ground

J3

DualPAC Output Connector

Pin
1
2
3

1&4 +Vout
2&5 -Vout
3 +Sense
6 -Sense

4
5
6

J1A & J1B

1

14 15

2

3

16 17 18 19

8

4

7

5

6

9

10 111213

24 25

20 21 22 23

Amp 25 pin connector #746862-2
plug for flat ribbon cable. Mates with
housing Amp #747548-2 plus slide
latch or similar.

STATUS/CONTROL
SIGNALS J10

3.38

(85,6mm)

4 MOUNTING HOLES EACH SURFACE
(M4/#8-32, .15 (3,8mm) MAX. PENETRATION)

NORMAL

AIR FLOW

CONNECTIONS J9

TOP

6.04 (153,4mm)
FRONT VIEW

.45 (11,4mm)

INPUT POWER

+

–

DC

DC

(129,5mm)

1.0

(25,4mm)

2.92

(74,2mm)

.22

(5,6mm)

5.10

DC

MegaPAC

WESTCOR

TOP VIEW

11.37 (288,8mm)

6.75 (171,4mm)

11.68 (296,7mm)
SIDE VIEW

DO NOT LOOSEN OR
TIGHTEN INNER NUTS

1/4 - 20 ZINC PLATED
STEEL, SERRATED
FLANGED NUTS
45 LB-IN MAX.

.62

(15,7mm)

1.85

(47mm)

OUTPUT

OUTPUT
RETURN

#4-40 CAPTIVE SCREWS
TO SECURE/REMOVE
CONVERTERPACS,
8 PLACES

DC MegaPAC Operator’s Manual

Rev. 3/04 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Pg. 15

Specifications

Input Characteristics

Input Voltage 12 Vdc (10-20), 24 Vdc (18-36), 36 Vdc (21-56),

48 Vdc (36-76),
72 Vdc (55-100)

Power Factor 1.0

Line Regulation 0.2% max. from 10% to full load

Inrush Current 5A peak @ 48 Vdc input

Conducted EMI BTR 2511

Issue 4

Transient Surge EN/IEC 1000-4-2 Level 4

Output Characteristics

Load Regulation 0.2% max. from 10% to 100% load

0.5% max. from 0% to 10% load

Setpoint Accuracy 1% for standard voltages

2% for special or adjustable voltages

Ripple and Noise Std. outputs: 2% or 100 mV p-p max., whichever is greater, 10% min. load

VXI options (

<

24V outputs): 50 mV p-p max for outputs <15 Vdc;

150 mV p-p max. for 24 Vdc outputs

QPAC, DualQPAC, JuniorPAC, RAMPAC: <10mV p-p max.

Overcurrent Protection 105-130% > 5V outputs & DualPACs, JuniorPACs, RAMPACs, DualQPACS,

JuniorQPACs

30-125%

<

5V outputs

Overvoltage Protection ModuPACs and QPACs: 115-135%

N/A to DualPACs, JuniorPACs, BatPACs, RAMPACs, DualQPACs and
JuniorQPACs

Efficiency 83% typical

Output Power 1600W @ 45°C (Output power dependent upon Input voltage)

Environmental Characteristics

Storage Temperature -40°C to +65°C

Operating Temperature C-grade: 0°C to +45°C full power, 0°C to +65°C half power

I-grade: -20°C to +45°C, -20°C to +65°C half power
See temperature derating curves.

Safety Approvals UL 1950 (2nd), CSA C22.2 No. 234, IEC 950, EN 60 950

Product Weights 9.25 lbs (4,2 kg) fully configured

0.7 s (0,32 kg) ConverterPAC

Warranty 1 year

Humidity 0-95% noncondensing

Altitude 15,000 feet maximum. Derates linearly.

Pg. 16 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Rev. 3/04

DC MegaPAC Operator’s Manual

DC MegaPAC Part Numbering

DC MegaPAC MDxA-xCxBxxx x

A

Number of outputs

eg. MD2-N8103 x

B

Number of modules

xxx Assigned by Mission Power Solutions

x

C

DC input voltage range

0 12 Vdc input (10-20V range)

1 24 Vdc input (21-32V range)

W 24 Vdc input (18-36V range)

2 36 Vdc input (21-56V range)

3 48 Vdc input (42-60V range)

N 48 Vdc input (36-76V range)

4 72 Vdc input (55-100V range)

ConverterPAC xCXxDV/xEAx

F

X ConverterPAC type

eg. 3M15V/10A M - ModuPAC L - QPAC (VI-200)

NM15V/10ADFIL D - DualPAC U - UniPAC

D15V/6.7A-12V/8.3AT J - JuniorPAC XL - QPAC (VI-900)

R - RAMPAC LD - DualQPAC (VI-J00)

B - BatPAC

x

C

DC input voltage range (only used for DC MegaPAC ConverterPACs)

0 12 Vdc input (10-20V range)

1 24 Vdc input (21-32V range)

W 24 Vdc input (18-36V range)

2 36 Vdc input (21-56V range)

3 48 Vdc input (42-60V range)

N 48 Vdc input (36-76V range)

4 72 Vdc input (55-100V range)

x

D

Voltage out

x

E

Current out (rounded to 1 decimal point)

x

F

Options (See below*). Can be multiple options.

*ConverterPAC Options

B Booster module M Military Grade module

D DC OK or Power Good (N/A on DualPAC) R RAM external

F Full 50-110% output adjustment S Trimpot removed for external BatPAC adjustment

F1 50-107.5% output adjustment T 90-110% output adjustment

F2 50-105% output adjustment T1 90-107.5% output adjustment

F3 50-102.5% output adjustment T2 90-105% output adjustment

F4 50-100% output adjustment T3 90-102.5% output adjustment

F5 60-110% output adjustment T4 90-100% output adjustment

F6 70-110% output adjustment T5 100-105% output adjustment

F7 80-110% output adjustment T6 100-110% output adjustment

F8 90-110% output adjustment V1 "VXI" low noise (150 mV or less) for 24V outputs

F9 100-110% output adjustment V2 "VXI" low noise (50 mV or less) for outputs < 24V

I Industrial Grade module V3 1% ripple or less for outputs >24V

K Custom SRF module used Z Other special feature

L Local Sense

DC MegaPAC Operator’s Manual

Rev. 3/04 Vicor 800-735-6200 Mission Power Solutions [phone] (phone) or [phone] (fax) Pg. 17

Notes

Vicor Corporation, Corp. Headquarters Vicor Corporation Westcor Division

25 Frontage Road 377 E. Butterfield Road 560 Oakmead Parkway
Andover, MA 01810 Suite 201 Sunnyvale, CA 94085
Tel: [phone] Lombard, IL 60148 Tel: [phone]
Fax: [phone] Tel: [phone] Fax: [phone]

Fax: [phone]

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Tel: [phone] Tel: [phone] Tel: [phone]
Free Phone France Only: Free Phone Germany Only: Fax: [phone]
0800 419 419 0130 18 29 18
Fax: [phone] Fax: [phone]

Vicor Italy Vicor Japan Co., Ltd. Vicor U.K.

Tel: [phone] Tel: [phone] Tel: [phone]
Free Phone Italy Only: Fax: [phone] Free Phone UK Only:
167-899-677 0800-980-8427
Fax: [phone] Fax: [phone]

Mission Power Solutions Inc

4168 Avenida de la Plata, # 105
Oceanside, CA 92056-6030
Tel: [phone]
Fax: [phone]

For more information about this or other Vicor products, or for assistance with component-based power system design,
contact the Vicor office nearest you. Vicor's comprehensive line of power solutions includes modular, high-density DC­DC converters and accessory components, configurable power supplies, and custom power systems.

Information furnished by Vicor is believed to be accurate and reliable. However, no responsibility is assumed by Vicor for its use. No license is grant­ed by implication or otherwise under any patent or patent rights of Vicor. Vicor components are not designed to be used in applications, such as life sup­port systems, wherein a failure or malfunction could result in injury or death. All sales are subject to Mission Power Solutions Terms and Conditions of
Sale, which are available upon request.

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