MIL-STD-704 Power Supplies

When you select a power supply for airborne equipment, the input source is not ordinary facility power. The supply becomes utilization equipment on the aircraft electric power system, and its input behavior affects power quality, source loading, transient response, upstream protection, thermal design, electromagnetic compatibility, and qualification results.

MIL-STD-704 defines the aircraft electric power characteristics provided at the input terminals of utilization equipment. It is an interface standard: the aircraft power system must provide power within the defined limits, and the connected equipment must operate, degrade safely, or recover as specified by the equipment detail specification.

Treating MIL-STD-704 as an input-power architecture requirement early, rather than a checkbox during qualification, is what keeps power conversion from becoming a late-stage integration problem. This page explains what MIL-STD-704 asks of a power supply and helps you match the requirement to the right Abbott architecture.

What MIL-STD-704 Asks of Your Power Supply

MIL-STD-704 is not simply a voltage list. It defines aircraft power behavior across operating conditions, and it places constraints on how utilization equipment behaves as a load. For power conversion hardware, that affects:

The practical takeaway: choose the supply as part of the aircraft power architecture, not as a late-stage commodity component.

Start With the Aircraft Power Type

The fastest way to narrow the selection is to identify the input power type first. MIL-STD-704 applications commonly separate into fixed-frequency AC, variable-frequency AC, 28 Vdc low-voltage DC, 270 Vdc high-voltage DC, and single-phase 60 Hz support power. Each path points to a different power-conversion architecture.

MIL-STD-704F Power Limits (Quick Reference)

MIL-STD-704F sets the voltage and frequency limits for each aircraft power type across normal, abnormal, transient, emergency, and starting conditions. Normal steady-state values are shown below. Abnormal and transient limits are defined as time-voltage envelopes; the peak excursions and controlling figures are noted so you can size input protection and holdup correctly.

Matching AC Input Coverage to MIL-STD-704

Several Abbott AC-DC switcher families accept a 95-260 Vac, 47-440 Hz single-phase input with power factor correction. That input window covers many common fixed-frequency aircraft AC cases, including 115 Vac at 400 Hz, 115 Vac at 60 Hz, and 230 Vac fixed-frequency single-phase inputs where the aircraft power architecture permits that connection.

This same wide-input architecture can reduce part-count and qualification burden when the same equipment family must support both aircraft and shipboard-derived AC inputs. For shipboard AC power, see our MIL-STD-1399 Section 300 guide.

Abbott Power Products for MIL-STD-704 Applications

Match your input power type, power level, output rails, environment, and evidence requirements to the appropriate Abbott architecture below. The AM200, AS200, CM500, CS500, and CM1000 switcher families use a 95-260 Vac, 47-440 Hz single-phase, power-factor-corrected input and are designed to meet MIL-STD-704 input requirements. The LDC200 addresses the 28 Vdc aircraft bus, the TR400 addresses 400 Hz three-phase AC-to-DC transformer rectifier requirements, and the LPS supports low-noise linear power and form-fit-function replacement.

	Series	Power	Configuration	Input	Output	Best for
	LDC200	200 W	Rugged 28 Vdc DC-DC converter, holdup option for undervoltage ride-through	18-36 Vdc MIL-STD-704 28 Vdc bus	3.3-28 Vdc standard outputs	28 Vdc aircraft bus conversion, intermediate/distribution bus, point-of-load rails, sensitive electronics, and pulsed loads
	TR400	100 W-100 kW unregulated; 1-15 kW regulated	400 Hz three-phase AC-to-DC transformer rectifier unit; inherent harmonic suppression, passive power factor correction	115 V delta; 115/200 V wye or 200 V delta, 400 Hz, 3φ	24, 28, 280, 300 Vdc; other voltages on request	Three-phase 400 Hz aircraft power, high-power bulk DC, DC distribution, and regulated or unregulated DC outputs
	AM200	200 W	Sealed single-phase AC-DC, IP65/IP67, MS3470 connectors	95-260 Vac, 47-440 Hz, 1φ	Configurable DC	Sealed airborne or multi-domain electronics requiring 115 Vac or 230 Vac AC input
	AS200	200 W	Rugged single-phase AC-DC	95-260 Vac, 47-440 Hz, 1φ	Configurable DC	Rugged 200 W AC-DC conversion where full sealing is not required
	CM500	500 W	Sealed single-phase AC-DC, IP65/IP67, MS3470 connectors	95-260 Vac, 47-440 Hz, 1φ	Configurable DC	Sealed 500 W aircraft AC applications; confirm single-phase allocation and load-balance requirements
	CS500	500 W	Rugged single-phase AC-DC, parallelable with single-wire current sharing	95-260 Vac, 47-440 Hz, 1φ	Configurable DC	Higher-power regulated DC rails where rugged packaging and current sharing are required
	CM1000	1000 W	Sealed single-phase AC-DC	95-260 Vac, 47-440 Hz, 1φ	Configurable DC	Power-dense aircraft AC applications where the aircraft power allocation supports the selected single-phase input
	LPS	12-210 W	Linear AC-DC; form-fit-function legacy replacement	105-125 Vac, 55-65 Hz or 380-420 Hz, 1φ	Single and dual outputs available	Low-noise linear rails, legacy replacement, DMSMS sustainment, and applications where the specified AC input matches the LPS configuration

Getting the Selection Right

The hard part of MIL-STD-704 is rarely the nominal voltage. It is ensuring the equipment behaves correctly during the operating conditions the program invokes and that the supply does not degrade the aircraft power system.

• Design to the full envelope, not the nominal voltage. The supply must survive and, where specified, keep operating through the abnormal, transient, emergency, and starting limits above, not just the normal steady-state band.
• Use the right architecture for three-phase 400 Hz power. For three-phase AC-to-DC conversion, start with the TR400 transformer rectifier unit rather than forcing a single-phase AC-DC supply into a three-phase allocation problem.
• Confirm single-phase authorization and load balance. For 500 W and 1000 W single-phase AC-DC selections, confirm aircraft power allocation, load balance, and detail-spec requirements before locking the architecture.
• Size transformer rectifier units around the real load profile. TRU harmonic-current performance depends on loading, so avoid nameplate margin that leaves the unit operating far below the qualification load condition.
• Separate input compatibility from EMI compliance. MIL-STD-704 does not cover electromagnetic interference or voltage spikes. Plan MIL-STD-461, shielding, filtering, bonding, and transient-protection strategy at the equipment level.
• For the 28 Vdc bus, check undervoltage and holdup early. The LDC200 accepts the MIL-STD-704 28 Vdc bus over 18-36 Vdc, and under-voltage continued operation is available with a holdup option. Select that option based on the required performance during low-voltage and starting events.

Selection Checklist

Define these items before you commit to a power supply:

Integrating the Supply

A MIL-STD-704-compatible power supply still needs a disciplined installation. Treat the power entry as an integrated subsystem:

• Keep input power, output power, and low-level control or sense wiring separated where practical.
• Use the aircraft grounding and bonding approach; do not use the chassis as a power return unless explicitly allowed by the program architecture.
• Terminate shields consistently at connectors and backshells.
• Place EMI filters close to the power entry when they control conducted emissions at the enclosure boundary.
• Route remote-sense leads as a controlled pair, and connect them on the power-supply side of any output protection that can interrupt the DC output path.
• For transformer rectifier units, verify phase wiring, phase-loss behavior, cooling method, and mounting orientation.
• Verify thermal performance at worst-case ambient, altitude, mounting orientation, load, and cooling condition.

The goal is to make the qualification configuration look like the installed configuration.

How Abbott Supports Your MIL-STD-704 Requirement

Abbott builds power conversion hardware for programs where electrical performance, environmental survivability, configuration control, and lifecycle support all matter. Our AC-DC switchers support aircraft AC input applications where 95-260 Vac, 47-440 Hz single-phase power is the right architecture. The LDC200 Series supports the MIL-STD-704 28 Vdc aircraft bus, the TR400 Series supports 400 Hz three-phase AC-to-DC transformer rectifier applications, and the LPS Series supports low-noise linear power and form-fit-function replacement.

We configure standard products electrically and mechanically to fit the application, maintain full configuration control, and support customers from consultation and prototyping through production and legacy sustainment. Abbott is AS9100 and ISO 9001 certified, and does not obsolete products without full consideration.