LDC200 DC DC Converter
DC to DC Converters

LDC200 Series

  • Category DC to DC Converters
  • Type Rugged Environment 28V Converters
  • Power 200 Watts
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LDC200 Series Introduction

The 28 V power subsystem in one box.

The LDC200 series is a 200 W single-output military DC-DC converter for airborne and ground platforms on the MIL-STD-704 28 VDC bus. It is an isolated, all-in-one replacement for what integrators normally assemble from parts: the converter, input EMI filtering designed to meet MIL-STD-461 CE101/CE102, continued operation through MIL-STD-704 transients to 80 VDC, and the protection set, packaged in one sealed, connectorized unit of 3.50 × 6.85 × 1.125 in and 2.0 lb maximum, with one DB-25 for power, sense, and control. It accepts the full 18–36 V input envelope and delivers standard outputs from 3.3 to 28 VDC. Efficiency reaches 91% minimum (93% typical) on the 28 V model at full load, and the unit holds full 200 W output to +85 °C baseplate, conduction-cooled, with no derating. For mission computers, communications, displays, and general platform electronics, it is the drop-in answer to the typical module-plus-filter-plus-suppressor assembly. Designed, built, and tested in-house, and priced as a standard catalog product.

The LDC200 pairs fast transient response (recovery from a no-load-to-full-load step in under 100 µs) with tight regulation (±0.1% line; ripple and noise down to ±0.3% on the 15–28 V models) and stability into unlimited output capacitance. That pairing lets one unit do dual duty. Fast-stepping digital loads such as processors, FPGAs, and GPUs get a rail that does not dip toward brownout when the load steps. Noise-sensitive analog loads such as receiver rails, sensor bias, and electro-optics get an output quiet and stiff enough not to require the usual linear post-regulator. The efficient switching topology enables the precision regulation with no linear-stage heat penalty. Integration margin built into a standard catalog unit.

One part number, both jobs. Standardizing the LDC200 across ordinary and sensitive 28 V loads allows for shortening the approved-parts list, consolidating sparing, aggregating volume onto one part number, and streamlining qualification.

Key Features

  • Wide Input Range
  • High Efficiency
  • Ultra-Precise <±0.1% Line and Load Regulation
  • Load Step Response <1% No Load to Full Load, <100μS
  • MIL-STD-461 CE102 Input
  • Compact, Lightweight Form Factor
  • MIL-STD-810 Environmental Requirements
  • Dual Duty Standard and Sensitive Loads

Specifications

  • DC INPUT
    MIL-STD-704 Input Power 28 VDC (18-36V) for Normal, Abnormal, Emergency Steady State Voltage.
    Under-voltage continued operation available with holdup (H) option.
  • EFFICIENCY
    91%-75% Min by Vout
    (93% Typ. for 28V)
  • LINE REGULATION
    ±0.1%
  • LOAD REGULATION
    ±0.1% to ±0.3% by Vout
  • RIPPLE AND NOISE (PARD)
    ±0.3% to ±2.0% by Vout
    When measured with 20MHz Bandwidth

  • LOAD TRANSIENT RESPONSE
    <0.5% to 2.0% by Vout
    No Load to Full Load
    <100μS
  • ISOLATION
    Dielectric Withstanding Voltage
  • DWV: INPUT TO OUTPUT
    200VDC
  • DWV: INPUT TO CASE
    200VDC
  • DWV: OUTPUT TO CASE
    200VDC
  • TEMPERATURE (STORAGE)
    -50°C to +100°C
  • TEMPERATURE (OPERATING)
    -40°C to +85°C baseplate with no power derating
  • CIRCUIT PROTECTION
    Each unit is completely protected against a short circuit or overload of any duration. The current limit is nominally set at 120% of full load. The output voltage automatically restores to normal when the short is removed.
  • INPUT PROTECTION
    Over-voltage continued operation up to 80 VDC transients (MIL-STD-704), under-voltage shutdown (holdup option available separately).
  • OVER TEMPERATURE PROTECTION
    Over-temperature shutdown +110°C±5°C, typical
  • REMOTE SENSING
    Compensates for voltage drop up to limits of input power. Unit operates at nominal voltage with sense lines disconnected.
  • CAPACITIVE LOADING
    Output load capacitance is unlimited.
  • CONTROL FEATURES
    ON/OFF “INHIBIT” - Short inhibit lines together, or apply TTL LOW from +INHIBIT to -INHIBIT.
  • WEIGHT
    2.0lbs max
  • ENVIRONMENTAL CONDITIONS
    MIL-STD-810
    Shock: Method 516.6, Procedure IV
    Vibration: Method 514.5
    Humidity: Method 507 (Converter operates without any evidence of degraded performance in non-condensing relative humidity up to 95%. All assemblies conformal coated).
    Altitude: Method 500.4, Procedure I & II
    Salt Fog: Method 509.4
    High Temperature: Method 501.4, Procedure I & II
    Low Temperature: Method 502.4, Procedure I
    Sand and Dust: Method 510.4, Procedure I & II
    Explosive Atmosphere: Method 511.4, Procedure
    Acceleration: Method 513.5, Procedure I & II
  • CONNECTOR (J1)
    DB25 163A17549X, MATE: 164X11789X
  • MATERIAL
    Aluminum 6061-T6 or eq
  • FINISH (BASEPLATE)
    Chemical Film MIL-DTL-5541, Type II, Class 3 (Clear)
  • FINISH (COVER)
    Anodize MIL-PRF-8625 Type 2 Class 2 (Black)
Fast, Stable Power for Mission Critical Loads

Low droop + fast recovery during high dI/dt load steps helps keep downstream electronics in regulation (reset immunity, tighter voltage margin).

Ideal for loads with large, fast current steps, such as Pulsed RF front ends (radar/EW, active antennas, T/R modules), software-defined radios, mission/AI compute nodes (CPU/FPGA/GPU), networked communications, and sensor processing where transient stability drives filtering size, architecture complexity, and qualification risk.

LOAD TRANSIENT RESPONSE, NL-FL:

INPUT: 28VDC
OUTPUT: 15VDC @ 13.3A, RESISTIVE LOAD
LOAD TRANSIENT DEVIATION OF 100mV (0.66%)
100μS RECOVERY TIME

 

LOAD TRANSIENT RESPONSE COMPARISON WITH TYPICAL DC-DC CONVERTER:

INPUT: 28VDC
OUTPUT: 20VDC @ 10.0A, RESISTIVE LOAD
OUTPUT VOLTAGE DEVIATION:
LDC200: 70mV (0.35%), COMPETITION: 580mV (2.80%)
OUTPUT VOLTAGE RECOVERY TIME:
LDC200: 100μS, COMPETITION: 1300μS

Mechanical Drawings

 

Standard Models

Model Number OUTPUT VOLTAGE OUTPUT CURRENT LINE REGULATION LOAD REGULATION RIPPLE AND NOISE (PARD) LOAD TRANSIENT RESPONSE (NL-FL) TURN ON OVERSHOOT EFFICIENCY (FULL LOAD) OUTPUT POWER
LDC200S3.3 3.3VDC 16.67A ±0.1% ±0.3% ±2.0% <2.0%,100μS <0.2% 75% MIN 55W
LDC200S5 5.0VDC 16.67A ±0.1% ±0.2% ±1.0% <2.0%,100μS <0.2% 80% MIN 83W
LDC200S12 12VDC 16.67A ±0.1% ±0.1% ±0.5% <2.0%,100μS <0.2% 88% MIN 200W
LDC200S13.6 13.6VDC 14.71A ±0.1% ±0.1% ±0.5% <1.0%,100μS <0.2% 88% MIN 200W
LDC200S15 15VDC 13.33A ±0.1% ±0.1% ±0.5% <1.0%,100μS <0.2% 89% MIN 200W
LDC200S24 24VDC 8.33A ±0.1% ±0.1% ±0.3% <0.5%,100μS <0.2% 90% MIN 200W
LDC200S28 28VDC 7.14A ±0.1% ±0.1% ±0.3% <0.5%,100μS <0.2% 91% MIN (93% TYP) 200W