to Baseplate Mounting Temperature 50W Power Output, +15V, -12V and ­15V Output Versions Available s 50V Input Bus s Internal EMI Suppression Circuitry designed to meet the requirements MIL-STD-461C s Short Circuit Protected X LA Input Undervoltage Shutdown F s Output Overvoltage Shutdown s Overtemperature Shutdown s Input Shutdown Control 9001 s Input Synchronization Control E s Output Synchronization Control RTIFIE D s Output Status Signal s Packaging ­ Non-Hermetic COB 4" x.9" housing with D connector

Aeroflex's ACT861X series of power supply modules are radiation hardened 50 Watt units designed for use in space applications. Using a double ended forward topology with synchronous rectifiers achieves high efficiency, and the use of Chip-On-Board (COB) construction together with planar magnetics allows Aeroflex to provide space quality components at down-to-earth prices. The ACT861X series are full featured single output converters, with EMI filtering, short circuit protection, input undervoltage shutdown, output overvoltage shutdown, overtemperature shutdown, input shutdown control and synchronization on both input and output sides. Other output voltages are available upon request. Aeroflex's ACT861X series of power supply modules are radiation hardened 50 Watt units designed for use in space applications. The block diagram shown in Figure 1 uses a two transistor (double ended) forward topology to minimize voltage stresses on the semiconductors, and synchronous rectifiers are used to achieve high efficiency. These full featured converters are intended to be used in the space environment, conduction cooled to a baseplate and interconnected to the system via a D connector. The converter includes features such as input undervoltage shutdown, output overvoltage shutdown, overtemperature shutdown, input shutdown control and synchronization on both input and output sides. No optocouplers are used in the converter to assure long term total dose hardness. The ACT861X series is fabricated as an encapsulated Chip-On-Board module in an aluminum housing. The Outline Drawing is shown in Figure 2. The input undervoltage shutdown disables the converter when the input bus is below the minimum specified setpoint. Nominal input current will be the shutdown current specified. This prevents the converter from generating low output voltages in the event of bus undervoltages and drawing high input currents when attempting to power the rated load with these low bus input voltages. When the input bus voltage is above the minimum specified in Table 1 the converter commences operation. Overtemperature protection is integral to the ACT861X series. An internal temperature sensor mounted near the higher power dissipating components shuts the converter off if the mounting temperature is above the threshold specified in Table 1. When the converter cools off it will turn back on with no cycling of input power required. The output overvoltage circuit uses a portion of the output voltage derived to power the internal logic (the bootstrap supply) to measure indirectly the output voltage. This voltage is sensed, and if it exceeds a predetermined threshold the converter will cycle at a nominal 100Hz frequency attempting to restart. Control of the ACT861X is achieved via the INHIBIT pin. This pin may be used as both an internal temperature monitor and to control the module. When INHIBIT is shorted to the IN_COM pin the module is disabled. Nominal current flowing through the INHIBIT line at this time is less than 1mA, and the on/off threshold is 6V above the negative return. When the converter temperature sensor at ­55°C the INHIBIT line will be approximately 85°C it will be approximately 6.7V. This affords the user a convenient way to measure the converter internal temperature. Synchronization may either be referenced to the output ground of the converter or input ground. When synchronization is referenced to the input ground a low impedance clock waveform, approximately 50% duty cycle, TTL compatible between 450 and 500KHz, should be applied to the SYNC_IN terminal and the IN_COM terminal. This will synchronize the switching power converter although not the feedback oscillator. it is desired to synchronize both the power converter and feedback oscillator a low impedance clock waveform, approximately 50% duty cycle, TTL compatible between 450 and 500KHz, should be applied to the SYNC_OUT terminal and the OUT_COM terminal. The STATUS output is an open collector signal, active low, referenced to OUT_COM that is asserted when the output voltage is within ±10% of the nominal output voltage.

Parameter Nominal Output Voltage Regulation, No Load to Full Load Stability, Over Operating Temperature Regulation, Over Line Voltage Ripple Output Overvoltage Shutdown Efficency, at Full Load Output Current Output Current Limit Output Voltage Accuracy Output Power Input Voltage Input Voltage Input Voltage, Transient Input EMI Input Undervoltage Threshold Input Current, at Full Load Input Current, at No Load Input Current, Shutdown Asserted Input Output Isolation Switching Frequency Transient Response Overshoot Output Short Circuit Duration Radiation, Total Dose Radiation, SEE/SEB Thermal Shutdown, Case Operating Temperature, Case Storage Temperature

Amperes, Maximum Amperes, Maximum % W, Maximum Volts, Minimum Volts, Maximum Volts, Maximum for 1 second ­ Volts, Maximum Amperes, Maximum Amperes, Maximum mAmperes, Maximum ­ KHz, Nominal ­ KRad (Si), Maximum MeV/cm2/mg, Maximum Minimum ­

50% load change, 5% Maximum deviation, returns to regulation band 1msec. At Turn On, Turn Off and Power Failure: None Will Withstand continious short without damage to +125°C