B4-51

• –40°C to +85°C operation

• 16 to 32 VDC input voltage

• Fully isolated

• Opto-coupler feedback

• Switching frequency

Single and dual outputs

typical 80 kHz, variable freq.

Triple output 200 kHz, fixed

• Topology – Flyback

• Inhibit function

• Indefinite short circuit protection

• Up to 75% efficiency

• Requires external capacitors

DESCRIPTION

The HR40 Series™ DC/DC converters offer the high efficiencies

associated with switching regulators, yet have full isolation of input

and output grounds. The units are built using thick-film hybrid tech-

nology and are sealed in metal packages for high-reliability applica-

tions. All models are guaranteed to pass a gross leak test (maximum

The HR40 Series devices are flyback energy storage switching

regulators which require a minimum of components resulting in

small package size. Single and dual models self-oscillate at an

operating frequency which is an approximate inverse function of the

load. At full load, the frequency is typically 80 kHz for single and dual

output models. Triple output models operate at a fixed frequency of

approximately 200 kHz. A transformer in the forward power circuit

and an opto-coupler in the feedback/control loop maintain input to

output isolation.

Models are available with single 5 volt, dual 12 or 15 volt, or triple

(+5 and either ±12 or ±15) outputs with an input voltage range of 16

to 32 VDC. Output power of up to 4 watts is available from the dual

output models for either balanced or unbalanced loads; however, at

least 25% of the total load should be on the positive output. The

single output device can provide 3.5 watts, and the triple output can

supply up to 3.2 watts. The high efficiency is almost constant over

the entire input voltage range and from approximately 25% of full

load to full load. This makes the unit ideal for battery applications.

An open collector TTL inhibit is provided to allow power shutdown

and startup from a logic input. An open circuit on the inhibit terminal

(pin 15) gives normal operation, and a TTL low level shuts down the

converter. The inhibit pin has an open circuit voltage of 12 to 28 V.

Input current in the shutdown mode will be less than 15 mA. Current

limiting is provided on each output for indefinite short circuit protec-

tion.

Due to the high efficiency, heat sinking requirements are minimized,

but consideration should be given to removing self-generated heat

when operating these devices at maximum ratings. To increase

dissipation, heat conducting material (PCB, copper sheet, heat sink,

etc.) should be brought into contact with the converter’s baseplate.

The converter can be operated at full load at a case temperature of

85°C, with the output power derated linearly to zero at 105°C.

External capacitors are required on the outputs. Operating the unit

without external capacitors will result in damage to the internal

circuitry. Minimum recommended capacitor values are given in

Tables 1 and 2. For optimum performance, low ESR (Equivalent

Series Resistance) solid tantalum capacitors are required. The

specifications on the following pages are based on the use of high-

quality solid tantalums. Operation with different types of capacitors

will seriously affect performance.

HR40 SERIES

4 WATT

Size (max.): 1.075 x 1.075 x 0.370 inches (27.31 x 27.31 x 9.40 mm)

See Section B8, case C2, for dimensions.

Weight:

20 grams maximum

Screening:

Standard only. See Section C2 for screening description.

MODELS

SINGLE

5

DUAL

±12

±15

TRIPLE

+5 & ±12

+5 & ±15