DS276

Overview

The DS276 is a low-power, line-powered RS-232 transceiver designed for battery-backed systems. It operates on a single 3V or 5V logic supply (VCC) and features full-duplex capability up to 20 kbps. The device steals negative power from the receive signal line (RXIN) during marking states to minimize static current drain. Electrical specifications include a dynamic supply current of 400 µA at VCC=3V with TXIN high, and a static supply current of 10 µA under the same conditions. The transmitter output slew rate is limited to less than 30 V/µs. Operating temperature ranges from 0°C to +70°C.

Feature Summary

• Line-powered operation that steals negative voltage from the RXIN signal line to reduce system power consumption
• Full-duplex serial communication interface compatible with standard RS-232-E signals
• Ultra-low static current draw achieved by maintaining the transmitter in a marking state when idle
• Integrated receiver translates RS-232 levels to CMOS/TTL logic with hysteresis for noise rejection

Applications

• Battery-operated handheld products requiring minimal power drain
• Laptop computers connected to external serial ports
• Remote sensor networks with long cable connections
• Portable medical instruments utilizing serial data transmission

Procurement Notes

Verify component authenticity through official manufacturer channels or authorized distributors. Confirm package type matches design requirements, as the DS276 is available in 8-pin DIP and SOIC formats. Check datasheet revisions for any updates to electrical characteristics or pin assignments before finalizing procurement orders.

Selection Notes

Select the DS276 for applications prioritizing ultra-low power consumption over strict RS-232 compliance. Ensure VDRV+ is maintained at a voltage greater than or equal to VCC. Consider external reservoir capacitors for full-duplex operation to sustain negative supply during spacing states. Verify cable length limitations due to potential voltage drop below standard RS-232 thresholds.

Part Context

The DS276 belongs to the Maxim Integrated family of low-power interface devices. It serves as a specialized solution for serial communication where traditional charge-pump transceivers would deplete battery life excessively. The device bridges the gap between standard RS-232 ports and low-voltage CMOS logic systems.

Replacement Considerations

Direct replacements are not explicitly listed in the provided documentation. Evaluate alternative RS-232 transceivers based on power consumption profiles and compatibility with existing circuit layouts. Ensure substitute components support the specific line-powered negative rail generation technique if low static current is critical.

FAQ

How does the DS276 generate its negative supply voltage?

The DS276 generates its negative supply by stealing current from the RXIN line when it is in a negative marking state. An external capacitor can be used to store this charge for use during positive spacing transitions.

What is the maximum data rate supported by the DS276?

The DS276 supports full-duplex operation at data rates up to 20 kbps.

Is the DS276 fully compliant with all RS-232 signal level requirements?

No, the DS276 is designed for low power rather than strict compliance. Output voltage swings may fall below the ±5V minimum required by the RS-232 specification, though most receivers interpret voltages above 2V correctly.