KA7631

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Overview

The KA7631 is a multi-output positive voltage regulator providing fixed precision outputs of 5.1V at up to 0.5A, 9V at up to 0.5A, and 12V at up to 1A with an external PNP transistor. It features a reset facility for Output 1, TTL input disable for Outputs 2 and 3, and protection against overvoltage, short circuits, and thermal shutdown.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Feature Summary

• Provides three fixed precision output voltages: 5.1V, 9V, and 12V.
• Includes internal reset circuitry that generates a pulse when Output 1 drops below the regulated value.
• Outputs 2 and 3 can be disabled via a TTL-compatible input signal.
• Integrates current limit protection, overvoltage protection, and thermal shutdown mechanisms.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Applications

• Multi-rail power supply systems requiring stable 5V, 9V, and 12V rails
• Embedded systems needing integrated voltage regulation and reset generation
• Industrial control units utilizing TTL-based output enable/disable logic

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Procurement Notes

Verify the specific part number suffix and manufacturer origin, as Fairchild Semiconductor assets have been acquired by onsemi. Confirm package type (10-SIP-H/S) and operating temperature range (0°C to +125°C). Ensure compatibility with legacy design requirements referencing original Fairchild documentation.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Selection Notes

Select this component for designs requiring simultaneous 5.1V, 9V, and 12V regulation without complex feedback networks. The KA7631 differs from the KA7630 primarily in its second output voltage (9V vs 8V). Use the external transistor configuration if Output 3 requires currents exceeding 0.5A.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Part Context

The KA7631 belongs to a family of fixed multi-output regulators designed to simplify power distribution in compact electronic systems. It consolidates multiple linear regulation functions into a single SIP package, reducing board space and component count compared to discrete solutions.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Replacement Considerations

The KA7630 is a direct functional substitute with identical pinout and features, differing only in Output 2 voltage (8V instead of 9V). Verify system tolerance for the 9V rail before swapping between these variants.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators FAQ

How is the reset delay time determined?

The reset pulse delay is determined by an external capacitor connected to the DEL.CAP pin. The delay time is calculated using the formula Trd = (Cd × 2.5) / 10µA.

What is the maximum current capability of Output 3?

Output 3 can deliver up to 1A when used with an external PNP transistor. Without the external transistor, it is limited to lower currents defined by the internal circuitry.

Can all outputs be disabled simultaneously?

Only Outputs 2 and 3 can be disabled via the TTL input. Output 1 does not have a disable function but has a reset facility.