onsemi KA7906

Overview

KA7906 from ON Semiconductor is a fixed-output, three-terminal negative voltage regulator delivering −6.0 V at up to 1 A output current, featuring internal thermal overload protection, short-circuit protection, and safe operating area compensation. It operates across 0°C to +125°C and maintains regulation with input voltages down to −9 V and up to −21 V in standard operation.

For engineers reviewing the KA7906 datasheet, pinout, applications, or equivalent options, this device serves as a drop-in replacement for legacy Fairchild KA7906TU and LM7906 variants in industrial power supplies, dual-rail analog systems, and embedded negative bias generation where stable −6 V rail integrity is critical under load and temperature variation.

Technical Context

The KA7906 implements a monolithic bipolar linear regulator architecture with built-in current limiting, thermal shutdown, and SOA-compensated output transistor. Its feedback loop stabilizes output voltage against line (input) and load variations using an internal bandgap reference and error amplifier.

It requires minimal external components: a 2.2 μF input capacitor (solid tantalum) and 1 μF output capacitor for stability and transient response. The device exhibits 2 V dropout at 1 A, 54–60 dB ripple rejection at 120 Hz, and −0.5 mV/°C temperature coefficient - confirming its suitability for precision negative supply rails in mixed-signal environments.

Key Specifications

Pinout & Package

KA7906 is housed in a TO-220 package (JEDEC variation AB), with leads designed for vertical mounting and heatsink attachment via the metal tab (pin 2). The case is electrically connected to pin 2 (Input).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar negative fixed-voltage regulator applications.

Compared with LM7906CT and KA7906A, the KA7906 provides optimal balance of cost, noise, and thermal robustness for industrial analog power rails, while KA7906A suits higher-accuracy needs and LM7906CT fits legacy National Semiconductor-based designs where minor spec trade-offs are acceptable.

Availability

KA7906 is available at Aetrix Electronics and suitable for industrial power supplies, analog signal conditioning, dual-rail audio preamps, and embedded control biasing requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for KA7906 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

ON Semiconductor (formerly Fairchild Semiconductor) is a global leader in intelligent power and sensing solutions, serving automotive, industrial, cloud computing, and consumer markets with high-reliability semiconductor components.

The KA7906 belongs to the KA79XX series of three-terminal negative regulators, designed specifically for robust, low-cost, fixed-voltage negative rail generation in industrial control, instrumentation, and legacy analog systems where simplicity and proven reliability are paramount.

FAQ

What is the maximum input voltage rating for KA7906?

The KA7906 has an absolute maximum input voltage of −35 V. However, for reliable continuous operation within specifications, the recommended input range is −9 V to −21 V. Exceeding −21 V increases power dissipation and thermal stress, requiring careful heatsink design to maintain junction temperature below 125°C. Always verify worst-case VI and IO conditions in your application before finalizing the input supply.

Does KA7906 require external capacitors, and what values are recommended?

Yes, KA7906 requires both input and output capacitors for stability and performance. A minimum 2.2 μF solid tantalum capacitor (CI) is required at the input, especially if the regulator is located remotely from the bulk filter. A 1 μF capacitor (CO) is required at the output to ensure transient response and loop stability. Aluminum electrolytic capacitors may be used if their value is ≥10× the specified minimum, and a reverse-protection diode (e.g., 1N4001) is added if CO exceeds 10 μF.

Can KA7906 be used in parallel to increase output current?

No, KA7906 is not designed for parallel operation. Its output voltage tolerance (±5%) and lack of current-sharing features mean paralleling units will cause unequal current distribution and potential thermal runaway. To deliver >1 A, use a higher-current regulator (e.g., KA7912 for −12 V with external pass transistor) or select a dedicated high-current negative regulator. Derating the KA7906 to 700 mA with enhanced heatsinking is safer than paralleling.

Is KA7906 pin-compatible with LM7906?

Yes, KA7906 is fully pin-compatible with LM7906 in TO-220 packages: Pin 1 = GND, Pin 2 = Input, Pin 3 = Output. Both share identical pinout, footprint, and basic electrical behavior. However, KA7906 offers superior thermal resistance (5°C/W vs. ~6.5°C/W for LM7906), lower typical noise (130 μV vs. 280 μV), and tighter line regulation - making it a functional and performance upgrade in most LM7906 designs.

What is the dropout voltage of KA7906, and how does it affect minimum input voltage?

The KA7906 has a dropout voltage of 2 V at 1 A load and +25°C. This means the input must be at least 2 V more negative than the output (i.e., ≤ −8 V) to maintain regulation. At higher temperatures or lower loads, dropout decreases slightly. For example, at 500 mA and 25°C, dropout is typically 1.8 V. Always include margin for line sag and temperature drift - design for VI ≤ −8.5 V minimum under worst-case conditions to ensure regulation across the full operating range.