Diodes Incorporated AS7809ADTR-E1

Overview

AS7809ADTR-E1 from Diodes Incorporated is a fixed-output +9V, 1A three-terminal positive linear voltage regulator in TO-252-2 (5) package with ±4% output voltage accuracy over –40°C to +125°C, internal short-circuit limiting, thermal shutdown, and safe-area protection-designed for post-regulation in switching power supplies and microprocessor core power on motherboards.

For engineers reviewing the AS7809ADTR-E1 datasheet, AS7809ADTR-E1 pinout, AS7809ADTR-E1 application, or AS7809ADTR-E1 equivalent, this device serves as a drop-in replacement for legacy 78xx-series regulators where 9V output, RoHS-compliant green packaging, and high-temperature stability are required in telecom and embedded control systems.

Technical Context

The AS7809ADTR-E1 implements a monolithic series-pass transistor architecture with bandgap reference, error amplifier, and current-limiting circuitry integrated into a single silicon die. It delivers regulated 9V output across input voltages up to 32V while maintaining line regulation ≤120mV and load regulation ≤120mV at 1A.

Thermal protection activates at +150°C junction temperature, and safe-area compensation prevents secondary breakdown during overload. Its TO-252-2 (5) package provides θ_JA = 100°C/W and θ_JC = 16°C/W, enabling 1A continuous operation with minimal heatsinking in compact PCB layouts.

Key Specifications

Pinout & Package

AS7809ADTR-E1 uses the TO-252-2 (5) surface-mount package (also labeled TO252 Type CJ), featuring a thermally enhanced exposed pad for improved heat dissipation. The package measures 10.4 × 6.2 mm with 2.54 mm lead pitch and is RoHS-compliant, halogen-free, and "Green" per Diodes' definition.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output linear regulator applications.

Compared with LM7809CDT-TR and MC7809BDTRKG, AS7809ADTR-E1 offers superior thermal resilience (150°C shutdown), full RoHS 3/Green compliance, and integrated safe-area protection-making it optimal for thermally demanding, environmentally regulated deployments.

Availability

AS7809ADTR-E1 is available at Aetrix Electronics and suitable for telecom power management, industrial PLC I/O modules, and motherboard peripherals requiring stable component supply, long-lifecycle support, and RoHS 3-compliant sourcing.

Supply support for AS7809ADTR-E1 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in IATF 16949-certified facilities.

The AS78XXA series was developed to replace legacy 78xx regulators with enhanced thermal safety, green packaging, and tighter parametric consistency for modern high-density power architectures.

FAQ

What is the maximum input voltage for AS7809ADTR-E1?

The absolute maximum input voltage is 36V, but the recommended operating range is 17.9V to 30V per the datasheet's Recommended Operating Conditions table. Exceeding 30V risks exceeding safe power dissipation limits at full 1A load, especially above 85°C ambient.

Does AS7809ADTR-E1 require external capacitors?

Yes: a minimum 0.33µF ceramic capacitor must be placed between INPUT and GND within 10mm of the device, and a minimum 0.1µF ceramic capacitor between OUTPUT and GND adjacent to the output pin. These are mandatory for stability and transient response per Figure 1 in DS36562 Rev. 7-2.

Is AS7809ADTR-E1 pin-compatible with standard 7809 regulators?

Yes, in TO-252-2 (5) configuration: Pin 1 = INPUT, Pin 2 = GND, Pin 3 = OUTPUT matches industry-standard 78xx pinout. However, note that some competing TO-252 variants use different pin assignments (e.g., Pin 1 = OUTPUT), so footprint verification against Diodes' package drawing is essential.

What thermal performance can be expected with no heatsink?

In still air with standard 1oz copper on a 2-layer PCB, AS7809ADTR-E1 in TO-252-2 (5) achieves θ_JA = 100°C/W. At 1A and 25°C ambient, junction temperature rises ~100°C - reaching 125°C, near its operational limit. For continuous 1A operation, a 25°C/W heatsink or 4-layer board with thermal vias is recommended.