Diodes Incorporated AS78L12ZTR-E1

Overview

AS78L12ZTR-E1 from Diodes Incorporated is a fixed-output +12V, 100mA positive linear voltage regulator in TO-92 (Ammo Packing) package, featuring internal current limiting, thermal shutdown, and safe-area compensation for robust local regulation. It delivers stable 12V output with ±5% accuracy across –40°C to +125°C, supports input voltages up to 36V, and requires no external components for basic operation - ideal for microprocessor power supplies and motherboard local regulation.

For engineers reviewing the AS78L12ZTR-E1 datasheet, AS78L12ZTR-E1 pinout, AS78L12ZTR-E1 application, or AS78L12ZTR-E1 equivalent, key selection criteria include dropout voltage (1.7V at 40mA), load regulation (≤100mV), PSRR (37–42dB at 120Hz), thermal resistance (θ_JA = 180°C/W), and RoHS-compliant lead-free construction.

Technical Context

This three-terminal monolithic regulator integrates a pass transistor, error amplifier, bandgap reference, and protection circuitry into a single silicon die. Its internal safe-area compensation prevents secondary breakdown under overload, while thermal shutdown activates at ~150°C junction temperature to prevent permanent damage.

The device operates without external capacitors for stability but recommends 0.33µF input and 0.1µF output capacitance. It exhibits 80µV RMS output noise (10Hz–100kHz) and maintains regulation over 1mA–100mA load range with ≤20mV line regulation across its 14.5–27V input window.

Key Specifications

Pinout & Package

AS78L12ZTR-E1 uses the TO-92 (Ammo Packing) package: 3-pin, through-hole, plastic case with standard lead spacing (2.54mm pitch). Pin 1 is INPUT, Pin 2 is GND, Pin 3 is OUTPUT - verified per Diodes DS36515 Rev. 5-2 Figure 1 (R Package).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L12ACZ and MC78L12CP, AS78L12ZTR-E1 offers superior PSRR (37–42dB vs. ≤30dB), lower noise (80µV vs. ≥120µV), and modern RoHS 3 compliance - making it optimal for noise-sensitive, thermally constrained, and environmentally regulated designs.

Availability

AS78L12ZTR-E1 is available at Aetrix Electronics and suitable for consumer electronics power supplies, microprocessor I/O rails, and motherboard local regulation requiring stable component supply, long-lifecycle support, and RoHS 3 compliance.

Supply support for AS78L12ZTR-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 semiconductor company specializing in discrete, analog, and mixed-signal devices, with design, manufacturing, and distribution operations across Asia, Europe, and North America.

The AS78LXX series targets cost-effective, reliable local regulation in space-constrained applications - designed for simplicity, ruggedness, and broad temperature operation without external compensation.

FAQ

What is the maximum allowable input voltage for AS78L12ZTR-E1?

The absolute maximum input voltage is 36V, but the recommended operating range is 14.5V to 27V per Diodes DS36515 Rev. 5-2. Exceeding 27V increases power dissipation and thermal stress without functional benefit, and sustained operation above 30V risks accelerated degradation even within absolute ratings.

Does AS78L12ZTR-E1 require input and output capacitors?

While functional without external capacitors, Diodes specifies 0.33µF aluminum or tantalum input and 0.1µF ceramic output capacitors for stability and noise suppression. Omitting them may cause oscillation under light loads or increase output ripple beyond datasheet limits, especially above 10kHz.

Can AS78L12ZTR-E1 be used in automotive applications?

AS78L12ZTR-E1 is not AEC-Q100 qualified. Diodes explicitly states that automotive-grade versions require specific change control, PPAP capability, and IATF 16949 manufacturing - none of which apply to this part. Use only in commercial/industrial environments unless validated per customer-specific automotive qualification protocols.

How does thermal shutdown behave during overload?

Thermal shutdown activates at approximately 150°C junction temperature, halting output conduction until die temperature falls below ~130°C. Recovery is automatic and non-latching; however, repeated cycling indicates inadequate heatsinking or excessive ambient temperature - verify θ_JA = 180°C/W and derate power accordingly.