Diodes Incorporated AZ78L09RTR-E1

Overview

AZ78L09RTR-E1 from BCD Semiconductor Manufacturing Limited is a fixed-output +9V, 100mA three-terminal positive linear regulator in SOT-89 package, featuring ±5% output voltage tolerance over –40°C to +125°C, internal short-circuit current limiting, and thermal shutdown protection. It delivers stable local regulation for microprocessor I/O rails and post-regulation of switching supplies.

For engineers reviewing the AZ78L09RTR-E1 datasheet, AZ78L09RTR-E1 pinout, AZ78L09RTR-E1 application, or AZ78L09RTR-E1 equivalent, key selection criteria include dropout voltage (1.6V), quiescent current (3–5mA), ripple rejection (38–44dB at 120Hz), and thermal resistance (84°C/W).

Technical Context

The AZ78L09RTR-E1 implements a monolithic bandgap-referenced error amplifier with series pass transistor, enabling precise +9V regulation across input voltages from 12V to 18V. Its architecture integrates thermal foldback and current-limit circuitry that activates before junction temperature exceeds 150°C.

Designed for low-noise analog and digital subsystems, it achieves 70μV RMS output noise (10Hz–100kHz) and maintains line regulation within 18–75mV over its full input range. Load regulation remains ≤90mV from 1mA to 100mA output current.

Key Specifications

Pinout & Package

SOT-89 package: 3-pin surface-mount plastic package with exposed thermal pad (pin 2 is GND and serves as primary thermal path). Dimensions: 4.4–4.6mm × 2.3–2.6mm × 1.5–1.7mm height.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L09ACZ/NOPB, AZ78L09RTR-E1 offers lower quiescent current and better ripple rejection in an SMT package; versus TL78L09ACDR, it trades ±2% initial accuracy for 0.4V lower dropout and 10°C wider operating range.

Availability

AZ78L09RTR-E1 is available at Aetrix Electronics and suitable for microprocessor I/O power supply, post-regulation for switching supply, HiFi audio bias rail, and instrumentation reference supply requiring stable component supply, RoHS compliance, and SOT-89 surface-mount compatibility.

Supply support for AZ78L09RTR-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

BCD Semiconductor Manufacturing Limited is a Shanghai-based analog IC manufacturer specializing in power management, linear regulators, and mixed-signal solutions for industrial, consumer, and automotive markets.

The AZ78LXX series was designed specifically for cost-sensitive, space-constrained applications requiring reliable fixed-voltage regulation without external components - targeting embedded controllers, audio systems, and instrumentation.

FAQ

What is the minimum input voltage required for stable 9V output regulation?

The AZ78L09RTR-E1 requires a minimum input voltage of 10.7V to maintain line regulation under all operating conditions, as specified in the datasheet. This accounts for the 1.6V dropout voltage plus margin for line and load transients. Operation below this threshold results in unregulated output and potential instability.

Can AZ78L09RTR-E1 be used without input or output capacitors?

No. The datasheet mandates a minimum 0.33μF ceramic input capacitor and 0.1μF ceramic output capacitor placed close to the device pins. Omitting either causes instability, excessive output noise, or failure to reject ripple - especially critical at high frequencies and during load transients.

How does thermal shutdown behave during sustained overload?

Under sustained overload, the AZ78L09RTR-E1's thermal shutdown circuit disables the pass transistor once junction temperature reaches ~150°C, dropping output voltage to near zero. It automatically recovers when temperature falls below ~135°C, enabling fault-tolerant operation without manual reset or latch-up.

Is AZ78L09RTR-E1 compatible with lead-free reflow profiles?

Yes. The E1 suffix confirms RoHS-compliant, lead-free termination with MSL3 rating. It supports standard JEDEC J-STD-020D reflow profiles, including peak temperatures up to 260°C for 10 seconds, and requires no special pre-bake or moisture sensitivity handling beyond standard SOT-89 guidelines.