Allegro MicroSystems A8430EEK

Overview

A8430EEK from Allegro MicroSystems is a constant-current, noninverting boost converter IC designed to drive white LED strings in portable electronics. It delivers up to 36 V output from 2.5–10 V input, supports up to 7 LEDs in series at 20 mA, features 1.2 MHz switching frequency, 300 mA internal switch current limit, and operates across –40°C to +85°C ambient temperature.

For engineers reviewing the A8430EEK datasheet, A8430EEK pinout, A8430EEK application, or A8430EEK equivalent, key selection criteria include its 5-pin MLPD package, 95 mV feedback reference voltage, shutdown current of 1 µA, programmable LED current via external sense resistor, and suitability for space-constrained battery-powered backlighting designs.

Technical Context

The A8430EEK uses constant-frequency current-mode control with an internal 1.2 MHz oscillator and integrated 300 mA N-channel MOSFET switch. Regulation is achieved by comparing the FB pin voltage (developed across an external sense resistor) to a precise 95 mV internal reference.

It operates in continuous conduction mode at typical loads but transitions to discontinuous mode at low currents, maintaining regulation down to zero average output current. Overvoltage protection requires external Zener clamping due to lack of internal OVP circuitry.

Key Specifications

Pinout & Package

The A8430EEK is housed in a 5-pin, 3 mm × 3 mm MLPD (Micro Leadframe Package Dual) surface-mount package with exposed thermal pad, 0.75 mm nominal height, and same PCB footprint as SOT-23-5.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar white LED driver applications.

Compared with AS1117-3.3 and LM3407MMX/NOPB, the A8430EEK offers optimized size and efficiency for mid-range LED counts (3–7) in legacy portable designs, though it requires external Zener clamping for OVP and lacks integrated protection features found in newer alternatives.

Availability

A8430EEK is available at Aetrix Electronics and suitable for smartphone backlighting, portable media player displays, PDA main displays, and mobile GPS unit backlighting requiring stable component supply despite end-of-life status.

Supply support for A8430EEK 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

Allegro MicroSystems is a U.S.-based semiconductor company specializing in high-performance magnetic sensing and power IC solutions for automotive, industrial, and consumer markets.

The A8430 product line was engineered specifically for compact, high-efficiency white LED backlighting in battery-powered portable electronics, emphasizing minimal external component count and thermal performance in ultra-thin packages.

FAQ

What is the function of the FB pin on the A8430EEK?

The FB (feedback) pin on the A8430EEK senses the voltage across the external current-sense resistor and compares it to an internal 95 mV reference to regulate LED current. It must be connected directly to the top of the sense resistor, with a dedicated low-impedance path to GND. The A8430EEK maintains constant current by adjusting switch duty cycle until the FB voltage equals 95 mV, making precise resistor selection critical for target LED current accuracy.

Can the A8430EEK drive more than four white LEDs?

Yes, the A8430EEK can drive up to seven white LEDs in series when supplied with up to 10 V input, as its output voltage capability reaches 36 V. From a 3 V supply, it supports five LEDs at 20 mA; from a 2.5 V supply, it supports four. Performance depends on forward voltage tolerance of the LED string and input voltage headroom - the A8430EEK's 36 V output ceiling ensures margin for worst-case V_F variation across temperature and manufacturing lot.

Does the A8430EEK include built-in overvoltage protection?

No, the A8430EEK does not include internal overvoltage protection. If the LED string opens, the feedback voltage drops to zero and the controller drives the switch to maximum duty cycle, causing uncontrolled output voltage rise. Allegro specifies that external Zener diode clamping - rated above the maximum expected LED string voltage and capable of sinking >0.1 mA - is mandatory for safe operation. This design choice reduces die size but places responsibility for OVP implementation on the system designer.

What package type does the A8430EEK use, and what are its thermal characteristics?

The A8430EEK uses a 5-pin MLPD (Micro Leadframe Package Dual) measuring 3 mm × 3 mm with 0.75 mm nominal height and an exposed thermal pad. Its junction-to-ambient thermal resistance is 50°C/W when mounted on a 4-layer PCB per Allegro's test conditions. The package shares the same PCB footprint as SOT-23-5, simplifying layout migration, and supports lead-free assembly with matte tin plating on the EK-T variant.

How is LED dimming implemented with the A8430EEK?

The A8430EEK supports two dimming methods: analog feedback modulation and PWM-enabled switching. For analog dimming, a control voltage is applied between FB and the sense resistor top to offset the 95 mV reference; for PWM dimming, a 1–10 kHz signal is applied directly to the EN pin to toggle the device on/off. Both methods preserve current regulation during active periods, and the A8430EEK's fast 1.2 MHz switching ensures minimal visible ripple even at low PWM duty cycles.