STMicroelectronics A22H165MJ

Overview

A22H165MJ from STMicroelectronics is a high-performance Class-G stereo headphone amplifier with integrated buck converter, I²C volume control, and zero-pop/click architecture-designed for space-constrained portable audio systems. It delivers 0.006% THD+N at 1 kHz, 100 dB PSRR at 217 Hz, and 2.1 mA total supply current at 100 µW/channel (10 dB crest factor), enabling high-fidelity playback in wearable fitness devices and smartphones.

For engineers reviewing the A22H165MJ datasheet, A22H165MJ pinout, A22H165MJ application, or A22H165MJ equivalent, key selection criteria include its flip-chip 16-bump package (1.65 mm × 1.65 mm), capacitor-less output architecture, independent channel shutdown, common-mode sense (CMS) pin for ground-noise rejection, and I²C-controlled digital volume range from –60 dB to +4 dB.

Technical Context

The A22H165MJ implements a dual-rail Class-G architecture where an integrated high-efficiency buck converter dynamically supplies the amplifier's HPVDD rail (1.2 V or 1.9 V) based on instantaneous audio signal amplitude-reducing power dissipation versus fixed-rail Class-AB designs. Its differential input stage features 25–34 kΩ impedance and supports ±1 V_rms differential input range.

Operation relies on external components: a 3.3 µH inductor (L1), two 2.2 µF flying capacitors (C1/C2), a 10 µF tank capacitor (Ct), and mandatory 12 Ω series output resistors (R_out). The CMS pin enables precise common-mode voltage sensing at the headphone jack ground, eliminating parasitic PCB ground noise without requiring output coupling capacitors.

Key Specifications

Pinout & Package

Package: Flip-chip, 16-bump, 1.65 mm × 1.65 mm, 400 µm pitch - optimized for ultra-thin mobile and wearable PCBs with minimal footprint and thermal resistance (R_thJA = 90 °C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar stereo headphone amplifier applications.

Compared with MAX98357AETE+T and TAS5707PAPR, the A22H165MJ uniquely combines Class-G efficiency, capacitor-less output, and CMS-based ground-noise cancellation in a 1.65 mm × 1.65 mm flip-chip package-making it optimal for ultra-compact, battery-sensitive wearable audio where analog signal integrity is paramount.

Availability

A22H165MJ is available at Aetrix Electronics and suitable for smartphone audio subsystems, wireless earbud drivers, fitness tracker audio feedback, and portable medical monitor audio alerts requiring stable component supply and long-term production continuity.

Supply support for A22H165MJ 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in microcontrollers, power management, analog, and MEMS technologies-with over 40 years of automotive- and industrial-grade product development expertise.

The A22H165MJ belongs to ST's Audio Power Amplifiers product line, engineered specifically for ultra-low-power, high-fidelity portable audio applications-including wearables, hearables, and battery-powered medical devices-where space, thermal budget, and battery life are critical constraints.

FAQ

What is the minimum external component count required for basic A22H165MJ operation?

The A22H165MJ requires seven mandatory external components: one 3.3 µH inductor (L1), two 2.2 µF flying capacitors (C1, C2), one 10 µF tank capacitor (Ct), two 2.2 µF decoupling capacitors (Cs, CSS), and two 12 Ω series output resistors (R_out). No output coupling capacitors are needed. All capacitors must be X5R dielectric with appropriate voltage ratings per the datasheet.

How does the CMS (common-mode sense) pin improve audio quality in real-world layouts?

The CMS pin connects directly to the headphone jack's ground contact point, allowing the IC to measure and actively reject PCB ground bounce induced by digital switching or power supply ripple. This improves PSRR by up to 20 dB at 217 Hz and reduces audible noise in compact layouts where analog and digital grounds share copper traces-verified in ST's evaluation board measurements.

Can the A22H165MJ drive 16 Ω, 32 Ω, and 47 Ω headphones without modification?

Yes-the A22H165MJ supports 16 Ω to 47 Ω loads with guaranteed performance. At 16 Ω, maximum output power is 80 mW (THD+N = 1%, V_CC = 4.8 V); at 32 Ω, it delivers 40 mW; and at 47 Ω, 25 mW. Output stability is ensured across this range using the mandatory 12 Ω series resistor and 0.8–100 nF output capacitor (C_out), as specified in Table 4.

What I²C register controls independent left/right channel shutdown?

Independent shutdown is controlled via Control Register CR1 (I²C address 0x01). Bit 0 (SHDN_L) enables/disables the left channel, and Bit 1 (SHDN_R) controls the right channel. Writing '0' to either bit places that channel into hardware shutdown (5 µA max current), while '1' enables normal operation. Both channels default to enabled after power-up or reset.