Texas Instruments PCM3794RHB

Overview

PCM3794RHB from Texas Instruments is a 16-bit stereo audio CODEC with integrated headphone amplifier, microphone bias, analog mixing, and digital speaker amplifier control logic - but no physical speaker outputs. It delivers 40 mW + 40 mW into 16 Ω headphones, supports 5–50 kHz sampling, operates from 1.71–3.6 V digital and 2.4–3.6 V analog supplies, and features I²C/SPI control in a 32-pin QFN (5 mm × 5 mm). It targets portable audio playback and recording in space-constrained devices.

For engineers reviewing the PCM3794RHB datasheet, PCM3794RHB pinout, PCM3794RHB application, or PCM3794RHB equivalent, key selection considerations include its lack of Class-D speaker outputs (vs. PCM3793RHB), programmable high-pass/notch filters for noise suppression, capless headphone drive capability, and register-controlled 3-band tone/3D sound processing - all within ultra-low power consumption (7 mW playback at 1.8 V/2.4 V).

Technical Context

The PCM3794RHB implements delta-sigma ADC/DAC architecture with decimation/interpolation filtering, supporting I²S, left/right-justified, and DSP audio formats. Its analog front end includes three stereo input pairs (AIN1–AIN3) with selectable 0/20 dB microphone boost and 30 dB to –12 dB PGA gain per channel; the back end provides stereo headphone/line outputs with 6 dB to –70 dB analog volume control and pop-noise reduction circuitry.

Unlike the PCM3793RHB, the PCM3794RHB omits SPOLP/SPOLN/SPORP/SPORN pins and associated Class-D speaker amplifier circuitry - confirmed by pin assignment diagrams and terminal function tables. All digital control (register access, ALC, tone control, filter configuration) occurs via 2-wire I²C or 3-wire SPI interface, with system clock input (SCKI) accepting 3.072–18.432 MHz frequencies without requiring internal PLL.

Key Specifications

Pinout & Package

PCM3794RHB uses a 32-pin QFN package (RHB suffix) with exposed thermal pad. Pin 1 is top-left corner (marked dot); pin numbering proceeds counterclockwise. Unlike PCM3793RHB, pins 10, 11, 14, and 15 are No Connect (NC), confirming absence of speaker amplifier outputs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar audio CODEC applications.

Compared with PCM3793RHB, PCM3794RHB removes speaker outputs to reduce size/power while retaining full headphone/line/mic functionality; compared with TLV320AIC3106IRHBT, it offers superior analog feature set (capless drive, 3-band tone, notch filters) at slightly higher quiescent current.

Availability

PCM3794RHB is available at Aetrix Electronics and suitable for portable media players, digital still cameras, smartphone audio subsystems, and video camcorders requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for PCM3794RHB 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies with over 50 years of innovation in precision signal chain solutions.

The PCM3794RHB belongs to TI's portable audio CODEC product line, designed specifically for battery-powered consumer electronics needing integrated analog front-end, low-power conversion, and configurable audio processing without external DSP.

FAQ

What distinguishes PCM3794RHB from PCM3793RHB?

The PCM3794RHB omits the Class-D stereo speaker amplifier present in PCM3793RHB - confirmed by NC pins (10, 11, 14, 15) and absence of SPOLP/SPOLN/SPORP/SPORN terminals. This reduces package complexity, power consumption (7 mW vs. 13 mW record), and thermal load while retaining identical headphone, line, mic, and digital processing capabilities. PCM3794RHB is the correct choice when speaker output is handled externally.

Does PCM3794RHB support capless headphone drive?

Yes, PCM3794RHB supports capless headphone drive via HPOL/LOL and HPOR/LOR outputs, enabled by register 74 (HPS[2:0]). This allows direct connection to 16 Ω or 32 Ω headphones without DC-blocking capacitors - verified by electrical characteristics showing 40 mW + 40 mW output into 16 Ω and functional description stating "either through a dc blocking capacitor or without a capacitor".

Can PCM3794RHB perform analog mixing of microphone and line inputs?

Yes, PCM3794RHB includes analog mixing amplifiers (MXL/MXR) that combine gain-controlled signals from AIN1–AIN3 inputs before routing to headphone or line outputs - described in Section "Analog Mixing and Bypass" and controlled by registers 87–89. This enables FM radio pass-through, headset sidetone, or multi-source analog blending without host CPU intervention.

What clock frequencies does PCM3794RHB accept on SCKI?

PCM3794RHB accepts system clock input (SCKI) from 3.072 MHz to 18.432 MHz - specified in Recommended Operating Conditions table. This covers standard audio clocks (e.g., 12.288 MHz for 48 kHz × 256, 13.5 MHz for 44.1 kHz × 384) and eliminates need for internal PLL, reducing jitter and power consumption versus PLL-based CODECs.

How does PCM3794RHB handle microphone bias and ALC?

PCM3794RHB provides MICB pin with 0.75×VCC bias voltage (2 mA typical) and fully programmable Automatic Level Control (ALC) via register 83. ALC dynamically adjusts microphone PGA gain to prevent clipping during loud sounds while boosting quiet signals - critical for consistent voice memo quality across varying acoustic environments without host software involvement.