Texas Instruments PCM3500EG4

Overview

PCM3500EG4 from Burr-Brown (now Texas Instruments) is a low-voltage, mono 16-bit voice/modem CODEC integrating delta-sigma ADC and DAC, on-chip crystal oscillator, and time-slot TDM serial interface. It operates from +2.7V to +3.6V, supports 7.2–26kHz sampling, delivers 88dB dynamic range at 8kHz, and targets portable speech processing and software modem AFEs.

For engineers reviewing the PCM3500EG4 datasheet, PCM3500EG4 pinout, PCM3500EG4 application, or PCM3500EG4 equivalent, this page provides verified functional identity, SSOP-24 package mapping, master/slave serial timing, loop-back mode behavior, and real-world power-down current (60µA typ) - all critical for embedded voice system integration and multi-CODEC TDM bus design.

Technical Context

The PCM3500EG4 implements dual delta-sigma modulation: a decimation filter in the ADC path and interpolation filter in the DAC path, both operating at 512× sampling rate (e.g., 4.096MHz at 8kHz fS). Its analog front end includes integrated anti-aliasing and output low-pass filters plus a programmable high-pass filter (HPFD pin) for DC blocking.

Serial interface operation supports three modes: Slave (FS/BCK inputs), Master (FS/BCK outputs), and Time Slot Mode (TSC=1), enabling up to four PCM3500EG4 devices on one 4-wire bus with frame sync chaining via FSO. Synchronization loss detection triggers automatic DAC output clamping to VCOM and DOUT high-impedance state within one FS period.

Key Specifications

Pinout & Package

PCM3500EG4 is housed in a 24-pin Small Outline Package (SSOP), per Burr-Brown drawing 338, with 0.64mm lead pitch and exposed pad not present. Pin functions are validated per datasheet PDS-1524B Rev B (2000) and SBAS117.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voice/modem CODEC applications.

Compared with TLV320AIC10CP and PCM3002E, PCM3500EG4 uniquely combines on-chip crystal oscillator, ADC-to-DAC loop-back, and scalable TDM - making it optimal for cost-sensitive, space-constrained mono voice systems requiring self-test and multi-device synchronization.

Availability

PCM3500EG4 is available at Aetrix Electronics and suitable for portable voice recorders, software modems, speech recognition front ends, and teleconferencing audio hubs requiring stable component supply across extended product lifecycles.

Supply support for PCM3500EG4 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

Burr-Brown Corporation, acquired by Texas Instruments in 2000, specialized in precision analog ICs including data converters, amplifiers, and interface products for industrial and communications markets.

The PCM3500EG4 belongs to Burr-Brown's voice-band CODEC product line, designed specifically for low-power, low-cost modem and speech processing AFEs in portable electronics - emphasizing integration, TDM scalability, and robust clock synchronization.

FAQ

What is the function of the HPFD pin on the PCM3500EG4?

The HPFD (High-Pass Filter Disable) pin on the PCM3500EG4 controls the internal high-pass filter in the ADC path. When HPFD is logic high, the DC-blocking HPF is disabled, allowing full-bandwidth analog input capture down to 0Hz. This is essential for applications like audio diagnostics or non-voice sensor signal acquisition where DC or sub-audio content must be preserved. The PCM3500EG4 defaults to HPF enabled when HPFD is low or unconnected due to its internal pull-down resistor.

Does the PCM3500EG4 support stereo audio?

No, the PCM3500EG4 is a mono CODEC - it contains one 16-bit delta-sigma ADC and one 16-bit delta-sigma DAC. It does not support native stereo operation. For stereo applications, designers must use two PCM3500EG4 devices (with TDM time-slot mode) or select a dedicated stereo part such as the PCM3002E. The PCM3500EG4 datasheet explicitly defines it as a "mono voice/modem CODEC", and all timing, filtering, and interface specifications assume single-channel operation.

How does the PCM3500EG4 handle clock synchronization loss?

The PCM3500EG4 continuously monitors phase alignment between the system clock (XTI/SCKIO) and frame sync (FS). If the phase deviation exceeds ±1.5 BCK periods, it detects synchronization loss and within one FS period forces the DAC output to VCOM (0.5×VCC) and places DOUT in high-impedance state. This fail-safe behavior prevents corrupted audio output and alerts the host processor. Recovery occurs automatically once synchronization is restored, with defined tADCDLY2 and tDACDLY2 delays before valid data resumes.

Can the PCM3500EG4 operate without an external crystal?

Yes, the PCM3500EG4 can operate without an external crystal by using an external master clock applied to either XTI (pin 17) or SCKIO (pin 15). When using SCKIO as clock input, XTI must be grounded. The required system clock frequency is exactly 512× the desired sampling frequency (e.g., 4.096MHz for 8kHz fS). Crystal operation is optional - the on-chip oscillator circuit is provided for systems lacking a stable master clock source, but is not mandatory for PCM3500EG4 functionality.

What is the purpose of the LOOP pin on the PCM3500EG4?

The LOOP (ADC-to-DAC Loop-Back) pin on the PCM3500EG4 enables internal signal routing where ADC digital output is fed directly to the DAC input, bypassing the serial interface. When LOOP is logic high, analog input on VIN appears at VOUT after conversion delay (tDACDLY1 ≈ 2048/fS), allowing hardware-level self-test and calibration without host intervention. This feature is especially valuable in production test environments and firmware validation for voice-enabled devices using PCM3500EG4.