Texas Instruments PCM3501E/2K

Overview

PCM3501E/2K from Burr-Brown (now Texas Instruments) is a low-voltage, mono 16-bit voice/modem CODEC integrating delta-sigma ADC and DAC, differential analog I/O, on-chip crystal oscillator, and time-slot TDM support for up to four devices on one serial bus. It operates from +2.7V to +3.6V, delivers 88dB dynamic range at 8kHz sampling, and targets modem AFE and portable speech applications.

For engineers reviewing the PCM3501E/2K datasheet, PCM3501E/2K pinout, PCM3501E/2K application, or PCM3501E/2K equivalent, key selection considerations include its 24-pin SSOP package, 7.2–26kHz programmable sampling rate, master/slave serial interface with 512fS system clock requirement, and integrated analog filters enabling glue-free DSP interfacing in space-constrained voice systems.

Technical Context

The PCM3501E/2K implements dual delta-sigma modulation architecture: a decimation filter chain with high-pass DC-blocking (HPFD-controllable) and anti-aliasing input filtering, plus interpolation and low-pass output filtering. Its digital core supports MSB-first two's complement data format, 16-bit frame length, and synchronous 4-wire serial I/O (FS, BCK, DIN, DOUT).

Timing operation is governed by strict synchronization between FS/BCK and the 512fS system clock - loss of phase alignment (>±1.5 BCK periods) forces DAC output to VCOM and places DOUT in high-impedance state within one frame. Time Slot Mode extends the serial bus to four CODECs via 64-bit frames with per-device FSO signaling.

Key Specifications

Pinout & Package

PCM3501E/2K is housed in a 24-lead Shrink Small Outline Package (SSOP), specified per drawing 338, rated for –25°C to +85°C operation, with θJA = 100°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV320AIC10IPFB and PCM3002E/2K, PCM3501E/2K uniquely combines modem-grade 56kbps readiness, integrated crystal oscillator, and scalable TDM - making it optimal for space-constrained, battery-aware, multi-channel voice AFEs where clock simplicity and synchronization robustness are critical.

Availability

PCM3501E/2K is available at Aetrix Electronics and suitable for software modem AFEs, portable voice recorders, speech recognition front-ends, and teleconferencing audio hubs requiring stable component supply across production lifecycles.

Supply support for PCM3501E/2K 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 solutions for industrial and communications markets.

The PCM3501E/2K belongs to Burr-Brown's voice and modem CODEC product line, designed specifically for low-power, low-cost analog front-ends in host-based communication systems where integration, small footprint, and system clock autonomy were primary constraints.

FAQ

What is the minimum sampling frequency supported by the PCM3501E/2K?

The PCM3501E/2K supports a minimum sampling frequency of 7.2 kHz, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. This enables compliance with G.723.1 and other narrowband voice codecs. At 7.2 kHz, the required system clock is 3.6864 MHz (512×fS), and analog performance remains within datasheet limits including 82 dB dynamic range and –85 dB THD+N.

Does the PCM3501E/2K require an external crystal, or can it operate with an external clock source?

The PCM3501E/2K supports both configurations: it can drive a parallel-resonant fundamental-mode crystal (e.g., 4.096 MHz) between XTI and XTO pins, or accept an external clock via XTI or SCKIO. When using external clock, XTI must be driven and XTO left open; if SCKIO is used as input, XTI must be grounded. The on-chip oscillator eliminates external clock ICs but is optional.

How does the PCM3501E/2K handle loss of synchronization between FS and the system clock?

When phase misalignment between FS and the 512fS system clock exceeds ±1.5 BCK periods, the PCM3501E/2K detects loss of synchronization within one frame period. It then forces the DAC output to VCOM (0.5VCC) and places DOUT in high-impedance state. Resynchronization occurs automatically once valid timing resumes, with defined delays (tADCDLY2 = 32/fS, tDACDLY2 = 32/fS) before valid data resumes.

Can the PCM3501E/2K be used in stereo applications?

No - the PCM3501E/2K is a mono CODEC with one ADC and one DAC channel. Stereo operation requires two PCM3501E/2K devices, which can be synchronized and time-multiplexed on a shared serial bus using Time Slot Mode. Each device occupies one 16-bit slot within a 64-bit frame, enabling deterministic interleaved capture and playback.

What is the function of the HPFD pin on the PCM3501E/2K?

The HPFD (High-Pass Filter Disable) pin on the PCM3501E/2K is a Schmitt-trigger input with internal pull-down. When driven high, it disables the digital high-pass filter in the ADC path, allowing DC and sub-audio signals (e.g., sensor outputs or electret mic bias) to pass through unattenuated. When low or floating, the HPF remains active with a corner frequency near 0.0002fS (e.g., ~1.6 Hz at 8kHz fS).