Texas Instruments PCM4201EVM, Руководство пользователя

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1 Introduction
HPF
Delta−Sigma
Modulator
Decimation
Filter
Voltage
Reference
V
REF
+
V
REF
−
V
IN
R+
V
IN
R
−
Power
V
DD
AGND
Reset
Logic
Clock
Control
Audio
Serial
Port
DGND V
CC
FSYNC
BCK
DATA
S/M
RATE
SCKI
RST
HPFD
1.1 PCM4201EVM Features
Introduction
The PCM4201 is a low power, high-performance, single channel audio analog-to-digital (A/D) converter
designed for use in battery-operated or portable professional audio applications, including digital wireless
microphones and digital audio recorders/processors. The PCM4201 features a 24-bit linear PCM data
output, with a data format compatible with digital signal processors and digital audio interface transmitters
(including the DIT4096 and DIT4192 from Texas Instruments).
The PCM4201 includes three sampling modes, supporting sampling rates up to 108kHz. The Normal
Speed Low Power mode supports sampling rates up to 54kHz, and employs 64x oversampling to reduce
overall converter power. The Normal Speed High Performance mode supports sampling rates up to 54kHz
with 128x oversampling, resulting in higher dynamic range than the Low Power mode, at the expense of
increased power dissipation. The Double Speed mode supports sampling frequencies up to 108kHz, and
is provided for those cases where higher sampling rates may be required.
A digital high-pass filter is included for DC removal. Dedicated control pins are included for sampling mode
selection, Slave/Master mode port operation, digital high-pass filter enable/disable, and reset/power-down
functions.
A +5V power supply is required for the analog section of the device, while a +3.3V power supply is
typically utilized for the digital circuitry. The digital supply may operate at voltages as low as +1.8V, with a
corresponding 10mW to 20mW reduction in power dissipation, depending upon the sampling mode
selection.
Figure 1 illustrates the functional block diagram for the PCM4201.
Figure 1. PCM4201 Functional Block Diagram
The PCM4201EVM provides a convenient platform for evaluating the performance and functions of the
PCM4201 device. The primary EVM features include:
•
Simple configuration using an onboard DIP switch
•
Differential voltage input supporting 3-pin XLR or balanced TRS connections
•
Differential input buffer and filter circuit utilizing the Texas Instruments OPA2134 dual op amp
•
Flexible input buffer power supply connection (dual or single supply options) and resistor/capacitor
configuration allow for circuit experimentation and op amp substitution
PCM4201EVM User's Guide 2 SBAU108A – January 2005 – Revised February 2005