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AN234

AK5394A to CS5381 Conversion

by Kevin L Tretter

1. Introduction

The CS5381 is a complete analog-to-digital converter for digital audio systems. The CS5381 performs

sampling, analog-to-digital conversion and anti-alias filtering, generating 24-bit values for both left and

right channels.

The CS5381 offers some unique advantages over the AK5394A including:

- Over 70% REDUCTION in package size (TSSOP)

- 50% less power consumption

- Fewer external components required (See Section 2)

- Overflow detect

- Integrated level shifters

- Over 80% less group delay (48kHz output sample rate)

Table 1 shows a comparison of the key specifications of these two devices.

Table 1. Comparison of Key Specifications

AK5394A CS5381

Conversion (Bits) 24 24

Dynamic Range (A-weighted) dB 123* 120

THD+N dB -110* -110

Analog Core Power Supply (VA) V +5.0 V +5.0 V

Digital Core Power Supply (VD) +3.3 V to +5.0 V +3.3 V to +5.0 V

Digital Interface Power Supply (VL) N/A +2.5 V to +5.0 V

Maximum Power mW 870 348

Maximum Sample Rate kHz 216 200

Package

28-pin SOP 24-pin SOIC/TSSOP

* Dynamic Range and THD+N specified with different input buffer topologies

JUL ‘03

AN234REV1

Summary of content (7 pages)

PAGE 1
AN234 AK5394A to CS5381 Conversion by Kevin L Tretter 1. Introduction The CS5381 is a complete analog-to-digital converter for digital audio systems. The CS5381 performs sampling, analog-to-digital conversion and anti-alias filtering, generating 24-bit values for both left and right channels.
PAGE 2
AN234 2. Typical Connection Diagrams +5 V to 3.3 V + 1 µF 0.1 µF * +5V + 1 µF 0.1 µF VD VL FILT+ 200 µF + VL 0.1 µF 10 k REFGND + +5V to 2.5V 1 µF 0.1 µF 5.1 Ω VA + 0.1 µF 1 µF 0.
PAGE 3
AN234 3. Pin Compatibility Table 1 shows the pins of the AK5394A and the corresponding pins of the CS5381. Please note that the AK5394A has 28 pins, and the CS5381 has 24 pins.
PAGE 4
AN234 4.2 AK5394A The AK5394A will automatically initiate a calibration sequence following a reset. The CAL pin (pin 9) is an output that indicates when a calibration sequence is in progress. This calibration technique is very similar to that described above for the CS5381. The AK5394A also has a ZCAL pin (pin 6) which allows the calibration input to be obtained from either the analog input pins or the VCOM pins. The high pass filter can be controlled via the HPFE pin (pin 19).
PAGE 5
AN234 634 Ω 470 pF C0G CS5381 91 Ω - 1 µF AIN+ + 634 Ω 634 Ω 100 kΩ VA 2700 pF C0G 470 pF C0G 100 kΩ 3.3 kΩ 91 Ω - AIN- + 3.3 kΩ 0.01 µF 100 µF 1 µF 0.01 µF VQ 634 Ω 470 pF C0G 91 Ω - 1 µF AIN+ + 634 Ω 634 Ω 100 kΩ VA 2700 pF C0G 470 pF C0G 100 kΩ 3.3 kΩ 91 Ω - AIN- + 3.3 kΩ 0.01 µF 100 µF Figure 3. Single-Ended to Differential Input Buffer 8.2 Fully Differential Input Buffer Figure 4 shows a fully differential analog input buffer.
PAGE 6
AN234 9. Capacitor Size on Reference Voltage Pin(s) The CS5381 and the AK5394A both require external capacitance on the internal reference voltage pin(s). On the CS5381, the internal reference voltage is output on FILT+ (pin 24). The AK5394A has four such pins, VREFL+, VREFL-, VREFR-, and VREFR+ (pins 1, 2, 27, and 28 respectively). Each of these pins require a large capacitor for noise decoupling.
PAGE 7
AN234 Contacting Cirrus Logic Support For a complete listing of Direct Sales, Distributor, and Sales Representative contacts, visit the Cirrus Logic web site at: http://www.cirrus.com/ IMPORTANT NOTICE Cirrus Logic, Inc. and its subsidiaries ("Cirrus") believe that the information contained in this document is accurate and reliable. However, the information is subject to change without notice and is provided "AS IS" without warranty of any kind (express or implied).