DAC 3555A
PRELIMINARY DATA SHEET
2
Micronas
Contents
Page
Section
Title
3
1.
Introduction
3
1.1.
Main Features
3
1.2.
Differences between DAC 3555A and DAC 3550A
6
2.
Functional Description
6
2.1.
I
2
S Interface
7
2.2.
Interpolation Filter
7
2.3.
Variable Sample and Hold
7
2.4.
3rd-order Noise Shaper and Multibit DAC
7
2.5.
Analog Low-pass
7
2.6.
Input Select and Mixing Matrix
7
2.7.
Postfilter Op Amps, Deemphasis Op Amps, and Line-Out
8
2.8.
Analog Volume
8
2.9.
Headphone Amplifier
9
2.10.
Clock System
9
2.10.1.
Standard Mode
9
2.10.2.
MPEG Mode
10
2.11.
I
2
C Bus Interface
10
2.12.
Registers
10
2.13.
Chip Select
11
2.14.
Power Modes
11
2.15.
Oscillator
12
3.
Specifications
12
3.1.
Outline Dimensions
13
3.2.
Pin Connections and Short Descriptions
15
3.3.
Pin Descriptions
15
3.3.1.
Power Supply Pins
15
3.3.2.
Analog Audio Pins
15
3.3.3.
Oscillator and Clock Pins
16
3.3.4.
Other Pins
16
3.3.5.
Pin Configuration
17
3.4.
Pin Circuits
18
3.5.
Control Registers
20
3.6.
Electrical Characteristics
20
3.6.1.
Absolute Maximum Ratings
21
3.6.2.
Recommended Operating Conditions
23
3.6.3.
Characteristics
28
4.
Applications
28
4.1.
Line Output Details
28
4.2.
Recommended Low-Pass Filters for Analog Outputs
29
4.3.
Recommendations for Filters and Deemphasis
29
4.4.
Recommendations for MegaBass Filter without Deemphasis
30
4.5.
Power-up/down Sequence
30
4.5.1.
Power-up Sequence
30
4.5.2.
Power-down Sequence
31
4.6.
Typical Applications
34
5.
Data Sheet History
PRELIMINARY DATA SHEET
DAC 3555A
Micronas
3
Stereo Audio DAC
1. Introduction
The DAC 3555A is a single-chip, high-precision, ste-
reo digital-to-analog converter designed for audio
applications. The employed conversion technique is
based on oversampling with noise-shaping. With Mic-
ronas' unique multibit sigma-delta technique, less sen-
sitivity to clock jitter, high linearity, and a superior S/N
ratio have been achieved. The DAC 3555A is con-
trolled via I
2
C bus.
Digital audio input data is received by a versatile I
2
S
interface. The analog back-end consists of internal
analog filters and op amps for cost-effective additional
external sound processing. The DAC 3555A provides
line-out, headphone/speaker amplifiers, and volume
control. Moreover, mixing additional analog audio
sources to the D/A-converted signal is supported.
The DAC 3555A is designed for all kinds of applica-
tions in the audio and multimedia field, such as:
MPEG players, CD players, DVD players, CD-ROM
players, mobile phones, etc.
The DAC 3555A ideally complements the MP3 audio
decoders MAS 3507D, MAS 35x9F, and PUC 303xA.
No crystal or external clock required for standard
applications with sample rates from 32 to 48 kHz
and 96 kHz.
It is required for automatic sample rate detection below
32 kHz, MPEG mode (refer to Section 2.10.1.), and
use of clock output CLKOUT.
1.1. Main Features
no master main input clock required
no external crystal required
integrated stereo headphone amplifier and mono
speaker amplifier
SNR of 103 dB(A)
I
2
C bus, I
2
S bus
internal clock oscillator
sample rates from 8 kHz to 96 kHz
analog deemphasis for 44.1 kHz
analog volume and balance: +18...
-
75 dB and mute
THD better than 0.01%
two additional analog stereo inputs (AUX) with
source selection and mixing
supply range: 2.7 V...5.5 V
zero-power mode
additional line-out
on-chip op amps for cost-effective external analog
sound processing
pin-compatible to DAC 3550A
PMQFP44 or PQFN40 package
1.2. Differences between DAC 3555A and
DAC 3550A
new zero-power mode
operation in I
2
C mode only. Stand-alone operation
is not supported.
new quiet wake-up mode: after power-on, the
DAC 3555A switches into zero-power mode. Wak-
ing-up is done via I
2
C command. This feature
avoids audible "plops".
sample rates up to 96 kHz
not register-compatible to DAC 3550A
Fig. 11: Block diagram of the DAC 3555A
WSI
CLI
DRI
OUTL
Inter-
DAC
Input
Select
polation
Filter
Volume
and
Headphone
Amplifier
I
2
S
Analog Inputs
and
Mixing
SDA
SCL
I
2
C
Line Out
OUTR
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