FEATURES
Low Cost, High Performance Stereo DACs
128 Times Oversampling Interpolation Filter
Multibit SD Modulator with Triangular PDF Dither
Discrete Time and Continuous Time Analog
Reconstruction Filters
Extremely Low Out-of-Band Energy
Buffered Outputs with 2 kV Output Load Drive
94 dB Dynamic Range, –90 dB THD+N Performance
Digital De-emphasis and Mute
60.18C Maximum Phase Linearity Deviation
Continuously Variable Sample Rate Support
Power-Down Mode
16-, 18- and 20-Bit I
2
S-Justified, Left-Justified Modes
Offered on AD1857
Accepts 24-Bit Word
16-Bit Right-Justified and DSP Serial Port Modes
Offered on AD1858
Single +5 V Supply
20-Pin SSOP Package
APPLICATIONS
Digital Cable TV and Direct Broadcast Satellite Set-Top
Decoder Boxes
Video Laser Disk, Video CD and CD-I Players
High Definition Televisions, Digital Audio Broadcast
Receivers
CD, CD-R, DAT, DCC and MD Players
Digital Audio Workstations, Computer Multimedia
Products
AD1857/AD1858
PRODUCT OVERVIEW
The AD1857/AD1858 are complete single-chip stereo digital
audio playback components. They each comprise an advanced
digital interpolation filter, a revolutionary “linearity-compensated”
multibit sigma-delta (∑∆) modulator with dither, a jitter-tolerant
DAC, switched capacitor and continuous time analog filters and
analog output drive circuitry. Other features include digital
de-emphasis processing and mute. The AD1857/AD1858
support continuously variable sample rates with essentially
linear phase response, and support 50/15 µs digital de-emphasis
intended for “Redbook” 44.1 kHz sample frequency playback
from Compact Discs. The user must provide a master clock that
is synchronous with the left/right clock at 256 or 384 times the
intended sample frequency.
The AD1857/AD1858 have a simple but very flexible serial data
input port that allows for glueless interconnection to a variety of
ADCs, DSP chips, AES/EBU receivers and sample rate converters. The AD1857 serial data input port can be configured
in either 16-bit, 18-bit or 20-bit left-justified or I
modes. The AD1858 serial data input port can be configured in
either 16-bit right-justified or DSP serial port compatible modes.
The AD1857/AD1858 accept serial audio data in MSB first,
twos-complement format. A power-down mode is offered to
minimize power consumption when the device is inactive. The
AD1857/AD1858 operate from a single +5V power supply.
They are fabricated on a single monolithic integrated circuit and
housed in 20-pin SSOP packages for operation over the
temperature range 0°C to +70°C.
2
S-justified
FUNCTIONAL BLOCK DIAGRAM
DIGITAL
SUPPLY
2
16-/18-/20-BIT
DATA INPUT
DIGITAL
SERIAL
MODE
3
SERIAL DATA
INTERFACE
INTERPOLATION
INTERPOLATION
DE-EMPHASIS
128x
FILTER
128x
FILTER
AD1857/AD1858
MUTE
MUTE
MUTE
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
Input Sample Rate44.1 kHz
Measurement Bandwidth20 Hz to 20 kHz
AD1857 Input Data Wordwidth18 Bits
AD1858 Input Data Wordwidth16 Bits
Load Capacitance100 pF
Load Impedance47 kΩ
Input Voltage HI (V
Input Voltage LO (V
I2S-Justified Mode (Ref. Figure 7) for AD1857, Right-Justified Mode (Ref. Figure 8) for AD1858.
Performance of the right and left channels are identical (exclusive of the Interchannel Gain Mismatch and Interchannel Phase Deviation specifications).
Values in bold typeface are tested, all others are guaranteed, not tested.
ANALOG PERFORMANCE
AD1857 Resolution18Bits
AD1858 Resolution16Bits
Dynamic Range (20 Hz to 20 kHz, –60 dB Input)
No A-Weight Filter91dB
With A-Weight Filter94dB
Total Harmonic Distortion + Noise–90–85dB
Analog Outputs
Single-Ended Output Range (± Full Scale)2.83.03.2V p-p
Output Impedance at Each Output Pin<200Ω
Output Capacitance at Each Output Pin20pF
Out-of-Band Energy (0.5 × F
CMOUT2.12.252.4V
DC Accuracy
Gain Error±3.067.5%
Interchannel Gain Mismatch0.0160.2dB
Gain Drift150300ppm/°C
Interchannel Crosstalk (EIAJ method)–120–100dB
Interchannel Phase Deviation±0.1Degrees
Mute Attenuation–100–90dB
De-emphasis Gain Error±0.1dB
)11.2896 MHz (256 × FS Mode)
MCLK
–0.5 dB Full Scale
)2.4 V
IH
)0.8 V
IL
to 100 kHz)–72.5dB
S
MinTypMaxUnits
0.0030.006%
DIGITAL I/O
MinMaxUnits
Input Voltage HI (VIH)2.4V
Input Voltage LO (V
Input Leakage (I
Input Leakage (I
)0.8V
IL
@ VIH = 2.4 V)10µA
IH
@ V
IL
= 0.8 V)10µA
IL
Input Capacitance20pF
–2–
REV. 0
DIGITAL TIMING (Guaranteed over 0°C to +70°C, AVDD = DVDD = +5.0 V ± 5%)
MinMaxUnits
AD1857/AD1858
t
DML
t
DMH
t
DMP
t
DML
t
DMH
t
DMP
t
DBH
t
DBL
t
DBP
t
DLS
t
DLH
t
DDS
t
DDH
t
PDRP
MCLK LO Pulse Width (256 × FS Mode)35ns
MCLK HI Pulse Width (256 × FS Mode)40ns
MCLK Period (256 × FS Mode)88.577ns
MCLK LO Pulse Width (384 × FS Mode)25ns
MCLK HI Pulse Width (384 × FS Mode)25ns
MCLK Period (384 × FS Mode)59.0514ns
BCLK HI Pulse Width20ns
BCLK LO Pulse Width20ns
BCLK Period354.308ns
LRCLK Setup20ns
LRCLK Hold5ns
SDATA Setup5ns
SDATA Hold10ns
PD/RST LO Pulse Width4 MCLK Periodsns
(355 ns @ 11.2896 MHz)
POWER
MinTypMaxUnits
Supplies
Voltage, Analog and Digital4.7555.25V
Analog Current3540mA
Analog Current – Power-Down3060µA
Digital Current2025mA
Digital Current – Power-Down511mA
Dissipation
Operation – Both Supplies275325mW
Operation – Analog Supply175200mW
Operation – Digital Supply100125mW
Power-Down – Both Supplies2556mW
Power Supply Rejection Ratio
1 kHz 300 mV p-p Signal at Analog Supply Pins–60dB
20 kHz 300 mV p-p Signal at Analog Supply Pins–50dB
Digital InputsDGND – 0.3DV
Analog OutputsAGND – 0.3AV
+ 0.3V
DD
+ 0.3V
DD
AGND to DGND–0.30.3V
Reference VoltageIndefinite Short Circuit to Ground
Soldering+300°C
10sec
*Stresses greater than those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions
for extended periods may affect device reliability.
Stopband nominally repeats itself at multiples of 128 × FS, where FS is the input word rate. Thus the digital filter will attenuate to 62 dB across the frequency
spectrum, except for a range ±0.55 × FS wide at multiples of 128 × FS.
Specifications subject to change without notice.
ORDERING GUIDE
PackagePackage
ModelTemperatureDescriptionOption*
AD1857JRS0°C to +70°C20-Lead SSOPRS-20
AD1857JRSRL0°C to +70°C20-Lead SSOPRS-20 on
13" Reels
AD1858JRS0°C to +70°C20-Lead SSOPRS-20
AD1858JRSRL0°C to +70°C20-Lead SSOPRS-20 on
13" Reels
*RS = Shrink Small Outline
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the AD1857/AD1858 feature proprietary ESD protection circuitry, permanent damage may occur on
devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are
recommended to avoid performance degradation or loss of functionality.
–4–
PIN CONFIGURATION
MCLK
PD/RST
MODE
NC
DEEMP
256
384/
AV
OUTL
AGND
CMOUT
DD
1
2
3
4
AD1857
5
AD1858
TOP VIEW
6
(Not to Scale)
7
8
9
10
NC = NO CONNECT
20
19
18
17
16
15
14
13
12
11
SDATA
BCLK
LRCLK
DV
DD
DGND
MUTE
AV
DD
OUTR
AGND
FILT
REV. 0
AD1857/AD1858
PIN LIST
Digital Audio Serial Input Interfaces
Pin NameNumberI/ODescription
SDATA20ISerial input, MSB first, containing two channels of 16, 18 or 20bits (AD1857) or
16 bits (AD1858) of twos complement data per channel.
BCLK19IBit clock input for input data. Need not run continuously; may be gated or used in a
burst fashion.
L
RCLK18ILeft/right clock input for input data. Must run continuously.
MODE3IInput serial data port mode control. Selects between I
(LO) on the AD1857. Selects between DSP serial port style mode (HI) and rightjustified (LO) on the AD1858. The state of the mode pin should be changed only when
the AD1857/AD1858 is held in reset (
PD/RST LO). Otherwise, the AD1857/
AD1858 serial port may lose synchronism.
Control and Clock Signals
Pin NameNumberI/ODescription
PD/RST2IPower-Down/Reset. The AD1857/AD1858 are placed in a low power consumption
“sleep” mode when this pin is held LO. The AD1857/AD1858 are reset on the
rising edge of this signal. Connect HI for normal operation.
DEEMP5IDe-emphasis. Digital de-emphasis is enabled when this input signal is HI. This is
used to impose a 50/15 µs response characteristic on the output audio spectrum at
an assumed 44.1 kHz sample rate.
MUTE15IMute. Assert HI to mute both stereo analog outputs of the AD1857/AD1858.
Deassert LO for normal operation.
MCLK1IMaster Clock Input. Connect to an external clock source at either 256 or 384 times
the intended sample frequency as determined by the 384/
nous with L
384/
2566ISelects the master clock mode as either 384 times the intended sample frequency
RCLK, but may have any phase with respect to LRCLK.
(HI) or 256 times the intended sample frequency (LO). The state of this input
should be hardwired to logic LO or logic HI or may be changed while the AD1857/
AD1858 is in power-down/reset. It must not be changed while the AD1857/AD1858
is operational.
2
S-justified (HI) and left-justified
256 pin. Must be synchro-
Analog Signals
Pin NameNumberI/ODescription
FILT11OVoltage Reference Filter Capacitor Connection. Bypass and decouple the voltage
reference with parallel 10 µF and 0.1 µF capacitors to the AGND pin.
CMOUT10OVoltage Reference Common Mode Output. Should be decoupled with 10 µF
capacitor to the AGND pin or plane. This output is available externally for dc
coupling and level-shifting. CMOUT should not have any signal dependent load,
or used where it will sink or source current.
OUTL8OLeft channel line level analog output.
OUTR13ORight channel line level analog output.
Power Supply Connections and Miscellaneous
Pin NameNumberI/ODescription
AV
DD
7, 14IAnalog Power Supply. Connect to analog +5 V supply.
AGND9, 12IAnalog Ground.
DV
DD
17IDigital Power Supply. Connect to digital +5 V supply.
DGND16IDigital Ground.
N/C4No Connect. Reserved. Do not connect.
REV. 0
–5–
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