AD1845JP Analog Devices Inc, AD1845JP Datasheet - Page 9

• Manufacturer Part Number: AD1845JP
• Description: IC CODEC STEREO 5V 16BIT 68PLCC
• Manufacturer: Analog Devices Inc
• Type: Stereo Audior

Specifications of AD1845JP

• Rohs Status: RoHS non-compliant
• Resolution (bits): 16 b
• Number Of Adcs / Dacs: 2 / 2
• Sigma Delta: Yes
• Dynamic Range, Adcs / Dacs (db) Typ: 81 / 82
• Voltage - Supply, Analog: 4.75 V ~ 5.25 V
• Voltage - Supply, Digital: 4.75 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 68-PLCC

Power Supplies
Pin Name
V
GNDA
V
GNDD
(Continued from page 1)
External circuit requirements are limited to a minimal number
of low cost support components. Anti-imaging DAC output
filters are incorporated on-chip. Dynamic range exceeds 80 dB
over the 20 kHz audio band. Sample rates from 4 kHz to 50 kHz
are supported from a single external crystal or clock source.
The AD1845 has built-in 8/16 mA (user selectable) bus drivers.
If 24 mA drive capability is required, the AD1845 generates
enable and direction controls for IC bus buffers such as the
74 245.
The codec includes a stereo pair of
verters and a stereo pair of
AD1845 mixer surpasses MPC Level-2 recommendations.
Inputs to the ADC can be selected from four stereo pairs of
analog signals: line (LINE), microphone (MIC), auxiliary line
#1 (AUX1), and post-mixed DAC output. A software-con-
trolled programmable gain stage allows independent gain for
each channel going into the ADC. In addition, the analog mixer
allows the mono input (M_IN), MIC, AUX1, LINE and auxil-
iary line #2 (AUX2) signals to be mixed with the DACs’ output.
The ADCs’ output can be digitally mixed with the DACs’ input.
The pair of 16-bit outputs from the ADCs is available over a
byte-wide bidirectional interface that also supports 16-bit digital
input to the DACs and control information. The AD1845 can
accept and generate 16-bit twos complement PCM linear digital
data in both little endian or big endian byte ordering, 8-bit
REV. C
CC
DD
AD1845
DATA7:0
DBDIR
PDRQ
CDRQ
CDAK
DBEN
PDAK
WR
INT
RD
CS
A1
A0
Figure 1. Interface to ISA Bus
PLCC
35 & 36
34 & 37
1, 7, 15,
19, 45,
54
2, 8, 16,
20, 25,
44, 53,
64
8
B
G
DIR
ADDRESS
DECODE
74_245
digital-to-analog converters. The
A
TQFP
41 & 42
40 & 43
10, 14,
55, 68,
88, 98
11, 15, 20,
54, 67,
79, 89,
99
analog-to-digital con-
8
18
AEN
SA19:2
SA1
SA0
IOWC
IORC
DATA7:0
DRQ <X>
DRQ <Y>
DAK <X>
DAK <Y>
IRQ <Z>
S
A
B
U
S
I
I/O
I
I
I
I
–9–
unsigned magnitude PCM linear data, and 8-bit -law or A-law
companded digital data.
The
attenuator provides independent user volume control over each
DAC channel. Nyquist images and shaped quantized noise are
removed from the DACs’ analog stereo output by on-chip
switched-capacitor and continuous-time filters.
The AD1845 supports multiple low power and power-down
modes to support notebook and portable computing multimedia
applications. The ADC, DAC, and mixer paths can be sus-
pended independently allowing the AD1845 to be used for
capture-only or playback-only, lessening power consumption
and extending battery life.
The AD1845 includes a variable sample frequency generator,
that allows the codec to instantaneously change sample rates
with a resolution of 1 Hz without “clicks” and “pops.” Addi-
tionally,
band regardless of the chosen sample rate. The codec uses the
variable sample frequency generator to derive all internal clocks
from a single external crystal or clock source.
Expanded Mode (MODE2)
MODE1 is the initial state of the AD1845. In this state the
AD1845 appears as an AD1848 compatible device. To access
the expanded modes of operation on the AD1845, the MODE2
bit should be set in the Miscellaneous Information Control
Register. When this bit is set to one, 16 additional indirect
registers can be addressed allowing the user to access the
AD1845’s expanded features. The AD1845 can return to
MODE1 operation by clearing the MODE2 bit. In both
MODE1 and MODE2, the capture and playback FIFOs are
active to prevent data loss.
The additional MODE2 functions are:
1. Full-Duplex DMA support.
2. MIC input mixer, mute and volume control.
3. Mono output with mute control.
4. Mono input with mixer volume control.
5. Software controlled advanced power-down modes.
6. Programmable sample rates from 4 kHz to 50 kHz in 1 Hz
increments.
DACs are preceded by a digital interpolation filter. An
quantization noise is kept out of the 20 kHz audio
Description
Analog Supply Voltage (+5 V).
Analog Ground.
Digital Supply Voltage (+5 V).
Digital Ground.
AD1845