Rainbow Electronics ISD4004 - Manual (Page 5)

ISD4004 Series
1 ISD
DETAILED DESCRIPTION
SPEECH/SOUND QUALITY
The ISD4004 ChipCorder series includes devices
offered at 4.0, 5.3, 6.4, and 8.0 KHz sampling fre-
quencies, allowing the user a choice of speech
quality options. Increasing the duration within a
product series decreases the sampling frequency
and bandwidth, which affects sound quality.
Please refer to the ISD4004 Series Product Summary
table on the second page to compare filter pass
band and product durations.
The speech samples are stored directly into on-chip
nonvolatile memory without the digitization and
compression associated with other solutions. Di-
rect analog storage provides a natural sounding
reproduction of voice, music, tones, and sound
effects not available with most solid-state solu-
tions.
DURATION
To meet end system requirements, the ISD4004 se-
ries products are single-chip solutions at 8, 10, 12,
16 minutes.
FLASH STORAGE
One of the benefits of ISD’s ChipCorder technology
is the use of on-chip nonvolatile memory, which pro-
vides zero-power message storage. The message
is retained for up to 100 years (typically) without
power. In addition, the device can be re-record-
ed (typically) over 100,000 times.
MICROCONTROLLER INTERFACE
A four-wire (SCLK, MOSI, MISO, SS) SPI interface is
provided for ISD4004 control and addressing
functions. The ISD4004 is configured to operate as
a peripheral slave device, with a microcontroller-
based SPI bus interface. Read/Write access to all
the internal registers occurs through this SPI inter-
face. An interrupt signal (INT) and internal read-
only Status Register are provided for handshake
purposes.
PROGRAMMING
The ISD4004 series is also ideal for playback-only
applications, where single or multiple message
Playback is controlled through the SPI port. Once
the desired message configuration is created, du-
plicates can easily be generated via an ISD pro-
grammer.
PIN DESCRIPTIONS
VOLTAGE INPUTS (V
CCA
, V
CCD
)
To minimize noise, the analog and digital circuits
in the ISD4004 devices use separate power busses.
These +3 V busses are brought out to separate
pins and should be tied together as close to the
supply as possible. In addition, these supplies
should be decoupled as close to the package as
possible.
GROUND INPUTS (V
SSA
, V
SSD
)
The ISD4004 series utilizes separate analog and
digital ground busses. The analog ground (V
SSA
)
pins should be tied together as close to the pack-
age as possible and connected through a low-
impedance path to power supply ground. The
digital ground (V
SSD
) pin should be connected
through a separate low-impedance path to pow-
er supply ground. These ground paths should be
large enough to ensure that the impedance be-
tween the V
SSA
pins and the V
SSD
pin is less than
3
W. The backside of the die is connected to V
SS
through the substrate resistance. In a chip-on-
board design, the die attach area must be con-
nected to V
SS
or left floating.