ISD4004 SERIES
6. PIN DESCRIPTION
PIN NAME
PIN NO.
FUNCTION
SOIC /
PDIP
TSOP
1
9
Slave Select: This input, when LOW, will select the
SS
ISD4004 device.
MOSI
2
10
Master Out Slave IN: This is the serial input to the
ISD4004 device when it is configured as slave. The master
microcontroller places data on the MOSI line one half-cycle
before the rising edge of SCLK for clocking into the device.
MISO
3
11
Master In Slave Out: This is the serial output (open drain)
of the ISD4004 device. This output goes into a high-
impedance state if the device is not selected.
VSSA / VSSD
11, 12,
23 / 4
1, 17, 18 /
12
Ground: The ISD4004 series utilizes separate analog and
digital ground busses. The analog ground (VSSA) pins
should be tied together as close as possible and connected
through a low-impedance path to power supply ground.
The digital ground (VSSD) pin should be connected through
a separate low-impedance path to power supply ground.
These ground paths should be large enough to ensure that
the impedance between the VSSA pins and the VSSD pin is
less than 3 Ω. The backside of the die is connected to VSS
through the substrate. For chip-on-board design, the die
attach area must be connected to VSS or left floating.
NC
5-10, 15,
19-22
3, 4, 13-
16, 19, 21,
23, 27, 28
Not connected
AUD OUT [1]
13
20
Audio Output: This pin provides an audio output of the
stored data and is recommended be AC coupled. It is
capable of driving a 5 KΩ impedance REXT
.
[1]
The AUD OUT pin is always at 1.2 volts when the device is powered up. When in playback, the output buffer
connected to this pin can drive a load as small as 5 KΩ. When in record, a built-in resistor connects AUD OUT to
the internal 1.2-volt analog ground supply. This resistor is approximately 850 KΩ, but will vary somewhat
according to the sample rate of the device. This relatively high impedance allows this pin to be connected to an
audio bus without loading it down.
Publication Release Date: October 26, 2005
- 7 -
Revision 1.2
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