6. PIN DESCRIPTION
A0, A1, A2,
A3, A4, A5,
A6, A7, A8
/ M0, M1,
M4, M5, M6
1, 2, 3, 8, 9, 10, Address/Mode Inputs: The Address/Mode Inputs have two functions
4, 5, 6, 11, 12, 13, depending on the level of the two Most Significant Bits (MSB) of the
7, 9, 10 14, 16, 17 address pins A7 and A8.
/ 1, 2,
5, 6, 7
/ 8, 9,
12, 13, 14
If either or both of the two MSBs are LOW, the inputs are all interpreted
as address bits and are used as the start address for the current record
or playback cycle. The address pins are inputs only and do not output
any internal address information during the operation. Address inputs
are latched by the falling edge of CE .
If both MSBs are HIGH, the Address/Mode inputs are interpreted as
Mode bits according to the Operational Mode table on page 12. There
are six operational modes (M0…M6) available as indicated in the table.
It is possible to use multiple operational modes simultaneously.
Operational Modes are sampled on each falling edge of CE , and thus
Operational Modes and direct addressing are mutually exclusive.
Auxiliary Input: The Auxiliary Input is multiplexed through to the output
amplifier and speaker output pins when CE is HIGH, P/ R is HIGH,
and playback is currently not active or if the device is in playback
overflow. When cascading multiple ISD2500 devices, the AUX IN pin is
used to connect a playback signal from a following device to the
previous output speaker drivers. For noise considerations, it is
suggested that the auxiliary input not be driven when the storage array
Ground: The ISD2500 series of devices utilizes separate analog and
digital ground busses. These pins should be connected separately
through a low-impedance path to power supply ground.
Speaker Outputs: All devices in the ISD2500 series include an on-chip
differential speaker driver, capable of driving 50 mW into 16 Ω from
AUX IN (12.2mW from memory).
 The speaker outputs are held at VSSA levels during record and power
down. It is therefore not possible to parallel speaker outputs of multiple
ISD2500 devices or the outputs of other speaker drivers.
 A single-end output may be used (including a coupling capacitor
between the SP pin and the speaker). These outputs may be used
individually with the output signal taken from either pin. However, the
use of single-end output results in a 1 to 4 reduction in its output power.
 Connection of speaker outputs in parallel may cause damage to the device.
 Never ground or drive an unused speaker output.