ISD1700A SERIES

Confidential

Publication Release Date: March 28, 2005

- 11 -

Revision A0

6 FUNCTIONAL DESCRIPTION

6.1.1

Audio Quality

Winbond’s patented ChipCorder

high-quality record and playback solution on a single chip. The input voice signals are stored

directly in the Flash memory and are reproduced in their natural form without any of the

compression artifacts caused by digital speech solutions.

6.1.2

Message Duration

The ISD1740A/50A/60A devices offer record and playback duration from 26 seconds to 120

seconds. Sampling rate and message duration are determined by an external resistor

Table 6.1 Duration vs. Sampling Frequency

Sample Rate

ISD1740A

ISD1750A

ISD1760A

12 kHz

26 sec

33 sec

40 sec

8 kHz

40 sec

50 sec

60 sec

6.4 kHz

50 sec

62 sec

75 sec

5.3 kHz

60 sec

75 sec

90 sec

4 kHz

80 sec

100 sec

120 sec

6.1.3

Flash Storage

The ISD1740A/50A/60A devices utilize embedded Flash memory to provide non-volatile

storage. A message can be retained for a minimum of 100 years without power. Additionally,

each device can be re-recorded over 10,000 times (typical).

The memory array provides storage for four special Sound Effects (SE) and the audio data. The

memory array is addressed by rows. A row is the minimum storage resolution by which the

memory can be addressed. The memory assignment is handled automatically by the internal

message management system.

The four sound effects occupy four rows of the first sixteen rows in the memory array. The

minimum storage resolution varies with the sampling frequency, as shown in Table 6.2.

Table 6.2 Minimum Storage Resolution vs. Sampling Frequency

Sampling Frequency

12 kHz

8 kHz

6.4 kHz

5.3 kHz

4 kHz

Minimum Storage Resolution

83.3 msec

125 msec

156 msec

187 msec

250 msec

For example, at 8 kHz sampling frequency, the minimum storage resolution is 125 msec, so, each

Sound Effect (SE) is approximately 0.5 seconds long. The remaining memory is dedicated to audio

data storage.