AS2525B austriamicrosystems, AS2525B Datasheet - Page 9

• Manufacturer Part Number: AS2525B
• Description: IC, SINGLE CHIP HANDS FREE PHONE, TQFP44
• Manufacturer: austriamicrosystems

Specifications of AS2525B

• Audio Control Type: Volume
• Output Power: 500mW
• Control Interface: Serial
• Control / Process Application: Volume Control For Earpiece & Loudspeaker
• Supply Voltage Range: 3V To 5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Datasheet AS2525
Memory Allocation
The EEPROM memory consists of three areas:
A = factory settings; B = user settings; C = stored numbers
The AS2525 is writing and reading to and from area B and
C during normal operation and user-code programming.
Area A is protected during normal operation and contains a
back-up copy of the factory settings. This back-up copy
can be loaded into area B by the user with the user-code
programming procedure "reset to factory settings". The
only way to change the factory settings in area A is by set-
up programming using password. After changing area A by
set-up programming, the AS2525 automatically performs a
"reset to factory settings" to load this changes also into
area B.
Functional Description
DC Conditions
The normal operating mode is from 15 mA to 100 mA. An
operating mode with reduced performance is from 5 mA to
15 mA. In the line-hold range from 0 mA to 5 mA the device
is in a power down mode.
The dc characteristic is determined by the voltage at LI pin
and a 30
calculated by the following equation:
VLI can be programmed to be 3.5 V or 4.5 V.
Table 7: DC mask selection
Revision 2.1
programmed in factory
Digit
[0]
[1]
…write/read by AS2525
[PG] + [0] + (Password) + [#] + [3] + (digit) + [PG]
V
LS
= V
DC Mask (dc voltage at pin LI)
Low dc mask, VLI = 3.5 Volt
High dc mask, VLI = 4.5 Volt
resistor between pin LI and LS. It can be
LI
+ I
LINE
Figure 3: Memory allocation for external EEPROM
* 30
C) stored numbers
A) factory settings
B) user settings
EEPROM
2/4 Wire Conversion
AS2525 has a built-in dual Wheatstone bridge with one
common ground. This provides a maximum of
independence of ac impedance and side-tone from each
other. One can adapt side-tone without changing the ac
impedance.
AC Impedance
The ac impedance of AS2525 is set to 1000
impedance can be adjusted by connecting an external
capacitor to the CI pin. With an external resistor of
approximately 1.5 k
programmed to 600
"reset to factory settings"
Set-up programming
User-code programming
VLine
Figure 4: DC characteristic with low dc mask
Z
AC(syn)
(V)
8
6
4
2
0
0
= 33
20
30
.
connected to the LS pin, it can be
40
ILine
60
80
(mA)
VLS
VLI
100
. A complex
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