Preliminary Data Sheet
AS2504
®
Austria Mikro Systeme International AG
Cordless telephone, answering
machine line interface
General Description
AS2504 is a CMOS integrated circuit that
incorporates DC and AC line adaptation (DC-
mask and synthesised AC-impedance of
1000Ω) as well as a speech circuit with
softclipping, line loss compensation and Rx-
volume control. It shall act as an a/b-line
powered or auxiliarily powered device, which is
controlled by a CPU.
Key Features
Analogue line interface and speech circuit
for a/b terminals on a 28-pin CMOS-IC
2 balanced transmit inputs
3 unbalanced transmit inputs
2 buffered single ended receive outputs
(R
L
>150Ω)
1 auxiliary single ended receive output
(R
L
>10kΩ)
Low noise (max. -72dBmp)
Soft clipping to avoid harsh distortion
Operating range from 15mA to 100mA
(down to 5mA with reduced performance)
Line loss compensation selectable by pin
option
Real and complex impedance selectable by
external components
Side tone adaptation selectable by external
components
Digital controls input for mode selection
Rx volume control
Application
Cordless base stations, answering machines,
a/b-line or auxiliary powered telephone sets.
Package
Available in 28 pin SOIC
Block Diagram
1/12
August 1998
AMSCO [ AUSTRIAMICROSYSTEMS AG ]
