mt8880cpr1 Zarlink Semiconductor, mt8880cpr1 Datasheet - Page 3

• Manufacturer Part Number: mt8880cpr1
• Description: Integrated Dtmf Transceiver With Motorola Compatible Processor Interface
• Manufacturer: Zarlink Semiconductor

Pin Description
Functional Description
The MT8880C Integrated DTMF Transceiver architecture consists of a high performance DTMF receiver with
internal gain setting amplifier and a DTMF generator which employs a burst counter such that precise tone bursts
and pauses can be synthesized. A call progress mode can be selected such that frequencies within the specified
passband can be detected. A standard microprocessor interface allows access to an internal status register, two
control registers and two data registers.
Input Configuration
The input arrangement of the MT8880C provides a differential-input operational amplifier as well as a bias source
(V
amp output (GS) for adjustment of gain. In a single-ended configuration, the input pins are connected as shown in
Figure 3.
Figure 4 shows the necessary connections for a differential input configuration.
20
18
19
20
Ref
8, 9,
16,17
) which is used to bias the inputs at V
24
22
23
24
Pin #
3,5,10,1
1, 16,
23-25
27
28
26
28
Name
St/GT Steering Input/Guard Time output (bidirectional). A voltage greater than V
V
ESt Early Steering output. Presents a logic high once the digital algorithm has detected a valid tone
NC No Connection.
DD
pair (signal condition). Any momentary loss of signal condition will cause ESt to return to a logic
low.
causes the device to register the detected tone pair and update the output latch. A voltage less than
V
time-constant; its state is a function of ESt and the voltage on St.
Positive power supply input (+5 V typical).
TSt
frees the device to accept a new tone pair. The GT output acts to reset the external steering
VOLTAGE GAIN
(A
Figure 3 - Single-Ended Input Configuration
V
) = R
C
F
/ R
DD
IN
/2. Provision is made for connection of a feedback resistor to the op-
R
Zarlink Semiconductor Inc.
IN
MT8880C
3
R
F
Description
IN+
IN-
GS
V
MT8880C
Ref
TSt
detected at St
Data Sheet