MT88L70
Data Sheet
2
Zarlink Semiconductor Inc.
Figure 2 - Pin Connections
Pin Description
Pin #
Name
Description
18
20
1
1
IN+
Non-Inverting Op-Amp (Input).
2
2
IN-
Inverting Op-Amp
(Input)
.
3
3
GS
Gain Select.
Gives access to output of front end differential amplifier for connection of
feedback resistor.
4
4
V
Ref
Reference Voltage (Output).
Nominally V
DD
/2 is used to bias inputs at mid-rail (see Figure 5
and Figure 6).
5
5
INH
Inhibit (Input).
Logic high inhibits the detection of tones representing characters A, B, C and
D. This pin input is internally pulled down.
6
6
PWDN
Power Down (Input).
Active high. Powers down the device and inhibits the oscillator. This
pin input is internally pulled down.
7
8
OSC1
Clock
(Input)
.
8
9
OSC2
Clock
(Output)
. A 3.579545 MHz crystal connected between pins OSC1 and OSC2
completes the internal oscillator circuit.
9
10
V
SS
Ground
(Input)
. 0 V typical.
10
11
TOE
Three State Output Enable (Input).
Logic high enables the outputs Q1-Q4. This pin is pulled
up internally.
11-
14
12-
15
Q1-Q4
Three State Data (Output).
When enabled by TOE, provide the code corresponding to the
last valid tone-pair received (see Table 1). When TOE is logic low, the data outputs are high
impedance.
15
17
StD
Delayed Steering (Output).
Presents a logic high when a received tone-pair has been
registered and the output latch updated; returns to logic low when the voltage on St/GT falls
below V
TSt
.
Early Steering (Output).
Presents a logic high once the digital algorithm has detected a valid
tone pair (signal condition). Any momentary loss of signal condition will cause ESt to return to
a logic low.
16
18
ESt
1
2
3
4
5
6
7
8
9
10
18
17
16
15
14
13
12
11
IN+
IN-
GS
VRef
INH
PWDN
OSC1
OSC2
VSS
VDD
St/GT
ESt
StD
Q4
Q3
Q2
Q1
TOE
18 PIN PDIP/SOIC
1
2
3
4
5
6
7
8
9
10
11
12
20
19
18
17
16
15
14
13
IN+
IN-
GS
VRef
INH
PWDN
NC
OSC1
OSC2
VSS
20 PIN SSOP
VDD
St/GT
ESt
StD
NC
Q4
Q3
Q2
Q1
TOE