MT91610 Datasheet, PDF (3/20 Pages) Mitel Networks Corporation – Analog Ringing SLIC

Preliminary Information
MT91610
Pin Description (continued)
Pin # Name
Description
20
Z1 Line Impedance Node 1. A resistor of scaled value "k" is connected between Z1 and Z2. This
connection can not be left open circuit.
21 CP5 Line Impedance AC couple. A 330 nF cap must be connected between this pin and Z1 (pin
20).
22
Z2 Line Impedance Node 2. This is the common connection node between Z1 and Z3.
23
Z3 Line Impedance Node 3. A resistive or complex network of scaled value "k" is connected
between Z3 and Z2. This connection can not be left open circuit.
24 GTX0 Gain Node 0. This is the common node between Z3 and VX where resistors are connected to
set the 2W to 4W gain.
25 VX Transmit Audio. 4W analog signal from the SLIC.
26 ESI External Signal Input. 12 / 16 KHz signal input.
27 GTX1 Gain Node 1. The common node between VR and the audio input from the CODEC or
switching network where resistors are fitted to set the 4W to 2W gain.
28 VR Receive Audio. 4W analog signal to the SLIC.
29 CP6 Ringing Cap. A 0.47uF cap should be connected between this pin and GND to filter out the
ringing signal.
30 RC Ringing Control. An active high (+5V) on this pin will set up the DC feed and gain of the SLIC
to apply 20 Hz ringing. When low (0V) set the SLIC in normal constant current mode of
operation.
31 UD UnBalance Detect. Logic high (+5V) indicates an offset current between Tip and Ring.
32 VBAT VBAT. The negative battery supply, typically at -48V.
33 SHK Switch Hook. This pin indicates the line state of the subscribers telephone. The output can also
be used for dial pulse monitoring. Logic high (+5V) indicates off hook condition.
34 CP7 Deglitching Cap. A 33nF should be connected between this pin and GND.
35 RV Ringing Voltage. 20 Hz sinusoidal or square wave AC in for balance ringing.
36 VEE Negative supply rail, -5V.
Functional Description
Refer to Figure 4 for MT91610 components
designation.
4 wire signal, which is the output from the SLIC to
the analog switch or voice CODEC.
Gain Control
The MT91610, with external bipolar transistors,
functions as an Analog Line SLIC for use in a 4 Wire
switched system. The SLIC performs all of the
BORSH functions while interfacing to a CODEC or
switching system.
2 Wire to 4 Wire Conversion
The SLIC performs 2 wire to 4 wire conversion by
taking the 4 wire signal from an analog switch or
voice CODEC, and converting it to a 2 wire
differential signal at Tip and Ring. The 2 wire signal
applied to tip and ring by the phone is converted to a
It is possible to set the Transmit and Receive gains
by the selection of the appropriate external
components.
The gains can be calculated by the following
formulae:
2W to 4W gain
Gain 2 - 4 = 20 Log [ R8 / R7]
4W to 2W gain
Gain 4 - 2 = 20 Log [0.891 * [R10 / R9)]
3