TEA1112AT NXP Semiconductors, TEA1112AT Datasheet - Page 6

• Manufacturer Part Number: TEA1112AT
• Manufacturer: NXP Semiconductors

Specifications of TEA1112AT

• Max Transmitter Gain: 53dB
• Receiver Gain (max): 32.7dB
• Operating Temp Range: -25C to 75C
• Package Type: SSOP
• Pin Count: 16
• Operating Current: 1.15mA
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Lead Free Status / Rohs Status: Not Compliant

Philips Semiconductors
The DC line current flowing into the set is determined by
the exchange supply voltage (V
resistance (R
(R
below 7.5 mA, the internal reference voltage (generating
V
that more sets can operate in parallel with DC line voltages
(excluding the polarity guard) down to an absolute
minimum voltage of 1.6 V. At currents below 7.5 mA, the
circuit has limited sending and receiving levels. This is
called the low voltage area.
Set impedance
In the audio frequency range, the dynamic impedance is
mainly determined by the R
impedance of the circuits is illustrated in Fig.8.
LED supply (pin I
The TEA1112; TEA1112A give an on-hook/off-hook status
indication. This is achieved by a current made available to
drive an LED connected between pins I
low voltage area, which corresponds to low line current
conditions, no current is available for this LED.
1997 Mar 26
handbook, halfpage
ref
line
Low voltage versatile telephone
transmission circuits with dialler interface
(1) Influence of R
(2) V
) is automatically adjusted to a lower value. This means
V ref
(V)
) and the reference voltage (V
Fig.5 Reference voltage adjustment by R
6.0
5.0
4.0
3.0
ref
10
without influence of R
4
exch
), the DC resistance of the telephone line
VA
LED
on V
10
)
ref
5
(1)
(2)
.
VA
CC
.
resistor. The equivalent
exch
10
ref
), the feeding bridge
6
). With line currents
LED
R VA ( )
and LN. In the
MGD176
10
VA
7
.
6
For line currents higher than a threshold, I
current increases proportionally to the line current (with a
ratio of one third). The I
19.5 mA (see Fig.9). If no LED device is used in the
application, the I
For 17 mA < I
This LED driver is referenced to SLPE. Consequently, all
the I
The AGC characteristics are not disturbed (see Fig.4).
Microphone amplifier (pins MIC+, MIC and GAS)
The TEA1112; TEA1112A have symmetrical microphone
inputs. The input impedance between pins MIC+ and
MIC is 64 k (2
pins MIC+/MIC to pin LN is set at 51.8 dB (typ). The gain
can be decreased by connecting an external resistor R
between pins GAS and REG. The adjustment range is
13 dB. A capacitor C
and REG can be used to provide a first-order low-pass
filter. The cut-off frequency corresponds to the time
constant C
resistor which sets the gain with a typical value of 69 k .
Automatic gain control is provided on this amplifier for line
loss compensation.
Microphone mute (pin MMUTE; TEA1112)
The microphone amplifier can be disabled by activating
the microphone mute function. When MMUTE is LOW, the
normal speech mode is entered, depending on the level on
MUTE (see Table 1). When MMUTE is HIGH, the
microphone amplifier inputs are disabled while the DTMF
input is enabled (no confidence tone is provided).
The voltage gain between LN and MIC+/MIC is
attenuated; the gain reduction is 80 dB (typ).
Microphone mute (pin MMUTE; TEA1112A)
The microphone amplifier can be disabled by activating
the microphone mute function. When MMUTE is LOW, the
microphone amplifier inputs are disabled while the DTMF
input is enabled (no confidence tone is provided).
The voltage gain between LN and MIC+/MIC is
attenuated; the gain reduction is 80 dB (typ). When
MMUTE is HIGH, the normal speech mode is entered,
depending on the level on MUTE (see Table 1).
LED
supply current will flow through the R
GAS
line
LED
(R
< 77 mA:
GASint
32 k ). The voltage gain from
pin should be shorted to pin SLPE.
GAS
LED
TEA1112; TEA1112A
connected between pins GAS
// R
I
current is internally limited to
LED
GAS
=
). R
I
--------------------- -
line
GASint
Product specification
3
–
17
LEDstart
is the internal
SLPE
, the I
resistor.
LED
GAS