U4037B-N
mC-Controlled
Speech and Ringer Circuit
Description
The
µC-controlled
telephone circuit U4037B-N is a lin-
ear integrated circuit for use in telephone sets. It contains
the speech circuit, tone-ringer interface, sidetone equiva-
lent and ear-protection rectifiers. The circuit is line
powered and contains all components necessary for
amplification of signals and adaptation to the line.
Features
D
DC characteristic adjustable
D
Receive gain adjustable
D
Symmetrical input of microphone amplifier
D
Anti-clipping in transmit direction
D
Automatic line-loss compensation
D
Symmetrical output of earpiece amplifier
D
Built-in ear protection
D
DTMF and MUTE input
D
Adjustable sidetone suppression independent
of sending and receiving amplification
D
Power down
D
Tone-ringer interface
D
2-bit D/A for volume control
D
Supply voltages for all functional blocks of a
subscriber set
D
Operation possible from 8-mA line currents
Benefits
D
Complete system integration of analog signal
processing on one chip
D
Very few external components
Applications
Telephone sets
Block Diagram
Speech
circuit
Power
supply
PWR
mC
Tone
ringer
14076
Ordering Information
Type
U4037B-NFL
U4037B-NFLG3
Package
SO24
SO24
Remarks
Taped and reeled
Rev. A3, 06-Mar-01
1 (7)
Preliminary Information
U4037B-N
Pin Description
Pin
6
MICO
ST
1
2
24 MIC2
23 MIC1
22 RECO2
21 RECO1
20 RIF
19 RECIN
18 VB
17 IMP
10
PD
9
16 GND
15 VL
14 IND
13 OUT1
16276
Symbol
VOL1
MU/
VOL2
7
TXACL 3
AGA
4
DTMF 5
VOL1 6
MU/VOL2 7
MEL 8
8
9
MEL
PD
VMP
VMP 10
VRING 11
OUT2 12
11
12
13
14
VRING
OUT2
OUT1
IND
Function
2-bit volume adjustment for tone
ringer
1. 2-bit volume adjustment for tone
ringer
2. Mute of microphone amplifier:
– Speech condition,
input MU/VOL2 low
– DTMF condition
input MU/VOL2 high
DTMF signal at Pin 5 is fed to
the line. A part of the DTMF-
signal is passed to the receiving
amplifier as a confidence signal
during dialing.
Input for melody
Active high input for reducing the
current consumption of the circuit,
simultaneously V
L
is shorted by an
internal switch
Regulated supply voltage 3.4 V for
peripheral circuits (esp. micropro-
cessors), minimum output current:
2 mA (ringing) 4 mA (speech mode)
Input for ringersupply voltage
Differential output for tone ringer
The internal equivalent inductance
of the circuit is proportional to the
value of the capacitor at this pin, a
resistor connected to ground may be
used to reduce the DC line voltage
Line voltage
Reference point for DC- and AC-
output signals
Impedance adjustment
Unregulated supply voltage for
peripheral circuits (voice switch),
limited to typically 7 V
Receiver input
Pin for adjustment of frequency
response and gain of receiver
Output of receiving amplifier
Inverting output of receiving ampl.
Inverting input of microphone ampl.
Non-inverting input of microphone
amplifier
Figure 1. Pinning
15
16
17
18
VL
GND
IMP
VB
Pin
1
2
3
4
5
Function
Output of microphone preamplifier
Sidetone reduction input
input resistance is approx. 25 kΩ.
TXACL Time constant of anti-clipping in
transmit path
AGA
Automatic gain adjustment with line
current, a resistor connected from
this pin to GND sets the starting
point maximum gain change: 6 dB.
DTMF Input for DTMF signals
Symbol
MICO
ST
19
20
21
22
23
24
RECIN
RIF
RECO1
RECO2
MIC1
MIC2
2 (7)
Rev. A3, 06-Mar-01
Preliminary Information
Rev. A3, 06-Mar-01
23k
33n
1n
1m
20k
MICO
33k
ST
RIF
RECO1
RECO2
TXACL
100n
50
50
560
+
TXACL
12k
MIC1
–
RECIN
220n
TXA
VL
10n
16V
RA
Power down
control
PD
10
1M
VMP
1k
15k
6.8n
*
*
MIC2
3.3n
10k
*
*
*
DTMF
AGA
AGA
DC – Mask
and
supply
VB
VMPREG1
VMP
1k
6.8n
3.3M
200k
12V
10
IMP
10m
*
5.6n
20k
*
10k
51k
1000
m
Tip
IND
*
*
Detailed Block Diagram with External Components
Figure 2. Application circuit
GND
4.7n
47
m
130k
Preliminary Information
VMPREG2
BUZA
VRING
10m
Volume
control
OUT1
OUT2 VOL1
MU/
VOL2
MEL
Ring
*
VMP
to
mC
m
C
16277
U4037B-N
*
Value depends on the application
3 (7)
U4037B-N
Absolute Maximum Ratings
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Line current
DC line voltage
Maximum input current
Junction temperature
Ambient temperature
Storage temperature
Total power dissipation,
T
amb
= 60°C
Parameters
Symbol
I
L
V
L
I
RING
T
j
T
amb
T
stg
P
tot
Value
140
12
15
125
–25 to +75
–55 to +150
520
Unit
mA
V
mA
°C
°C
°C
W
Thermal Resistance
Junction ambient
SO24
Parameters
Symbol
R
thJA
Value
75
Unit
K/W
Electrical Characteristics
f = 1 kHz, 0 dBm = 775 mV
rms
, I
MP
= 2 mA, T
amb
= 25°C, Z
ear
= 68 nF + 100
W,
Z
M
= 68 nF, unless otherwise specified
Parameters
DC characteristics
Test Conditions / Pin
Symbol
Min.
Typ.
2.4
5.0
7.5
9.4
48
Max.
Unit
I
L
= 2 mA
I
L
= 14 mA
4.6
DC voltage drop over circuit
V
L
I
L
= 60 mA
8.8
I
L
= 100 mA
Transmission amplifier, I
L
= 14 mA, V
MIC
= 2 mV, unless otherwise specified
Transmitting amplification
G
T
47
I
L
w
14 mA,
Frequency response
DG
T
f = 300 to 3400 Hz
Gain change with current
I
L
= 14 to 100 mA
DG
T
Gain deviation
T
amb
= –10 to +60
°C
DG
T
CMRR of microphone
CMRR
60
amplifier
Input resistance of MIC amplifier
R
i
I
L
> 14 mA
Distortion at line
d
t
V
L
= 700 mV
rms
I
L
> 19 mA, d < 5%
Maximum output voltage
V
mic
= 10 mV
V
Lmax
1.8
CTXA = 1
mF
Noise at line psophometrically
I
L
> 14 mA
no
weighted
G
T
= 48 dB
Anti-clipping attack time
CTXA = 1
mF
release time
each 3 dB overdrive
I
L
= 100 mA,
Line-loss compensation
DG
TI
–6.4
RAGA = 20 kW
Mute suppression
G
TM
60
I
L
w
14 mA
5.4
V
10.0
49
"0.5
"0.5
"0.5
dB
dB
dB
dB
dB
kW
2
%
dBm
dBmp
ms
–5.2
dB
dB
80
50
3
–80
0.5
9
–5.8
80
4.2
–72
4 (7)
Rev. A3, 06-Mar-01
Preliminary Information
U4037B-N
Electrical Characteristics (continued)
Parameters
Test Conditions / Pin
Symbol
Min.
Receiving amplifier, I
L
= 14 mA, unless otherwise specified, V
GEN
= 300 mV
Receiving amplification
G
R
Adjustment range
G
R
–8
Amplification of DTMF signal from I
L
w
14 mA,
G
RM
14
DTMF IN to RECO 1, 2
V
DTMF
= 8 mV
I
L
> 14 mA,
Frequency response
DG
RF
f = 300 to 3400 Hz
Gain change with current
I
L
= 14 to 100 mA
DG
R
Gain deviation
T
amb
= –10 to +60°C
DG
R
I
L
w
14 mA
Ear protection differential
EP
V
GEN
= 11 V
rms
MUTE suppression
DG
R
60
I
L
w
14 mA
Output voltage d
v
2%
I
L
= 14 mA
0.775
differential
Z
ear
= 68 nF + 100
W
I
L
= 14 mA
Output voltage d
v
5%
Z
ear
= 68 nF + 100
W
1.2
differential
RDC = infinite
Z
ear
= 68 nF + 100
W
Receiving noise
ni
I
L
w
14 mA
psophometrically weighted
Output resistance
each output against GND
Ro
RAGA = 20 kW,
Line-loss compensation
DG
RI
–7.0
I
L
= 100 mA
I
L
= 8 mA, I
MP
= 1 mA
I
M
= 300
mA
Gain at low operating current
G
R
10.5
V
GEN
= 100 mV
RDC = 68 kW
DTMF-amplifier
test conditions: IMP = 2 mA
I
L
= 15 mA,
DTMF amplification
VDTMF = 8 mV
G
D
40.7
Mute active
I
L
= 15 mA
Gain deviaton
G
D
T
amb
= –10 to +60
°C
Input resistance
RGT = 15 kW
R
i
15
I
L
w
15 mA,
Distortion of DTMF signal
d
D
V
L
= 0 dBm
Gain deviation with current
I
L
= 15 to 100 mA
DGD
Supply voltages, V
mic
= 10 mV, T
amb
= – 10 to + 60°C
I
L
= 8 mA,
V
MP
RDC = 130 kW
V
MP
3.1
I
MP
= 1 mA
Ringing part, I
VMP
= 1 mA
Maximum output voltage
V
RING
= 20 V
V
out
f = 300 Hz to 3400 Hz
Input impedance in speech mode
I
L
> 15 mA,
R
i
50
V
TIP/RING
= 1.5 V
rms
Typ.
Max.
12
12
20
"0.5
"0.5
"0.5
2.2
Unit
dB
dB
dB
dB
dB
dB
V
rms
dB
V
rms
V
rms
–64
40
–6.0
–5.0
dBmp
W
dB
12
13.5
dB
41.7
42.7
"0.5
dB
dB
kW
%
dB
20
25
2
"0.5
3.4
3.6
V
25
V
pp
kW
Rev. A3, 06-Mar-01
5 (7)
Preliminary Information