Features
•DC Characteristic Adjustable
•Receive Gain Adjustable
•Symmetrical Input of Microphone Amplifier
•Anti-clipping in Transmit Direction
•Automatic Line-loss Compensation
•Symmetrical Output of Earpiece Amplifier
•Built-in Ear Protection
•DTMF and MUTE Input
•Adjustable Sidetone Suppression Independent of Sending and
Receiving Amplification
•Power Down
•Tone-ringer Interface
•2-bit D/A for Volume Control
•Supply Voltages for All Functional Blocks of a Subscriber Set
•Operation Possible from 8-mA Line Currents
Applications
•Telephone Sets
Benefits
•Complete System Integration of Analog Signal Processing on One Chip
•Very Few External Components
1. Description
The microcontroller-controlled telephone circuit U4037B-N is a linear integrated circuit
for use in telephone sets. It contains the speech circuit, tone-ringer interface, sidetone
equivalent and ear-protection rectifiers. The circuit is line powered and contains all
components necessary for amplification of signals and adaptation to the line.
Figure 1-1. Block Diagram
Micro-
controller
Power
supply
Speech
circuit
Tone
ringer
PWR
Microcontroller-
controlled
Speech and
Ringer Circuit
U4037B-N
Rev. 4742B–CORD–11/05
2
4742B–CORD–11/05
U4037B-N
2. Pin Configuration
Figure 2-1. Pinning SO24
1
2
3
4
5
6
7
8
10
9
23
18
17
16
14
15
13
12
11
24
21
22
19
20
VOL1
MU/VOL2
MEL
PD
VMP
VRING
AGA
DTMF
OUT2
TXACL
ST
MICO
RECIN
VB
IMP
GND
VL
IND
RECO1
RIF
OUT1
RECO2
MIC1
MIC2
3
4742B–CORD–11/05
U4037B-N
Table 2-1. Pin Description
Pin Symbol Function
1 MICO Output of microphone preamplifier
2 ST Sidetone reduction input, input resistance is approximately 25 kΩ
3 TXACL Time constant of anti-clipping in transmit path
4AGA
Automatic gain adjustment with line current, a resistor connected from this pin to GND sets the starting
point maximum gain change: 6 dB
5 DTMF Input for DTMF signals
6 VOL1 2-bit volume adjustment for tone ringer
7MU/VOL2
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
8 MEL Input for melody
9PD
Active high input for reducing the current consumption of the circuit, VL simultaneously is shorted by an
internal switch
10 VMP 3.4V regulated supply voltage for peripheral circuits (especially microprocessors), minimum output
current: 2 mA (ringing), 4 mA (speech mode)
11 VRING Input for ringer supply voltage
12 OUT2 Differential output for tone ringer
13 OUT1
14 IND 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
15 VL Line voltage
16 GND Reference point for DC- and AC-output signals
17 IMP Impedance adjustment
18 VB Unregulated supply voltage for peripheral circuits (voice switch), limited to typically 7V
19 RECIN Receiver input
20 RIF Pin for adjustment of frequency response and gain of receiver
21 RECO1 Output of receiving amplifier
22 RECO2 Inverting output of receiving amplifier
23 MIC1 Inverting input of microphone amplifier
24 MIC2 Non-inverting input of microphone amplifier
4
4742B–CORD–11/05
U4037B-N
Figure 2-2. Detailed Block Diagram with External Components
Power down
control
VMPREG1
MIC1
MIC2
VMP
DTMF
TXACL
TXACLMICOST
RA
RECO1RECO2
AGA
TXA
DC - Mask
and
supply
AGA
PD
RECIN
V
L
IMP
IND
GND
VRING
Volume
control
BUZA
VMPREG2
OUT1VOL1MU/MEL
VB
VMP
47 µ
1000 µ
To microcontroller
Tip
Ring
Micro-
controller
VMP
+
-
RIF
OUT2
10k
4.7n
51k
5.6n20k
1k
10k
15k
1k
12k
6.8n
6.8n
3.3n
1 µ
23k
20k
560
100n
33n5050
33k
1n
220n
10 µ
10 µ
10
1M
16 V
200k
130k
10
10n
12 V
3.3M
Value depends on the application
VOL2
*
*
**
*
**
*
*
**
5
4742B–CORD–11/05
U4037B-N
3. Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Parameters Symbol Value Unit
Line current IL140 mA
DC line voltage VL12 V
Maximum input current IRING 15 mA
Junction temperature Tj125 °C
Ambient temperature Tamb –25 to +75 °C
Storage temperature Tstg –55 to +150 °C
Total power dissipation, Tamb = 60°C Ptot 520 W
4. Thermal Resistance
Parameters Symbol Value Unit
Junction ambient RthJA 75 K/W
5. Electrical Characteristics
f = 1 kHz, 0 dBm = 775 mVrms, IMP = 2 mA, Tamb = 25°C, Zear = 68 nF + 100Ω, ZM = 68 nF, unless otherwise specified
Parameters Test Conditions Symbol Min. Typ. Max. Unit
DC Characteristics
DC voltage drop over circuit
IL = 2 mA
IL = 14 mA
IL = 60 mA
IL = 100 mA
VL4.6
8.8
2.4
5.0
7.5
9.4
5.4
10.0
V
Transmission Amplifier, IL = 14 mA, VMIC = 2 mV, Unless Otherwise Specified
Transmitting amplification GT47 48 49 dB
Frequency response IL ≥ 14 mA
f = 300 to 3400 Hz ∆GT±0.5 dB
Gain change with current IL = 14 to 100 mA ∆GT±0.5 dB
Gain deviation Tamb = –10 to +60°C ∆GT±0.5 dB
CMRR of microphone
amplifier CMRR 60 80 dB
Input resistance of MIC amplifier Ri50 kW
Distortion at line IL > 14 mA
VL = 700 mVrms dt2%
Maximum output voltage
IL > 19 mA, d < 5%
VMIC = 10 mV
CTXA = 1 µF
VLmax 1.8 3 4.2 dBm
Noise at line psophometrically
weighted
IL > 14 mA
GT = 48 dB no –80 –72 dBmp
Anti-clipping attack time
release time
CTXA = 1 µF
each 3 dB overdrive
0.5
9ms
Line-loss compensation IL = 100 mA, RAGA = 20 kΩ∆GTI –6.4 –5.8 –5.2 dB
Mute suppression IL ≥ 14 mA GTM 60 80 dB
6
4742B–CORD–11/05
U4037B-N
Receiving Amplifier, IL = 14 mA, Unless Otherwise Specified, VGEN = 300 mV
Receiving amplification GR12 dB
Adjustment range GR–8 12 dB
Amplification of DTMF signal from
DTMF IN to RECO 1, 2
IL ≥ 14 mA
VDTMF = 8 mV GRM 14 20 dB
Frequency response IL > 14 mA
f = 300 to 3400 Hz ∆GRF ±0.5 dB
Gain change with current IL = 14 to 100 mA ∆GR±0.5 dB
Gain deviation Tamb = –10 to + 60°C ∆GR±0.5 dB
Ear protection differential IL ≥ 14 mA
VGEN = 11 Vrms EP 2.2 Vrms
MUTE suppression IL ≥ 14 mA ∆GR60 dB
Output voltage d ≤ 2% differential IL = 14 mA, Zear = 68 nF + 100Ω0.775 Vrms
Output voltage d ≤ 5% differential
IL = 14 mA
Zear = 68 nF + 100Ω
RDC = infinite
1.2 Vrms
Receiving noise psophometrically
weighted
Zear = 68 nF + 100Ω
IL ≥ 14 mA ni –64 dBmp
Output resistance Each output against GND Ro 40 Ω
Line-loss compensation RAGA = 20 kΩ
IL = 100 mA ∆GRI –7.0 –6.0 –5.0 dB
Gain at low operating current
IL = 8 mA, IMP = 1 mA
IM = 300 µA
VGEN = 100 mV
RDC = 68 kΩ
GR10.5 12 13.5 dB
DTMF-amplifier Test Conditions: IMP = 2 mA
DTMF amplification
IL = 15 mA
VDTMF = 8 mV
Mute active
GD40.7 41.7 42.7 dB
Gain deviaton IL = 15 mA
Tamb = –10 to +60°C GD±0.5 dB
Input resistance RGT = 15 kΩRi15 20 25 kΩ
Distortion of DTMF signal IL ≥ 15 mA
VL = 0 dBm dD2%
Gain deviation with current IL = 15 to 100 mA ∆GD ±0.5 dB
Supply Voltages, VMIC = 10 mV, Tamb = –10 to +60°C
VMP
IL = 8 mA
RDC = 130 kΩ
IMP = 1 mA
VMP 3.1 3.4 3.6 V
Ringing Part, IVMP = 1 mA
Maximum output voltage VRING = 20V Vout 25 Vpp
Input impedance in speech mode
f = 300 Hz to 3400 Hz
IL > 15 mA
VTIP/RING = 1.5 Vrms
Ri50 kΩ
5. Electrical Characteristics (Continued)
f = 1 kHz, 0 dBm = 775 mVrms, IMP = 2 mA, Tamb = 25°C, Zear = 68 nF + 100Ω, ZM = 68 nF, unless otherwise specified
Parameters Test Conditions Symbol Min. Typ. Max. Unit
7
4742B–CORD–11/05
U4037B-N
Ringing part:
Ringer output voltage
f = 25 Hz, CBUZ = 50 nF
VTIP/RING = 63 Vrms Vout 28 Vpp
VTIP/RING = 45 Vrms Vout 18 Vpp
VTIP/RING = 25 Vrms Vout 7V
pp
Volume adjustment steps
11
10
01
00
0
–6
–12
–24
dB
Zener diode voltage IRING = 25 mA VRINGmax 28.5 V
PD Input
PD input current PD active, IL > 14 mA, VPD = VMP Ipd 9µA
Input voltage PD = active
PD = inactive
Vpd
Vpd
2
0.3 V
Voltage drop at VL
PD = active
IL = 14 mA
IL = 100 mA
VL
VL
1.5
1.9 V
Internal current comsumption at VBVB = 3.5V
PD = active, IL = 0 mA IB300 µA
5. Electrical Characteristics (Continued)
f = 1 kHz, 0 dBm = 775 mVrms, IMP = 2 mA, Tamb = 25°C, Zear = 68 nF + 100Ω, ZM = 68 nF, unless otherwise specified
Parameters Test Conditions Symbol Min. Typ. Max. Unit
8
4742B–CORD–11/05
U4037B-N
7. Package Information
6. Ordering Information
Extended Type Number Package Remarks
U4037B-NFLY SO24 Pb-free
U4037B-NFLG3Y SO24 Taped and reeled, Pb-free
technical drawings
according to DIN
specifications
Package SO24
Dimensions in mm 15.55
15.30
2.35
0.4
1.27 13.97
9.15
8.65
0.25
0.10
7.5
7.3
0.25
10.50
10.20
24 13
112
Printed on recycled paper.
4742B–CORD–11/05
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