u4090b-p ATMEL Corporation, u4090b-p Datasheet - Page 6

• Manufacturer Part Number: u4090b-p
• Description: U4090b-p Monolithic Integrated Feature Phone Circuit Emi Improved
• Manufacturer: ATMEL Corporation

Table 2-1.
Note:
3. DC Line Interface and Supply-voltage Generation
6
Pin
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
Filters against electromagnetic interference (EMI) are located at following pins: MIC1, MIC2, RECIN, TXIN, STIS, STIL and
RAC.
U4090B-P
Pin Description (Continued)
Symbol
RECO2
RECO1
RECIN
MUTR
TLDR
TTXA
IREF
TXIN
STIS
AGA
STO
STIL
RAC
VM
GR
The DC line interface consists of an electronic inductance and a dual-port output stage which
charges the capacitors at V
In order to improve the supply during worst-case operating conditions, two PNP current sources
- I
parallel are unable to conduct current.
A flowchart for the control of the current sources
VMPS is achieved.
Function
Time constant of receive level detector
Automatic gain adjustment with line current, a resistor connected from this pin to GND sets the starting
point, maximum gain change: 6 dB.
Internal reference current generation; RREF = 62 k ; IREF = 20 µA
Sidetone reduction output
Output resistance approximate: 300 ,
Maximum load impedance: 10 k .
Reference node for microphone-earphone and loudspeaker amplifier, supply for electret microphone
(IM 700 mA)
Three-state mute input
1. Normal operation
2. Mute for ear piece
3. Mute for RECIN signal
Condition of earpiece mute is stored
Inverting output of receiving amplifier
Input for sidetone network (short loop) or for answering machine
Input for sidetone network (long loop)
Input of receiving amplifier for AC coupling in feedback path
Output of receiving amplifier
A resistor connected from this pin to GND sets the receiving amplification of the circuit; amplifier RA1 can
be muted by applying VMP to GR
Time constant of anti-clipping in transmit path
Input of receiving path; input impedance is typically 80 k
Input of intermediate transmit stage, input resistance is typically 20 k
BOPT
L = R
and I
SENSE
MPSOPT
- hand an extra amount of current to the supply voltages when the NPNs in
C
IND
((R
MPS
DC
and V
R
30
B
. The value of the equivalent inductance is given by:
)/(R
DC
+ R
30
(Figure
))
3-2) shows how a priority for supply
4741C–CORD–11/05