73m2901cl TDK Corp., 73m2901cl Datasheet - Page 11

• Manufacturer Part Number: 73m2901cl
• Description: V.22 Single Chip Modem
• Manufacturer: TDK Corp.

MODEM PERFORMANCE
CHARACTERISTICS
The curves presented in this data sheet define
modem IC performance under a variety of line
conditions typical of those encountered over Public
Switched Telephone Network.
BER VS. SNR
This test represents the ability of the modem to
operate over noisy lines with a minimum amount of
data transfer errors. Since some noise is generated
in the best dial up lines, the modem must operate
with the lowest signal to noise ratio (SNR) possible.
Better modem performance is indicated by test
curves that are closest to the BER axis. A narrow
spread between curves representing the four line
parameters indicates minimal variation in
RECOMMENDED SCHEMATIC ARRANGEMENT
VCC3_3D
J1
CON10
10
VCC3_3A
9
8
7
6
5
4
3
2
1
+
RXDB
DTRB
TXDB
RIB
DCDB
DSRB
CTSB
RTSB
VCC3_3
C1
R1
10uF
10K
RST
VCC3_3D
TXDB
C11
0.1uF
+
C12
10uF
HOOKB
RXDB
DTRB
RIB
DCDB
DSRB
CTSB
RTSB
VCC3_3
25
26
27
28
29
30
31
32
R20
22K
TXDB
U1
VPD
RXD
RXCLK
DTR
USR20
RING
RELAY
RI
10uF
C2
27pF
C5
VCC3_3D
+
11.0592 MHz
Y1
RESET
VREF
2901CL_TQFP32
RINGB/PPUB/LIUB/LREVB
TXAN
+
TXAP
VNA
VBG
RXA
VPA
C13
10uF
LIUCHECKB
C6
0.1uF
16
15
14
13
12
11
10
9
C3
33pF
C14
0.1uF
RST
VREF
RXA
VBG
TXAP
11
VCC3_3D
C7
0.1uF
performance while operating over a range of typical
operating conditions. A DPSK modem will exhibit
better BER performance test curves receiving in the
low band (answer mode) than in the high band
(originate mode).
BER VS. RECEIVE LEVEL
This test measures the dynamic range of the
modem. Because signal levels vary widely over dial
up lines, the widest possible dynamic range is
desirable. The SNR is held constant at the indicated
values as the Receive level is lowered from a very
high to a very low signal level. The width of the bowl
of these curves, taken at the BER break points is the
measure of the dynamic range.
C8
0.1uF
R23
V.22bis Single Chip Modem
+
TXAN
C9
22uF
NC
RXA
TXAP
C20
C10
0.1uF
0.1uF
R17
475
RXA_TAP
VCC3_3A
HOOKB
R15
5.1K
R13
21K
VCC3_3D
VCC3_3D
R18
100
R16
100
T1P3
R28
TXAN
.082UF
C4
R2
2K
120K
ISOLATION BARRIER
U11P2
U10P2
6
5
4
73M2901CL
3
4
T1
671-8005
LDA110*
2
1
U2
1
2
U3
TLP627
U4
TLP627
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