Modem Filter. XR-2120A Datasheet

XR-2120A Filter. Datasheet pdf. Equivalent

XR-2120A Datasheet
Recommendation XR-2120A Datasheet
Part XR-2120A
Description 212A/V.22 Modem Filter
Feature XR-2120A; XR·2120AADVANCE INFORMATION 212A/V.22 Modem Filter GENERAL DESCRIPTION The XR-2120A is a filter sy.
Manufacture Exar
Datasheet
Download XR-2120A Datasheet




Exar XR-2120A
XR·2120AADVANCE INFORMATION
212A/V.22 Modem Filter
GENERAL DESCRIPTION
The XR-2120A is a filter system for performing the com-
plete filter function for Bell 212A or CCITI V.22 type
modems. The XR-2120A supplies both transmit and re-
ceive filtering functions for the standard 1200 Hz and
2400 Hz 212A1V.22 carrier frequencies. Also supplied
are mode switching, internal clock generators, input
anti-aliasing filters, output reconstruction filters, and
digitally controlled transmit and receive gains. Addition-
al features included are CCITI notch filters, additional
pin selectable equalization for worst case phone lines
and complete analog loopback function.
The XR-2120A utilizes silicon gate CMOS technology
and switched-capacitor circuit techniques to minimize
external components and enhance overall perform-
ance.
The XR-2120A, available in a 24-Pin Package, is de-
signed to operate from dual 5 volt or a single 10 volt
power supply.
FEATURES
1200 Hz/2400 Hz Transmit and Receive Bandpass
Filters
Mode Switching for Answer/Originate
Internal Anti-Aliasing Filters
Complete On-Board Output Reconstruction Filters
Self-Contained Analog Loopback Function
Digitally Programmable Transmit and Receive Gains
Additional Pin-Selectable Equalization for Worst Case
Phone Lines
Single or Split Supply Operation
Low Supply Current
CCITI Notch Filter (1800 Hz)
Center Frequencies Movable with Clock Input
APPLICATIONS
Bell 212A1CCITI V.22 Transmit and Receive Filtering
Answer Back Signal Filtering
ABSOLUTE MAXIMUM RATINGS
Power Supply
11V
Power Dissipation
1.0W
Derate Above 25° C
5 mW/·C
Operating Temperature Range
C to 70·C
Storage Temperature Range
-65· C to 150·e
Any input Voltage
VSS - 0.3V to VDD + 0.3V
FUNCTIONAL BLOCK DIAGRAM
VSSlI
vssttrG
'OB
VINY
tXCOUT
ANAlOGGND
NOTCH EN
ALSSP
ALBEN
AV'
UtlN
MODE
ORDERING INFORMATION
Part Number
XR-2120ACN
XR-2120ACP
Package
Ceramic
Plastic
operallng Tamperatura
o·e to 70·e
o·e to 70·e
SYSTEM DESCRIPTION
The XR-2120A is made up of five main signal blocks;
Digitally programmable gain transmit and receive am-
plifiers, input anti-aliasing filters, switched capaCitor
bandpass filters centered at 1200 Hz and 2400 Hz, out-
put RC active filters, and 3600 Hz oscillator and mixer.
These blocks serve to (1) Amplify and condition incom-
ing signals, (2) Remove noise and signals which may
cause aliasing problems in the bandpass filters, (3) Pro-
vide precise bandpass filtering and phase equalization,
(4) Provide output reconstruction and filtering, and, (5)
Perform analog loop back functions.
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Exar XR-2120A
XR·2120A
ELECTRICAL CHARACTERISTICS
Test Conditions: VDD = 5V, VSS = -5V, XIN = 1,8432 MHz, TJ = 25Q C, unless 'otherwise specified.
SYMBOL
PARAMETER
VDD
Power Supply
VSS
IDD
Voltage
Power Supply
ISS Current
DIGITAL SECTION
CLK OUT CLK OUT Drive Capability
II Digital Input Current
VIH Input High Voltage
VIL Input Low Voltage
VOH
Output High Voltage
VOL
Output Low Voltage
ANALOG SECTION
fol Bandpass Center
fob Frequencies
BW 3 dB Bandwidth of Filters
MIN
4.75
4.75
2.4
2.6
1190
2380
Avt Transmit Gain at
5
Avt Center Frequency
14
Avr Receive Gain at
10
Avr Center Frequency
19
Ri Input Impedance
Ci Input Capacitance
ei range
Input Dynamic Range
Va swing
Output Voltage Swing
7,2
CHSEP
Channel Separation
60
Note: 1, Filter Characteristics Shown in Figure
2, Test Circuit Shown in Figure
TYP
5,0
-5.0
20
-20
1200
2400
±480
6
15
11
20
100
80
8,2
MAX
5.25
-5,25
40
-40
50
10
0,8
0,5
1210
2420
7
16
12
21
10
UNITS
V
V
mA
mA
pF
p.A
V
V
V
V
Hz
Hz
Hz
dB
dB
dB
dB
Kohm
pF
dB
Vp-p
dB
CONDITIONS
VIN = VDD or GND
IOH = 400 p.A
IOL = 1.6 MA
See Note 1
See Note 1
Either Band
See Note 1
Avt = HIGH
Avt = LOW
Avr = LOW
Avr = HIGH
RL = 600 ohm
See Note 2
1-85



Exar XR-2120A
XR·2120A
OJr--....VDD
~ SUBSTRATE
r-----------~13 MODE
AVR
A:::::~:::00 J,~l
I
I
I
_____ JI
INPUT
SWITCHING
MODE
GND
R
~--~--,
VSS
VSS LB 24 RECEIVE OUTPUT
FILTER
OUTPUT
MODE
SWITCHING
HIGH ,..----110 EQ EN
BAND
FILTER
--8JDIGGND
ANALOG
ALBSP 17~+-------~~ LOOP BACK ~-------+-~
OSCILLATOR
~INPUT 9
PINS
12 AND
GND
100K
14
~----t20 TXC OUT
RXC OUT 7 ~------i
VI NV 211--=--:-==,------,
ALB
MIXER
EQUIVALENT SCHEMATIC DIAGRAM
1·86







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