CF8223A
FSK Decoder and DTMF Receiver IC
OVERVIEW
The CF8223A is a FSK (Frequency shift keying) decoder and DTMF (Dual tone multi-frequency) receiver IC.
It is fabricated using a CMOS process and features a power-down function for low power dissipation opera-
tion. The FSK decoder and DTMF receiver have the same performance characteristics as dedicated ICs that
perform the same functions, with the added benefit of an FSK decoder/DTMF receiver auto-select function
*
using the telephone tip/ring input signal. It also features a ring (call signal) signal detection circuit, making for
easy construction of low power dissipation, high-performance analog telephone-related applications.
*: Auto-select function operates if the FSK signal conforms to the Bellcore GR-30-CORE standard.
FEATURES
I
PAD LAYOUT
(Unit:
µm)
I
I
I
I
I
I
I
I
Both FSK signal caller-ID information services
and DTMF signal caller-ID information services
supported
FSK decoder/DTMF receiver auto-select function
Ring (call signal) signal detection circuit built-in
Serial I/O
Input gain adjustment circuit built-in
Power-down mode
Single supply operation: 3.0V ± 10%
3.579545MHz external crystal oscillator fre-
quency
Molybdenum-gate CMOS process
RING
TIP
VDD
DV
(2810, 3160)
GS
DOUT
AGND
FSK/DTMF
RDIN
IC
APPLICATIONS
RDRC
OSCIN
I
I
I
Telephones, fax machines and modems that sup-
port caller-ID information services
Adapters for caller-ID information service func-
tions
Telephones, fax machines and modems that sup-
port remote operation functions
(0, 0)
RDET
PDWN
GND OSCOUT
Pad size : 90
µ
m
×
90
µ
m
ORDERING INFORMATION
Device
CF8223A
Package
Chip form
NIPPON PRECISION CIRCUITS INC.—1
CF8223A
BLOCK DIAGRAM
FSK/DTMF
Differential
Amplifier
TIP
RING
GS
FSK Decoder
DV
Band Pass
Filter
FSK
Decoder
Logic
DOUT
FSK/DTMF
Discriminator
Logic
High Group
Filter
Dial Tone
Filter
Low Group
Filter
DTMF
Decoder
Logic
DTMF Receiver
AGND
Bias
Circuit
OSC
Ring Detect
VDD GND PDWN
OSCIN
OSCOUT
RDIN
RDRC
RDET
PIN DESCRIPTION
Pad dimensions
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Name
TIP
RING
GS
AGND
RDIN
RDRC
RDET
PDWN
1
GND
OSCOUT
OSCIN
IC
FSK/DTMF
DOUT
DV
VDD
I/O
I
I
O
O
I
I/O
O
I
–
O
I
I
O
Ol
O
–
Function
X
Tip input. Connected to the telephone line through a protection circuit
Ring input. Connected to the telephone line through a protection circuit
Input-stage amplifier gain-select output. Used to adjust the gain of the input-stage amplifier.
Analog ground output. Internal reference voltage (V
DD
/2) output level
Ring detector input. Used for line reversal and ring signal detection. Connected for ring detection
of attenuated ring signals.
Ring detector RC terminal. Connected to an RC network which sets the ring detector delay time.
Ring detector output. RDRC-input Schmitt-trigger buffer output. LOW-level output when ring
signal is detected.
Power-down control input. LOW-level for normal operation. HIGH-level for power-down state.
In the power-down state, pins AGND, OSCOUT, DOUT, and DV are HIGH.
Ground. Connected to the system ground potential.
Crystal oscillator output. The crystal oscillator element is connected between this pin and
OSCIN.
Crystal oscillator input. The crystal oscillator element is connected between this pin and
OSCOUT.
Test input. Tied LOW for normal operation.
FSK/DTMF discriminator output. HIGH-level output when receiving FSK signal, and LOW-level
output when receiving DTMF signal.
Demodulator output. Demodulated FSK or DTMF signal output. HIGH-level output in power-
down state.
Data trigger output. Data is output on DOUT when this pin goes LOW.
Supply
1046
638
176
176
176
176
596
1063
1634
2053
2634
2634
2634
2634
2211
1612
[µm]
Y
2934
2934
2665
1954
1534
492
226
226
226
226
506
1550
1942
2623
2934
2934
1. Shimitt trigger input
NIPPON PRECISION CIRCUITS INC.—2
CF8223A
SPECIFICATIONS
Absolute Maximum Ratings
GND = 0V
Parameter
Supply voltage range
Input voltage range
DC input current
Storage temperature range
Symbol
V
DD
V
IN
I
IN
T
stg
Rating
−0.5
to 5.0
−
0.3 to V
DD
+ 0.3
±10
−40
to 125
Unit
V
V
mA
°C
Recommended Operating Conditions
GND = 0V
Rating
Parameter
Supply voltage
Clock frequency
Clock frequency accuracy
Operating temperature
Symbol
V
DD
f
CLK
∆f
C
T
a
Condition
min
2.7
–
−0.1
−20
typ
–
3.579545
–
–
max
3.3
–
+0.1
85
V
MHz
%
°C
Unit
DC Electrical Characteristics
V
DD
= 3.0V ± 0.3V, GND = 0V, f
CLK
= 3.579545MHz, T
a
=
−20
to 85°C unless otherwise noted.
Rating
Parameter
Symbol
Condition
min
Supply current consumption
I
DD
PDWN = 0V, RDIN = 0V,
RDRC = 0V, all other inputs
open
PDWN = V
DD
, RDIN = 0V,
RDRC = 0V, all other inputs
open
–
typ
–
max
4.5
mA
Unit
Power-down state current
PDWN, RDIN, RDRC LOW-level input
voltage
PDWN, RDIN, RDRC HIGH-level input
voltage
OSCIN LOW-level input voltage
OSCIN HIGH-level input voltage
DOUT, DV, RDET, FSK/DTMF
LOW-level output current
DOUT, DV, RDET, FSK/DTMF
HIGH-level output current
PDWN, RDIN input leakage current
RDRC output leakage current
I
DPD
–
–
15
µA
V
IL1
V
IH1
V
IL2
V
IH2
I
OL
I
OH
I
IN
I
OFF
When external clock input
When external clock input
–
0.7V
DD
–
0.7V
DD
2
–
−1
–
–
–
–
–
–
–
–
–
0.3V
DD
–
0.3V
DD
–
–
−0.8
1
1
V
V
V
V
mA
mA
µA
µA
NIPPON PRECISION CIRCUITS INC.—3
CF8223A
AC Electrical Characteristics
FSK decoder
V
DD
= 3.0V ± 0.3V, GND = 0V, f
CLK
= 3.579545MHz, T
a
=
−20
to 85°C unless otherwise noted.
Rating
Parameter
Detection sensitivity
Symbol
Condition
min
Typical application circuit
Mark signal and SPACE
signal are same level.
Noise: Random noise from
200Hz to 3400Hz.
−40
typ
−37.5
max
0
dBm
Unit
Noise reduction ratio
20
–
–
dB
DTMF receiver
V
DD
= 3.0V ± 0.3V, GND = 0V, f
CLK
= 3.579545MHz, T
a
=
−20
to 85°C unless otherwise noted.
Rating
Parameter
Detection frequency deviation
Non-detection frequency deviation
Typical application circuit
Detection sensitivity
Non-detection sensitivity
Signal level error
High-frequency rejection ratio
Noise rejection ratio
Dial tone rejection ratio
1. Input signal is up to V
DD
level.
Typical application circuit
1
Symbol
Condition
min
±1.5% ± 2
±3.5
−32.0
–
–
–
–
–
typ
–
–
–
–
–
18
12
20
max
–
–
0.0
−50.0
6
–
–
–
Hz
%
dBm
dBm
dB
dB
dB
dB
Unit
Input-stage amplifier Characteristics
V
DD
= 3.0V ± 0.3V, GND = 0V, f
CLK
= 3.579545MHz, T
a
=
−20
to 85°C unless otherwise noted.
Rating
Parameter
Input leakage current
Input resistance
DC open-loop voltage gain
Unity gain frequency
Load capacitance
Load resistance
Symbol
I
IN
R
IN
A
VOL
f
C
C
L
R
L
Condition
min
–
–
30
80
–
50
typ
–
1
–
–
–
–
max
1
–
–
–
100
–
µA
MΩ
dB
kHz
pF
kΩ
Unit
NIPPON PRECISION CIRCUITS INC.—4
CF8223A
Timing Characteristics
Oscillator
V
DD
= 3.0V ± 0.3V, GND = 0V, T
a
=
−20
to 85°C unless otherwise noted.
Rating
Parameter
Clock HIGH-level pulsewidth
Clock LOW-level pulsewidth
Clock rise time
Clock fall time
Symbol
t
WH
t
WL
t
r
t
f
Condition
min
110
110
–
–
typ
–
–
–
–
max
–
–
30
30
ns
ns
ns
ns
Unit
FSK decoder
V
DD
= 3.0V ± 0.3V, GND = 0V, f
CLK
= 3.579545MHz, T
a
=
−20
to 85°C unless otherwise noted.
Rating
Parameter
Power-down release time
Oscillator start-up time
Mark signal to DV ON time
FSK flag setup time
FSK flag hold time
Input to DOUT delay time
DOUT rise time
DOUT fall time
DOUT data rate
Symbol
t
DPD
t
DOSC
t
DED
t
AF
t
AH
t
ADD
t
Dr0
t
Df0
t
DWL/H
DV = LOW
Condition
min
–
–
–
–
–
–
–
–
1188
typ
8
5
–
–
–
1
–
–
1200
max
–
–
3.75
833
(1/1.2kHz)
10
5
20
20
1212
ms
ms
ms
µ
s
ns
ms
ns
ns
baud
Unit
DTMF receiver
V
DD
= 3.0V ± 0.3V, GND = 0V, f
CLK
= 3.579545MHz, T
a
=
−20
to 85°C unless otherwise noted.
Rating
Parameter
DOUT, DV rise time
DOUT, DV fall time
Signal detection time
Received signal non-detection time
Pause detection time
Pause non-detection time
DV output data delay time
Power-down release time
Oscillator start-up time
DOUT data rate
DTMF flag setup time
Symbol
t
Dr0
t
Df0
t
RE
t
RE
t
PA
t
PR
t
BDD
t
DPD
t
DOSC
t
DWL/H
t
AF
DV
DV
DV
DV
Condition
min
–
–
–
20
–
20
–
–
–
1188
–
typ
–
–
–
–
–
–
–
8
5
1200
–
max
20
20
45
–
25
–
5
–
–
1212
833
(1/1.2kHz)
ns
ns
ms
ms
ms
ms
ms
ms
ms
baud
µs
Unit
NIPPON PRECISION CIRCUITS INC.—5
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