CXA1994AM/BM
M-ary FSK Demodulating Comparator
Description
The CXA1994AM/BM is a comparator which allows
the M-ary (4-level) FSK data to be demodulated in
combination with an FM IF amplifier for pagers.
Features
•
Low power consumption
70µA (at V
CC
= 1.4V, including the current on
battery saving control pin)
•
Low voltage operation
V
CC
= 1.0 to 4.0V
Applications
M-ary FSK pagers
Function
•
Window comparator for MSB detection
•
Battery saving control pin
•
Threshold level adjustment pin
8 pin SOP (Plastic)
Absolute Maximum Ratings
(Ta = 25°C)
•
Supply voltage
V
CC
7.0
•
Operating temperature
•
Storage temperature
Operating Conditions
•
Supply voltage
Topr
Tstg
–20 to +75
–65 to +150
V
°C
°C
V
CC
1.0 to 4.0
V
Block Diagram
GND
B.S.
8
7
6
1
2
3
DATA IN
Sony reserves the right to change products and specifications without prior notice. This information does not convey any license by
any implication or otherwise under any patents or other right. Application circuits shown, if any, are typical examples illustrating the
operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits.
TH CONT
REF
V
CC
DATA OUT
5
4
NC
–1–
E96428A8Y
CXA1994AM/BM
Pin Description
Pin
No.
1
Symbol
V
CC
Pin
voltage
1.5V
V
CC
Equivalent circuit
Vcc.
Description
2
TH CONT
—
2
Adjusts the threshold level for
comparator.
GND
V
CC
3
DATA IN
0.2V
3
Signal input.
Connected to the COMP IN pin of
the CXA1484A.
GND
4
REF
0.2V
4
Reference input.
Connected to the SENSE pin of the
CXA1484A.
5
5
DATA OUT
—
GND
Comparator output.
6
7
NC
GND
—
0
V
CC
Ground.
8
B.S.
—
8
Battery saving control.
GND
–2–
CXA1994AM/BM
Electrical Characteristics
Item
Current consumption
Current consumption
Comparator input voltage high level
Comparator input voltage low level
Comparator output saturation voltage
Logic input voltage high level
Logic input voltage low level
Symbol
I
CC
I
CCS
V
COMPH
V
COMPL
Vsat
V
THH
V
THL
0.9
V
REF
as a reference
V
REF
as a reference
Condition
(V
CC
= 1.4V, Ta = 25°C)
Min.
Typ.
70
Max.
100
6
50
–50
0.4
Unit
µA
µA
mV
mV
V
V
0.35
V
Pin Description
1. V
CC
2. TH CONT
Power supply pin of 1V or more
This pin adjusts the threshold level and the default is approximately ±50mV from the
reference voltage. The threshold level can be set lower by inserting a resistor between V
CC
and this pin. (The level cannot be set higher.)
The signal after passing through the data filter of the IF IC (CXA1484A) is input.
Connects to the reference voltage pin of the IF IC. (Pin 15 of the CXA1484A)
Comparator output.
Not connected.
Ground.
Battery saving control pin. Battery saving state for low; normal operation for high.
3. DATA IN
4. REF
5. DATA OUT
6. NC
7. GND
8. B.S.
–3–
CXA1994AM/BM
Electrical Characteristics Measurement Circuit
B.S. control
DATA OUT
8
7
6
5
CXA1994AM/BM
1
V
CC
1V to 4V
2
3
4
REF [from REF (0.2V) IF of IC]
0.01µ
1µ
5.1k
DATA IN [from DATA (DC 0.2V) of IF IC]
∗
The comparator level can be set lower by inserting a resistor between Pin 1 (V
CC
) and Pin 2.
–4–
Application Circuit
LVA OUT
REG OUT
NRZ OUT
DATA OUT
C2
10p to 120p
S1
C8
10µ
BS
R2
47k
C10
2200P
GND
12
11
8
LVA
VB REG
NRZ COMP
CHARGE
REG
QUAD DET
IF LIM
1
2
3
5
7
8
C9
10µ
CERAFIL
GND
R6
33k
6
4
9
R10
43k
Ceramic
Discriminator R9
43k
10
C12 2200p
R12
43k
C14
10µ
C15
0.01µ
2
OP AMP
OP AMP
7
GND
18
17
16
15
14
GND
13
R5
47k
R8
43k
R11
43k
R7
43k
C13
0.01µ
C16
0.1µ
GND
A
S
PNP
L1
1.8µ
C3
0.01µ
R4
GND 75k
SENSE R3
22k
R14
47k
20
GND
19
6
5
–5–
C6
10µ
S
GND
GND
C7
0.01µ
F
S2
MIX
OSC
3
4
1
C4
22p
XTAL
C5
15p
V
CC
= 1.0 to 4.0
C11
0.01µ
GND
CXA1994AM/BM
GND
CXA1484A
CXA1994AM/BM
Application circuits shown are typical examples illustrating the operation of the devices. Sony cannot assume responsibility for
any problems arising out of the use of these circuits or for any infringement of third party patent and other right due to same.
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