NJM2592
470MHz INPUT MIXER AND 455kHz FM IF DEMODULATOR IC
GENERAL DESCRIPTION
The NJM2592
is a wide-operating voltage, low-current
FM IF demodulator IC with 455kHz(standard) IF frequency.
It includes an oscillator, mixer, limiting amplifier, quadrature
detector, active filter, and FSK comparator.
The NJM2592
also has a RSSI circuit and RSSI comparator
for carrier sense.
NJM2592V
PACKAGE OUTLINE
FEATURES
Wide Operating Voltage
1.8V to 9.0V
Low Operating Current
2.2mA type. at V
+
=2.0V, external local oscillator input
Maximum Mixer Input Signal
Frequency
470MHz (reference value)
Level
0dBm
Mixer Input Resistance
50Ω
IF Frequency
455kHz (standard)
Conventional Quadrature Detector
External Phase-shifting Capacitor
External Discriminator or LC Resonant Circuit
RSSI Comparator with Open-Collector Output
Quick Charge/Discharge Circuit for FSK Reference Voltage
Bipolar Technology
Package Outline
SSOP20
BLOCK DIAGRAM
MIX
IN
20
SENSE RSSI
CARRIER
FSK
CHARGE
LPF
SW
OUT
GND LEVEL OUT SENSE OUT
19
18
17
+
-
16
15
-
+
14
13
+
-
FILTER AMP
LPF
IN
12
AF
OUT
11
MIXER
RSSI COMP FSK COMP
BUFFER
RSSI
+
-
IF AMP
CHARGE
QUAD
DET
OSC
1
OSC
(B)
2
OSC
(E)
3
MIX
OUT
4
V+
5
IF
IN
6
DEC
7
8
9
10
QUAD
IN
IF
FSK
FSK
VREF1 VREF2 OUT
Ver.2004-08-25
-1-
NJM2592
ABSOLUTE MAXIMUM RATINGS
PARAMETER
Supply Voltage
Power Dissipation
Mixer Input Signal Level
Operating Temperature
Storage Temperature
SYMBOL
V
+
Pd
VmixMAX
Topr
Tstg
RATINGS
10.0
300
0
- 40 to +85
- 40 to +125
(Ta=25°C)
UNIT
V
mW
dBm
°C
°C
(Ta=25°C)
MIN.
1.8
TYP.
2.5
MAX.
9.0
UNIT
V
RECOMMENDED OPERATING CONDITION
PARAMETER
Supply Voltage
SYMBOL
V
+
TEST CONDITIONS
ELECTRICAL CHARACTERISTICS
(
Ta=25°C, V
+
=2.0V, fmix=430MHz, flo=429.545MHz, fif=455kHz, fmod=600Hz, fdev=±4kHz, unless otherwise noted)
PARAMETER
Current Consumption
Mixer Conversion Gain
Mixer 3 rd Order Intercept
Mixer Input Resistance
Mixer Input Capacitance
Mixer Output Resistance
Signal to Noise Ratio 1
Signal to Noise Ratio 2
Signal to Noise Ratio 3
-3dB Limiting Sensitivity
AM Rejection Ratio
IF Amplifier Input Resistance
RSSI Output Voltage
SYMBOL
Iccq
Gmix
IP3
R in M
Cin M
R oM
S/N1
S/N2
S/N3
Vin(lim)
AMR
RinIF
Vrssi
IF input
VinIF=40dBuVEMF
Mixer input
VinMIX=60dBuVEMF
IF input
VinIF=60dBuVEMF
IF input
VinIF=25dBuVEMF
IF input
IF input, AM=30%
VinIF=60dBuVEMF
TEST CONDITIONS
No signal
VinMIX=60dBuVEMF,
Measured at Pin3, without IF
filter, terminated with 2kΩ
MIN.
1.8
16
-
-
-
-
-
-
-
-
-
-
(0.3)
TYP.
2.2
20
95
(50)
(2.0)
2.0
60
60
30
22
50
2.0
0.45
MAX.
2.8
24
-
-
-
-
-
-
-
-
-
-
(0.65)
UNIT
mA
dB
dBuV
Ω
pF
kΩ
dB
dB
dB
dBuVEMF
dB
kΩ
V
The values shown in parenthesis are reference values.
-2-
Ver.2004-08-25
NJM2592
PARAMETER
Demodulated Output Level
Duty Ratio of Wave Shaped Output
Quick Charge/Discharge Current
High Level Leak Current of
CARRIER SENSE Terminal
Low Level Voltage of
CARRIER SENSE Terminal
Bias Current of
SENSE LEVEL Terminal
High Level Leak Current of
FSK OUT Terminal
Low Level Voltage of
FSK OUT Terminal
SYMBOL
V od
DR
Ich
IcryH
VcryL
I level
IfskH
VfskL
TEST CONDITIONS
IF input
VinIF =60dBuVEMF
IF Input
VinIF=60dBuVEMF
FSK REF=GND
LPFOUT=0.4V
V
CARRIER SENSE
=V
+
I
CARRIER SENSE
=100uA
V
CARRIER SENSE
=0.8V
V
FSK OUT
=V
+
I
FSK OUT
=100uA
MIN.
75
40
35
-
-
-
-
-
TYP.
85
50
65
(0.0)
0.1
(0.0)
(0.0)
0.1
MAX.
95
60
110
-
0.4
-
-
0.4
UNIT
mVrms
%
uA
uA
V
uA
uA
dB
The values shown in parenthesis are reference values.
Ver.2004-08-25
-3-
NJM2592
TEST CIRCUIT
This test circuit allows the measurement of all parameters described in “ELECTRICAL CHARACTERISTICS”. This
test circuit includes some electrical switches that should be in the suitable position for the measurement of each
parameter.
Circuit diagram
RSSI
CARRIER
FSK
OUT SENSE OUT
CHARGE
SWITCH
+
V
Hi
Lo
10u
1000p
430MHz
V
+
V
+
100k
1000p
68k
0.01u
68k
560p
68k
3300p
100k
20
19
18
17
+
-
16
15
-
+
14
13
+
-
12
11
MIXER
RSSI COMP FSK COMP
BUFFER
FILTER AMP
RSSI
+
-
IF AMP
CHARGE
QUAD
DET
OSC
1
2
1000p
51
429.545MHz
3
1000p
4
10u
5
V
+
0.1u
6
0.1u
7
8
9
22p
(2)
10
V
+
+
10u
3.3k
CD
10u
B
A
IF FILTER
IF SW
51
455kHz
CD
: Ceramic discriminator, CDBCB455KCAY66 (Murata Manufacturing Co., Ltd, Japan)
IF FILTER : Ceramic filter, CFWB455KEFA004 (Murata Manufacturing Co., Ltd., Japan)
Measurement condition
“Condition1” is the condition for the case of IF input :
IF SW
: in the A position.
IF IN input signal : input frequency(fif) = 455kHz, input level(VinIF)= 60dBuVEMF,
modulation frequency(fmod)=600Hz, deviation fdev=±4kHz
“Condition 2” is the condition for the case of Mixer Input :
IF SW
: in the B position
MIX IN input signal: input frequency(fmix)=430MHz, input level(VinMIX)=60dBuVEMF,
modulation frequency(fmod)=600Hz, deviation fdev=±4kHz
OSC(E)input signal: input frequency(fosc)=429.545MHz, input level(VinOSC)=105dBuVEMF
CERAMIC DISCRIMINATOR (especially designed for NJM2592)
To optimize some important performance, the following ceramic discriminator CD is available. For more information
on this CD and 450kHz CD, please contact the CD supplier.
CDBCB455KCAY71 (Murata Manufacturing Co., Ltd., Japan)
with the external capacitance of 33pF located between pin 9 and pin10.
-4-
Ver.2004-08-25
NJM2592
TERMINAL FUNCTION (
Ta=25°C, V
+
=2.0V
)
Pin No.
SYMBOL
EQUIVARENT CIRCUIT
VOLTAGE
FUNCTION
Base / Emitter Terminal
Colpitts - type oscillator is formed
with an external oscillator element
of crystal unit or SAW resonator.
Output of an external oscillator
circuit can also input to pin1 or
pin2.
1
OSC (B)
1
2
V+
-
20p
-
2
OSC (E)
V+
Mixer Output
An external 455kHz ceramic filter is
connected. The typical output
impedance is 2kΩ.
1.1V
3
MIX OUT
3
1.4k
4
V+
-
Supply Voltage
IF Limiter Amplifier Input
This is an input to the IF amplifier
after passing through 455kHz
ceramic filter. The typical input
impedance is 2kΩ.
IF Decoupling
An external decoupling capacitor
is connected to enhance stability.
V+
5
IF IN
50k
1k
5
6
1.94V
1k
6
DEC
1.94V
V+
7
FSK VREF1
7
0.55V
FSK Reference Input
This pin is an input of reference
voltage for FSK comparator. An
external capacitor is connected to
create an average DC level of FM
demodulated signal. The choice of
this capacitor is dependent on the
speed of data signal.
A quick charge/discharge circuit
offers the voltage of pin 7 comes
the same voltage of pin 11 quickly.
Ver.2004-08-25
-5-
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