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Электронный компонент: 5962-9559801MRA

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REV. C
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
a
AD641
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
Analog Devices, Inc., 1999
250 MHz Demodulating
Logarithmic Amplifier
FEATURES
Logarithmic Amplifier Performance
Usable to 250 MHz
44 dB Dynamic Range
2.0 dB Log Conformance
37.5 mV/dB Voltage Output
Stable Slope and Intercepts
2.0 nV/
Hz Input Noise Voltage
50
V Input Offset Voltage
Low Power
5 V Supply Operation
9 mA (+V
S
), 35 mA (V
S
) Quiescent Current
Onboard Resistors
Onboard 10 Attenuator
Dual Polarity Current Outputs
Direct Coupled Differential Signal Path
APPLICATIONS
IF/RF Signal Processing
Received Signal Strength Indicator (RSSI)
High Speed Signal Compression
High Speed Spectrum Analyzer
ECM/Radar
PIN CONFIGURATIONS
20-Lead Plastic DIP (N)
20-Lead Cerdip (Q)
TOP VIEW
(Not to Scale)
20
19
18
17
16
15
14
13
12
11
1
2
3
4
5
6
7
8
9
10
AD641
ATN COM
CKT COM
INPUT
ATN LO
ATN COM
ATN IN
BL1
V
S
ITC
OUTPUT
BL2
ATN OUT
+INPUT
RG1
RG0
RG2
LOG OUT
LOG COM
+V
S
+OUTPUT
20-Lead PLCC (P)
3 2 1 20 19
9 10 11 12 13
18
17
16
15
14
4
5
6
7
8
TOP VIEW
(Not to Scale)
PIN 1
IDENTIFIER
ATN COM
CKT COM
AD641
ATN COM
ATN LO
INPUT
+INPUT
ATN OUT
BL2
SIG OUT
SIG +OUT
+V
S
LOG COM
ATN IN
BL1
V
S
ITC
RG1
RG0
RG2
LOG OUT
PRODUCT DESCRIPTION
The AD641 is a 250 MHz, demodulating logarithmic amplifier
with an accuracy of
2.0 dB and 44 dB dynamic range. The
AD641 uses a successive detection architecture to provide an
output current that is logarithmically proportional to its input
voltage. The output current can be converted to a voltage using
one of several on-chip resistors to select the slope. A single
AD641 provides up to 44 dB of dynamic range at speeds up to
250 MHz, and two cascaded AD641s together can provide
58 dB of dynamic range at speeds up to 250 MHz. The AD641
is fully stable and well characterized over either the industrial or
military temperature ranges.
The AD641 is not a logarithmic building block, but rather a
complete logarithmic solution for compressing and measuring
wide dynamic range signals. The AD641 is comprised of five
stages and each stage has a full wave rectifier, whose current
depends on the absolute value of its input voltage. The output
of these stages are summed together to provide the demodulated
output current scaled at 1 mA per decade (50
A/dB).
Without utilizing the 10
input attenuator, log conformance of
2.0 dB is maintained over the input range 44 dBm to 0 dBm.
The attenuator offers the most flexibility without significantly
impacting performance.
The 250 MHz bandwidth and temperature stability make this
product ideal for high speed signal power measurement in RF/
IF systems. ECM/Radar and Communication applications are
routinely in the 100 MHz180 MHz range for power measure-
ment. The bandwidth and accuracy, as well as dynamic range,
make this part ideal for high speed, wide dynamic range signals.
The AD641 is offered in industrial (40
C to +85
C) and mili-
tary (55
C to +125
C) package temperature ranges. Industrial
versions are available in plastic DIP and PLCC; MIL versions
are packaged in cerdip.
REV. C
2
AD641SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
AD641A
AD641S
Parameter
Conditions
Min
Typ
Max
Min
Typ
Max
Units
TRANSFER FUNCTION
1
(I
OUT
= I
Y
LOG |V
IN
/V
X
|for V
IN
= 0.75 mV to
200 mV dc)
LOG AMPLIFIER PERFORMANCE
3 dB Bandwidth
250
250
MHz
Voltage Compliance Range
0.3
+V
S
1
0.3
+V
S
1
V
Slope Current, I
Y
0.98
1.00
1.02
0.98
1.00
1.02
mA
Accuracy vs. Temperature
0.002
0.002
%/
C
Over Temperature
T
MIN
to T
MAX
0.98
1.02
mA
Intercept dBm
250 MHz
40.84 40.43 39.96
40.84 40.43
39.96
dBm
Over Temperature
T
MIN
to T
MAX
,
250 MHz
40.59
39.47
dBm
Zero Signal Output Current
2
0.2
0.2
mA
ITC Disabled
Pin 8 to COM
0.27
0.27
mA
Maximum Output Current
2.3
2.3
mA
DYNAMIC RANGE
Single Configuration
44
44
dB
Over Temperature
T
MIN
to T
MAX
40
38
dB
Dual Configuration
58
58
dB
Over Temperature
T
MIN
to T
MAX
52
52
dB
LOG CONFORMANCE
f = 250 MHz
Single Configuration
44 dBm to 0 dBm
0.5
2.0
0.5
2.0
dB
Over Temperature
42 dBm to 4 dBm; T
MIN
to T
MAX
1.0
2.5
dB
42 dBm to 2 dBm, T
MIN
to T
MAX
1.0
2.5
Dual Configuration
S: 60 dBm to 2 dBm;
0.5
2.0
0.5
2.0
dB
Over Temperature
A: 56 dBm to 4 dBm, T
MIN
to T
MAX
1.0
2.5
1.0
2.5
dB
LIMITER CHARACTERISTICS
Flatness
44 dBm to 0 dBm @ 10.7 MHz
1.6
1.6
dB
Phase Variation
44 dBm to 0 dBm @ 10.7 MHz
2.0
2.0
Degrees
INPUT CHARACTERISTICS
Input Resistance
Differential
500
500
k
Input Offset Voltage
Differential
50
200
50
200
V
vs. Temperature
0.8
0.8
V/
C
Over Temperature
T
MIN
to T
MAX
300
V
vs. Supply
2
2
V/V
Input Bias Current
7
25
7
25
A
Input Bias Offset
1
1
A
Common Mode Input Range
2
+0.3
2
+0.3
V
SIGNAL INPUT (Pins 1, 20)
Input Capacitance
Either Pin to COM
2
2
pF
Noise Spectral Density
1 kHz to 10 MHz
2
2
nV/
Hz
Tangential Sensitivity
BW = 100 MHz
72
72
dBm
INPUT ATTENUATOR
(Pins 2, 3, 4, 5 & 19)
Attenuation
3
Pins 5 to Pin 19
20
20
dB
Input Resistance
Pins 5 to 3/4
300
300
APPLICATION RESISTORS
(Pins 15, 16, 17)
0.995
1.000
1.005
0.995
1.000
1.005
k
OUTPUT CHARACTERISTICS
(Pins 10, 11)
Peak Differential Output
4
180
180
mV
Output Resistance
Either Pin to COM
75
75
Quiescent Output Voltage
Either Pin to COM
90
90
mV
POWER SUPPLY
Voltage Supply Range
4.5
7.5
4.5
7.5
V
Quiescent Current
+V
S
(Pin 12)
T
MIN
to T
MAX
9
15
9
15
mA
V
S
(Pin 7)
T
MIN
to T
MAX
35
60
35
60
mA
NOTES
1
Logarithms to base 10 are used throughout. The response is independent of the sign of V
IN
.
2
The zero-signal current is a function of temperature unless internal temperature compensation (ITC) pin is grounded.
3
Attenuation ratio trimmed to calibrate intercept to 10 mV when in use. It has a temperature coefficient of +0.3%/
C.
4
The fully limited signal output will appear to be a square wave; its amplitude is proportional to absolute temperature.
Specifications subject to change wi
thout notice.
(V
S
= 5 V; T
A
= +25 C, unless otherwise noted)
REV. C
AD641
3
ORDERING GUIDE
Temperature
Package
Package
Model
Range
Description
Option
AD641AN
40
C to +85
C
Plastic DIP
N-20
AD641AP
40
C to +85
C
PLCC
P-20A
5962-9559801MRA 55
C to +125
C Cerdip
Q-20
AD641-EB
Evaluation Board
THERMAL CHARACTERISTICS
JC
JA
( C/W)
( C/W)
20-Lead Plastic DIP Package (N)
24
61
20-Lead Cerdip Package (Q)
25
85
20-Lead Plastic Leadless Chip Carrier (P)
28
75
ABSOLUTE MAXIMUM RATINGS*
Supply Voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.5 V
Input Voltage (Pin 1 or Pin 20 to COM) . . . 3 V to +300 mV
Attenuator Input Voltage (Pin 5 to Pin 3/4) . . . . . . . . . . .
4 V
Storage Temperature Range, Q . . . . . . . . . . 65
C to +150
C
Storage Temperature Range, N, P . . . . . . . . 65
C to +125
C
Ambient Temperature Range, Rated Performance
Industrial, AD641A . . . . . . . . . . . . . . . . . . 40
C to +85
C
Military, AD641S . . . . . . . . . . . . . . . . . . 55
C to +125
C
Lead Temperature Range (Soldering 60 sec) . . . . . . . . +300
C
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may adversely affect device reliability.
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD641 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
WARNING!
ESD SENSITIVE DEVICE
REV. C
AD641
4
Typical DC Performance Characteristics
1.015
1.010
1.005
1
0.995
0.990
0.985
0.980
60 40 20
0
20
40 60 80 100 120 140
TEMPERATURE C
SLOPE CURRENT mA
Figure 1. Slope Current, I
Y
, vs.
Temperature
4.5
5.0
5.5
6.0
6.5
7.0
7.5
POWER SUPPLY VOLTAGES Volts
INTERCEPT VOLTAGE mV
1.015
1.010
1.005
1.000
0.995
0.990
0.985
Figure 4. Intercept Voltage, V
X
, vs.
Supply Voltages
INPUT VOLTAGE mV
(EITHER SIGN)
OUTPUT CURRENT mA
2
1.0
0.1
1.0
1000.0
10.0
100.0
1
1.2
1.4
1.6
1.8
2.0
2.2
2.4
0.8
0.6
0.4
0.2
0
0.2
0.4
ERROR dB
0
Figure 7. DC Logarithmic Transfer
Function and Error Curve for Single
AD641
1.20
1.15
1.10
1.05
1.00
0.95
0.90
60 40 20
0
20
40 60 80 100 120 140
TEMPERATURE C
INTERCEPT mV
0.85
Figure 2. Intercept Voltage, V
X
, vs.
Temperature
14
13
12
11
10
9
8
7
60 40 20 0
20
40
60 80 100 120 140
TEMPERATURE C
INTERCEPT mV
Figure 5. Intercept Voltage (Using
Attenuator) vs. Temperature
2.5
2.0
1.5
1.0
0.5
60 40 20
0
20 40 60
80 100 120 140
TEMPERATURE C
0
ABSOLUTE ERROR dB
Figure 8. Absolute Error vs. Tempera-
ture, V
IN
=
1 mV to
100 mV
4.5
5.0
5.5
6.0
6.5
7.0
7.5
POWER SUPPLY VOLTAGES Volts
SLOPE CURRENT mV
1.006
1.004
1.002
1.000
0.998
0.996
0.994
Figure 3. Slope Current, I
Y
, vs. Supply
Voltages
60 40 20
0
20
40
60 80 100 120 140
TEMPERATURE C
DEVIATION OF INPUT OFFSET VOLTAGE mV
0
0.1
+0.4
+0.3
+0.2
+0.1
0.2
0.3
INPUT OFFSET VOLTAGE
DEVIATION WILL BE WITHIN
SHADED AREA.
Figure 6. Input Offset Voltage Devia-
tion vs. Temperature
2.5
2.0
1.5
1.0
0.5
60 40 20
0
20
40 60
80 100 120 140
TEMPERATURE C
0
ABSOLUTE ERROR dB
Figure 9. Absolute Error vs. Tempera-
ture, Using Attenuator. V
IN
=
10 mV
to
1 V, Pin 8 Grounded to Disable ITC
Bias
REV. C
AD641
5
Typical AC Performance Characteristics
INPUT LEVEL dBm
2.25
2.00
0.25
2
48 44 40
4
1.25
0.50
0.25
0.00
1.75
1.50
0.75
1.00
OUTPUT CURRENT mA
52
36 32 28 24 20 16 12 8
0
50MHz
150MHz
190MHz
210MHz
250MHz
Figure 10. AC Response at 50 MHz, 150 MHz, 190 MHz,
210 MHz at 250 MHz, vs. dBm Input (Sinusoidal Input)
INPUT FREQUENCY MHz
INTERCEPT LEVEL dBm
87.5
70.0
50
250
100
150
170
190
210
230
85.0
80.0
77.5
75.0
72.5
82.5
Figure 11. Intercept Level (dBm) vs. Frequency (Cascaded
AD641s--Sinusoidal Input)
Figure 12. Baseband Pulse Response of Single AD641,
Inputs of 1 mV, 10 mV and 100 mV
ERROR IN dB
INPUT LEVEL dBm
2.00
1.75
0.50
2
48 44 40
4
1.00
0.25
0.00
0.25
1.50
1.25
0.50
0.75
OUTPUT mA
52
36 32 28 24 20 16 12 8
0
+25 C
+125 C
55 C
+25 C
+125 C
55 C
OUTPUT
+25 C
+125 C
55 C
+125 C
ERROR
+25 C
55 C
5
4
3
2
1
0
1
2
3
4
5
Figure 13. Logarithmic Response and Linearity at
200 MHz, T
A
for T
A
= 55
C, +25
C, +125
C
INPUT FREQUENCY MHz
1.0
0.95
0.75
50
250
150
190
210
0.90
0.85
0.80
SLOPE CURRENT mA
Figure 14. Slope Current, I
Y
, vs. Input Frequency
10
0%
5s
5s
20mV
20mV
100
90
Figure 15. Baseband Pulse Response of Cascaded AD641s
at Inputs of 0.2 mV, 2 mV, 20 mV and 200 mV