ELANTEC EL2082

EL2082C
EL2082C
Current-Mode Multiplier
Features
General Description
# Flexible inputs and outputs, all
ground referred
# 150 MHz large and small-signal
bandwidth
# 46 dB of calibrated gain control
range
# 70 dB isolation in disable mode
@ 10 MHz
# 0.15% diff gain and 0.05§ diff
phase performance at NTSC
using application circuit
# Operates on g 5V to g 15V power
supplies
# Outputs may be paralleled to
function as a multiplexer
The EL2082 is a general purpose variable gain control building
block, built using an advanced proprietary complementary bipolar process. It is a two-quandrant multiplier, so that zero or
negative control voltages do not allow signal feedthrough and
very high attenuation is possible. The EL2082 works in current
mode rather than voltage mode, so that the input impedance is
low and the output impedance is high. This allows very wide
bandwidth for both large and small signals.
Applications
#
#
#
#
#
#
#
#
#
Level adjust for video signals
Video faders and mixers
Signal routing multiplexers
Variable active filters
Video monitor contrast control
AGC
Receiver IF gain control
Modulation/demodulation
General ‘‘cold’’ front-panel
control of AC signals
The IIN pin replicates the voltage present on the VIN pin; therefore, the VIN pin can be used to reject common-mode noise and
establish an input ground reference. The gain control input is
calibrated to 1 mA/mA signal gain for 1V of control voltage.
The disable pin (E) is TTL-compatible, and the output current
can comply with a wide range of output voltages.
Because current signals rather than voltages are employed, multiple inputs can be summed and many outputs wire-or’ed or
mixed.
The EL2082 operates from a wide range of supplies and is available in standard 8-pin plastic DIP or 8-lead SO.
Connection Diagram
8-Pin DIP/SO
Ordering Information
Package
Outline Ý
EL2082CN
Part No.
0§ C to a 75§ C
Temp. Range
8-Pin P-DIP
MDP0031
EL2082CS
0§ C to a 75§ C
8-Pin SO
MDP0027
2082 – 1
Top View
January 1996, Rev D
Note: All information contained in this data sheet has been carefully checked and is believed to be accurate as of the date of publication; however, this data sheet cannot be a ‘‘controlled document’’. Current revisions, if any, to these
specifications are maintained at the factory and are available upon your request. We recommend checking the revision level before finalization of your design documentation.
© 1992 Elantec, Inc.
EL2082C
Current-Mode Multiplier
Absolute Maximum Ratings (TA e 25§ C)
VS
VIN, IOUT
VE, VGAIN
IIN
Voltage between VS a and VSb
Voltage
Input Voltage
Input Current
a 33V
PD
TA
TJ
TST
g VS
b 1 to a 7V
g 5 mA
Maximum Power Dissipation
See Curves
Operating Temperature Range
0§ C to a 75§ C
Operating Junction Temperature
150§ C
b 65§ C to a 150§ C
Storage Temperature
Important Note:
All parameters having Min/Max specifications are guaranteed. The Test Level column indicates the specific device testing actually
performed during production and Quality inspection. Elantec performs most electrical tests using modern high-speed automatic test
equipment, specifically the LTX77 Series system. Unless otherwise noted, all tests are pulsed tests, therefore TJ e TC e TA.
Test Level
I
II
III
IV
V
Test Procedure
100% production tested and QA sample tested per QA test plan QCX0002.
100% production tested at TA e 25§ C and QA sample tested at TA e 25§ C ,
TMAX and TMIN per QA test plan QCX0002.
QA sample tested per QA test plan QCX0002.
Parameter is guaranteed (but not tested) by Design and Characterization Data.
Parameter is typical value at TA e 25§ C for information purposes only.
DC Electrical Characteristics
Parameter
VIO
Description
Temp
Input Offset Voltage
Min
Full
b 20
Typ
IOO
Output Offset Current
Full
b 100
RINI
IIN Input Impedance; IIN e 0, 0.35 mA
Full
75
95
VCMRR
Voltage Common-Mode Rejection Ratio
VIN e b10V, a 10V
Full
45
55
ICMRR
Offset Current Common-Mode Rejection
Ratio, VIN e b10V, a 10V
Full
VPSRR
Offset Voltage Power Supply Rejection
Ratio, VS e g 5V to g 15V
Full
IPSRR
Offset Current Power Supply Rejection
Ratio, VS e g 5V to g 15V
Full
IBVIN
VIN Bias Current
Full
b 10
RINV
VIN Input Impedance; VIN e b10V, a 10V
Full
0.5
Nlini
Signal Nonlinearity; IIN e b0.7 mA,
b 0.35 mA, 0 mA, a 0.35 mA, a 0.7 mA
Full
ROUT
Output Impedance VOUT e b10V, a 10V
Full
2
0.5
60
Test
Level
Units
20
II
mV
100
II
mA
115
II
X
II
dB
II
mA/V
II
dB
10
II
mA/V
10
II
mA
II
MX
II
%
II
MX
5
80
1
1.0
0.10
0.25
Max
0.5
0.4
TD is 3.0in
(VS e g 15V, VG e 1V, VE e 0.8V, VOUT e 0, VIN e 0, IIN e 0)
EL2082C
Current-Mode Multiplier
DC Electrical Characteristics Ð Contd.
Parameter
Description
Temp
Min
VOUT
Output Swing; VGAIN e 2V, IIN g 2 mA,
RL e 4.0K
Full
VIOG
VOS, Gain Control, Extrapolated
from VGAIN e 0.1V, 1V
AI
Nling
Typ
Max
Test
Level
Units
b 11
a 11
II
V
Full
b 15
15
II
mV
Current Gain, IIN g 350 mA
Full
0.9
1.0
1.1
II
mA/mA
Nonlinearity of Gain Control,
VGAIN e 0.1V, 0.5V, 1V
Full
2
5
II
%
ISO
Input Isolation with VGAIN e b0.1V
Full
b 80
II
dB
VINH
E Logic High Level
Full
2.0
II
V
VINL
E Logic Low Level
Full
0.8
II
V
ILH
Input Current of E, VE e 5V
Full
b 50
50
II
mA
ILL
Input Current of E, VE e 0
Full
b 50
50
II
mA
IODIS
IOUT, Disabled E e 2.0V
Full
g 10
II
mA
IS
Supply Current
Full
16
II
mA
b 96
13
TD is 2.8in
(VS e g 15V, VG e 1V, VE e 0.8V, VOUT e 0, VIN e 0, IIN e 0)
AC Electrical Characteristics
Parameter
Description
Min
b 3 dB
Test
Level
Units
150
30
150
V
V
V
MHz
MHz
MHz
20
V
MHz
12
V
(mA/mA)/ms
Typ
Max
BW1
BW2
BWp
Current Mode Bandwidth
BWg
Gain Control Bandwidth
SRG
Gain Control Slew Rate
TREC
Recovery Time from VG k 0
250
V
ns
TEN
Enable Time from E Pin
200
V
ns
TDIS
Disable Time from E Pin
30
V
ns
DG
Differential Gain,
NTSC with IIN e b0.35 mA to a 0.35 mA
0.25
V
%
DP
Differential Phase,
NTSC with IIN e b0.35 mA to a 0.35 mA
0.05
V
Degree
g 0.1 dB
Power, IIN e 1 mA p-p
VG from 0.2V to 2V
3
TD is 2.4in
(RL e 25X, CL e 4 pF, CIIN e 2 pF, TA e 25§ C, VG e 1V, VS e g 15V)
EL2082C
Current-Mode Multiplier
Typical Performance Curves
Current Gain vs
Frequency for Different Gains
Current Gain
vs Frequency
Current Gain Flatness
Frequency Response in
Voltage Input Mode
Harmonic Distortion vs
Input Amplitude
Output Current Noise
vs Frequency
2082 – 2
4
EL2082C
Current-Mode Multiplier
Typical Performance Curves Ð Contd.
Differential Gain Error
vs DC Offset Current
Differential Phase Error vs
DC Offset Current
2082 – 3
Gain Control Recovery From
Vg e b 0.1V
Gain Pin Transient Response
2082 – 5
2082 – 4
Gain Control Pin
Frequency Response
IOUT vs IIN
Normalized Gain Error
vs VGAIN Voltage
2082 – 6
5
EL2082C
Current-Mode Multiplier
Typical Performance Curves Ð Contd.
Current Gain vs
Supply Voltage
Current Gain vs
Temperature
2082 – 7
Output Capacitance vs
Output Voltage
Enable Pin Response
2082 – 9
2082 – 8
Supply Current vs
Supply Voltage
Supply Current vs
Die Temperature
2082 – 10
6
EL2082C
Current-Mode Multiplier
Typical Performance Curves Ð Contd.
8-Pin Plastic DIP
Maximum Power Dissipation
vs Ambient Temperature
8-Lead SO
Maximum Power Dissipation
vs Ambient Temperature
2082 – 11
2082 – 12
Applications Information
The EL2082 is best thought of as a current-conveyor with variable current gain. A current input to the
IIN pin will be replicated as a current driven out the IOUT pin, with a gain controlled by VGAIN. Thus,
an input of 1 mA will produce an output current of 1 mA for VGAIN e 1V. An input of 1 mA will
produce an output of 2 mA for VGAIN e 2V. The useable VGAIN range is zero to a 2V. A negative level
on VGAIN, even only b 20 mV, will yield very high signal attenuation.
The EL2082 in Conjunction with Op-Amps
This resistor-load circuit shows a simple method of converting voltage signals to currents and vice
versa:
Gain e
VGAIN
1V
#R
RL
IN a 95X
J#
RF a RG
RG
J
EL2082 a Op-Amp
2082 – 13
RIN would typically be 1 kX for video level inputs, or 10 kX for g 10V instrumentation signals. The
higher the value of RIN (the lower the input current), the lower the distortion levels of the EL2082 will
be. An approximate expression of the nonlinearity of the EL2082 is:
Nonlinearity (%) e 0.3*IIN (mA)2
Optimum input current level is a tradeoff between distortion and signal-to-noise-ratio. The distortion
and input range do not change appreciably with VGAIN levels; distortion is set by input currents alone.
7
EL2082C
Current-Mode Multiplier
Applications Information Ð Contd.
The output current could be terminated with a 1 kX load resistor to achieve a nominal voltage gain of 1
at the EL2082, but the IOUT, load, and stray capacitances would limit bandwidth greatly. The lowest
practical total capacitance at IOUT is about 12 pF, and this gives a 13 MHz bandwidth with a 1 kX
load. In the above example a 100X load is used for an upper limit of 130 MHz. The operational
amplifier gives a gain of a 10 to bring the overall gain to unity. Wider bandwidth yet can be had by
installing CIN. This is a very small capacitor, typically 1 pf–2 pF, and it bolsters the gain above
100 MHz. Here is a table of results for this circuit used with various amplifiers:
Operational
Amplifier
EL2020
EL2020
EL2130
EL2030
EL2090
EL2120
EL2120
EL2070
EL2071
EL2075
Power
Supplies
g 5V
g 15V
g 5V
g 15V
g 15V
g 5V
g 15V
g 5V
g 5V
g 5V
Rf
Rg
CIN
b 3 dB
Bandwidth
0.1 dB
Bandwidth
Peaking
620
620
620
620
240
220
220
200
1.5K
620
68
68
68
68
27
24
24
22
240
68
Ð
Ð
Ð
Ð
Ð
Ð
Ð
2 pF
2 pF
2 pF
34 MHz
40 MHz
73 MHz
93 MHz
60 MHz
57 MHz
65 MHz
150 MHz
200 MHz
270 MHz
5.6 MHz
7.4 MHz
11 MHz
12 MHz
10 MHz
10 MHz
11 MHz
30 MHz
30 MHz
30 MHz
0
0
1.0 dB
1.3 dB
0.5 dB
0.4 dB
0.3 dB
0.4 dB
0
1.5 dB
Maximum bandwidth is maintained over a gain range of a 6 to b 16 dB; bandwidth drops at lower
gains. If wider gain range with full bandwidth is required, two or more EL2082’s can be cascaded with
the IOUT of one directly driving the IIN of the next.
The EL2082 can also be used with an I
x V operational circuit:
VGAIN
Gain e b
1V
#R
RF
IN a 95X
J
2082 – 14
Inverting
EL2082 a Op-Amp
The circuit above gives a negative gain. The main concern of this connection involves the total IOUT
and stray capacitances at the amplifier’s input. When using traditional op-amps, the pole caused by
these capacitances can make the amplifier less stable and even cause oscillations in amplifiers whose
gain-bandwidth is greater than 5 MHz. A typical cure is to add a capacitor Cf in the 2 pF–10 pF range.
This will reduce overall bandwidth, so a capacitor CIN can be added to regain frequency response. The
ratio Cf/CIN is made equal to RIN/Rf.
8
EL2082C
Current-Mode Multiplier
Applications Information Ð Contd.
Operational
Amplifier
EL2020
EL2020
EL2130
EL2030
Power
Supplies
g 5V
g 15V
g 5V
g 15V
Rf
RIN
Rg
b 3 dB
Bandwidth
0.1 dB
Bandwidth
Peaking
1k
1k
1k
1k
910
910
910
910
Ð
Ð
Ð
Ð
29 MHz
34 MHz
61 MHz
82 MHz
4.3 MHz
5.3 MHz
9.7 MHz
12.3 MHz
0
0
0
0
g 5V
EL2171
2k
1.8k
1k
114 MHz
with the EL2171 the EL2082 had g 15V supplies and the EL2171 required a 150X output load.
11 MHz
1.2 dB
The EL2120 and EL2090 are suitable in this circuit but they are compensated for 300X feedback
resistors. RIN would have to be reduced greatly to obtain unity gain and the increased signal currents
would cause the EL2082 to display much increased distortion. They could be used if the input resistor
were maintained at 910X and Rf reduced for a b (/3 gain, or if Rf e 1k and an overall bandwidth of
25 MHz were acceptable.
The EL2082 can also be used within an op-amp’s feedback loop:
Gain e b
EL2082 in feedback
inverting gain
1V
VGAIN
#
RF a 95X
RIN
J
2082 – 15
With voltage-mode op-amps, the same concern about capacitance at the summing node exists, so Cf and
CIN should be used. As before, current-feedback amplifiers tend to solve the problem. However, in this
circuit the inherent phase lag of the EL2082 detracts from the phase margin of the op-amp, and some
overall bandwidth reduction may result. The EL2082 appears as a 3.0 ns delay, well past 100 MHz.
Thus, for a 20 MHz loop bandwidth, the EL2082 will subtract 20 MHz c 3.0 ns c 360 degrees e 21.6
degrees. The loop path should have at least 55 degrees of phase margin for low ringing in this connection. Loop bandwidth is always reduced by the ratio RIN/(RIN a Rf) with voltage mode op-amps.
9
TD is 1.3in
Current-feedback amplifiers eliminate this difficulty. Because their -input is a very low impedance,
capacitance at the summing point of an inverting operational circuit is far less troublesome. Here is a
table of results of various current-feedback circuits used in the inverting circuit:
EL2082C
Current-Mode Multiplier
Applications Information Ð Contd.
Current-feedback op-amps again solve the summing-junction capacitance problem in this connection.
The loop bandwidth here becomes a matter of transimpedance over frequency and its phase characteristics. Unfortunately, this is generally poorly documented in amplifier data sheets. A rule of thumb is
that the transimpedance falls to the value of the recommended feedback resistor at a frequency of
F b 3 dB/4 to F b 3 dB/2, where F b 3 dB is the unity-gain closed-loop bandwidth of the amplifier. The
phase margin of the op-amp is usually close to 90 degrees at this frequency.
In general, Rf is initially the recommended value for the particular amplifier and is then empirically
adjusted for amplifier stability at maximum VGAIN, then RIN is set for the overall circuit gain required. Sometimes a very small Cf can be used to improve loop stability, but it often must be in series
with another resistor of value around Rf/2.
A virtue of placing the EL2082 in feedback is that the input-referred noise will drop as gain increases.
This is ideal for level controls that are used to set the output to a constant level for a variety of inputs
as well as AGC loops. Furthermore, the EL2082 has a relatively constant input signal amplitude for a
variety of input levels, and its distortion will be relatively constant and controllable by setting Rf. Note
that placing the EL2082 in the feedback path causes the circuit bandwidth to vary inversely with gain.
The next circuit shows use of the EL2082 in the feedback path of a non-inverting op-amp:
Gain e
EL2082 in feedback
non-inverting gain
1V
Vg
#
RF a 95X
Rg
J
2082 – 16
This example has the same virtues with regards to noise and distortion as the preceding circuit; and its
bandwidth shrinks with increasing gain as well. The typical 12 pF sum of EL2082 output capacitance in
parallel with stray capacitance necessitates the inclusion of Cf to prevent a feedback pole. Because of
this 12 pF capacitance at the op-amp -input, current-feedback op-amps will generally not be useable. As
before, the loop bandwidth and phase margin must accommodate the extra phase lag of the EL2082.
10
EL2082C
Current-Mode Multiplier
Applications Information Ð Contd.
Using the VIN Pin
The VIN pin can be used instead of the IIN pin so:
b Vg
IOUT
e
Gm e
VIN
1v
#R
1
g a 95X
J
The VIN pin used
as signal input
2082 – 17
This connection is useful when a high input impedance is required. There are a few caveats when using
the VIN pin. The first is that VIN has a 250 V/ms slew rate limitation. The second is that the inevitable
CSTRAY across Rg causes a gain zero and gain INCREASES above the 1/(2q CSTRAY Rg) frequency
and can peak as much as 20 dB with large CSTRAY. A graph of gain vs. frequency for several CSTRAYS
is included in the typical performance curves. In general, if wide bandwidth and frequency flatness is
desired, the IIN pin should be used.
The VIN pin does make an excellent ground reference pin, for instance when low-frequency noise is to
be rejected. The next schematic shows the EL2082 VIN pin rejecting possible 60 Hz hum induced on an
RF input cable:
Using the VIN pin
as a ground reference
to reject hum and noise
2082 – 18
This example shows VIN rejecting low-frequency field-induced noise but not adding peaking since the
0.01 mF bypass capacitor shunts high-frequency signals to local ground.
Reactive Couplings with the EL2082
The following sketch is an excerpt of a receiver IF amplifier showing methods of connecting the
EL2082 to reactive networks:
Example Reactive
Couplings with EL2082’s
2082 – 19
11
EL2082C
Current-Mode Multiplier
Applications Information Ð Contd.
The IIN pin of the EL2082 looks like 95X well past 100 MHz, and the output looks like a simple
current-source in parallel with about 5 pF. There is no particular problem with any resistance or
reactance connected to IIN or IOUT. The mixer output is generally sent to a crystal filter, which
required a few hundred ohm terminating impedance. The impedance of the IIN pin of the first EL2082
is transformed to about 400X by the 2:1 transformer T1. The two EL2082’s are used as variable-gain IF
amplifiers, with small gains offered by each. The output of the first EL2082 is coupled to the second by
the resonant matching network L1 – C1. For a Q of 5, Xc1 e x11 e 5 c 95X, approximately. The
impedance seen at the first EL2082’s IOUT will be about Q2 c 95X, or 2.5k, and by impedance transformation alone the first gain cell delivers 28 dB of gain at Vg e 1V. More gain cells can be used for a
wider range of (calibrated) AGC compliance.
The E input can be used as a high-speed noise blanker gate.
Linearized Fader/Gain Control
The following circuit is an example of placing two EL2082’s in the feedback network of an op-amp to
significantly reduce their distortions:
Linearized Gain Control/Fader
VOUT e K # VA
a (1 b K) # VB
where O s K s 1
2082 – 20
Dual EL2082 Fader with EL2030
NTSC Differential Gain Error
Dual EL2082 Fader with EL2030
NTSC Differential Phase Error
2082 – 21
2082 – 22
12
EL2082C
Current-Mode Multiplier
Applications Information Ð Contd.
The circuit sums two inputs A and B, such that the sum of their respective path gains is unity, as
controlled by the potentiometer. When the potentiometer’s wiper is fully down, the slightly negative
voltage at the Vg of the B-side EL2082 cuts off the B signal to better than 70 dB attenuation at
3.58 MHz. The A-side EL2082 is at unity gain, so the only (error) signal presented to the op-amp’s -input is the same (error) signal at the IIN of the A-side EL2082. The circuit thus outputs -AIN. Since the
error signal required by the op-amp is very small, even at video frequencies, the current through the Aside EL2082 is small and distortion is minimized.
At 50% potentiometer setting, equal error output signals flow from the EL2082’s, since the op-amp still
requires little net -input current. The EL2082’s essentially buck each other to establish an output, and
50% gain occurs for both the A and B inputs. The EL2082’s now contribute distortion, but less than in
previous connections. The op-amp sees a constant 1k feedback resistor regardless of potentiometer
setting, so frequency response is stable for all gain settings.
A single-input gain control is implemented by simply grounding BIN.
Distortion can be improved by increasing the input resistors to lower signal currents. This will lower
the overall gain accordingly, but will not affect bandwidth, which is dependent upon the feedback
resistors. Reducing the signal input amplitude is an analagous tactic, but the noise floor will effectively
rise.
Another strategy to reduce distortion in video systems is to use DC restoration circuitry, such as the
EL2090 ahead of the fader inputs to reduce the range of signals to be dealt with; the b 0.7V to a 0.7V
possible range of inputs (due to capacitor coupling) would be changed to a stabilized b 0.35V to a 0.35V
span.
The EL2020, EL2030, and EL2120 (at reduced bandwidth since it is compensated for 300X feedback
resistors) all give the same video performance at NTSC operation.
Variable Filters
This circuit is the familiar state-variable configuration, similar to the bi-quad:
Voltage Tuneable Bi-Quad Filter
F0 e
Vg
1V
# 2q (R
1
a 95X)C
J
2082 – 23
13
EL2082C
Current-Mode Multiplier
Applications Information Ð Contd.
Frequency-setting resistors R are each effectively adjusted in value by an EL2082 to effect voltage-variable tuning. Two gain controls yields a linear frequency adjustment; using one gives a square-root-ofcontrol voltage tuning. The EL2082’s could be placed in series with the integrator capacitors instead to
yield a tuning proportional to 1/Vg.
The next circuit is one of a new class of ‘‘CCII’’ filters that use the current-conveyor element. Basic
information is available in the April 1991, volume 38, number 4 edition of the IEEE Transactions on
Circuits and Systems journal, pages 456 through 461 of the article ‘‘The Single CCII Biquads with
High-Input Impedance’’, by Shen-Iuan Liu and Hen-Wai Tsao.
fO e 160 kHz
‘‘CCII’’ Class Filter
2082 – 24
This interesting filter uses the current output of the EL2082 to generate a bandpass voltage output and
the intermediate node provides a second-order low-pass filter output. Both outputs should be buffered
so as not to warp characteristics, although the VIN of the next EL2082 can be driven directly in the case
of cascaded filters. The VGAIN input acts as a Q and peaking adjust point around the nominal 1V value.
The resistor at IOUT could serve as the frequency trim, and Q trimmed subsequently with VGAIN.
Negative Components
The following circuit converts a component or two-terminal network to a variable and even negative
replica of that impedance:
Variable or Negative Impedance Converter
ZIN e
(Z a 95X)
(1 b Vg/1V)
2082 – 25
14
EL2082C
Current-Mode Multiplier
Applications Information Ð Contd.
A negative impedance is simply an impedance whose current flows reverse to the normal sense. In the
above circuit, the current through Z is replicated by the EL2082 and inverted (IOUT flows inverted to
the sense of IIN in the EL2082) and summed back to the input. When Vg e 0 or Vg k 0, the input
impedance is simply Z a 95X. When Vg e 1V, the negative of the current through Z is summed with
the input and the input impedance is ‘‘infinite’’. When Vg e 2V, twice the negative of the current
through Z is summed with the input resulting in an input impedance of b Z–95X.
Thus variable capacitors can be simulated by substituting the capacitor as Z. ‘‘Negative’’ capacitors
result for Vg l 1V, and capacitance needs to be present in parallel with the input to prevent oscillations.
Inductors or complicated networks also work for Z, but a net negative impedance will result in oscillations.
EL2082 Macromodel
This macromodel has been designed to work with PSPICE (copywritten by the Microsim Corporation).
E500 buffers in the VIN voltage and presents it to the RINI resistor to emulate the IIN pin. E501
supplies the non-linearity of the current channel and replicates the IIN current to a ground referenced
voltage. R500 and C500 provide the bandwidth limitation on the current signal. E502 supplies the
VGAIN non-linearity and drives the L501/R501/C501 to shape the gain control frequency response.
E503 does the actual gain-control multiplication, and drives delay line T500 to better simulate the
actual phase characteristics of the part G500 creates the current output, and ROUT with COUT provide
proper output parasitics.
Schematic of
EL2082 Macromodel
2082 – 26
The model is good at frequency and linearity estimates around Vg e 1V and nominal temperatures, but
has several limitations:
The VIN channel is not slew limited
Noise is not modeled
Temperature effects are not modeled
CMRR and PSRR are not modeled
Frequency response does not vary with Vg
The Vg channel does not give zero gain for
Vg k 0; the output gain reverses–don’t use
Vg k 0
The Vg channel is not slew limited
Frequency response does not vary with supply
voltage
Unfortunately, the polynomial expressions and two-input multiplication may not be available on every
simulator. Results have been confirmed by laboratory results in many situations with this macromodel,
within its capabilities.
15
Current-Mode Multiplier
TAB WIDE
EL2082C
EL2082C
EL2082 Macromodel
Iout
l
4
5
6
7
8)
TD is 4.1in
*:
Vgain
Iin
*
l
Vin
*
l
l
*
l
l
l
*
l
l
l
.SUBCKT EL2082macro (1
2
3
***
*** I-to-I gain cell macromodel ***
***
******
Cini 2 0 2P
C500 502 0 0.9845P
C501 505 0 1000P
Cout 6 0 5P
******
L501 503 504 0.1U
******
Rsilly1 1 0 1E9
Rsilly2 505 0 1E9
Rini 2 500 95
Rinv 3 0 2Meg
Rout 6 0 1Meg
R500 501 502 1000
R501 504 505 5
R502 506 507 50
R503 508 0 50
******
E500 500 0 3 0 1
E501 501 0 POLY(1) (2,500) 0 2 0 -.8
E502 503 0 POLY(1) (1,0) 0 1.05 -.05
E503 506 0 POLY(2) (505,0) (502,0) 0 0 0 0 1
G500 6 0 508 0 -0.0105
T500 508 0 507 0 Z0450 TD41.95N
******
.ENDS
General Disclaimer
Specifications contained in this data sheet are in effect as of the publication date shown. Elantec, Inc. reserves the right to make changes
in the circuitry or specifications contained herein at any time without notice. Elantec, Inc. assumes no responsibility for the use of any
circuits described herein and makes no representations that they are free from patent infringement.
January 1996, Rev D
WARNING Ð Life Support Policy
Elantec, Inc. products are not authorized for and should not be
used within Life Support Systems without the specific written
consent of Elantec, Inc. Life Support systems are equipment intended to support or sustain life and whose failure to perform
when properly used in accordance with instructions provided can
be reasonably expected to result in significant personal injury or
death. Users contemplating application of Elantec, Inc. products
in Life Support Systems are requested to contact Elantec, Inc.
factory headquarters to establish suitable terms & conditions for
these applications. Elantec, Inc.’s warranty is limited to replacement of defective components and does not cover injury to persons or property or other consequential damages.
Elantec, Inc.
1996 Tarob Court
Milpitas, CA 95035
Telephone: (408) 945-1323
(800) 333-6314
Fax: (408) 945-9305
European Office: 44-71-482-4596
16
Printed in U.S.A.