DATASHEET

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January 1996, Rev. D
NO R Data
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8-INT
1-88
®
EL4430, EL4431
FN7167
Video Instrumentation Amplifiers
Features
The EL4430 and EL4431 are video
instrumentation amplifiers which are
ideal for line receivers, differential-tosingle-ended converters, transducer interfacing, and any
situation where a differential signal must be extracted from a
background of common-mode noise or DC offset.
• Fully differential inputs and feedback
• Differential input range of ±2V
• Common-mode range of ±12V
• High CMRR at 4MHz of 70dB
• Stable at gains of 1, 2
These devices have two differential signal inputs and two
differential feedback terminals. The FB terminal connects to
the amplifier output, or a divided version of it to increase
circuit gain, and the REF terminal is connected to the output
ground or offset reference.
The EL4430 is compensated to be stable at a gain of 1 or
more, and the EL4431 for a gain of 2 or more.
The amplifiers have an operational temperature of -40°C to
+85°C and are packaged in plastic 8-pin DIP and SO-8.
The EL4430 and EL4431 are fabricated with Elantec’s
proprietary complementary bipolar process which gives
excellent signal symmetry and is free from latchup.
• Calibrated and clean input clipping
• EL4430—80MHz @ G = 1
• EL4431—160MHz GBWP
• 380V/µs slew rate
• 0.02% or ° differential gain or phase
• Operates on ±5 to ±15V supplies with no AC degradation
Applications
• Line receivers
• “Loop-through” interface
• Level translation
Pinout
• Magnetic head pre-amplification
• Differential-to-single-ended conversion
EL4430, EL4431
(8-PIN PDIP, SO)
TOP VIEW
Ordering Information
PART
NUMBER
1
TEMP. RANGE
PACKAGE
PKG. NO.
EL4430CN
-40°C to +85°C
8-Pin PDIP
MDP0031
EL4430CS
-40°C to +85°C
8-Pin SO
MDP0027
EL4431CN
-40°C to +85°C
8-Pin PDIP
MDP0031
EL4431CS
-40°C to +85°C
8-Pin SO
MDP0027
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2003. All Rights Reserved. Elantec is a registered trademark of Elantec Semiconductor, Inc.
All other trademarks mentioned are the property of their respective owners.
EL4430, EL4431
Absolute Maximum Ratings (TA = 25°C)
V+
VS
VIN
VIN
IIN
Positive Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . 16.5V
V+ to V- Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . .33V
Voltage at any Input or Feedback . . . . . . . . . . . . . . . V+ to VDifference between Pairs of Inputs or Feedback. . . . . . . . .6V
Current into any Input, or Feedback Pin . . . . . . . . . . . . . 4mA
IOUT
PD
TA
TS
Continuous Output Current . . . . . . . . . . . . . . . . . . . . . . 30mA
Maximum Power Dissipation . . . . . . . . . . . . . . . . See Curves
Operating Temperature Range . . . . . . . . . . . .-40°C to +85°C
Storage Temperature Range. . . . . . . . . . . . .-60°C to +150°C
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typical values are for information purposes only. Unless otherwise noted, all tests
are at the specified temperature and are pulsed tests, therefore: TJ = TC = TA
Open-Loop DC Electrical Specifications
PARAMETER
VDIFF
Power supplies at ±5V, TA = 25°C. For the EL4431, RF = RG = 500Ω.
DESCRIPTION
Differential input voltage (VCM = 0)
Clipping
MIN
TYP
2.0
2.3
V
1.8
V
0.1% nonlinearity
VCM
Common-mode range (VDIFF = 0)
MAX
UNITS
VS = ±5V
±2
±3.0
V
VS = ±15V
±12
±13.0
V
VOS
Input offset voltage
2
8
mV
IB
Input bias current (IN+, IN-, REF, and FB terminals)
12
20
µA
IOS
Input offset current between IN+ and IN- and between REF and FB
0.2
2
µA
RIN
Input resistance
100
230
kΩ
CMRR
Common-mode rejection ratio
70
90
dB
PSRR
Power supply rejection ratio
60
dB
EG
Gain error, excluding feedback resistors
VO
Output voltage swing EL4430
Output voltage swing EL4431
ISC
Output short-circuit current
IS
Supply current, VS = ±15V
2
-1.5
-0.2
VS = ±5V
±2
±2.8
V
VS = ±15V
±12
±12.8
V
VS = ±5V
±2.5
±3.0
V
VS = ±15V
±12.5
±13.0
V
40
90
mA
13.5
+0.5
16
%
mA
EL4430, EL4431
Closed-Loop AC Electrical Specifications
PARAMETER
BW, -3dB
BW, ±0.1dB
Peaking
Power supplies at ±12V, TA = 25°C, RL = 500Ω for the EL4430, RL = 150Ω for the
EL4431, CL = 15pF. For the EL4431, RF = RG = 500Ω.
DESCRIPTION
-3dB small-signal bandwidth
0.1dB flatness bandwidth
Frequency response peaking
MIN
TYP
MAX
UNITS
EL4430
82
MHz
EL4431
80
MHz
EL4430
20
MHz
EL4431
14
MHz
EL4430
0.6
dB
EL4431
1.0
dB
SR
Slew rate, VOUT between -2V and +2V
380
V/µs
VN
Input-referred noise voltage density
26
nV/√Hz
dG
Differential gain error, Voffset between
-0.7V and +0.7V
EL4430
0.02
%
EL4431, RL = 150Ω
0.04
%
Differential gain error, Voffset between
-0.7V and +0.7V
EL4430
0.02
(°)
EL4431, RL = 150Ω
0.08
(°)
Settling time, to 0.1% from a 4V step
EL4430
48
ns
dθ
TS
Test Circuit
3
EL4430, EL4431
Typical Performance Curves
EL4430 and EL4431
Common-Mode Rejection
Ratio vs Frequency
EL4430 Frequency Response
vs Gain
EL4430 Frequency Response
for Various RL, CL
VS = ±5V
EL4430 Frequency Response
for Various RL, CL
VS = ±15V
EL4431 Frequency Response
vs Gain
EL4431 Frequency Response
for Various RL, CL
VS = ±5V
EL4431 Frequency Response
for Various RL, CL
VS = ±15V
EL4430 Differential Gain
and Phase vs Input Offset
Voltage for VS = ±5V
4
EL4430 Differential Gain
and Phase vs Input Offset
Voltage for VS = ±12V
EL4430 Differential Gain
and Phase Error vs RL
EL4430, EL4431
Typical Performance Curves
(Continued)
EL4431 Differential Gain
and Phase vs Input Offset
Voltage for VS = ±5V
EL4431 Differential Gain
and Phase vs Input Offset
Voltage for VS = ±12V
EL4430 Nonlinearity
vs Input Signal Span
EL4431 Differential Gain
and Phase Error vs RL
EL4431 Nonlinearity
vs Input Signal Span
EL4430 -3dB Bandwidth
and Peaking vs Supply
Voltage for AV = +1
EL4430 -3dB Bandwidth
and Peaking vs Die
Temperature for AV = +1
EL4430 Gain, -3dB Bandwidth
and Peaking vs Load Resistance
for AV = +1
EL4431 -3dB Bandwidth
and Peaking
vs Supply Voltage
EL4431 -3dB Bandwidth
and Peaking vs Die
Temperature for AV = +2
EL4431 Gain, -3dB Bandwidth
and Peaking vs Load
Resistance for AV = +2
5
EL4430, EL4431
Typical Performance Curves
(Continued)
Slew Rate
vs Supply Voltage
Slew Rate
vs Die Temperature
Common Mode Input Range
vs Supply Voltage
Offset Voltage
vs Die Temperature
Supply Current
vs Supply Voltage
6
Supply Current
vs Die Temperature
Input Voltage and Current
Noise vs Frequency
Bias Current
vs Die Temperature
Power Dissipation
vs Ambient Temperature
EL4430, EL4431
Applications Information
Input Connections
The EL4430 and EL4431 are designed to convert a fully
differential input to a single-ended output. It has two sets of
inputs; one which is connected to the signal and does not
respond to its common-mode level, and another which is
used to complete a feedback loop with the output. Here is a
typical connection:
The input transistors can be driven from resistive and
capacitive sources, but are capable of oscillation when
presented with an inductive input. It takes about 80nH of
series inductance to make the inputs actually oscillate,
equivalent to 4 of unshielded wiring or about 6 of
unterminated input transmission line. The oscillation has a
characteristic frequency of 500MHz. Often, placing one’s
finger (via a metal probe) or an oscilloscope probe on the
input will kill the oscillation. Normal high-frequency
construction obviates any such problems, where the input
source is reasonably close to the input. If this is not possible,
one can insert series resistors of approximately 51Ω to de-Q
the inputs.
Signal Amplitudes
The gain of the feedback divider is H. The transfer function of
the part is:
VOUT = AO × ((VIN+) - (VIN-) + (VREF - VFB)).
VFB is connected to VOUT through a feedback network, so
VFB = H × VOUT. AO is the open-loop gain of the amplifier,
and is about 600 for the EL4430 and EL4431. The large
value of AO drives:
(VIN+) - (VIN-) + (VREF - VFB)→0.
Rearranging and substituting for VFB:
VOUT = ((VIN+) - (VIN-) + VREF)/H.
Thus, the output is equal to the difference of the VINs and
offset by VREF, all gained up by the feedback divider ratio.
The input impedance of the FB terminal (equal to RIN of the
input terminals) is in parallel with an RG, and raises circuit
gain slightly.
The EL4430 is stable for a gain of 1 (a direct connection
between VOUT and FB) or more and the EL4431 for gains of
2 or more. It is important to keep the feedback divider’s
impedance at the FB terminal low so that stray capacitance
does not diminish the loop’s phase margin. The pole caused
by the parallel of resistors RF and RG and stray capacitance
should be at least 200MHz; typical strays of 3pF thus require
a feedback impedance of 270Ω or less. Two 510Ω resistors
are acceptable for a gain of 2; 300Ω and 2700Ω make a
good gain-of-10 divider. Alternatively, a small capacitor
across RF can be used to create more of a frequencycompensated divider. The value of the capacitor should
scale with the parasitic capacitance at the FB terminal input.
It is also practical to place small capacitors across both the
feedback resistors (whose values maintain the desired gain)
to swamp out parasitics. For instance, two 10pF capacitors
(for a gain of 2) across equal divider resistors will dominate
parasitic effects and allow a higher divider resistance.
7
Signal input common-mode voltage must be between
(V-)+3V and (V+)-3V to ensure linearity. Additionally, the
differential voltage on any input stage must be limited to ±6V
to prevent damage. The differential signal range is ±2V in the
EL4430 and EL4431. The input range is substantially
constant with temperature.
The Ground Pin
The ground pin draws only 6µA maximum DC current, and
may be biased anywhere between (V-)+2.5V and (V+)-3.5V.
The ground pin is connected to the IC’s substrate and
frequency compensation components. It serves as a shield
within the IC and enhances CMRR over frequency, and if
connected to a potential other than ground, it must be
bypassed.
Power Supplies
The instrumentation amplifiers work well on any supplies
from ±3V to ±15. The supplies may be of different voltages
as long as the requirements of the Gnd pin are observed
(see the Ground Pin section for a discussion). The supplies
should be bypassed close to the device with short leads.
4.7µF tantalum capacitors are very good, and no smaller
bypasses need be placed in parallel. Capacitors as low as
0.01µF can be used if small load currents flow.
Single-polarity supplies, such as +12V with +5V can be
used, where the ground pin is connected to +5V and V- to
ground. The inputs and outputs will have to have their levels
shifted above ground to accommodate the lack of negative
supply.
The dissipation of the amplifiers increases with power supply
voltage, and this must be compatible with the package
chosen. This is a close estimate for the dissipation of a
circuit:
PD= 2 × VS × IS, max + (VS-VO) × VO/RPAR
EL4430, EL4431
Output Loading
where
IS, max is the maximum supply current
VS is the ± supply voltage (assumed equal)
VO is the output voltage
RPAR is the parallel of all resistors loading the output
For instance, the EL4431 draws a maximum of 16mA and we
might require a 2V peak output into 150Ω and a
270Ω + 270Ω feedback divider.
The RPAR is 117Ω. The dissipation with ±5V supplies is
201mW. The maximum supply voltage that the device can
run on for a given PD and the other parameter is:
VS, max = (PD + VO2/RPAR)/(2IS + VO/RPAR)
The maximum dissipation a package can offer is:
PD, max = (TJ, max - TA max)/θJA
where
TJ, max is the maximum die junction temperature, 150°C
for reliability, less to retain optimum electrical
performance.
TA, max is the ambient temperature, 70°C for commercial
and 85°C for industrial range.
θJA is the thermal resistance of the mounted package,
obtained from datasheet dissipation curves.
The more difficult case is the SO-8 package. With a
maximum die temperature of 150°C and a maximum
ambient temperature of 85°C, the 65°C temperature rise and
package thermal resistance of 170°C/W gives a dissipation
of 382mW at 85°C. This allows a maximum supply voltage of
±8.5V for the EL4431 operated in our example. If an EL4430
were driving a light load (RPAR→∞), it could operate on
±15V supplies at a 70°C maximum ambient.
8
The output stage of the instrumentation amplifiers is very
powerful. It typically can source 80mA and sink 120mA. Of
course, this is too much current to sustain and the part will
eventually be destroyed by excessive dissipation or by metal
traces on the die opening. The metal traces are completely
reliable while delivering the 30mA continuous output given in
the Absolute Maximum Ratings table in this datasheet, or
higher purely transient currents.
Gain or gain accuracy degrades only 10% from no load to
100Ω load. Heavy resistive loading will degrade frequency
response and video distortion for loads <100Ω.
Capacitive loads will cause peaking in the frequency
response. If capacitive loads must be driven, a small-valued
series resistor can be used to isolate it (12Ω to 51Ω should
suffice). A 22Ω series resistor will limit peaking to 2.5dB with
even a 220pF load.
EL4430, EL4431
EL4430,EL4431 Macromodel
*Macromodel
*This is a Pspice-compatible macromodel of the EL4430 video instrumentation amplifier assembled
*as a sub circuit. The pins are numbered sequentially as the subcircuit interface nodes. T1 is a
*transmission line which provides a good emulation of the more complicated real device. This model
*correctly displays the characteristics of input clipping, frequency response, CMRR both AC and DC,
*output clipping, output sensitivity to capacitive loads, gain accuracy, slewrate limiting, input bias
*current and impedance. The macromodel does not exhibit proper results with respect to supply current,
*supply sensitivities, offsets, output current limit, differential gain or phase, nor temperature.
*Connections:
IN+
|
VIN|
|
V|
|
|
V+
|
|
|
| VFB
|
|
|
| |
VREF
|
|
|
| |
|
VOUT
|
|
|
| |
|
|
GND
|
|
|
| |
|
|
|
.SUBCKT EL4430/EL 3 4 2 7 6 5 8 1
***
***EL4430macromodel***
***
i1710.00103
i2711.00103
i3712.00105
i4713.00105
v17143
v27153
v31923
******
c1111.03p
c2121.03p
c31812.1p
c416170.6p
******
r110112000
r212132000
r310130e6
r41621000
r51721000
r61811.27e6
r7232120
r8218100
******
1121850n
******
d11114diode
d21214diode
d31815diode
d41918diode
.modeldioded(tt=120n)
******
q1163101pnp
q2174111pnp
q3165121pnp
q4176131pnp
.modelpnppnp(bf=90va=44tr=50n)
******
g11811716.0005
9
EL4430, EL4431
e12011181.0
t1221201z0=50td=1.5n
r1t122150
e22312211.0
******
.ENDS
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries 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 Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
10
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