INTERSIL EL8102IWZ-T7

EL8102, EL8103
®
Data Sheet
February 19, 2004
500MHz Rail-to-Rail Amplifiers
Features
The EL8102, EL8103 represent
single rail-to-rail amplifiers with a
-3dB bandwidth of 500MHz and slew
rate of 600V/µs. Running off a very low 5.6mA supply
current, the EL8102, EL8103 also feature inputs that go to
0.15V below the VS- rail.
• 500MHz -3dB bandwidth
The EL8102 includes a fast-acting disable/power-down
circuit. With a 25ns disable and a 200ns enable, the EL8102
is ideal for multiplexing applications.
The EL8102, EL8103 are designed for a number of general
purpose video, communication, instrumentation, and
industrial applications. The EL8102 is available in 8-pin SO
and 6-pin SOT-23 packages and the EL8103 is available in a
5-pin SOT-23 package. All are specified for operation over
the -40°C to +85°C temperature range.
• 600V/µs slew rate
• Low supply current = 5.6mA
• Supplies from 3V to 5.0V
• Rail-to-rail output
• Input to 0.15V below VS• Fast 25ns disable (EL8102 only)
• Low cost
Applications
• Video amplifiers
• Portable/hand-held products
• Communications devices
Ordering Information
PART
NUMBER
FN7104.5
Pinouts
EL8102
(8-PIN SO)
TOP VIEW
PACKAGE
TAPE & REEL
PKG. DWG. #
EL8102IS
8-Pin SO
-
MDP0027
EL8102IS-T7
8-Pin SO
7”
MDP0027
EL8102IS-T13
8-Pin SO
13”
MDP0027
EL8102IW-T7
6-Pin SOT-23
7” (3K pcs)
MDP0038
EL8102IW-T7A
6-Pin SOT-23
7” (250 pcs)
MDP0038
IN+ 3
EL8103IW-T7
5-Pin SOT23
7” (3K pcs)
MDP0038
VS- 4
EL8103IW-T7A
5-Pin SOT23
7” (250 pcs)
MDP0038
NC 1
8 ENABLE
IN- 2
7 VS+
+
6 OUT
5 NC
EL8102
(6-PIN SOT-23)
TOP VIEW
OUT 1
6 VS+
VS- 2
5 ENABLE
+ -
IN+ 3
4 IN-
EL8103
(5-PIN SOT-23)
TOP VIEW
OUT 1
5 VS+
VS- 2
+ IN+ 3
1
4 IN-
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. 2004. All Rights Reserved. Elantec is a registered trademark of Elantec Semiconductor, Inc.
All other trademarks mentioned are the property of their respective owners.
EL8102, EL8103
Absolute Maximum Ratings (TA = 25°C)
Supply Voltage from VS+ to VS- . . . . . . . . . . . . . . . . . . . . . . . . . 5.5V
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . VS+ +0.3V to VS- -0.3V
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2V
Continuous Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . 40mA
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Curves
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . -65°C to +125°C
Ambient Operating Temperature . . . . . . . . . . . . . . . . -40°C to +85°C
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . +125°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. Typ values are for information purposes only. Unless otherwise noted, all tests are
at the specified temperature and are pulsed tests, therefore: TJ = TC = TA
Electrical Specifications
PARAMETER
VS+ = 5V, VS- = GND, TA = 25°C, VCM = 2.5V, RL to 2.5V, AV = 1, Unless Otherwise Specified
DESCRIPTION
CONDITIONS
MIN
TYP
MAX
UNIT
-8
-0.8
+8
mV
INPUT CHARACTERISTICS
VOS
Offset Voltage
TCVOS
Offset Voltage Temperature Coefficient Measured from TMIN to TMAX
IB
Input Bias Current
VIN = 0V
IOS
Input Offset Current
VIN = 0V
TCIOS
Input Bias Current Temperature
Coefficient
Measured from TMIN to TMAX
CMRR
Common Mode Rejection Ratio
VCM = -0.15V to +3.5V
CMIR
Common Mode Input Range
RIN
Input Resistance
CIN
Input Capacitance
AVOL
Open Loop Gain
3
-9
-6
0.1
70
µA
0.6
µA
2
nA/°C
95
dB
VS- -0.15
Common Mode
µV/°C
VS+ -1.5
V
3.5
MΩ
0.5
pF
90
dB
VOUT = +1.5V to +3.5V, RL = 150Ω to GND
80
dB
30
mΩ
4.9
V
VOUT = +1.5V to +3.5V, RL = 1kΩ to GND
75
OUTPUT CHARACTERISTICS
ROUT
Output Resistance
AV = +1
VOP
Positive Output Voltage Swing
RL = 1kΩ
4.85
RL = 150Ω
4.6
VON
Negative Output Voltage Swing
4.7
V
RL = 150Ω
100
150
mV
RL = 1kΩ
25
50
mV
IOUT
Linear Output Current
ISC (source)
Short Circuit Current
RL = 10Ω
ISC (sink)
Short Circuit Current
65
mA
70
80
mA
RL = 10Ω
120
150
mA
VS+ = 4.5V to 5.5V
70
95
dB
POWER SUPPLY
PSRR
Power Supply Rejection Ratio
IS-ON
Supply Current - Enabled
5.6
IS-OFF
Supply Current - Disabled
30
µA
6
mA
ENABLE (EL8102 ONLY)
tEN
Enable Time
200
ns
tDS
Disable Time
25
ns
VIH-ENB
ENABLE Pin Voltage for Power-up
0.8
V
VIL-ENB
ENABLE Pin Voltage for Shut-down
2
V
IIH-ENB
ENABLE Pin Input Current High
8.6
µA
IIL-ENB
ENABLE Pin Input for Current Low
0.01
µA
2
EL8102, EL8103
Electrical Specifications
PARAMETER
VS+ = 5V, VS- = GND, TA = 25°C, VCM = 2.5V, RL to 2.5V, AV = 1, Unless Otherwise Specified (Continued)
DESCRIPTION
CONDITIONS
MIN
TYP
MAX
UNIT
AC PERFORMANCE
BW
-3dB Bandwidth
AV = +1, RF = 0Ω, CL = 5pF
500
MHz
AV = -1, RF = 1kΩ, CL = 5pF
140
MHz
AV = +2, RF = 1kΩ, CL = 5pF
165
MHz
AV = +10, RF = 1kΩ, CL = 5pF
18
MHz
BW
±0.1dB Bandwidth
AV = +1, RF = 0Ω, CL = 5pF
35
MHz
Peak
Peaking
AV = +1, RL = 1kΩ, CL = 5pF
1
dB
GBWP
Gain Bandwidth Product
200
MHz
PM
Phase Margin
RL = 1kΩ, CL = 5pF
55
°
SR
Slew Rate
AV = 2, RL = 100Ω, VOUT = 0.5V to 4.5V
600
V/µs
tR
Rise Time
2.5VSTEP, 20% - 80%
4
ns
tF
Fall Time
2.5VSTEP, 20% - 80%
2
ns
OS
Overshoot
200mV step
10
%
500
tPD
Propagation Delay
200mV step
1
ns
tS
0.1% Settling Time
200mV step
15
ns
dG
Differential Gain
AV = +2, RF = 1kΩ, RL = 150Ω
0.01
%
dP
Differential Phase
AV = +2, RF = 1kΩ, RL = 150Ω
0.01
°
eN
Input Noise Voltage
f = 10kHz
12
nV/√Hz
iN+
Positive Input Noise Current
f = 10kHz
1.7
pA/√Hz
iN-
Negative Input Noise Current
f = 10kHz
1.3
pA/√Hz
Pin Descriptions
PIN
EL8102IS
EL8102IW
EL8103IW
1
NAME
FUNCTION
NC
Not connected
2
4
4
IN-
Inverting input
3
3
3
IN+
Non-inverting input
4
2
2
VS-
Negative power supply
NC
Not connected
5
6
1
1
OUT
Amplifier output
7
6
5
VS+
Positive power supply
8
5
3
ENABLE
Enable and disable input
EL8102, EL8103
Simplified Schematic Diagram
VS+
I1
I2
R7
R6
Q5
R8
Q7
VBIAS1
Q6
R3
R1
R2
Q1
IN+
Q2
DIFFERENTIAL TO
SINGLE ENDED
DRIVE
GENERATOR
IN-
VBIAS2
Q3
OUT
Q4
Q8
R4
R5
R9
VS-
Typical Performance Curves
5
VS=5V
AV=1
RL=1kΩ
CL=5pF
GAIN (dB)
3
NORMALIZED GAIN (dB)
5
VOP-P=200mV
1
-1
VOP-P=1V
-3
VOP-P=2V
-5
100K
1M
10M
100M
3
RF=RG=1kΩ
1
-1
-3
RF=RG=500Ω
VS=5V
AV=2
RL=1kΩ
CL=5pF
-5
100K
1G
1M
FREQUENCY (Hz)
100M
1G
FIGURE 2. SMALL SIGNAL FREQUENCY RESPONSE
vs RF AND RG
4
VS=5V
CL=5pF
RL=1kΩ
AV=2
NORMALIZED GAIN (dB)
4
NORMALIZED GAIN (dB)
10M
FREQUENCY (Hz)
FIGURE 1. FREQUENCY RESPONSE FOR VARIOUS OUTPUT
VOLTAGE LEVELS
2
RF=RG=2kΩ
AV=1
0
AV=5
-2
AV=10
-4
-6
100K
1M
10M
100M
1G
FREQUENCY (Hz)
FIGURE 3. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS NON-INVERTING GAINS
4
2
VS=5V
CL=5pF
RL=1kΩ
RF=1kΩ
AV=-1
0
AV=-5
-2
-4
-6
100K
AV=-10
1M
10M
100M
1G
FREQUENCY (Hz)
FIGURE 4. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS INVERTING GAINS
EL8102, EL8103
Typical Performance Curves (Continued)
5
9
RL=100Ω
RL=1kΩ
GAIN (dB)
GAIN (dB)
3
11
VS=5V
AV=1
CL=5pF
VOP-P=200mV
1
-1
VS=5V
AV=2
CL=5pF
RF=RG=1kΩ
RL=500Ω
7
5
RL=1kΩ,
150Ω
RL=500Ω
-3
3
-5
100K
1M
10M
100M
1
100K
1G
1M
FREQUENCY (Hz)
FIGURE 5. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS RLOAD
NORMALIZED GAIN (dB)
GAIN (dB)
CL=10pF
CL=5pF
-1
CL=1.5pF
-3
-5
100K
1M
10M
100M
9
CL=14pF
5
CL=9pF
3
CL=5pF
1M
110
30
225
RL=150Ω
-10
135
RL=1kΩ
-30
45
100M
-45
1G
FREQUENCY (Hz)
FIGURE 9. OPEN LOOP GAIN AND PHASE vs FREQUENCY
5
GAIN (dB)
315
PHASE (°)
GAIN (dB)
70 R =150Ω
L
10M
1G
-10
405
1M
100M
FIGURE 8. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS CL
RL=1kΩ
100K
10M
FREQUENCY (Hz)
FIGURE 7. SMALL SIGNAL FREQUENCY RESPONSE vs CL
10K
CL=20pF
7
1
100K
1G
CL=30pF
VS=5V
AV=2
RL=1kΩ
RF=RG=1kΩ
FREQUENCY (Hz)
-90
1K
1G
11
VS=5V
AV=1
RL=1kΩ
VOP-P=200mV
1
-50
100M
FIGURE 6. SMALL SIGNAL FREQUENCY RESPONSE vs
VARIOUS RLOAD
5
3
10M
FREQUENCY (Hz)
VS=5V
AV=1
RL=1kΩ
-50
-70
-90
-110
1K
10K
100K
1M
10M
100M
1G
FREQUENCY (Hz)
FIGURE 10. DISABLED OUTPUT ISOLATION FREQUENCY
RESPONSE
EL8102, EL8103
Typical Performance Curves (Continued)
-10
550
500
BANDWIDTH (MHz)
PSRR (dB)
-30
PSRR-
-50
-70
PSRR+
-90
450
AV=1
RL=1kΩ
CL=5pF
400
350
300
250
AV=2
200
-110
1K
150
10K
100K
1M
10M
100M
3
4
3.5
FIGURE 11. POWER SUPPLY REJECTION
RATIO vs FREQUENCY
1
0.1
RL=1K
CL=5pF
1.5
AV=1
1
AV=2
0.5
0
100K
1M
10M
3
100M
3.5
4.5
4
FREQUENCY (Hz)
5
5.5
VS (V)
FIGURE 14. SMALL SIGNAL PEAKING vs SUPPLY VOLTAGE
FIGURE 13. OUPUT IMPEDANCE vs FREQUENCY
-15
10
-35
8
-55
6
IS (mA)
CMRR (dB)
5.5
2
PEAKING (dB)
IMPEDANCE (Ω)
2.5
10
-75
-95
-115
100K
5
FIGURE 12. SMALL SIGNAL BANDWIDTH vs
SUPPLY VOLTAGE
100
0.01
10K
4.5
VS (V)
FREQUENCY (Hz)
4
2
0
1M
10M
100M
FREQUENCY (Hz)
FIGURE 15. COMMON-MODE REJECTION RATIO vs
FREQUENCY
6
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
VS (V)
FIGURE 16. SUPPLY CURRENT vs SUPPLY VOLTAGE
EL8102, EL8103
Typical Performance Curves (Continued)
-70
VS=5V
RL=1kΩ
CL=5pF
AV=2
-70
-75
[email protected]
DISTORTION (dBc)
DISTORTION (dBc)
-60
[email protected]
-80
@1
HD2
-90
MHz
Hz
[email protected]
MH z
[email protected]
2
3
-80
[email protected]
4
VS=5V
f=5MHz
-90
HD3 @
AV =1
VO=1VP-P for AV=1
VO=2VP-P for AV=2
2K
1K
VOP-P (V)
RLOAD (Ω)
FIGURE 17. HARMONIC DISTORTION vs OUTPUT VOLTAGE
FIGURE 18. HARMONIC DISTORTION vs LOAD RESISTANCE
-50
1K
-70
AV=2
HD2 @
-80
-90
[email protected]=1
[email protected]=2
@
HD3
-100
VOLTAGE NOISE (nV/√Hz)
CURRENT NOISE (pA/√Hz),
VS=5V
RL=1kΩ
CL=5pF
VO=1VP-P for AV=1
VO=2VP-P for AV=2
-60
DISTORTION (dBc)
AV =1
HD3 @
AV =2
-100
100
5
AV =2
-85
-95
[email protected]
-100
1
[email protected]
AV=1
1
10
100
eN
10
IN+
1
10
40
FREQUENCY (MHz)
FIGURE 19. HARMONIC DISTORTION vs FREQUENCY
1K
10K
100K
VS=5V, AV=1, RL=1kΩ to 2.5V, CL=5pF
3.5
2.5
2.5
1.5
FIGURE 21. LARGE SIGNAL TRANSIENT
RESPONSE - RISING
7
10M
FIGURE 20. VOLTAGE AND CURRENT NOISE vs FREQUENCY
3.5
2ns/DIV
1M
FREQUENCY (Hz)
VS=5V, AV=1, RL=1kΩ TO 2.5V, CL=5pF
1.5
100
IN-
2ns/DIV
FIGURE 22. LARGE SIGNAL TRANSIENT
RESPONSE - FALLING
EL8102, EL8103
Typical Performance Curves (Continued)
VS=5V, AV=1, RL=1kΩ TO 2.5V, CL= 5pF
VS=5V, AV=5, RL=1kΩ TO 2.5V
VIN
2.6
5
2.5
2.4
2.5
2.6
VOUT
2.5
0
2.4
10ns/DIV
2µs/DIV
FIGURE 23. SMALL SIGNAL TRANSIENT REPONSE
FIGURE 24. OUTPUT SWING
VS=5V, AV=5, RL=1kΩ TO 2.5V
CH1
ENABLE
INPUT
5
2.5
CH2
VOUT
0
CH1, CH2, 1V/DIV, M=100ns
2µs/DIV
FIGURE 25. OUTPUT SWING
FIGURE 26. ENABLED RESPONSES
JEDEC JESD51-7 HIGH EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
POWER DISSIPATION (W)
1.4
ENABLE
INPUT
CH1
CH2
VOUT
1.2
1 909mW
SO8
θJA=110°C/W
0.8
0.6
435mW
0.4
SOT23-5/6
θJA=230°C/W
0.2
0
0
CH1, CH2, 0.5V/DIV, M=20ns
FIGURE 27. DISABLED RESPONSE
8
25
50
75 85 100
125
150
AMBIENT TEMPERATURE (°C)
FIGURE 28. PACKAGE POWER DISSIPATION vs AMBIENT
TEMPERATURE
EL8102, EL8103
Typical Performance Curves (Continued)
JEDEC JESD51-3 LOW EFFECTIVE
THERMAL CONDUCTIVITY TEST BOARD
POWER DISSIPATION (W)
1
0.9
0.8
0.7 625mW
0.6
0.5
SO8
θJA=160°C/W
391mW
0.4
0.3
0.2
SOT23-5/6
θJA=256°C/W
0.1
0
0
25
50
75 85 100
125
150
AMBIENT TEMPERATURE (°C)
FIGURE 29. PACKAGE POWER DISSIPATION vs AMBIENT TEMPERATURE
Description of Operation and Application
Information
Product Description
The EL8102, EL8103 are wide bandwidth, single supply, low
power and rail-to-rail output voltage feedback operational
amplifiers. Both amplifiers are internally compensated for
closed loop gain of +1 of greater. Connected in voltage
follower mode and driving a 1kΩ load, the EL8102, EL8103
have a -3dB bandwidth of 500MHz. Driving a 150Ω load, the
bandwidth is about 350MHz while maintaining a 600V/us
slew rate. The EL8102 is available with a power down pin to
reduce power to 30µA typically while the amplifier is
disabled.
Input, Output and Supply Voltage Range
The EL8102, EL8103 have been designed to operate with a
single supply voltage from 3V to 5.0V. Split supplies can also
be used as long as their total voltage is within 3V to 5.0V.
The amplifiers have an input common mode voltage range
from 0.15V below the negative supply (VS- pin) to within
1.5V of the positive supply (VS+ pin). If the input signal is
outside the above specified range, it will cause the output
signal to be distorted.
The output of the EL8102, EL8103 can swing rail to rail. As
the load resistance becomes lower, the ability to drive close
to each rail is reduced. For the load resistor 1kΩ, the output
swing is about 4.9V at a 5V supply. For the load resistor
150Ω, the output swing is about 4.6V.
Choice of Feedback Resistor and Gain Bandwidth
Product
For applications that require a gain of +1, no feedback
resistor is required. Just short the output pin to the inverting
input pin. For gains greater than +1, the feedback resistor
forms a pole with the parasitic capacitance at the inverting
input. As this pole becomes smaller, the amplifier’s phase
margin is reduced. This causes ringing in the time domain
9
and peaking in the frequency domain. Therefore, RF has
some maximum value that should not be exceeded for
optimum performance. If a large value of RF must be used, a
small capacitor in the few pF range in parallel with RF can
help to reduce the ringing and peaking at the expense of
reducing the bandwidth.
As far as the output stage of the amplifier is concerned, the
output stage is also a gain stage with the load. RF and RG
appear in parallel with RL for gains other than +1. As this
combination gets smaller, the bandwidth falls off.
Consequently, RF also has a minimum value that should not
be exceeded for optimum performance. For gain of +1, RF=0
is optimum. For the gains other than +1, optimum response
is obtained with RF between 300Ω to 1kΩ.
The EL8102, EL8103 have a gain bandwidth product of
200MHz. For gains ≥5, its bandwidth can be predicted by the
following equation:
Gain × BW = 200MHz
Video Performance
For good video performance, an amplifier is required to
maintain the same output impedance and the same
frequency response as DC levels are changed at the output.
This is especially difficult when driving a standard video load
of 150Ω, because the change in output current with DC level.
Special circuitry has been incorporated in the EL8102,
EL8103 to reduce the variation of the output impedance with
the current output. This results in dG and dP specifications
of 0.01% and 0.01°, while driving 150Ω at a gain of 2. Driving
high impedance loads would give a similar or better dG and
dP performance.
Driving Capacitive Loads and Cables
The EL8102, EL8103 can drive 10pF loads in parallel with
1kΩ with less than 5dB of peaking at gain of +1. If less
peaking is desired in applications, a small series resistor
(usually between 5Ω to 50Ω) can be placed in series with the
EL8102, EL8103
output to eliminate most peaking. However, this will reduce
the gain slightly. If the gain setting is greater than 1, the gain
resistor RG can then be chosen to make up for any gain loss
which may be created by the additional series resistor at the
output.
When used as a cable driver, double termination is always
recommended for reflection-free performance. For those
applications, a back-termination series resistor at the
amplifier’s output will isolate the amplifier from the cable and
allow extensive capacitive drive. However, other applications
may have high capacitive loads without a back-termination
resistor. Again, a small series resistor at the output can help
to reduce peaking.
Where:
TJMAX = Maximum junction temperature
TAMAX = Maximum ambient temperature
θJA = Thermal resistance of the package
The maximum power dissipation actually produced by an IC
is the total quiescent supply current times the total power
supply voltage, plus the power in the IC due to the load, or:
For sourcing:
V OUT
PD MAX = V S × I SMAX + ( V S – V OUT ) × ---------------R
L
For sinking:
Disable/Power-Down
The EL8102 can be disabled and placed its output in a high
impedance state. The turn off time is about 25ns and the turn
on time is about 200ns. When disabled, the amplifier’s
supply current is reduced to 30µA typically, thereby
effectively eliminating the power consumption. The
amplifier’s power down can be controlled by standard TTL or
CMOS signal levels at the ENABLE pin. The applied logic
signal is relative to VS- pin. Letting the ENABLE pin float or
applying a signal that is less than 0.8V above VS- will enable
the amplifier. The amplifier will be disabled when the signal
at ENABLE pin is 2V above VS-.
Output Drive Capability
The EL8102, EL8103 do not have internal short circuit
protection circuitry. They have a typical short circuit current
of 80mA sourcing and 150mA sinking for the output is
connected to half way between the rails with a 10Ω resistor.
If the output is shorted indefinitely, the power dissipation
could easily increase such that the part will be destroyed.
Maximum reliability is maintained if the output current never
exceeds ±40mA. This limit is set by the design of the internal
metal interconnections.
Power Dissipation
With the high output drive capability of the EL8102, EL8103,
It is possible to exceed the 125°C absolute maximum
junction temperature under certain load current conditions.
Therefore, it is important to calculate the maximum junction
temperature for the application to determine if the load
conditions or package types need to be modified for the
amplifier to remain in the safe operating area.
The maximum power dissipation allowed in a package is
determined according to:
T JMAX – T AMAX
PD MAX = --------------------------------------------θ JA
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PD MAX = V S × I SMAX + ( V OUT – V S- ) × I LOAD
Where:
VS = Total supply voltage
ISMAX = Maximum quiescent supply current
VOUT = Maximum output voltage of the application
RLOAD = Load resistance tied to ground
ILOAD = Load current
By setting the two PDMAX equations equal to each other, we
can solve the output current and RLOAD to avoid the device
overheat.
Power Supply Bypassing and Printed Circuit
Board Layout
As with any high frequency device, a good printed circuit
board layout is necessary for optimum performance. Lead
lengths should be as short as possible. The power supply
pin must be well bypassed to reduce the risk of oscillation.
For normal single supply operation, where the VS- pin is
connected to the ground plane, a single 4.7µF tantalum
capacitor in parallel with a 0.1µF ceramic capacitor from VS+
to GND will suffice. This same capacitor combination should
be placed at each supply pin to ground if split supplies are to
be used. In this case, the VS- pin becomes the negative
supply rail.
For good AC performance, parasitic capacitance should be
kept to a minimum. Use of wire wound resistors should be
avoided because of their additional series inductance. Use
of sockets should also be avoided if possible. Sockets add
parasitic inductance and capacitance that can result in
compromised performance. Minimizing parasitic capacitance
at the amplifier’s inverting input pin is very important. The
feedback resistor should be placed very close to the
inverting input pin. Strip line design techniques are
recommended for the signal traces.
EL8102, EL8103
Typical Applications
+2.5V
VIDEO SYNC PULSE REMOVER
Many CMOS analog to digital converters have a parasitic
latch up problem when subjected to negative input voltage
levels. Since the sync tip contains no useful video
information and it is a negative going pulse, we can chop it
off. Figure 30 shows a gain of 2 connections for EL8102,
EL8103. Figure 31 shows the complete input video signal
applied at the input, as well as the output signal with the
negative going sync pulse removed.
B 2MHz
1VP-P
+
75Ω
-2.5V
1K
75Ω
VOUT
1K
+2.5V
A 2MHz
2VP-P
75Ω
+
75Ω
-2.5V
5V
1K
VIN
75Ω
VS+
+
1K
VOUT
-
VS-
75Ω
ENABLE
75Ω
1K
FIGURE 32. TWO TO ONE MULTIPLEXER
1K
FIGURE 30. SYNC PULSE REMOVER
0V
-0.5V
ENABLE
-1.5V
-2.5V
1V
VIN
0.5V
1V
0V
0V
1V
B
A
-1V
0.5V
VOUT
0V
M = 50ns/DIV
FIGURE 33.
M = 10µs/DIV
SINGLE SUPPLY VIDEO LINE DRIVER
FIGURE 31. VIDEO SIGNAL
MULTIPLEXER
Besides the normal power down usage, the ENABLE pin of
the EL8102 can be used for multiplexing applications. Figure
32 shows two EL8102 with the outputs tied together, driving
a back terminated 75Ω video load. A 2VP-P 2MHz sine wave
is applied to Amp A and a 1VP-P 2MHz sine wave is applied
to Amp B. Figure 33 shows the ENABLE signal and the
resulting output waveform at VOUT. Observe the breakbefore-make operation of the multiplexing. Amp A is on and
VIN1 is passed through to the output when the ENABLE
signal is low and turns off in about 25ns when the ENABLE
signal is high. About 200ns later, Amp B turns on and VIN2 is
passed through to the output. The break-before-make
operation ensures that more than one amplifier isn’t trying to
drive the bus at the same time.
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The EL8102 and EL8103 are wideband rail-to-rail output op
amplifiers with large output current, excellent dG, dP, and low
distortion that allow them to drive video signals in low supply
applications. Figure 34 is the single supply non-inverting
video line driver configuration and Figure 35 is the inverting
video ling driver configuration. The signal is AC coupled by
C1. R1 and R2 are used to level shift the input and output to
provide the largest output swing. RF and RG set the AC gain.
C2 isolates the virtual ground potential. RT and R3 are the
termination resistors for the line. C1, C2 and C3 are selected
big enough to minimize the droop of the luminance signal.
EL8102, EL8103
5V
RF
1kΩ
VIN
C1
47µF
R1
10K
R3
C3
470µF 75Ω
+
RT
75Ω
VOUT
VIN
C1
RG
47µF 500Ω
-
R2
10K
75Ω
RG
1kΩ
5V
RT
75Ω
5V
R3
C3
470µF 75Ω
VOUT
+
R1
10K
75Ω
RF
1kΩ
R2
10K
C2
220µF
NORMALIZED GAIN (dB)
FIGURE 34. 5V SINGLE SUPPLY NON INVERTING
VIDEO LINE DRIVER
C2
220µF
FIGURE 35. SINGLE SUPPLY INVERTING VIDEO LINE DRIVER
4
3
2
1
AV = 2
0
-1
-2
AV = -2
-3
-4
-5
-6
100K
1M
10M
100M 500M
FREQUENCY (Hz)
FIGURE 36. VIDEO LINE DRIVER FREQUENCY RESPONSE
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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
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