ETC EL5492CS

Quad 600MHz Current Feedback Amplifier with Enable
®
Features
General Description
• 600MHz -3dB bandwidth
• 6mA supply current (per amplifier)
• Single and dual supply operation,
from 5V to 10V
• Fast enable/disable (EL5492AC
only)
• Single (EL5192C), dual
(EL5292C), and triple (EL5392C)
available
• High speed, 1GHz product
available (EL5191C)
• Low power, 4mA, 300MHz
product available (EL5193C,
EL5293C, EL5393C, & EL5493C)
The EL5492C and EL5492AC are quad current feedback amplifiers
with a very high bandwidth of 600MHz. This makes these amplifiers
ideal for today’s high speed video and monitor applications.
Applications
With a supply current of just 6mA per amplifier and the ability to run
from a single supply voltage from 5V to 10V, these amplifiers are also
ideal for hand held, portable or battery powered equipment.
The EL5492AC also incorporates an enable and disable function to
reduce the supply current to 100µA typical per amplifier. Allowing the
CE pin to float or applying a low logic level will enable the amplifier.
The EL5492C is offered in the industry-standard 14-pin SO (0.150")
package and the EL5492AC in the ultra-small 24-pin LPP package.
Both operate over the industrial temperature range of -40°C to +85°C.
20 IND-
21 OUTD
22 NC
23 OUTA
Pin Configurations
Video amplifiers
Cable drivers
RGB amplifiers
Test equipment
Instrumentation
Current to voltage converters
24 INA-
•
•
•
•
•
•
NC 1
19 NC
OUTA 1
Ordering Information
INA+ 2
18 IND+
CEA 3
17 CED
14 OUTD
INA- 2
Package
Tape &
Reel
Outline #
14-Pin SO (0.150")
-
MDP0027
EL5492CS-T7
14-Pin SO (0.150")
7”
MDP0027
EL5492CS-T13
14-Pin SO (0.150")
13”
MDP0027
EL5492ACL
24-Pin LPP
-
MDP0046
EL5492ACL-T7
24-Pin LPP
7”
MDP0046
EL5492ACL-T13
24-Pin LPP
13”
MDP0046
VS+ 4
Thermal Pad
A
-
D
+
+
13 IND-
INA+ 3
12 IND+
VS+ 4
11 VS-
16 VS-
CEB 5
15 CEC
INB+ 6
14 INC+
INB+ 5
10 INC+
-
INB- 6
+
B
+
C
9 INC-
INC- 12
OUTB 7
8 OUTC
EL5492CS
[14-Pin SO (0.150")]
EL5492ACL
(24-Pin LPP - Top View)
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-ELANTEC or 408-945-1323 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Elantec ® is a registered trademark of Elantec Semiconductor, Inc.
Copyright © Intersil Americas Inc. 2002. All Rights Reserved
February 28, 2002
OUTC 11
NC 10
13 NC
INB- 8
NC 7
OUTB 9
Part No
EL5492CS
EL5492C, EL5492AC
EL5492C, EL5492AC
®
EL5492C, EL5492AC
EL5492C, EL5492AC
Quad 600MHz Current Feedback Amplifier with Enable
Absolute Maximum Ratings (T
A
= 25°C)
Values beyond absolute maximum ratings can cause the device to be prematurely damaged. Absolute maximum ratings are stress ratings only and
functional device operation is not implied.
11V
Supply Voltage between VS+ and VSMaximum Continuous Output Current
50mA
Operating Junction Temperature
Power Dissipation
Pin Voltages
Storage Temperature
Operating Temperature
125°C
See Curves
VS- - 0.5V to VS+ +0.5V
-65°C to +150°C
-40°C to +85°C
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 Characteristics
VS+ = +5V, VS- = -5V, RF = 750Ω for AV = 1, RF = 375Ω for AV = 2, RL = 150Ω, TA = 25°C unless otherwise specified.
Parameter
Description
Conditions
Min
Typ
Max
Unit
AC Performance
BW
-3dB Bandwidth
AV = +1
600
MHz
AV = +2
300
MHz
25
MHz
2300
V/µs
BW1
0.1dB Bandwidth
SR
Slew Rate
VO = -2.5V to +2.5V, AV = +2
tS
0.1% Settling Time
VOUT = -2.5V to +2.5V, AV = -1
9
ns
CS
Channel Separation
f = 5MHz
60
dB
2000
eN
Input Voltage Noise
4.1
nV/√Hz
iN-
IN- Input Current Noise
20
pA/√Hz
iN+
IN+ Input Current Noise
dG
Differential Gain Error
dP
Differential Phase Error
[1]
[1]
50
pA/√Hz
AV = +2
0.015
%
AV = +2
0.04
°
DC Performance
VOS
Offset Voltage
TCVOS
Input Offset Voltage Temperature Coefficient
ROL
Transimpediance
-10
Measured from TMIN to TMAX
1
10
mV
5
µV/°C
200
400
kΩ
Input Characteristics
CMIR
Common Mode Input Range
±3
±3.3
V
CMRR
Common Mode Rejection Ratio
42
50
dB
+IIN
+ Input Current
-60
3
60
µA
-IIN
- Input Current
-35
4
35
µA
RIN
Input Resistance
37
kΩ
CIN
Input Capacitance
0.5
pF
V
Output Characteristics
VO
RL = 150Ω to GND
±3.4
±3.7
RL = 1kΩ to GND
±3.8
±4.0
V
Output Current
RL = 10Ω to GND
95
120
mA
ISON
Supply Current - Enabled
No load, VIN = 0V
5
ISOFF
Supply Current - Disabled
No load, VIN = 0V
PSRR
Power Supply Rejection Ratio
DC, VS = ±4.75V to ±5.25V
55
-IPSR
- Input Current Power Supply Rejection
DC, VS = ±4.75 to ±5.25V
-2
IOUT
Output Voltage Swing
Supply
2
6
7.5
mA
100
150
µA
2
µA/V
75
dB
Quad 600MHz Current Feedback Amplifier with Enable
Electrical Characteristics
VS+ = +5V, VS- = -5V, RF = 750Ω for AV = 1, RF = 375Ω for AV = 2, RL = 150Ω, TA = 25°C unless otherwise specified.
Parameter
Description
Conditions
Min
Typ
Max
Unit
Enable (EL5492AC only)
tEN
Enable Time
40
ns
tDIS
Disable Time [2]
600
ns
IIHCE
CE Pin Input High Current
CE = VS+
0.8
6
µA
IILCE
CE Pin Input Low Current
CE = VS-
0
-0.1
µA
VIHCE
CE Input High Voltage for Power-down
VILCE
CE Input Low Voltage for Power-down
VS+ - 1
V
VS + - 3
1. Standard NTSC test, AC signal amplitude = 286mVP-P, f = 3.58MHz
2. Measured from the application of CE logic signal until the output voltage is at the 50% point between initial and final values
3
V
EL5492C, EL5492AC
EL5492C, EL5492AC
Quad 600MHz Current Feedback Amplifier with Enable
Typical Performance Curves
Non-Inverting Frequency Response (Gain)
Non-Inverting Frequency Response (Phase)
6
90
AV=2
2
0
-2
-90
AV=1
AV=2
Phase (°)
Normalized Magnitude (dB)
AV=1
AV=5
-6
AV=5
AV=10
-180
AV=10
-10
-270
RF=750Ω
RL=150Ω
-14
1M
RF=750Ω
RL=150Ω
10M
100M
-360
1M
1G
10M
Frequency (Hz)
1G
Inverting Frequency Response (Phase)
6
90
AV=-1
2
AV=-2
AV=-1
0
-2
Phase (°)
Normalized Magnitude (dB)
100M
Frequency (Hz)
Inverting Frequency Response (Gain)
AV=-5
-6
-10
-90
AV=-2
AV=-5
-180
-270
RF=375Ω
RL=150Ω
-14
1M
RF=375Ω
RL=150Ω
10M
100M
-360
1M
1G
10M
Frequency (Hz)
6
RL=150Ω
2pF added
Normalized Magnitude (dB)
6
1pF added
2
-2
-10
1M
1G
Frequency Response for Various RL
10
-6
100M
Frequency (Hz)
Frequency Response for Various CIN-
Normalized Magnitude (dB)
EL5492C, EL5492AC
EL5492C, EL5492AC
0pF added
AV=2
RF=375Ω
RL=150Ω
RL=100Ω
2
RL=500Ω
-2
-6
-10
AV=2
RF=375Ω
10M
100M
-14
1M
1G
Frequency (Hz)
10M
100M
Frequency (Hz)
4
1G
Quad 600MHz Current Feedback Amplifier with Enable
Typical Performance Curves
Frequency Response for Various CL
Frequency Response for Various RF
14
6
12pF added
6
Normalized Magnitude (dB)
Normalized Magnitude (dB)
250Ω
10
8pF added
2
AV=2
RF=375Ω
RL=150Ω
-2
-6
1M
0pF added
10M
100M
475Ω
-2
620Ω
-6
750Ω
AV=2
RG=RF
RL=150Ω
-10
-14
1M
1G
10M
Frequency (Hz)
100M
1G
Frequency (Hz)
Frequency Response for Various Common-Mode Input
Voltages
Group Delay vs Frequency
3.5
6
VCM=3V
2.5
Normalized Magnitude (dB)
3
Group Delay (ns)
375Ω
2
AV=2
RF=375Ω
2
1.5
1
AV=1
RF=750Ω
0.5
0
1M
100M
10M
-2
VCM=-3V
-6
-10
-14
1M
1G
VCM=0V
2
AV=2
RF=375Ω
RL=150Ω
10M
100M
1G
Frequency (Hz)
Frequency (Hz)
Transimpedance (ROL) vs Frequency
PSRR and CMRR vs Frequency
10M
20
0
Phase
1M
-180
10k
PSRR/CMRR (dB)
100k
Phase (°)
Magnitude (Ω)
PSRR+
0
-90
-270
Gain
1k
-20
PSRR-40
-60
CMRR
-360
100
1k
10k
100k
1M
10M
Frequency (Hz)
100M
-80
10k
1G
5
100k
1M
10M
Frequency (Hz)
100M
1G
EL5492C, EL5492AC
EL5492C, EL5492AC
Quad 600MHz Current Feedback Amplifier with Enable
Typical Performance Curves
-3dB Bandwidth vs Supply Voltage for Non-Inverting Gains
-3dB Bandwidth vs Supply Voltage for Inverting Gains
800
350
300
600
AV=1
-3dB Bandwidth (MHz)
-3dB Bandwidth (MHz)
RF=750Ω
RL=150Ω
400
AV=2
200
AV=5
AV=10
AV=-1
250
AV=-2
200
AV=-5
150
100
50
0
RF=375Ω
RL=150Ω
0
5
6
7
8
10
9
5
6
7
Total Supply Voltage (V)
9
10
Peaking vs Supply Voltage for Inverting Gains
4
4
RF=750Ω
RL=150Ω
AV=1
RF=375Ω
RL=150Ω
AV=-1
3
Peaking (dB)
3
Peaking (dB)
8
Total Supply Voltage (V)
Peaking vs Supply Voltage for Non-Inverting Gains
2
1
AV=-2
2
1
AV=2
AV=10
AV=-5
0
0
5
6
7
8
9
10
5
6
7
Total Supply Voltage (V)
9
10
-3dB Bandwidth vs Temperature for Inverting Gains
1400
500
RF=750Ω
RL=150Ω
1200
400
AV=1
-3dB Bandwidth (MHz)
1000
8
Total Supply Voltage (V)
-3dB Bandwidth vs Temperature for Non-Inverting Gains
-3dB Bandwidth (MHz)
EL5492C, EL5492AC
EL5492C, EL5492AC
800
600
400
AV=5
AV=10
AV=2
300
RF=375Ω
RL=150Ω
AV=-1
AV=-2
200
AV=-5
100
200
0
-40
10
60
110
0
-40
160
Ambient Temperature (°C)
10
60
110
Ambient Temperature (°C)
6
160
Quad 600MHz Current Feedback Amplifier with Enable
Typical Performance Curves
Peaking vs Temperature
Voltage and Current Noise vs Frequency
2
1k
RL=150Ω
AV=1
Voltage Noise (nV/√Hz)
Current Noise (pA/√Hz)
Peaking (dB)
1.5
1
AV=-1
0.5
AV=-2
100
in+
in-
10
en
0
AV=2
-0.5
-50
-50
0
50
1
100
100
1k
10k
100k
Frequency (Hz)
Ambient Temperature (°C)
10
10
8
1
0.1
0.01
6
4
2
0.001
100
0
1k
10k
1M
100k
Frequency (Hz)
10M
100M
1G
0
2nd and 3rd Harmonic Distortion vs Frequency
2
4
6
8
Supply Voltage (V)
10
12
Two-Tone 3rd Order
Input Referred Intermodulation Intercept (IIP3)
-20
30
AV=+2
VOUT=2VP-P
RL=100Ω
-40
-50
2nd Order
Distortion
-60
-70
3rd Order
Distortion
-80
-90
20
15
10
5
0
-5
-10
-100
1
AV=+2
RL=150Ω
25
Input Power Intercept (dBm)
-30
Harmonic Distortion (dBc)
10M
Supply Current vs Supply Voltage
100
Supply Current (mA)
Output Impedance (Ω)
Closed Loop Output Impedance vs Frequency
1M
10
Frequency (MHz)
AV=+2
RL=100Ω
-15
10
100
100
Frequency (MHz)
7
200
EL5492C, EL5492AC
EL5492C, EL5492AC
Quad 600MHz Current Feedback Amplifier with Enable
Typical Performance Curves
Differential Gain/Phase vs DC Input
Voltage at 3.58MHz
Differential Gain/Phase vs DC Input
Voltage at 3.58MHz
0.03
0.03
AV=2
RF=RG=375Ω
RL=150Ω
dG (%) or dP (°)
0.01
0.01
0
dG
-0.01
-0.02
0
-0.03
-0.04
-0.05
0
0.5
dG
-0.02
-0.04
-0.5
-0.06
-1
1
dP
-0.01
-0.03
-0.05
-1
AV=1
RF=750Ω
RL=500Ω
0.02
dP
dG (%) or dP (°)
0.02
-0.5
DC Input Voltage
0
0.5
1
DC Input Voltage
Output Voltage Swing vs Frequency
THD<0.1%
Output Voltage Swing vs Frequency
THD<1%
9
10
RL=500Ω
7
RL=500Ω
Output Voltage Swing (VPP)
8
Output Voltage Swing (VPP)
EL5492C, EL5492AC
EL5492C, EL5492AC
RL=150Ω
6
5
4
3
2
1
8
RL=150Ω
6
4
2
AV=2
AV=2
0
0
1
10
Frequency (MHz)
1
100
Small Signal Step Response
10
Frequency (MHz)
100
Large Signal Step Response
VS=±5V
RL=150Ω
AV=2
RF=RG=375Ω
VS=±5V
RL=150Ω
AV=2
RF=RG=375Ω
200mV/div
1V/div
10ns/div
10ns/div
8
Quad 600MHz Current Feedback Amplifier with Enable
Typical Performance Curves
Settling Time vs Settling Accuracy
Transimpedance (RoI) vs Temperature
25
500
AV=2
RF=RG=375Ω
RL=150Ω
VSTEP=5VP-P output
450
15
RoI (kΩ)
Settling Time (ns)
20
10
400
350
5
0
0.01
0.1
300
-40
1
10
PSRR and CMRR vs Temperature
110
160
110
160
ICMR and IPSR vs Temperature
90
2.5
80
PSRR
2
ICMR/IPSR (µA/V)
70
PSRR/CMRR (dB)
60
Die Temperature (°C)
Settling Accuracy (%)
60
CMRR
50
40
30
ICMR+
1.5
1
IPSR
0.5
0
ICMR-0.5
20
10
-40
10
60
110
-1
-40
160
10
Die Temperature (°C)
60
Die Temperature (°C)
Offset Voltage vs Temperature
Input Current vs Temperature
60
3
40
Input Current (µA)
VOS (mV)
2
1
0
20
IB0
-20
IB+
-40
-1
-60
-2
-40
10
60
110
-80
-40
160
10
60
Temperature (°C)
Die Temperature (°C)
9
110
160
EL5492C, EL5492AC
EL5492C, EL5492AC
Quad 600MHz Current Feedback Amplifier with Enable
Typical Performance Curves
Positive Input Resistance vs Temperature
Supply Current vs Temperature
50
8
45
7
40
6
Supply Current (mA)
RIN+ (kΩ)
35
30
25
20
15
10
5
4
3
2
1
5
0
-40
10
60
110
0
-40
160
10
Temperature (°C)
60
110
160
Temperature (°C)
Positive Output Swing vs Temperature for Various Loads
Negative Output Swing vs Temperature for Various Loads
4.2
-3.5
4.1
150Ω
-3.6
4
-3.7
3.9
-3.8
VOUT (V)
VOUT (V)
1kΩ
3.8
3.7
-3.9
1kΩ
-4
150Ω
3.6
-4.1
3.5
-40
10
50
110
-4.2
-40
160
10
Temperature (°C)
60
160
Slew Rate vs Temperature
135
4600
AV=2
RF=RG=375Ω
RL=150Ω
4400
4200
Sink
Slew Rate (V/µS)
130
110
Temperature (°C)
Output Current vs Temperature
IOUT (mA)
EL5492C, EL5492AC
EL5492C, EL5492AC
125
Source
120
4000
3800
3600
3400
3200
115
-40
10
60
110
3000
-40
160
Die Temperature (°C)
10
60
Die Temperature (°C)
10
110
160
Quad 600MHz Current Feedback Amplifier with Enable
Typical Performance Curves
Channel-to-Channel Isolation vs Frequency
Enable Response
0
Gain (dB)
-20
500mV/div
-40
-60
5V/div
-80
-100
100k
1M
10M
100M
400M
20ns/div
Frequency (Hz)
Package Power Dissipation vs Ambient Temperature
JEDEC JESD51-3 Low Effective Thermal Conductivity (Single
Layer) Test Board
Disable Response
1
833mW
Power Dissipation (W)
0.8
500mV/div
714mW
0.6
SO14 (0.150”)
120°C/W
LPP24
140°C/W
0.4
0.2
5V/div
0
0
400ns/div
25
50
75 85
100
Ambient Temperature (°C)
Package Power Dissipation vs Ambient Temperature
JEDEC JESD51-7 High Effective Thermal Conductivity (4 layer)
Test Board - LPP exposed diepad soldered to PCB per JESD51-5
3
LP
2
37
4
P2
/
°C
W
Power Dissipation (W)
2.5 2.703W
1.5
1.136W
SO1
4 (0
.150
”)
88°
C /W
1
0.5
0
0
25
50
75 85
100
125
150
Ambient Temperature (°C)
11
125
150
EL5492C, EL5492AC
EL5492C, EL5492AC
EL5492C, EL5492AC
EL5492C, EL5492AC
Quad 600MHz Current Feedback Amplifier with Enable
Pin Descriptions
EL5492CS
14-Pin SO
(0.150")
EL5492ACL
24-Pin LPP
Pin Name
1
23
OUTA
Function
Equivalent Circuit
Output, channel A
VS+
OUT
VSCircuit 1
2
24
INA-
Inverting input, channel A
VS+
IN+
IN-
VSCircuit 2
3
2
INA+
Non-inverting input, channel A
3
CEA
Chip enable, channel A
(see circuit 2)
VS+
CE
VSCircuit 3
4
4
VS+
Positive supply
5
5
CEB
Chip enable, channel B
6
INB+
Non-inverting input, channel B
6
(see circuit 2)
8
INB-
Inverting input, channel B
(see circuit 2)
7
9
OUTB
Output, channel B
(see circuit 1)
8
11
OUTC
Output, channel C
(see circuit 1)
9
12
INC-
Inverting input, channel C
(see circuit 2)
10
14
INC+
Non-inverting input, channel C
(see circuit 2)
15
CEC
Chip enable, channel C
(see circuit 3)
11
16
VS-
Negative supply
(see circuit 3)
17
CED
Chip enable, channel D
12
18
IND+
Non-inverting input, channel D
(see circuit 2)
13
20
IND-
Inverting input, channel D
(see circuit 1)
21
OUTD
Output, channel D
(see circuit 1)
1, 7, 10, 13,
19, 22
NC
14
(see circuit 3)
No connection
12
Quad 600MHz Current Feedback Amplifier with Enable
Applications Information
Product Description
resistors giving slightly less peaking and bandwidth
because of additional series inductance. Use of sockets,
particularly for the SO (0.150") package, should be
avoided if possible. Sockets add parasitic inductance and
capacitance which will result in additional peaking and
overshoot.
The EL5492C is a current-feedback operational amplifier that offers a wide -3dB bandwidth of 600MHz and a
low supply current of 6mA per amplifier. The EL5492C
works with supply voltages ranging from a single 5V to
10V and they are also capable of swinging to within 1V
of either supply on the output. Because of their currentfeedback topology, the EL5492C does not have the normal gain-bandwidth product associated with voltagefeedback operational amplifiers. Instead, its -3dB bandwidth to remain relatively constant as closed-loop gain is
increased. This combination of high bandwidth and low
power, together with aggressive pricing make the
EL5492C the ideal choice for many low-power/highbandwidth applications such as portable, handheld, or
battery-powered equipment.
Disable/Power-Down
The EL5492AC amplifier can be disabled placing its
output in a high impedance state. When disabled, the
amplifier supply current is reduced to < 600µ A. The
EL5492AC is disabled when its CE pin is pulled up to
within 1V of the positive supply. Similarly, the amplifier
is enabled by floating or pulling its CE pin to at least 3V
below the positive supply. For ±5V supply, this means
that an EL5492AC amplifier will be enabled when CE is
2V or less, and disabled when CE is above 4V. Although
the logic levels are not standard TTL, this choice of
logic voltages allows the EL5492AC to be enabled by
tying CE to ground, even in 5V single supply applications. The CE pin can be driven from CMOS outputs.
For varying bandwidth needs, consider the EL5191C
with 1GHz on a 9mA supply current or the EL5193C
with 300MHz on a 4mA supply current. Versions
include single, dual, and triple amp packages with 5-pin
SOT23, 16-pin QSOP, and 8-pin or 16-pin SO (0.150")
outlines.
Capacitance at the Inverting Input
Any manufacturer’s high-speed voltage- or currentfeedback amplifier can be affected by stray capacitance
at the inverting input. For inverting gains, this parasitic
capacitance has little effect because the inverting input is
a virtual ground, but for non-inverting gains, this capacitance (in conjunction with the feedback and gain
resistors) creates a pole in the feedback path of the
amplifier. This pole, if low enough in frequency, has the
same destabilizing effect as a zero in the forward openloop response. The use of large-value feedback and gain
resistors exacerbates the problem by further lowering
the pole frequency (increasing the possibility of
oscillation.)
Power Supply Bypassing and Printed Circuit
Board Layout
As with any high frequency device, good printed circuit
board layout is necessary for optimum performance.
Low impedance ground plane construction is essential.
Surface mount components are recommended, but if
leaded components are used, lead lengths should be as
short as possible. The power supply pins must be well
bypassed to reduce the risk of oscillation. The combination of a 4.7µF tantalum capacitor in parallel with a
0.01µF capacitor has been shown to work well when
placed at each supply pin.
For good AC performance, parasitic capacitance should
be kept to a minimum, especially at the inverting input.
(See the Capacitance at the Inverting Input section) Even
when ground plane construction is used, it should be
removed from the area near the inverting input to minimize any stray capacitance at that node. Carbon or
Metal-Film resistors are acceptable with the Metal-Film
The EL5492C has been optimized with a 375Ω feedback
resistor. With the high bandwidth of these amplifiers,
these resistor values might cause stability problems
when combined with parasitic capacitance, thus ground
plane is not recommended around the inverting input pin
of the amplifier.
13
EL5492C, EL5492AC
EL5492C, EL5492AC
EL5492C, EL5492AC
EL5492C, EL5492AC
Quad 600MHz Current Feedback Amplifier with Enable
Feedback Resistor Values
Video Performance
The EL5492C has been designed and specified at a gain
of +2 with RF approximately 375Ω. This value of feedback resistor gives 300MHz of -3dB bandwidth at AV=2
with 2dB of peaking. With AV=-2, an RF of 375Ω gives
275MHz of bandwidth with 1dB of peaking. Since the
EL5492C is a current-feedback amplifier, it is also possible to change the value of RF to get more bandwidth.
As seen in the curve of Frequency Response for Various
RF and RG, bandwidth and peaking can be easily modified by varying the value of the feedback resistor.
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 of the change in output current
with DC level. Previously, good differential gain could
only be achieved by running high idle currents through
the output transistors (to reduce variations in output
impedance.) These currents were typically comparable
to the entire 6mA supply current of each EL5492C
amplifier. Special circuitry has been incorporated in the
EL5492C to reduce the variation of output impedance
with current output. This results in dG and dP specifications of 0.015% and 0.04°, while driving 150Ω at a gain
of 2.
Because the EL5492C is a current-feedback amplifier,
its gain-bandwidth product is not a constant for different
closed-loop gains. This feature actually allows the
EL5492C to maintain about the same -3dB bandwidth.
As gain is increased, bandwidth decreases slightly while
stability increases. Since the loop stability is improving
with higher closed-loop gains, it becomes possible to
reduce the value of RF below the specified 375Ω and
still retain stability, resulting in only a slight loss of
bandwidth with increased closed-loop gain.
Video performance has also been measured with a 500Ω
load at a gain of +1. Under these conditions, the
EL5492C has dG and dP specifications of 0.03% and
0.05°, respectively.
Output Drive Capability
Supply Voltage Range and Single-Supply
Operation
In spite of its low 6mA of supply current, the EL5492C
is capable of providing a minimum of ±95mA of output
current. With a minimum of ±95mA of output drive, the
EL5492C is capable of driving 50Ω loads to both rails,
making it an excellent choice for driving isolation transformers in telecommunications applications.
The EL5492C has been designed to operate with supply
voltages having a span of greater than 5V and less than
10V. In practical terms, this means that the EL5492C
will operate on dual supplies ranging from ±2.5V to
±5V. With single-supply, the EL5492C will operate
from 5V to 10V.
Driving Cables and Capacitive Loads
When used as a cable driver, double termination is
always recommended for reflection-free performance.
For those applications, the back-termination series resistor will decouple the EL5492C from the cable and allow
extensive capacitive drive. However, other applications
may have high capacitive loads without a back-termination resistor. In these applications, a small series resistor
(usually between 5Ω and 50Ω) can be placed in series
with the output to eliminate most peaking. The gain
resistor (RG) can then be chosen to make up for any gain
loss which may be created by this additional resistor at
the output. In many cases it is also possible to simply
increase the value of the feedback resistor (RF) to reduce
the peaking.
As supply voltages continue to decrease, it becomes necessary to provide input and output voltage ranges that
can get as close as possible to the supply voltages. The
EL5492C has an input range which extends to within 2V
of either supply. So, for example, on ±5V supplies, the
EL5492C has an input range which spans ±3V. The output range of the EL5492C is also quite large, extending
to within 1V of the supply rail. On a ±5V supply, the
output is therefore capable of swinging from -----4V to
+4V. Single-supply output range is larger because of the
increased negative swing due to the external pull-down
resistor to ground.
14
Quad 600MHz Current Feedback Amplifier with Enable
where:
Current Limiting
TMAX = Maximum ambient temperature
The EL5492C has no internal current-limiting circuitry.
If the output is shorted, it is possible to exceed the Absolute Maximum Rating for output current or power
dissipation, potentially resulting in the destruction of the
device.
θJA = Thermal resistance of the package
n = Number of amplifiers in the package
PDMAX = Maximum power dissipation of each amplifier in the package
Power Dissipation
PDMAX for each amplifier can be calculated as follows:
With the high output drive capability of the EL5492C, it
is possible to exceed the 125°C Absolute Maximum
junction temperature under certain very high load current conditions. Generally speaking when RL falls below
about 25Ω, it is important to calculate the maximum
junction temperature (T JMAX) for the application to
determine if power supply voltages, load conditions, or
package type need to be modified for the EL5492C to
remain in the safe operating area. These parameters are
calculated as follows:
V O U TMA X
PDMA X = ( 2 × V S × I S MA X ) + ( V S - V OU TMA X ) × -------------------------RL
where:
VS = Supply voltage
ISMAX = Maximum supply current of 1A
VOUTMAX = Maximum output voltage (required)
RL = Load resistance
T JM A X = T M AX + ( θ JA × n × PD M AX )
15
EL5492C, EL5492AC
EL5492C, EL5492AC
EL5492C, EL5492AC
EL5492C, EL5492AC
Quad 600MHz Current Feedback Amplifier with Enable
Effective May 15, 2002, Elantec, a leader in high performance analog products, is now a part of Intersil Corporation.
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.
February 28, 2002
For information regarding Intersil Corporation and its products, see www.intersil.com
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