Intersil EL5191ACW-T7 1ghz current feedback amplifier with enable Datasheet

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EL5191, EL5191A
Data Sheet
August 3, 2005
1GHz Current Feedback Amplifier with
Enable
The EL5191 and EL5191A amplifiers are of the current
feedback variety and exhibit a very high bandwidth of 1GHz.
This makes these amplifiers ideal for today’s high speed
video and monitor applications, as well as a number of RF
and IF frequency designs.
FN7180.2
Features
• 1GHz -3dB bandwidth
• 9mA supply current
• Single and dual supply operation, from 5V to 10V supply
span
• Fast enable/disable (EL5191A only)
With a supply current of just 9mA and the ability to run from
a single supply voltage from 5V to 10V, these amplifiers offer
very high performance for little power consumption.
• Available in SOT-23 packages
The EL5191A 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.
• Lower power, 300MHz product available (EL5193,
EL5293, EL5393)
The EL5191 is offered in the 5-pin SOT-23 package and the
EL5191A is available in the 6-pin SOT-23 as well as the
industry-standard 8-pin SO packages. Both operate over the
industrial temperature range of -40°C to +85°C.
Applications
Ordering Information
• RGB amplifiers
• High speed, 600MHz product available (EL5192, EL5292,
and EL5392)
• Pb-Free plus anneal available (RoHS compliant)
• Video amplifiers
• Cable drivers
PACKAGE
TAPE &
REEL
PKG. DWG. #
EL5191CS
8-Pin SO
-
MDP0027
EL5191CSZ
(See Note)
8-Pin SO
(Pb-free)
-
MDP0027
• Current to voltage converters
EL5191CSZ-T7
(See Note)
8-Pin SO
(Pb-free)
7”
MDP0027
Pinouts
EL5191CSZ-T13
(See Note)
8-Pin SO
(Pb-free)
13”
MDP0027
EL5191CW-T7
5-Pin SOT-23
7”
MDP0038
EL5191CWZ-T7
(See Note)
5-Pin SOT-23
(Pb-free)
7”
MDP0038
EL5191ACW-T7
6-Pin SOT-23
7” (3K pcs)
MDP0038
EL5191ACW-T7A
6-Pin SOT-23
7” (250 pcs)
MDP0038
IN- 2
EL5191ACWZ-T7
(See Note)
6-Pin SOT-23
(Pb-free)
7” (3K pcs)
MDP0038
IN+ 3
EL5191ACWZ-T7A
(See Note)
6-Pin SOT-23
(Pb-free)
7” (250 pcs)
MDP0038
VS- 4
PART NUMBER
• Test equipment
• Instrumentation
EL5191A
(8-PIN SO)
TOP VIEW
NC 1
EL5191ACS
8-Pin SO
-
MDP0027
EL5191ACS-T7
8-Pin SO
7”
MDP0027
EL5191ACS-T13
8-Pin SO
13”
MDP0027
EL5191ACSZ
(See Note)
8-Pin SO
(Pb-free)
-
MDP0027
OUT 1
EL5191ACSZ-T7
(See Note)
8-Pin SO
(Pb-free)
7”
MDP0027
VS- 2
EL5191ACSZ-T13
(See Note)
8-Pin SO
(Pb-free)
13”
MDP0027
8 CE
7 VS+
+
6 OUT
5 NC
EL5191
(5-PIN SOT-23)
TOP VIEW
EL5191A
(6-PIN SOT-23)
TOP VIEW
6 VS+
OUT 1
5 CE
VS- 2
4 IN-
IN+ 3
+ -
5 VS+
+ IN+ 3
4 IN-
NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets;
molding compounds/die attach materials and 100% matte tin plate termination finish,
which are RoHS compliant and compatible with both SnPb and Pb-free soldering
operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow
temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2004, 2005. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
EL5191, EL5191A
Absolute Maximum Ratings (TA = 25°C)
Supply Voltage between VS+ and VS-. . . . . . . . . . . . . . . . . . . . .11V
Maximum Continuous Output Current . . . . . . . . . . . . . . . . . . . 50mA
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . 125°C
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Curves
Pin Voltages. . . . . . . . . . . . . . . . . . . . . . . . . VS- -0.5V to VS+ +0.5V
Storage Temperature. . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C
Ambient Operating Temperature . . . . . . . . . . . . . . . .-40°C to +85°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
Electrical Specifications
VS+ = +5V, VS- = -5V, RF = 392Ω for AV = 1, RF = 250Ω 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
1000
MHz
AV = +2
600
MHz
30
MHz
2800
V/µs
7
ns
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
eN
Input Voltage Noise
3.8
nV/√Hz
iN-
IN- Input Current Noise
25
pA/√Hz
iN+
IN+ Input Current Noise
55
pA/√Hz
dG
Differential Gain Error (Note 1)
AV = +2
0.035
%
dP
Differential Phase Error (Note 1)
AV = +2
0.04
°
2400
DC PERFORMANCE
VOS
Offset Voltage
TCVOS
Input Offset Voltage Temperature
Coefficient
ROL
Transimpedance
-15
Measured from TMIN to TMAX
1
15
mV
5
µV/°C
150
300
kΩ
INPUT CHARACTERISTICS
CMIR
Common Mode Input Range
±3
±3.3
V
CMRR
Common Mode Rejection Ratio
42
50
dB
-ICMR
- Input Current Common Mode Rejection
-6
+IIN
+ Input Current
-120
-IIN
- Input Current
-60
RIN
Input Resistance
27
kΩ
CIN
Input Capacitance
0.5
pF
6
µA/V
40
120
µA
5
60
µA
OUTPUT CHARACTERISTICS
VO
RL = 150Ω to GND
±3.4
±3.7
V
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
8
9
11
mA
ISOFF
Supply Current - Disabled
No load, VIN = 0V
100
150
µA
IOUT
Output Voltage Swing
SUPPLY
2
EL5191, EL5191A
Electrical Specifications
VS+ = +5V, VS- = -5V, RF = 392Ω for AV = 1, RF = 250Ω for AV = 2, RL = 150Ω, TA = 25°C unless otherwise
specified. (Continued)
PARAMETER
DESCRIPTION
CONDITIONS
MIN
TYP
75
PSRR
Power Supply Rejection Ratio
DC, VS = ±4.75V to ±5.25V
55
-IPSR
- Input Current Power Supply Rejection
DC, VS = ±4.75V to ±5.25V
-2
MAX
UNIT
dB
2
µA/V
ENABLE (EL5191A ONLY)
tEN
Enable Time
40
ns
tDIS
Disable Time
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
NOTE:
1. Standard NTSC test, AC signal amplitude = 286mVP-P, f = 3.58MHz
3
VS+ - 1
V
VS+ - 3
V
EL5191, EL5191A
Typical Performance Curves
Non-Inverting Frequency Response (Gain)
SOT-23 Package
Non-Inverting Frequency Response (Phase)
6
90
AV = 2
0
-2
-90
AV = 1
AV = 2
Phase (°)
Normalized Magnitude (dB)
AV = 1
2
AV = 5
-6
AV = 5
-180
AV =A10
V
AV = 10
-10
-270
RF = 390Ω
RL = 150Ω
-14
1M
10M
100M
RF = 390Ω
RL = 150Ω
-360
1M
1G
10M
Frequency (Hz)
Inverting Frequency Response (Gain)
SOT-23 Package
90
AV=-1
2
-2
AV=-2
-6
AV=-5
-10
0
Phase (°)
Normalized Magnitude (dB)
1G
Inverting Frequency Response (Phase)
6
AV = -1
-90
AV = -2
AV = -5
-180
-270
RF = 250Ω
RL = 150Ω
-14
1M
10M
100M
-360
1M
1G
RF = 250Ω
RL = 150Ω
10M
Frequency (Hz)
Frequency Response for Various CIN-
Frequency Response for Various RL
Normalized Magnitude (dB)
2pF added
1pF added
2
-2
-10
1M
1G
6
6
-6
100M
Frequency (Hz)
10
Normalized Magnitude (dB)
100M
Frequency (Hz)
0pF added
AV = 2
RF = 250Ω
RL = 150Ω
10M
100M
Frequency (Hz)
4
1G
RL = 100Ω
2
RL = 150Ω
RL = 500Ω
-2
-6
-10
-14
1M
AV = 2
RF = 250Ω
10M
100M
Frequency (Hz)
1G
EL5191, EL5191A
Typical Performance Curves
(Continued)
Frequency Response for Various CL
Frequency Response for Various RF
14
6
Normalized Magnitude (dB)
Normalized Magnitude (dB)
150Ω
10
6pF added
6
4pF added
2
-2
-6
1M
AV = 2
RF = 250Ω
RL=150Ω
0pF added
10M
100M
2
250Ω
-2
375Ω
-6
500Ω
-10
-14
1M
1G
AV = 2
RG = RF
RL = 150Ω
10M
Frequency (Hz)
Group Delay vs Frequency
1G
Frequency Response for Various Common-Mode
Input Voltages
3.5
6
VCM = 3V
Normalized Magnitude (dB)
3
Group Delay (ns)
100M
Frequency (Hz)
2.5
AV = 2
RF = 250Ω
2
AV = 1
RF = 390Ω
1.5
1
0.5
0
1M
10M
100M
-2
VCM = -3V
-6
-10
-14
1M
1G
VCM = 0V
2
AV = 2
RF = 250Ω
RL = 150Ω
10M
Frequency (Hz)
100M
1G
Frequency (Hz)
Transimpedance (ROL) vs Frequency
PSRR and CMRR vs Frequency
10M
20
0
Phase
100k
-180
10k
-270
Gain
1k
PSRR/CMRR (dB)
0
-90
Phase (°)
Magnitude (Ω)
1M
PSRR+
-20
PSRR-40
-60
CMRR
-360
100
1k
10k
100k
1M
10M
Frequency (Hz)
5
100M
1G
-80
10k
100k
1M
10M
Frequency (Hz)
100M
1G
EL5191, EL5191A
Typical Performance Curves
(Continued)
-3dB Bandwidth vs Supply Voltage for NonInverting Gains
-3dB Bandwidth vs Supply Voltage for Inverting
Gains
1200
600
RF = 390Ω
RL = 150Ω
AV = -2
500
-3dB Bandwidth (MHz)
-3dB Bandwidth (MHz)
1000
AV = 1
800
600
AV = 2
400
AV = 10
AV = 5
200
AV = -1
400
300
AV = -5
200
100
0
RF = 250Ω
RL = 150Ω
0
5
7
6
8
9
5
10
6
Total Supply Voltage (V)
Peaking vs Supply Voltage for Non-Inverting Gains
4
RF = 390Ω
RL=150Ω
3.5
AV = 1
3
Peaking (dB)
3
Peaking (dB)
10
9
Peaking vs Supply Voltage for Inverting Gains
4
2.5
2
1.5
1
AV = 2
0.5
AV = -1
2
AV = -2
1
AV = -5
RF = 250Ω
RL = 150Ω
AV = 10
0
0
5
6
7
8
9
5
10
6
Total Supply Voltage (V)
8
9
10
Non-Inverting Frequency Response (Phase)
SO8 Package
Non-Inverting Frequency Response (Gain)
SO8 Package
90
AV = 1
2
AV = 5
100M
Frequency (Hz)
6
AV = 5
-180
-270
RF = 392Ω
RL = 150Ω
10M
-90
AV = 10
AV = 10
-10
AV = 2
0
Phase (°)
-6
AV = 1
AV = 2
-2
-14
1M
7
Total Supply Voltage (V)
6
Normalized Magnitude (dB)
8
7
Total Supply Voltage (V)
1G 1.6G
-360
1M
RRFF== 392Ω
392Ω
RL = 150Ω
10M
100M
Frequency (Hz)
1G
EL5191, EL5191A
Typical Performance Curves
(Continued)
Inverting Frequency Response (Gain)
SO8 Package
Inverting Frequency Response (Phase)
SO8 Package
6
90
AV = -2
AV = -1
-2
AV = -5
-6
-10
-90
AV = -5
-180
-270
-14
1M
RF = 250Ω
RL = 150Ω
10M
100M
-360
1M
1G
RF = 250Ω
RL = 150Ω
10M
Frequency (Hz)
100M
1G
Frequency (Hz)
-3dB Bandwidth vs Temperature for Non-Inverting
Gains
-3dB Bandwidth vs Temperature for Inverting
Gains
2000
700
RF = 250Ω
RL = 150Ω
600
-3dB Bandwidth (MHz)
-3dB Bandwidth (MHz)
AV = -2
0
Phase (°)
Normalized Magnitude (dB)
AV = -1
2
1500
AV=1
1000
AV=2
AV=5
500
AV=10
AV = -1
500
400
AV = -2
300
AV = -5
200
100
0
-40
10
60
110
0
-40
160
RF=250Ω
RL=150Ω
10
Ambient Temperature (°C)
60
110
160
Ambient Temperature (°C)
Peaking vs Temperature
Voltage and Current Noise vs Frequency
3
1k
RL = 150Ω
Voltage Noise (nV/√Hz)
Current Noise (pA/√Hz)
Peaking (dB)
2.5
AV = 1
2
1.5
AV = -1
1
0.5
iN+
100
i N-
10
eN
AV = -2
0
-40
10
60
110
Ambient Temperature (°C)
7
160
1
100
1k
10k
100k
Frequency (Hz)
1M
10M
EL5191, EL5191A
Typical Performance Curves
(Continued)
Supply Current vs Supply Voltage
10
10
8
Supply Current (mA)
Output Impedance (Ω)
Closed Loop Output Impedance vs Frequency
100
1
0.1
0.01
0.001
100
6
4
2
0
1k
100k
10M
1M
Frequency (Hz)
10k
100M
1G
0
10
12
30
-30
Input Power Intercept (dBm)
AV = +2
VOUT = 2VP-P
RL = 100Ω
-20
Harmonic Distortion (dBc)
4
6
8
Supply Voltage (V)
Two-Tone 3rd Order
Input Referred Intermodulation Intercept (IIP3)
2nd and 3rd Harmonic Distortion vs Frequency
-10
-40
2nd Order
Distortion
-50
-60
-70
3rd Order
Distortion
-80
-90
-100
1
10
Frequency (MHz)
100
25
20
15
10
5
0
-5
-10
-15
10
200
Differential Gain/Phase vs DC Input
Voltage at 3.58MHz
100
200
Differential Gain/Phase vs DC Input
Voltage at 3.58MHz
0.03
AV = 2
RF = RG = 250Ω
RL = 150Ω
dP
0.02
dG (%) or dP (°)
0.01
AV = +2
RL = 100Ω
Frequency (MHz)
0.03
dG (%) or dP (°)
2
dG
-0.01
-0.03
AV = 1
RF = 375Ω
RL = 500Ω
dP
0.01
0
dG
-0.01
-0.02
-0.03
-0.05
-1
-0.5
0
DC Input Voltage
8
0.5
1
-0.04
-1
-0.5
0
DC Input Voltage
0.5
1
EL5191, EL5191A
Typical Performance Curves
(Continued)
Output Voltage Swing vs Frequency
THD < 1%
Output Voltage Swing vs Frequency
THD < 0.1%
10
RL = 500Ω
RL = 500Ω
Output Voltage Swing (VPP)
Output Voltage Swing (VPP)
10
8
RL = 150Ω
6
4
2
8
RL = 150Ω
6
4
2
AV = 2
0
1
AV = 2
0
10
Frequency (MHz)
100
200
1
Small Signal Step Response
10
Frequency (MHz)
Large Signal Step Response
VS = ±5V
RL = 150Ω
AV = 2
RF = RG = 250Ω
VS = ±5V
RL = 150Ω
AV = 2
RF = RG = 250Ω
200mV/div
1V/div
10ns/div
10ns/div
Transimpedance (ROI) Vs Temperature
Settling Time vs Settling Accuracy
375
25
AV = 2
RF = RG = 250Ω
RL= 150Ω
VSTEP = 5VP-P output
20
350
325
15
RoI (kΩ)
Settling Time (ns)
100
10
300
275
250
5
225
0
0.01
0.1
Settling Accuracy (%)
9
1
200
-40
10
60
Die Temperature (°C)
110
160
EL5191, EL5191A
Typical Performance Curves
(Continued)
PSRR and CMRR vs Temperature
ICMR and IPSR vs Temperature
90
2.5
ICMR/IPSR (µA/V)
PSRR/CMRR (dB)
ICMR+
2
PSRR
70
50
CMRR
30
1.5
IPSR
1
0.5
ICMR-
0
-0.5
10
-40
10
60
110
-1
-40
160
10
Die Temperature (°C)
60
110
160
110
160
110
160
Die Temperature (°C)
Offset Voltage vs Temperature
Input Current vs Temperature
2
140
Input Current (µA)
120
VOS (mV)
1
0
100
80
60
IB+
40
20
IB0
-1
-40
10
60
110
-20
-40
160
10
Die Temperature (°C)
60
Temperature (°C)
Positive Input Resistance vs Temperature
Supply Current vs Temperature
35
10
Supply Current (mA)
30
RIN (kΩ)
25
20
15
10
9
5
0
-40
10
60
Temperature (°C)
10
110
160
8
-40
10
60
Temperature (°C)
EL5191, EL5191A
Typical Performance Curves
(Continued)
Negative Output Swing vs Temperature for Various
Loads
Positive Output Swing vs Temperature for Various
Loads
4.2
-3.5
4.1
-3.6
150Ω
1kΩ
-3.7
VOUT (V)
VOUT (V)
4
3.9
3.8
3.7
-3.8
-3.9
1kΩ
-4
150Ω
-4.1
3.6
3.5
-40
10
60
110
-4.2
-40
160
10
Output Current vs Temperature
110
160
Slew Rate vs Temperature
140
5000
AV = 2
RF = RG = 250Ω
RL = 150Ω
Sink
135
4500
Slew Rate (V/µS)
IOUT (mA)
60
Temperature (°C)
Temperature (°C)
130
125
Source
120
115
-40
10
60
110
160
4000
3500
3000
-40
Die Temperature (°C)
10
60
Die Temperature (°C)
Enable Response
Disable Response
500mV/div
500mV/div
5V/div
5V/div
20ns/div
Typical Performance Curves
11
(Continued)
400ns/div
110
160
EL5191, EL5191A
JEDEC JESD51-7 HIGH EFFECTIVE
THERMAL CONDUCTIVITY TEST BOARD
0.5
1.2
POWER DISSIPATION (W)
POWER DISSIPATION (W)
1.4
1 909mW
SO8
0.8
θJA=110°C/W
0.6
0.4
0.2
0
0
25
50
75 85 100
125
0.45
0.4 435mW
0.35
SOT23-5/6
0.3
θJA=230°C/W
0.25
0.2
0.15
0.1
0.05
0
150
JEDEC JESD51-7 HIGH EFFECTIVE
THERMAL CONDUCTIVITY TEST BOARD
0
25
AMBIENT TEMPERATURE (°C)
JEDEC JESD51-3 LOW EFFECTIVE
THERMAL CONDUCTIVITY TEST BOARD
0.45
0.9
POWER DISSIPATION (W)
POWER DISSIPATION (W)
1
0.8
0.7 625mW
0.6
SO8
θJA=160°C/W
0.5
0.4
0.3
0.2
0.1
0
0
25
50
75 85 100
125
AMBIENT TEMPERATURE (°C)
12
50
75 85 100
125
150
AMBIENT TEMPERATURE (°C)
150
JEDEC JESD51-3 LOW EFFECTIVE
THERMAL CONDUCTIVITY TEST BOARD
391mW
0.4
0.35
θ
0.3
JA
0.25
0.2
SO
=2
T2
3
56 -5-6
°C
/W
0.15
0.1
0.05
0
0
25
50
75 85 100
125
AMBIENT TEMPERATURE (°C)
150
EL5191, EL5191A
Pin Descriptions
8-PIN SO
5-PIN SOT-23 6-PIN SOT-23 PIN NAME
1, 5
2
4
4
FUNCTION
NC
Not connected
IN-
Inverting input
EQUIVALENT CIRCUIT
VS+
IN+
IN-
VS-
Circuit 1
3
3
3
IN+
Non-inverting input
4
2
2
VS-
Negative supply
6
1
1
OUT
Output
(See circuit 1)
VS+
OUT
VS-
Circuit 2
7
5
8
6
VS+
Positive supply
5
CE
Chip enable
VS+
CE
VS-
Circuit 3
13
EL5191, EL5191A
Applications Information
Product Description
The EL5191 is a current-feedback operational amplifier that
offers a wide -3dB bandwidth of 1GHz and a low supply
current of 9mA per amplifier. The EL5191 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 current-feedback topology, the
EL5191 does not have the normal gain-bandwidth product
associated with voltage-feedback 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 EL5191 the ideal choice for many low-power/highbandwidth applications such as portable, handheld, or
battery-powered equipment.
For varying bandwidth needs, consider the EL5192 with
600MHz on a 6mA supply current or the EL5193 with
300MHz on a 4mA supply current. Versions include single,
dual, and triple amp packages with 5-pin SOT-23, 16-pin
QSOP, and 8-pin or 16-pin SO outlines.
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 resistors giving slightly less
peaking and bandwidth because of additional series
inductance. Use of sockets, particularly for the SO package,
should be avoided if possible. Sockets add parasitic
inductance and capacitance which will result in additional
peaking and overshoot.
Disable/Power-Down
The EL5191A amplifier can be disabled placing its output in
a high impedance state. When disabled, the amplifier supply
current is reduced to < 150µA. The EL5191A 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 EL5191A amplifier will be
14
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 EL5191A to be
enabled by tying CE to ground, even in 5V single supply
applications. The CE pin can be driven from CMOS outputs.
Capacitance at the Inverting Input
Any manufacturer’s high-speed voltage- or current-feedback
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 open-loop response. The use of large
value feedback and gain resistors exacerbates the problem
by further lowering the pole frequency (increasing the
possibility of oscillation.)
The EL5191 has been optimized with a 250Ω 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.
Feedback Resistor Values
The EL5191 has been designed and specified at a gain of +2
with RF approximately 250Ω. This value of feedback resistor
gives 600MHz of -3dB bandwidth at AV = 2 with about 2dB of
peaking. With AV = -2, that same RF gives 450MHz of
bandwidth with 0.6dB of peaking. Since the EL5191 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.
Because the EL5191 is a current-feedback amplifier, its
gain-bandwidth product is not a constant for different closedloop gains. This feature actually allows the EL5191 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 250Ω and still retain stability,
resulting in only a slight loss of bandwidth with increased
closed-loop gain.
Supply Voltage Range and Single-Supply
Operation
The EL5191 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 EL5191 will
operate on dual supplies ranging from ±2.5V to ±5V. With
single-supply, the EL5191 will operate from 5V to 10V.
EL5191, EL5191A
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
EL5191 has an input range which extends to within 2V of
either supply. So, for example, on ±5V supplies, the EL5191
has an input range which spans ±3V. The output range of
the EL5191 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.
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 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 9mA
supply current of each EL5191 amplifier. Special circuitry
has been incorporated in the EL5191 to reduce the variation
of output impedance with current output. This results in dG
and dP specifications of 0.035% and 0.04°, while driving
150Ω at a gain of 2.
Video performance has also been measured with a 500Ω
load at a gain of +1. Under these conditions, the EL5191 has
dG and dP specifications of 0.02% and 0.02°, respectively.
Current Limiting
The EL5191 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.
Power Dissipation
With the high output drive capability of the EL5191, 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
(TJMAX) for the application to determine if power supply
voltages, load conditions, or package type need to be
modified for the EL5191 to remain in the safe operating area.
These parameters are calculated as follows:
T JMAX = T MAX + ( θ JA × n × PD MAX )
where:
TMAX = Maximum ambient temperature
θJA = Thermal resistance of the package
n = Number of amplifiers in the package
PDMAX = Maximum power dissipation of each amplifier in
the package
PDMAX for each amplifier can be calculated as follows:
V OUTMAX
PD MAX = ( 2 × V S × I SMAX ) + ( V S - V OUTMAX ) × ---------------------------R
L
Output Drive Capability
In spite of its low 9mA of supply current, the EL5191 is
capable of providing a minimum of ±95mA of output current.
With a minimum of ±95mA of output drive, the EL5191 is
capable of driving 50Ω loads to both rails, making it an
excellent choice for driving isolation transformers in
telecommunications applications.
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 EL5191 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.
15
where:
VS = Supply voltage
ISMAX = Maximum supply current of 1A
VOUTMAX = Maximum output voltage (required)
RL = Load resistance
EL5191, EL5191A
Typical Application Circuits
0.1µF
+5V
IN+
VS+
OUT
INVS0.1µF
-5V
250Ω
5Ω
0.1µF
VOUT
+5V
IN+
VS+
OUT
5Ω
INVS0.1µF
-5V
250Ω
250Ω
VIN
INVERTING 200mA OUTPUT CURRENT DISTRIBUTION AMPLIFIER
250Ω
250Ω
0.1µF
+5V
IN+
VS+
OUT
INVS0.1µF
250Ω
-5V
250Ω
+5V
0.1µF
VIN
IN+
VS+
OUT
IN-
VOUT
VS0.1µF
-5V
FAST-SETTLING PRECISION AMPLIFIER
16
EL5191, EL5191A
Typical Application Circuits
(Continued)
0.1µF
0.1µF
+5V
IN+
+5V
IN+
VS+
VS+
OUT
OUT
IN-
INVS-
VS0.1µF
0.1µF
-5V
-5V
250Ω
0.1µF
120Ω
250Ω
250Ω
VOUT+
0.1µF
1kΩ
+5V
240Ω
0.1µF
+5V
IN+
VS+
OUT
IN-
0.1µF
120Ω
IN+
VOUT-
OUT
1kΩ
VS-
VS+
IN-
0.1µF
-5V
250Ω
VOUT
VS0.1µF
-5V
250Ω
VIN
250Ω
Transmitter
250Ω
Receiver
DIFFERENTIAL LINE DRIVER/RECEIVER
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.
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17
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