intersil EL5156, EL5157, EL5256, EL5257 DATA SHEET

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®
EL5156, EL5157, EL5256, EL5257
Data Sheet July 2, 2004
<1mV Voltage Offset, 600MHz Amplifiers
The EL5156, EL5157, EL5256, and EL5257 are 600MHz bandwidth -3dB
voltage mode feedback amplifiers with DC accuracy of <0.01%, 1mV offsets and 40kV/V open loop gains. These amplifiers are ideally suited for applications ranging from precision measurement instrumentation to high speed video and monitor applications demanding the very highest linearity at very high frequency. Capable of operating with as little as 6.0mA of current from a single supply ranging from 5V to 12V and dual supplies ranging from ±2.5V to ±5.0V these amplifiers are also well suited for handheld, portable and battery-powered equipment. With their capability to output as much as 140mA, member of this family is comfortable with demanding load conditions.
Single amplifiers are available in SOT-23 packages and duals in a 10-pin MSOP package for applications where board space is critical. Additionally, singles and duals are available in the industry-standard 8-pin SO package. All parts operate over the industrial temperature range of -40°C to +85°C.
Ordering Information
FN7386.2
Features
• 600MHz -3dB bandwidth, 240MHz 0.1dB bandwidth
• 700V/µs slew rate
• <1mV input offset
• Very high open loop gains 92dB
• Low supply current = 6mA
• 140mA output current
• Single supplies from 5V to 12V
• Dual supplies from ±2.5V to ±5V
• Fast disable on the EL5156 and EL5256
•Low cost
Applications
•Imaging
• Instrumentation
•Video
• Communications devices
PAR T
NUMBER PACKAGE TAPE & REEL PKG. DWG. #
EL5156IS 8-Pin SO - MDP0027
EL5156IS-T7 8-Pin SO 7” MDP0027
EL5156IS-T13 8-Pin SO 13” MDP0027
EL5157IW-T7 5-Pin SOT-23 7” (3K pcs) MDP0038
EL5157IW-T7A 5-Pin SOT-23 7” (250 pcs) MDP0038
EL5256IY 10-Pin MSOP - MDP0043
EL5256IY-T7 10-Pin MSOP 7” MDP0043
EL5256IY-T13 10-Pin MSOP 13” MDP0043
EL5257IS 8-Pin SO - MDP0027
EL5257IS-T7 8-Pin SO 7” MDP0027
EL5257IS-T13 8-Pin SO 13” MDP0027
EL5257IY 8-Pin MSOP - MDP0043
EL5257IY-T7 8-Pin MSOP 7” MDP0043
EL5257IY-T13 8-Pin MSOP 13” MDP0043
1
Copyright © Intersil Americas Inc. 2004. All Rights Reserved. Elantec is a registered trademark of Elantec Semiconductor, Inc.
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.
All other trademarks mentioned are the property of their respective owners.
Pinouts
EL5156
(8-PIN SO)
TOP VIEW
EL5156, EL5157, EL5256, EL5257
EL5157
(5-PIN SOT-23)
TOP VIEW
1
NC
IN-
2
IN+
3
VS-
4
(10-PIN MSOP)
TOP VIEW
INA+
1
CEA
2
VS-
3
4
CEB
INB+
5 6
-
+
EL5256
-
+
+
-
10
8
7
6
5
9
8
7
CE
VS+
OUT
NC
INA-
OUTA
VS+
OUTB
INB-
OUT
VS-
IN+
OUTA
INA-
INA+
VS-
1
2
3
(8-PIN SO)
TOP VIEW
1
2
3
4
-+
EL5257
­+
5
VS+
IN-
4
8
VS+
OUTB
7
INB-
6
­INB+
+
5
2
EL5156, EL5157, EL5256, EL5257
Absolute Maximum Ratings (T
Supply Voltage between V
Maximum Continuous Output Current . . . . . . . . . . . . . . . . . . . 50mA
Pin Voltages. . . . . . . . . . . . . . . . . . . . . . . . . GND -0.5V to V
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Curves
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 = T
and GND. . . . . . . . . . . . . . . . . . . 13.2V
S
Electrical Specifications V
= 25°C)
A
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +125°C
Storage Temperature. . . . . . . . . . . . . . . . . . . . . . . . -65°C to +150°C
+0.5V
S
A
+ = +5V, VS- = -5V, CE = +5V, RF = RG = 562Ω, RL = 150Ω, TA = 25°C, unless otherwise specified.
S
Ambient Operating Temperature . . . . . . . . . . . . . . . .-40°C to +85°C
Current into I
+, IN-, CE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5mA
N
PARAMETER DESCRIPTION CONDITIONS MIN TYP MAX UNIT
AC PERFORMANCE
BW -3dB Bandwidth A
= +1, RL = 500Ω, CL = 4.7pF 600 MHz
V
AV = +2, RL = 150 180 MHz
GBWP Gain Bandwidth Product R
BW1 0.1dB Bandwidth A
= 150 210 MHz
L
= +2 70 MHz
V
SR Slew Rate VO = -3.2V to +3.2V, AV = +2, RL = 150 500 640 V/µs
V
= -3.2V to +3.2V, AV = +1, RL = 500 700 V/µs
O
t
S
dG Differential Gain Error A
0.1% Settling Time AV = +1 15 ns
= +2, RL = 150 0.005 %
V
dP Differential Phase Error AV = +2, RL = 150 0.04 °
V
N
I
N
Input Referred Voltage Noise 12 nV/Hz
Input Referred Current Noise 5.5 pA/√Hz
DC PERFORMANCE
V
OS
T
CVOS
A
VOL
Offset Voltage -1 0.5 1 mV
Input Offset Voltage Temperature Coefficient
Measured from T
MIN
to T
MAX
-3 µV/°C
Open Loop Gain VO is from -2.5V to 2.5V 10 40 kV/V
INPUT CHARACTERISTICS
CMIR Common Mode Input Range Guaranteed by CMRR test -2.5 +2.5 V
CMRR Common Mode Rejection Ratio V
I
B
Input Bias Current EL5156 & EL5157 -1 -0.4 +1 µA
= 2.5V to -2.5V 80 108 dB
CM
EL5256 & EL5257 -600 -200 +600 nA
I
R
C
OS
IN
IN
Input Offset Current -250 100 +250 nA
Input Resistance 10 25 M
Input Capacitance 1pF
OUTPUT CHARACTERISTICS
V
I
OUT
OUT
Output Voltage Swing RL = 150 to GND ±3.4 ±3.6 V
= 500 to GND ±3.6 ±3.8 V
R
L
Peak Output Current RL = 10 to GND ±80 ±140 mA
ENABLE (EL5156 and EL5256 ONLY)
t
t
EN
DIS
Enable Time 200 ns
Disable Time 300 ns
3
EL5156, EL5157, EL5256, EL5257
Electrical Specifications V
+ = +5V, VS- = -5V, CE = +5V, RF = RG = 562Ω, RL = 150Ω, TA = 25°C, unless otherwise specified.
S
PARAMETER DESCRIPTION CONDITIONS MIN TYP MAX UNIT
I
IHCE
I
ILCE
V
IHCE
V
ILCE
CE Pin Input High Current CE = VS+0-1µA
CE Pin Input Low Current CE = VS- 5 13 25 µA
CE Input High Voltage for Power-down VS+ -1 V
CE Input Low Voltage for Power-up VS+ -3 V
SUPPLY
I
SON
I
SOFF
PSRR Power Supply Rejection Ratio DC, V
Supply Current - Enabled (per amplifier) No load, V
Supply Current - Disabled (per amplifier) No load, V
= ±3.0V to ±6.0V 75 90 dB
S
= 0V, CE = +5V 5.1 6.0 6.9 mA
IN
= 0V, CE = 5V 5 13 25 µA
IN
Typical Performance Curves
4
RL=150
3
=4.7pF
C
L
2
1
0
-1
-2
-3
-4
NORMALIZED GAIN (dB)
-5
-6 100K 1M 100M 1G
AV=+10
AV=+5
10M
FREQUENCY (Hz)
AV=+2
AV=+1
135
RL=150
90
=4.7pF
C
L
45
0
-45
-90
-135
PHASE (°)
-180
-225
-270
-315 100K 1M 100M 1G
AV=+5
AV=+10
10M
FREQUENCY (Hz)
AV=+2
FIGURE 1. SMALL SIGNAL FREQUENCY RESPONSE - GAIN FIGURE 2. SMALL SIGNAL FREQUENCY RESPONSE -
PHASE FOR VARIOUS GAINS
4
VS=±5V
3
A
=+2
V
=562
R
2
F=RG
1
0
-1
-2
-3
-4
NORMALIZED GAIN (dB)
-5
-6 100K 1M 100M 1G
RL=500
RL=150
RL=750
RL=50
10M
FREQUENCY (Hz)
FIGURE 3. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS R
L
FIGURE 4. SMALL SIGNAL FREQUENCY RESPONSE FOR
5
AV=+1
4
=500
R
L
3
2
1
0
-1
GAIN (dB)
-2
-3
-4
-5 100K 1M 100M 1G
FREQUENCY (Hz)
VARIOUS C
L
CL=27pF
CL=10pF
CL=4.7pF
CL=1pF
10M
4
EL5156, EL5157, EL5256, EL5257
Typical Performance Curves (Continued)
5
AV=+2
4
R
=500
L
=500
R
3
F=RG
2
1
0
-1
-2
-3
NORMALIZED GAIN (dB)
-4
-5 100K 1M 100M 1G
10M
FREQUENCY (Hz)
22pF
10pF
8.2pF
4.7pF
0pF
FIGURE 5. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS C
5
AV=+5
4
=500
R
L
3
2
1
0
-1
-2
-3
NORMALIZED GAIN (dB)
-4
-5 100K 1M 100M 1G
L
100pF
82pF
68pF
22pF
10M
FREQUENCY (Hz)
16
AV=+2
14
12
10
8
6
4
GAIN (dB)
2
0
-2
-4 100K 1M 100M 1G
R R
F=RG
=150
L
=562
180pF
100pF
33pF
10pF
0pF
10M
FREQUENCY (Hz)
FIGURE 6. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS C
5
RL=500
4
=4.7pF
C
L
3
A
=+1
V
2
1
0
-1
-2
NORMALIZED GAIN (dB)
-3
-4
100K 1M 10M 500M
L
±2.0V
±3.0V
±4.0V
±5.0V
100M
FREQUENCY (Hz)
FIGURE 7. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS C
5
4
3
2
1
0
-1
-2 AV=+1
-3
NORMALIZED GAIN (dB)
=500
R
L
=4.7pF
C
-4
L
-5
100K 1M 100M 1G
L
AV=+1
AV=+2
AV=+5
10M
FREQUENCY (Hz)
FIGURE 9. EL5256 SMALL SIGNAL FREQUENCY
RESPONSE FOR VARIOUS GAINS
5
FIGURE 8. FREQUENCY RESPONSE vs POWER SUPPLY
4
VS=±5V
3
R
=620
F
=150
R
2
L
1
0
-1
-2
-3
-4
NORMALIZED GAIN (dB)
-5
-6 100K 1M 100M 1G
FREQUENCY (Hz)
AV=-1
AV=-2
10M
FIGURE 10. SMALL SIGNAL INVERTING FREQUENCY
RESPONSE FOR VARIOUS GAINS
EL5156, EL5157, EL5256, EL5257
Typical Performance Curves (Continued)
4
AV=+1
3
=0.2pF
C
L
2
1
0
-1
-2
-3
-4
NORMALIZED GAIN (dB)
-5
-6 100K 1M 100M 1G
FREQUENCY (Hz)
RL=500
RL=300
RL=150
10M
FIGURE 11. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS R
5
AV=+2
4
=500
R
L
3
=4.7pF
C
L
R
=500
F
2
1
0
-1
-2
-3
NORMALIZED GAIN (dB)
-4
-5 100K 1M 100M 200M
L
12pF
8.2pF
4.7pF
0.2pF
0pF
10M
FREQUENCY (Hz)
5
AV=+1
4
=4.7pF
C
L
3
2
1
0
-1
-2
-3
NORMALIZED GAIN (dB)
-4
-5 100K 1M 100M 1G
10M
FREQUENCY (Hz)
500
200
100
50
FIGURE 12. EL5256 SMALL SIGNAL FREQUENCY
RESPONSE FOR VARIOUS R
4
AV=+5
3
C
=4.7pF
L
=500
R
L
2
=102
R
F
1
0
-1
-2
-3
NORMALIZED GAIN (dB)
-4
-5
100K 1M 100M 200M
68pF
47pF
22pF
4.7pF 0pF
FREQUENCY (Hz)
L
10M
FIGURE 13. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS C
4
VS=±5V
3
=+2
A
V
2
=150
R
L
=4.7pF
C
L
1
0
-1
-2
-3
-4
NORMALIZED GAIN (dB)
-5
-6 100K 1M 100M 1G
IN
RF=RG=1k
350
562
500
250
10M
FREQUENCY (Hz)
FIGURE 15. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS R
AND R
F
G
6
FIGURE 14. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS C
6
AV=+2
5
=4.7pF
C
L
4
=500
R
L
3
2
1
0
-1
NORMALIZED GAIN
-2
-3
-4 100K 1M 100M 1G
IN
RF=RG=3k
2k
1k
500
200
10M
FREQUENCY (Hz)
FIGURE 16. EL5256 SMALL SIGNAL FREQUENCY
RESPONSE FOR VARIOUS R
F/RG
EL5156, EL5157, EL5256, EL5257
Typical Performance Curves (Continued)
5
AV=+2
4
=200
R
L
=4.7pF
3
C
L
2
1
0
-1
-2
NORMALIZED GAIN (dB)
-3
-4
-5 100K 1M 10M 600M
15dBm
17dBm
20dBm
FREQUENCY (Hz)
-20dBm
10dBm
100M
FIGURE 17. LARGE SIGNAL FREQUENCY RESPONSE FOR
VARIOUS INPUT AMPLITUDES
0
AV=+5
-10
=500
R
L
=4.7pF
C
-20
L
-30
-40
-50
-60
-70
CROSS TALK (10dB)
-80
-90
-100 100K 1M 100M 1G
10M
FREQUENCY (Hz)
FIGURE 19. EL5256 CROSS TALK vs FREQUENCY CHANNEL
A TO B & B TO A
5
4
3
2
1
0
-1
-2 AV=+1
-3
NORMALIZED GAIN (dB)
=500
R
L
=4.7pF
C
-4
L
-5
100K 1M 100M 1G
CHANNEL #1
CHANNEL #2
10M
FREQUENCY (Hz)
FIGURE 18. CHANNEL TO CHANNEL FREQUENCY
RESPONSE
700
600
500
400
300
BW (MHz)
200
100
0
4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5
AV=+1,RL=500, CL=5pF
AV=+1, RL=150
AV=+2,RL=150
V
(V)
S
FIGURE 20. BANDWIDTH vs SUPPLY VOLTAGE
4
AV=+5
3
=4.7pF
C
L
2
1
0
-1
-2
-3
-4
NORMALIZED GAIN (dB)
-5
-6 100K 1M 100M 1G
100
50
10M
FREQUENCY (Hz)
500
1000
FIGURE 21. SMALL SIGNAL FREQUENCY RESPONSE FOR
VARIOUS R
L
7
1K
100
V
10K
N
I
N
1M
VOLTAGE NOISE (nV/√Hz),
CURRENT NOISE (pA/√Hz)
10
1
100 100K 10M
10
1K
FREQUENCY (Hz)
FIGURE 22. VOLTAGE AND CURRENT NOISE vs FREQUENCY
EL5156, EL5157, EL5256, EL5257
Typical Performance Curves (Continued)
-20
-30
-40
-50
-60
-70
CMRR (dB)
-80
-90
-100
-110
100 1K 100K 100M
10K
FREQUENCY (Hz)
10M1M
1
0
0
0
AV=+2 R
=0
L
=400
R
0
1
0
G=RF
1
0
1
IMPEDANCE (Ω)
0
1
0
.
0
.
0
0
1
1K
10K 100K 100M
FREQUENCY (Hz)
1M
10M
FIGURE 23. CMRR
-10 VS=±5V
-20
=+2
A
V
R
=150
-30
L
-40
-50
-60
-70
-80
-90
DISABLED ISOLATION (dB)
-100
-110 100K 1M 100M 1G
10M
FREQUENCY (Hz)
FIGURE 25. INPUT TO OUTPUT ISOLATION vs FREQUENCY -
DISABLE
AV=+2
=500
R
L
SUPPLY=±5.0V ±12.3mA
ENABLE 192ns
TIME (400ns/DIV)
DISABLE 322ns
FIGURE 27. ENABLE/DISABLE RESPONSE
FIGURE 24. OUTPUT IMPEDANCE
6.1
6
5.9
5.8
(mA)
5.7
S
I
5.6
5.5
5.4
5.3
4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 1010.5 1111.5 12
IS-
IS+
V
(V)
S
FIGURE 26. SUPPLY CURRENT vs SUPPLY VOLTAGE
0.8
A
=+1
V
0.7 RL=500
0.6
=5pF
C
L
0.5
0.4
0.3
PEAKING (dB)
0.2
0.1
0
4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 V
(V)
S
FIGURE 28. PEAKING vs SUPPLY VOLTAGE
8
EL5156, EL5157, EL5256, EL5257
Typical Performance Curves (Continued)
AV=+2
=500
R
L
SUPPLY=±5.0V ±12.3mA OUTPUT=200mV
P-P
0
(40mV/DIV)
OUT
V
RISE 20%-80% T=2.025ns
TIME (4ns/DIV)
FIGURE 29. SMALL SIGNAL RISE TIME
AV=+2
=500
R
L
SUPPLY=±5.0V ±12.3mA OUTPUT=2.0V
0
(400mV/DIV)
OUT
V
P-P
RISE 20%-80% T=1.657ns
TIME (2ns/DIV)
0
(40mV/DIV)
OUT
AV=+2
V
=500
R
L
SUPPLY=±5.0V ±12.3mA OUTPUT=200mV
P-P
TIME (4ns/DIV)
FALL 80%-20% T=1.91ns
FIGURE 30. SMALL SIGNAL FALL TIME
AV=+2
=500
R
L
SUPPLY=±5.0V ±12.3mA OUTPUT=2.0V
0
(400mV/DIV)
OUT
V
TIME (2ns/DIV)
FALL 80%-20% T=1.7ns
P-P
FIGURE 31. LARGE SIGNAL RISE TIME
JEDEC JESD51-7 HIGH EFFECTIVE THERMAL CONDUCTIVITY TEST BOARD
1.8
1.6
1.4
1.136W
1.2
1
0.8
543mW
0.6
0.4
POWER DISSIPATION (W)
0.2
0
0
SOT23-5
=230°C/W
θ
JA
25 125 15075 10050 85
AMBIENT TEMPERATURE (°C)
=110°C/W
θ
JA
SO8
FIGURE 33. PACKAGE POWER DISSIPATION vs AMBIENT
TEMPERATURE
9
FIGURE 32. LARGE SIGNAL FALL TIME
JEDEC JESD51-3 LOW EFFECTIVE THERMAL CONDUCTIVITY TEST BOARD
1.2
1
781mW
POWER DISSIPATION (W)
0.8
0.6
0.4
0.2
0
0
488mW
SOT23-5
=256°C/W
θ
JA
25 125 15075
AMBIENT TEMPERATURE (°C)
=160°C/W
θ
JA
SO8
10050 85
FIGURE 34. PACKAGE POWER DISSIPATION vs AMBIENT
TEMPERATURE
EL5156, EL5157, EL5256, EL5257
Typical Performance Curves (Continued)
JEDEC JESD51-7 HIGH EFFECTIVE THERMAL CONDUCTIVITY TEST BOARD
1
0.9
870mW
0.8
0.7
0.6
0.5
0.4
0.3
0.2
POWER DISSIPATION (W)
0.1
0
0 25 50 75 100 125
AMBIENT TEMPERATURE (°C)
MSOP8/10
θJA=115°C/W
85
FIGURE 35. PACKAGE POWER DISSIPATION vs AMBIENT
TEMPERATURE
JEDEC JESD51-3 LOW EFFECTIVE THERMAL CONDUCTIVITY TEST BOARD
0.6
0.5 486mW
0.4
0.3
0.2
0.1
POWER DISSIPATION (W)
0
0 255075100125
AMBIENT TEMPERATURE (°C)
MSOP8/10
θJA=206°C/W
85
FIGURE 36. PACKAGE POWER DISSIPATION vs AMBIENT
TEMPERATURE
10
EL5156, EL5157, EL5256, EL5257
Product Description
The EL5156, EL5157, EL5256, and EL5257 are wide bandwidth, single or dual supply, low power and low offset voltage feedback operational amplifiers. Both amplifiers are internally compensated for closed loop gain of +1 or greater. Connected in voltage follower mode and driving a 500 load, the -3dB bandwidth is about 610MHz. Driving a 150 load and a gain of 2, the bandwidth is about 180MHz while maintaining a 600V/µs slew rate. The EL5156 and EL5256 are available with a power down pin to reduce power to 17µA typically while the amplifier is disabled.
Input, Output and Supply Voltage Range
The EL5156 and EL5157 families have been designed to operate with supply voltage from 5V to 12V. That means for single supply application, the supply voltage is from 5V to 12V. For split supplies application, the supply voltage is from ±2.5V to ±5V. The amplifiers have an input common mode voltage range from 1.5V above the negative supply (V to 1.5V below the positive supply (V signal is outside the above specified range, it will cause the output signal distorted.
The outputs of the EL5156 and EL5157 families can swing from -4V to 4V for V lower, the output swing is lower. If the load resistor is 500Ω, the output swing is about -4V at a 4V supply. If the load resistor is 150, the output swing is from -3.5V to 3.5V.
= ±5V. As the load resistance becomes
S
+ pin). If the input
S
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 and peaking in the frequency domain. Therefore, RF can't be very big for optimum performance. If a large value of RF must be used, a small capacitor in the few Pico farad range in parallel with RF can help to reduce the ringing and peaking at the expense of reducing the bandwidth.
For gain of +1, RF = 0 is optimum. For the gains other than +1, optimum response is obtained with RF between 500 to 750.
The EL5156 and EL5157 families have a gain bandwidth product of 210MHz. For gains > = 5, its bandwidth can be predicted by the following equation: (Gain)X(BW) = 210MHz.
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 150, because of the change in output current with DC level. The dG and dP for these families are about 0.006%
- pin)
S
and 0.04%, while driving 150 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 EL5156 and EL5157 families can drive 27pF loads in parallel with 500 with less than 5dB of peaking at gain of +1. If less peaking is desired in applications, a small series resistor (usually between 5 to 50) can be placed in series with the 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.
Disable/Power-Down
The EL5156 and EL5256 can be disabled and their output placed in a high impedance state. The turn off time is about 330ns and the turn on time is about 130ns. When disabled, the amplifier's supply current is reduced to 17µA 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 V applying a signal that is less than 0.8V above V the amplifier. The amplifier will be disabled when the signal at ENABLE pin is above V
- pin. Letting the ENABLE pin float or
S
+ -1.5V.
S
- will enable
S
Output Drive Capability
The EL5156 and EL5157 families do not have internal short circuit protection circuitry. They have a typical short circuit current of 95mA and 70mA. If the output is shorted indefinitely, the power dissipation could easily overheat the die or the current could eventually compromise metal integrity. Maximum reliability is maintained if the output current never exceeds ±40mA. This limit is set by the design of the internal metal interconnect. Note that in transient applications, the part is robust.
Power Dissipation
With the high output drive capability of the EL5156 and EL5157 families, 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.
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EL5156, EL5157, EL5256, EL5257
The maximum power dissipation allowed in a package is determined according to:
T
PD
MAX
JMAXTAMAX
-------------------------------------------- -=
Θ
JA
Where:
T
= Maximum junction temperature
JMAX
= Maximum ambient temperature
T
AMAX
= Thermal resistance of the package
θ
JA
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:
PD
MAXVSISMAX
n
VSV
()
i1=
OUTi
V
-----------------
×+×=
OUTi
R
Li
For sinking:
n
V
()
I
PD
MAXVSISMAX
i1=
OUTiVS
×+×=
LOADi
Where:
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 sort as possible. The power supply pin must be well bypassed to reduce the risk of oscillation. For normal single supply operation, where the V connected to the ground plane, a single 4.7µF tantalum capacitor in parallel with a 0.1µF ceramic capacitor from V 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 V
- pin becomes the negative
S
supply rail.
For good AC performance, parasitic capacitance should be kept to 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.
- pin is
S
S
+
V
= Supply voltage
S
= Maximum quiescent supply current
IS
MAX
= Maximum output voltage of the application
V
OUT
= Load resistance tied to ground
R
LOAD
= Load current
I
LOAD
N = number of amplifiers (Max = 2)
By setting the two PD
equations equal to each other, we
MAX
can solve the output current and R overheat.
to avoid the device
LOAD
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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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