INTERSIL EL5371

EL5171, EL5371
®
Data Sheet
February 16, 2005
FN7307.5
250MHz Differential Twisted-Pair Drivers
Features
The EL5171 and EL5371 are single and triple bandwidth
amplifiers with an output in differential form. They are
primarily targeted for applications such as driving twistedpair lines in component video applications. The input signal
is single-ended and the outputs are always in differential
form.
• Fully differential outputs and feedback
On the EL5171 and EL5371, two feedback inputs provide
the user with the ability to set the gain of each device (stable
at minimum gain of one). For a fixed gain of two, please see
EL5170 and EL5370.
The output common mode level for each channel is set by
the associated VREF pin, which have a -3dB bandwidth of
over 50MHz. Generally, these pins are grounded but can be
tied to any voltage reference.
All outputs are short circuit protected to withstand temporary
overload condition.
The EL5171 and EL5371 are specified for operation over the
full -40°C to +85°C temperature range.
• 250MHz 3dB bandwidth
• 800V/µs slew rate
• Low distortion at 5MHz
• Single 5V or dual ±5V supplies
• 90mA maximum output current
• Low power - 8mA per channel
• Pb-Free available (RoHS compliant)
Applications
• Twisted-pair driver
• Differential line driver
• VGA over twisted-pair
• ADSL/HDSL driver
• Single ended to differential amplification
Ordering Information
PART
NUMBER
• Input range ±2.3V typ.
• Transmission of analog signals in a noisy environment
PACKAGE
TAPE &
REEL
PKG. DWG. #
EL5171IS
8-Pin SO
-
MDP0027
EL5171IS-T7
8-Pin SO
7”
MDP0027
EL5171IS-T13
8-Pin SO
13”
MDP0027
EL5171ISZ
(See Note)
8-Pin SO
(Pb-free)
-
MDP0027
EL5171ISZ-T7
(See Note)
8-Pin SO
(Pb-free)
7”
MDP0027
EL5171ISZ-T13
(See Note)
8-Pin SO
(Pb-free)
13”
MDP0027
EL5371IU
28-Pin QSOP
-
MDP0040
EL5371IU-T7
28-Pin QSOP
7”
MDP0040
EL5371IU-T13
28-Pin QSOP
13”
MDP0040
Pinouts
FBP 1
IN+ 2
NOTE: Intersil Pb-free 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.
EL5371
(28-PIN QSOP)
TOP VIEW
EL5171
(8-PIN SO)
TOP VIEW
REF 3
FBN 4
8 OUT+
+
-
NC 1
7 VS-
INP1 2
6 VS+
INN1 3
5 OUT-
REF1 4
+
-
27 FBP1
26 FBN1
25 OUT1B
NC 5
24 VSP
INP2 6
23 VSN
INN2 7
22 OUT2
REF2 8
NC 9
+
-
21 FBP2
20 FBN2
INP3 10
19 OUT2B
INN3 11
18 OUT3
REF3 12
NC 13
EN 14
1
28 OUT1
+
-
17 FBP3
16 FBN3
15 OUT3B
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-352-6832 | 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.
EL5171, EL5371
Absolute Maximum Ratings (TA = 25°C)
Supply Voltage (VS+ to VS-) . . . . . . . . . . . . . . . . . . . . . . . . . . . .12V
Maximum Output Current. . . . . . . . . . . . . . . . . . . . . . . . . . . . ±60mA
Storage Temperature Range . . . . . . . . . . . . . . . . . .-65°C to +150°C
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . +135°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. 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
VS+ = +5V, VS- = -5V, TA = 25°C, VIN = 0V, RLD = 1kΩ, RF = 0, RG = OPEN, CLD = 2.7pF, Unless Otherwise
Specified
PARAMETER
DESCRIPTION
CONDITIONS
MIN
TYP
MAX
UNIT
AC PERFORMANCE
BW
-3dB Bandwidth
AV = 1, CLD = 2.7pF
250
MHz
AV = 2, RF = 500, CLD = 2.7pF
60
MHz
AV = 10, RF = 500, CLD = 2.7pF
10
MHz
50
MHz
BW
±0.1dB Bandwidth
AV = 1, CLD = 2.7pF
SR
Slew Rate (EL5171)
VOUT = 3VP-P, 20% to 80%
600
800
1000
V/µs
Slew Rate (EL5371)
VOUT = 3VP-P, 20% to 80%
540
700
1000
V/µs
TSTL
Settling Time to 0.1%
VOUT = 2VP-P
TOVR
GBWP
10
ns
Output Overdrive Recovery Time
20
ns
Gain Bandwidth Product
100
MHz
AV =1, CLD = 2.7pF
50
MHz
VREFBW (-3dB) VREF -3dB Bandwidth
VREFSR+
VREF Slew Rate - Rise
VOUT = 2VP-P, 20% to 80%
90
V/µs
VREFSR-
VREF Slew Rate - Fall
VOUT = 2VP-P, 20% to 80%
50
V/µs
VN
Input Voltage Noise
at 10kHz
26
nV/√Hz
IN
Input Current Noise
at 10kHz
2
pA/√Hz
HD2
Second Harmonic Distortion
VOUT = 2VP-P, 5MHz
-94
dBc
VOUT = 2VP-P, 20MHz
-94
dBc
VOUT = 2VP-P, 5MHz
-77
dBc
VOUT = 2VP-P, 20MHz
-75
dBc
HD3
Third Harmonic Distortion
dG
Differential Gain at 3.58MHz
RL = 300Ω, AV = 2
0.1
%
dθ
Differential Phase at 3.58MHz
RL = 300Ω, AV = 2
0.5
°
eS
Channel Separation
at f = 1MHz
90
dB
INPUT CHARACTERISTICS
VOS
Input Referred Offset Voltage
IIN
Input Bias Current (VIN+, VIN-)
IREF
Input Bias Current (VREF)
RIN
Differential Input Resistance
CIN
Differential Input Capacitance
DMIR
Differential Mode Input Range
CMIR+
Common Mode Positive Input Range at VIN+, VIN-
CMIR-
Common Mode Negative Input Range at VIN+, VIN- Tested only for EL5371
VREFIN +
Positive Reference Input Voltage Range (EL5371)
2
Tested only for EL5371
VIN+ = VIN- = 0V
±1.5
±25
mV
-14
-6
-3
µA
0.5
1.3
4
µA
300
kΩ
1
pF
±2.1
±2.3
3.1
3.4
-4.5
3.5
±3.8
±2.5
V
V
-4.2
V
V
FN7307.5
February 16, 2005
EL5171, EL5371
Electrical Specifications
VS+ = +5V, VS- = -5V, TA = 25°C, VIN = 0V, RLD = 1kΩ, RF = 0, RG = OPEN, CLD = 2.7pF, Unless Otherwise
Specified (Continued)
PARAMETER
DESCRIPTION
CONDITIONS
VREFIN -
Negative Reference Input Voltage Range (EL5371)
VREFOS
Output Offset Relative to VREF (EL5371)
CMRR
Input Common Mode Rejection Ratio (EL5371)
VIN = ±2.5V
Gain
Gain Accuracy
MIN
VIN+ = VIN- = 0V
TYP
MAX
UNIT
-3.3
-3
V
±60
±100
mV
70
82
dB
VIN = 1 (EL5171)
0.981
0.996
1.011
V
VIN = 1 (EL5371)
0.978
0.993
1.008
V
OUTPUT CHARACTERISTICS
VOUT
Output Voltage Swing
RL = 500Ω to GND (EL5171)
RL = 500Ω to GND (EL5371)
IOUT(Max)
ROUT
Maximum Output Current
±3.6
±3.4
V
±3.9
V
RL = 10Ω, VIN = ±3.24 (EL5171)
±70
±90
±120
mA
RL = 10Ω, VIN = ±3.24 (EL5371)
±50
±70
±90
mA
Output Impedance
130
mΩ
SUPPLY
VSUPPLY
Supply Operating Range
IS(ON)
Power Supply Current - Per Channel
IS(OFF)+
Positive Power Supply Current - Disabled (EL5371) EN pin tied to 4.8V
IS(OFF)-
Negative Power Supply Current - Disabled (EL5371)
PSRR
Power Supply Rejection Ratio
VS+ to VS-
4.75
6.8
11
V
7.5
8.2
mA
1.7
10
µA
-200
-120
µA
VS from ±4.5V to ±5.5V (EL5171)
70
84
dB
VS from ±4.5V to ±5.5V (EL5371)
65
83
dB
ENABLE (EL5371 ONLY)
tEN
Enable Time
215
ns
tDS
Disable Time
0.95
µs
VIH
EN Pin Voltage for Power-Up
VIL
EN Pin Voltage for Shut-Down
IIH-EN
EN Pin Input Current High
At VEN = 5V
IIL-EN
EN Pin Input Current Low
At VEN = 0V
VS+ 1.5
VS+ 0.5
V
122
-10
V
130
-8
µA
µA
Pin Descriptions
EL5171
EL5371
PIN NAME
1
17, 21, 27
FBP1, 2, 3
Feedback from non-inverting output
2
2, 6, 10
INP1, 2, 3
Non-inverting inputs
3
3, 7, 11
INN1, 2, 3
Inverting inputs, note that on EL5171, this pin is also the REF pin
4
16, 20, 26
FBN1, 2, 3
Feedback from inverting output
5
15, 19, 25
OUT1B, 2B, 3B
6
24
VSP
Positive supply
7
23
VSN
Negative supply
8
18, 22, 28
OUT1, 2, 3
1, 5, 9, 13
NC
4, 8, 12
REF1, 2, 3
14
EN
3
PIN FUNCTION
Inverting outputs
Non-inverting outputs
No connects, grounded for best crosstalk performance
Reference input, sets common-mode output voltage
ENABLE
FN7307.5
February 16, 2005
Connection Diagrams
EL5171
RF1
CL1
5pF
-5V
INP
RG
REF
4
RS1
50Ω
RS1
50Ω
1 FBP
OUT 8
2 INP
VSN 7
3 REF
VSP 6
4 FBN
OUTB 5
OUT
RLD
1kΩ
OUTB
RF3
+5V
CL2
5pF
EL5371
+5V
INN1
REF1
INP2
INN2
REF2
INP3
INN3
REF3
RSP1
50Ω
RSN1
50Ω
RSR1
50Ω
RSP2
50Ω
RSN2
50Ω
RSR2
50Ω
RSP3
50Ω
RSN3
50Ω
RSR3
50Ω
1 NC
OUT1 28
2 INP1
FBP1 27
3 INN1
FBN1 26
4 REF1
OUT1B 25
5 NC
VSP 24
6 INP2
VSN 23
7 INN2
OUT2 22
8 REF2
FBP2 21
9 NC
FBN2 20
10 INP3
OUT2B 19
11 INN3
OUT3 18
12 REF3
FBP3 17
13 NC
FBn3 16
14 EN
OUT3B 15
RF
RG
RLD1
1kΩ
RF
RF
RG
RLD2
1kΩ
RF
RF
RG
FN7307.5
February 16, 2005
-5V
ENABLE
EL5171, EL5371
INP1
RLD3
1kΩ
RF
CL1
5pF
CL1B
5pF
CL2
5pF
CL2B
5pF
CL3
5pF
CL3B
5pF
EL5171, EL5371
Typical Performance Curves
AV = 1, RLD = 1kΩ, CLD = 2.7pF
RLD = 1kΩ, CLD = 2.7pF
4
NORMALIZED MAGNITUDE (dB)
4
3
MAGNITUDE (dB)
2
1
0
VOP-P = 200mV
-1
-2
-3
VOP-P = 1VP-P
-4
-5
-6
1M
10M
100M
3
2
1
0
-1
AV = 1
-2
AV = 5
-3
-4
AV = 10
-5
-6
1M
1G
10M
FIGURE 1. FREQUENCY RESPONSE
AV = 1, RLD = 1kΩ
5
3
4
2
3
1
RLD = 1kΩ
0
RLD = 500Ω
-1
-2
RLD = 200Ω
MAGNITUDE (dB)
NORMINALIZED GAIN (dB)
AV = 1, CLD = 2.7pF
CLD = 23pF
0
-1
CLD = 9pF
-2
-5
-4
100M
CLD = 34pF
1
-3
10M
CLD = 56pF
2
-4
CLD = 2.7pF
-5
1M
1G
FREQUENCY (Hz)
10
9
9
NORMALIZED GAIN (dB)
NORMALIZED GAIN (dB)
1G
AV = 2, RF = 1kΩ, CLD = 2.7pF
AV = 2, RLD = 1kΩ, CLD = 2.7pF
8
RF = 1kΩ
6
RF = 500Ω
5
4
3
RF = 200Ω
8
7
6
RLD = 1kΩ
5
4
RLD = 500Ω
3
2
RLD = 200Ω
1
1
0
1M
100M
FIGURE 4. FREQUENCY RESPONSE vs CLD
10
7
10M
FREQUENCY (Hz)
FIGURE 3. FREQUENCY RESPONSE vs RLD
2
1G
FIGURE 2. FREQUENCY RESPONSE FOR VARIOUS GAIN
4
-6
1M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
-3
AV = 2
10M
100M
FREQUENCY (Hz)
FIGURE 5. FREQUENCY RESPONSE
5
400M
0
1M
10M
100M
400M
FREQUENCY (Hz)
FIGURE 6. FREQUENCY RESPONSE vs RLD
FN7307.5
February 16, 2005
EL5171, EL5371
Typical Performance Curves
(Continued)
100
5
4
2
IMPEDENCE (Ω)
MAGNITUDE (dB)
3
1
0
-1
-2
10
1
-3
-4
-5
100K
1M
10M
0.1
10K
100M
100K
FREQUENCY (Hz)
FIGURE 7. FREQUENCY RESPONSE - VREF
100
-10
90
70
-30
-40
CMRR (dB)
PSRR (dB)
100M
80
-20
PSRR-
-50
PSRR+
-60
60
50
40
30
-70
20
-80
10
10K
100K
1M
10M
0
100K
100M
1M
FREQUENCY (Hz)
10M
100M
1G
FREQUENCY (Hz)
FIGURE 9. PSRR vs FREQUENCY
FIGURE 10. CMRR vs FREQUENCY
1K
-30
-40
-50
100
GAIN (dB)
VOLTAGE NOISE (nV/√Hz),
CURRENT NOISE (pA/√Hz)
10M
FIGURE 8. OUTPUT IMPEDANCE vs FREQUENCY
0
-90
1K
1M
FREQUENCY (Hz)
EN
10
CH1 <=> CH2, CH2 <=> CH3
-70
-80
IN
1
10
-60
100
1K
10K
100K
-90
1M
10M
FREQUENCY (Hz)
FIGURE 11. VOLTAGE AND CURRENT NOISE vs FREQUENCY
6
CH1 <=> CH3
-100
100K
1M
10M
100M
1G
FREQUENCY (Hz)
FIGURE 12. CHANNEL ISOLATION vs FREQUENCY
FN7307.5
February 16, 2005
EL5171, EL5371
Typical Performance Curves
(Continued)
VS = ±5V, AV = 1, RLD = 1kΩ
-50
-55
-55
-60
-60
DISTORTION (dB)
DISTORTION (dB)
VS = ±5V, AV = 1, RLD = 1kΩ
-50
-65
-70
HD3 (f = 20MHz)
-75
HD3 (f = 5MHz)
-80
-85
HD2 (f
-90
Hz )
(
HD2
-95
-100
= 20M
1
1.5
2
2.5
3
f=
3.5
HD3 (f = 5MHz)
-65
HD3 (f = 20MH
-70
-75
-80
Hz)
HD2 (f = 5M
-85
z)
5M H
HD2 (f = 20MHz)
-90
4
4.5
-95
1
5
z)
2
3
4
VOP-P, DM (V)
5
6
7
8
9
10
VOP-P, DM (V)
FIGURE 13. HARMONIC DISTORTION vs DIFFERENTIAL
OUTPUT VOLTAGE
FIGURE 14. HARMONIC DISTORTION vs DIFFERENTIAL
OUTPUT VOLTAGE
VS = ±5V, AV = 2, VOP-P, DM = 2V
VS = ±5V, AV = 1, VOP-P, DM = 1V
-40
-50
-55
-65
HD
-70
-75
3
(f
HD
3
=
HD
-80
-85
20
M
Hz
2 (f
HD2
(f
-90
(f
=
5M
Hz
)
)
=2
0M
Hz
)
= 5M
Hz)
-70
HD2 (f
-80
300
400
500
600
700
800
= 20MH
z)
HD2 (f = 5MHz)
-100
200
200
300
400
500
600
700
800
900
1000
900 1000
RLD (Ω)
RLD (Ω)
FIGURE 15. HARMONIC DISTORTION vs RLD
FIGURE 16. HARMONIC DISTORTION vs RLD
VS = ±5V, RLD = 1kΩ, VOP-P, DM = 1V for AV = 1,
VOP-P, DM = 2V for AV = 2
HD3 (AV = 1)
-50
DISTORTION (dB)
HD3 (f = 5MHz)
-60
-90
-95
-100
100
-40
HD3 (f = 20MHz)
-50
DISTORTION (dB)
DISTORTION (dB)
-60
-60
3
HD
-70
(A V
=2
)
HD2 (AV =
HD2 (AV
2)
= 1)
50mV/DIV
-80
-90
-100
0
10
20
30
40
50
60
FREQUENCY (MHz)
FIGURE 17. HARMONIC DISTORTION vs FREQUENCY
7
10ns/DIV
FIGURE 18. SMALL SIGNAL TRANSIENT RESPONSE
FN7307.5
February 16, 2005
EL5171, EL5371
Typical Performance Curves
(Continued)
M = 100ns, CH1 = 500mV/DIV, CH2 = 5V/DIV
0.5V/DIV
CH1
CH2
10ns/DIV
100ns/DIV
FIGURE 19. LARGE SIGNAL TRANSIENT RESPONSE
FIGURE 20. ENABLED RESPONSE
JEDEC JESD51-3 LOW EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
M = 200ns, CH1 = 500mV/DIV, CH2 = 5V/DIV
POWER DISSIPATION (W)
1.2
CH1
CH2
1.010W
1
QSOP28
θJA=99°C/W
0.8
625mW
0.6
0.4
SO8
θJA=160°C/W
0.2
0
200ns/DIV
0
25
50
75 85 100
125
150
AMBIENT TEMPERATURE (°C)
FIGURE 21. DISABLED RESPONSE
POWER DISSIPATION (W)
1.4
FIGURE 22. PACKAGE POWER DISSIPATION vs AMBIENT
TEMPERATURE
JEDEC JESD51-7 HIGH EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
1.2
1.266W
1
909mW
QSOP28
θJA=79°C/W
0.8
0.6
SO8
θJA=110°C/W
0.4
0.2
0
0
25
50
75 85 100
125
150
AMBIENT TEMPERATURE (°C)
FIGURE 23. PACKAGE POWER DISSIPATION vs AMBIENT TEMPERATURE
8
FN7307.5
February 16, 2005
EL5171, EL5371
Simplified Schematic
VS+
R1
IN+
R3
R2
IN-
FBP
R4
R7
R8
FBN
VB1
OUT+
RCD
REF
RCD
VB2
CC
OUT-
R9
R10
CC
R5
R6
VS-
Description of Operation and Application
Information
Product Description
The EL5171 and EL5371 are wide bandwidth, low power
and single ended to differential output amplifiers. The
EL5171 is a single channel differential amplifier. Since the
IN- pin and REF pin are tired together internally, the EL5171
can be used as a single ended to differential converter. The
EL5371 is a triple channel differential amplifier. The EL5371
have a separate IN- pin and REF pin for each channel. It can
be used as single/differential ended to differential converter.
The EL5171 and EL5371 are internally compensated for
closed loop gain of +1 of greater. Connected in gain of 1 and
driving a 1kΩ differential load, the EL5171 and EL5371 have
a -3dB bandwidth of 250MHz. Driving a 200Ω differential
load at gain of 2, the bandwidth is about 30MHz. The
EL5371 is available with a power down feature to reduce the
power while the amplifier is disabled.
Input, Output, and Supply Voltage Range
The EL5171 and EL5371 have been designed to operate
with a single supply voltage of 5V to 10V or a split supplies
with its total voltage from 5V to 10V. The amplifiers have an
input common mode voltage range from -4.5V to 3.4V for
±5V supply. The differential mode input range (DMIR)
between the two inputs is from -2.3V to +2.3V. The input
voltage range at the REF pin is from -3.3V to 3.8V. If the
input common mode or differential mode signal is outside the
above-specified ranges, it will cause the output signal
distorted.
Differential and Common Mode Gain Settings
For EL5171, since the IN- pin and REF pin are bounded
together as the REF pin in an 8-pin package, the signal at
the REF pin is part of the common mode signal and also part
of the differential mode signal. For the true balance
differential outputs, the REF pin must be tired to the same
bias level as the IN+ pin. For a ±5V supply, just tire the REF
pin to GND if the IN+ pin is biased at 0V with a 50Ω or 75Ω
termination resistor. For a single supply application, if the
IN+ is biased to half of the rail, the REF pin should be biased
to half of the rail also.
The gain setting for EL5171 is:
R F1 + R F2

V ODM = V IN + ×  1 + ---------------------------
RG


2R 

V ODM = V IN + ×  1 + ----------F-
RG 

V OCM = V REF = 0V
Where:
• VREF = 0V
• RF1 = RF2 = RF
EL5371 has a separate IN- pin and REF pin. It can be used
as a single/differential ended to differential converter. The
voltage applied at REF pin can set the output common mode
voltage and the gain is one.
The output of the EL5171 and EL5371 can swing from -3.9V
to +3.9V at 1kΩ differential load at ±5V supply. As the load
resistance becomes lower, the output swing is reduced.
9
FN7307.5
February 16, 2005
EL5171, EL5371
Driving Capacitive Loads and Cables
The gain setting for EL5371 is:
The EL5171 and EL5371 can drive 50pF differential
capacitor in parallel with 1kΩ differential load 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 each 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.
R F1 + R F2

V ODM = ( V IN + – V IN - ) ×  1 + ---------------------------
RG


2R 

V ODM = ( V IN + – V IN - ) ×  1 + ----------F-
RG 

V OCM = V REF
Where:
• RF1 = RF2 = RF
RF1
FBP
VIN+
VIN-
V O+
IN+
RG
VREF
INREF
V O-
FBN
RF2
FIGURE 24.
Choice of Feedback Resistor and Gain Bandwidth
Product
For applications that require a gain of +1, no feedback
resistor is required. Just short the OUT+ pin to FBP pin and
OUT- pin to FBN 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 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 Pico farad range
in parallel with RF can help to reduce the ringing and
peaking at the expense of reducing the bandwidth.
The bandwidth of the EL5171 and EL5371 depends on the
load and the feedback network. RF and RG appear in
parallel with the load 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 bandwidth performance. For gain
of +1, RF = 0 is optimum. For the gains other than +1,
optimum response is obtained with RF between 500Ω to
1kΩ.
The EL5171 and EL5371 have a gain bandwidth product of
100MHz for RLD = 1kΩ. For gains ≥5, its bandwidth can be
predicted by the following equation:
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 (for EL5371 only)
The EL5371 can be disabled and placed its outputs in a high
impedance state. The turn off time is about 0.95µs and the
turn on time is about 215ns. When disabled, the amplifier's
supply current is reduced to 1.7µA for IS+ and 120µA for IStypically, thereby effectively eliminating the power
consumption. The amplifier's power down can be controlled
by standard CMOS signal levels at the ENABLE pin. The
applied logic signal is relative to VS+ pin. Letting the EN pin
float or applying a signal that is less than 1.5V below VS+ will
enable the amplifier. The amplifier will be disabled when the
signal at EN pin is above VS+ - 0.5V.
Output Drive Capability
The EL5171 and EL5371 have internal short circuit
protection. Its typical short circuit current is ±90mA for
EL5171 and ±70mA for EL5371. 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 ±60mA. This
limit is set by the design of the internal metal
interconnections.
Power Dissipation
With the high output drive capability of the EL5171 and
EL5371. It is possible to exceed the 135°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.
Gain × BW = 100MHz
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EL5171, EL5371
The maximum power dissipation allowed in a package is
determined according to:
T JMAX – T AMAX
PD MAX = -------------------------------------------Θ JA
By setting the two PDMAX equations equal to each other, we
can solve the output current and RLD to avoid the device
overheat.
Power Supply Bypassing and Printed Circuit
Board Layout
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:
∆V O

PD = i ×  V S × I SMAX + V S × ------------
R LD 

Where:
• VS = Total supply voltage
• ISMAX = Maximum quiescent supply current per channel
• ∆VO = Maximum differential output voltage of the
application
• RLD = Differential load resistance
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 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 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.
• ILOAD = Load current
• i = Number of channels
Typical Applications
RF
FBP
50
TWISTED PAIR
IN+
IN+
RT
RG
INREF
EL5171/
EL5371
50
IN-
ZO = 100Ω
FBN
EL5172/
EL5372
VO
REF
RF
RFR
RGR
FIGURE 25. TWISTED PAIR CABLE RECEIVER
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EL5171, EL5371
As the signal is transmitted through a cable, the high
frequency signal will be attenuated. One way to compensate
RF
this loss is to boost the high frequency gain at the receiver
side.
Gain
(dB)
FBP
RT
75
RGC
VO+
IN+
RG
IN-
CL
REF
VO-
FBN
fL
RF
2R
DC Gain = 1 + ----------FRG
fH
frequency
1
f L ≅ ------------------------2πR G C C
2R F
( HF )Gain = 1 + -------------------------R G || R GC
1
f H ≅ ----------------------------2πR GC C C
FIGURE 26. TRANSMIT EQUALIZER
SO Package Outline Drawing
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EL5171, EL5371
QSOP Package Outline Drawing
NOTE: The package drawing shown here may not be the latest version. To check the latest revision, please refer to the Intersil website at
http://www.intersil.com/design/packages/index.asp
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
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