INTERSIL EL5178

EL5178, EL5378
®
Data Sheet
March 8, 2005
FN7491.1
700MHz Differential Twisted-Pair Drivers
Features
The EL5178 and EL5378 are single and triple high
bandwidth amplifiers with an output in differential form. They
are primarily targeted for applications such as driving
twisted-pair lines in component video applications. The
inputs can be in either single-ended or differential form but
the outputs are always in differential form.
• Fully differential inputs, outputs, and feedback
On the EL5178 and EL5378, two feedback inputs provide
the user with the ability to set the gain of each device (stable
at minimum gain of 2).
• Differential input range ±2.3V
• 700MHz 3dB bandwidth
• 1000V/µs slew rate
• Low distortion at 5MHz and 20MHz
• Single 5V or dual ±5V supplies
• 60mA maximum output current
The output common mode level for each channel is set by
the associated REF pin, which have a -3dB bandwidth of
over 110MHz. Generally, these pins are grounded but can be
tied to any voltage reference.
• Low power - 12.5mA per channel
All outputs are short circuit protected to withstand temporary
overload condition.
• Twisted-pair driver
The EL5178 is available in 8-pin MSOP and SO packages
and EL5378 is available in a 28-pin QSOP package. All
specified for operation over the full -40°C to +85°C
temperature range.
• Pb-free available (RoHS compliant)
Applications
• Differential line driver
• VGA over twisted-pair
• ADSL/HDSL driver
• Single ended to differential amplification
• Transmission of analog signals in a noisy environment
Pinouts
EL5378
(28-PIN QSOP)
TOP VIEW
EL5178
(8-PIN MSOP, SO)
TOP VIEW
FBP 1
IN+ 2
REF 3
8 OUT+
+
-
FBN 4
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.
EL5178, EL5378
Ordering Information
PART
NUMBER
PACKAGE
TAPE &
REEL
PKG. DWG. #
PART
NUMBER
TAPE &
REEL
PKG. DWG. #
EL5178IS
8-Pin SO
-
MDP0027
EL5178IYZ
(See Note)
8-Pin MSOP
(Pb-Free)
-
MDP0043
EL5178IS-T7
8-Pin SO
7”
MDP0027
EL5178IYZ-T7
(See Note)
8-Pin MSOP
(Pb-Free)
7”
MDP0043
EL5178IS-T13
8-Pin SO
13”
MDP0027
EL5178IYZ-T13
(See Note)
8-Pin MSOP
(Pb-Free)
13”
MDP0043
EL5178ISZ
(See Note)
8-Pin SO
(Pb-Free)
-
MDP0027
EL5378IU
28-Pin QSOP
-
MDP0040
EL5178ISZ-T7
(See Note)
8-Pin SO
(Pb-Free)
7”
MDP0027
EL5378IU-T7
28-Pin QSOP
7”
MDP0040
EL5178ISZ-T13
(See Note)
8-Pin SO
(Pb-Free)
13”
MDP0027
EL5378IU-T13
28-Pin QSOP
13”
MDP0040
EL5178IY
8-Pin MSOP
-
MDP0043
EL5378IUZ
(See Note)
28-Pin QSOP
(Pb-Free)
-
MDP0040
EL5178IY-T7
8-Pin MSOP
7”
MDP0043
EL5378IUZ-T7
(See Note)
28-Pin QSOP
(Pb-Free)
7”
MDP0040
EL5178IY-T13
8-Pin MSOP
13”
MDP0043
EL5378IUZ-T13
(See Note)
28-Pin QSOP
(Pb-Free)
13”
MDP0040
PACKAGE
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.
2
FN7491.1
March 8, 2005
EL5178, EL5378
Absolute Maximum Ratings (TA = 25°C)
Supply Voltage (VS+ to VS-) . . . . . . . . . . . . . . . . . . . . . . . . . . . .12V
Maximum Output Current. . . . . . . . . . . . . . . . . . . . . . . . . . . . ±60mA
Input Current (all inputs and references) . . . . . . . . . . . . . . . . . . 4mA
ESD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MM 300V, HBM 3kV
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
PARAMETER
VS+ = +5V, VS- = -5V, TA = 25°C, VIN = 0V, RLD = 1kΩ, CLD = 2.7pF, [RF = 604Ω, RG = 402Ω (EL5178)],
[RF = 402Ω, RG = 274Ω (EL5378)], unless otherwise specified.
DESCRIPTION
CONDITIONS
MIN
TYP
MAX
UNIT
AC PERFORMANCE
BW
-3dB Bandwidth
AV = 2, CLD = 2.7pF
700
MHz
AV = 5, CLD = 2.7pF
80
MHz
AV = 2, CLD = 2.7pF, RLD = 200Ω
320
MHz
45
MHz
BW
±0.1dB Bandwidth
AV = 2, CLD = 2.7pF
SR
Slew Rate, Differential (EL5178)
VOUT = 3VP-P, 20% to 80%
650
850
V/µs
Slew Rate, Differential (EL5378)
VOUT = 3VP-P, 20% to 80%
650
1000
V/µs
TSTL
Settling Time to 0.1%
VOUT = 2VP-P
35
ns
TOVR
Output Overdrive Recovery Time
AV = 2
20
ns
GBWP
Gain Bandwidth Product
350
MHz
VREFBW (-3dB) VREF -3dB Bandwidth (EL5378)
CLD = 2.7pF
110
MHz
VREFSR+
VREF Slew Rate - Rise (EL5378)
VOUT = 2VP-P, 20% to 80%
134
V/µs
VREFSR-
VREF Slew Rate - Fall (EL5378)
VOUT = 2VP-P, 20% to 80%
70
V/µs
VN
Input Voltage Noise
at 10kHz
18
nV/√Hz
IN
Input Current Noise
at 10kHz
1.5
pA/√Hz
HD2
Second Harmonic Distortion
VOUT = 2VP-P, 5MHz
-83
dBc
VOUT = 2VP-P, 20MHz
-72
dBc
VOUT = 2VP-P, 5MHz
-88
dBc
VOUT = 2VP-P, 20MHz
-70
dBc
HD3
Third Harmonic Distortion
dG
Differential Gain at 3.58MHz
RLD = 300Ω, AV =2
0.06
%
dθ
Differential Phase at 3.58MHz
RLD = 300Ω, AV =2
0.13
°
eS
Channel Separation (EL5378)
at F = 1MHz
90
dB
INPUT CHARACTERISTICS
VOS
Input Referred Offset Voltage
IIN
Input Bias Current (VIN+, VIN-)
IREF
Input Bias Current (VREF) (EL5378)
RIN
Differential Input Resistance
150
kΩ
CIN
Differential Input Capacitance
1
pF
DMIR
Differential Mode Input Range (EL5378)
±2.3
V
CMIR+
Common Mode Positive Input Range at
VIN+, VIN- (EL5378)
3.4
V
3
VREF = ±3.0V
±1.9
±30
mV
-20
-14
-7
µA
0.05
2.3
4
µA
3.1
FN7491.1
March 8, 2005
EL5178, EL5378
Electrical Specifications
PARAMETER
VS+ = +5V, VS- = -5V, TA = 25°C, VIN = 0V, RLD = 1kΩ, CLD = 2.7pF, [RF = 604Ω, RG = 402Ω (EL5178)],
[RF = 402Ω, RG = 274Ω (EL5378)], unless otherwise specified. (Continued)
DESCRIPTION
CONDITIONS
MIN
TYP
MAX
UNIT
-4.4
-4.1
V
CMIR-
Common Mode Negative Input Range at
VIN+, VIN- (EL5378)
VREFIN +
Positive Reference Input Voltage Range
(EL5378)
VREFIN -
Negative Reference Input Voltage Range VIN+ = VIN- = 0V
(EL5378)
-3.3
-3.2
V
VREFOS
Output Offset Relative to VREF (EL5378)
±50
±100
mV
CMRR
Input Common Mode Rejection Ratio
VIN+ = VIN- = 0V
VIN = ±2.5V
3.2
3.7
V
65
78
dB
V
OUTPUT CHARACTERISTICS
VOUT
Output Voltage Swing
RL = 1kΩ
±3.4
±3.7
IOUT(Max)
Maximum Output Current
RL = 10Ω, VIN+ = ±3.2V
±50
±60
ROUT
Output Impedance
±100
130
mA
mΩ
SUPPLY
VSUPPLY
Supply Operating Range
IS(ON)
Power Supply Current - Per Channel
IS(OFF)+
Positive Power Supply Current - Disabled EN pin tied to 4.8V
(EL5378)
IS(OFF)-
Negative Power Supply Current Disabled (EL5378)
PSRR
Power Supply Rejection Ratio
VS+ to VS-
4.75
10
VS from ±4.5V to ±5.5V
11
V
12.5
14
mA
1.7
10
µA
-200
-120
µA
60
75
dB
ENABLE (EL5378 ONLY)
tEN
Enable Time
130
ns
tDS
Disable Time
1.2
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
4
VS+ 1.5
VS+ 0.5
V
123
-20
V
-8
200
µA
µA
FN7491.1
March 8, 2005
EL5178, EL5378
Pin Descriptions
EL5178
EL5378
PIN NAME
PIN FUNCTION
1
17, 21, 27
FBP1, 2, 3
Feedback from non-inverting outputs
2
2, 6, 10
INP1, 2, 3
Non-inverting inputs
3
3, 7, 11
INN1, 2, 3
Inverting inputs, note that on EL5178, this pin is also the REF pin
4
16, 20, 26
FBN1, 2, 3
Feedback from inverting outputs
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
No connect; grounded for best crosstalk performance
4, 8, 12
REF1, 2, 3
Reference inputs, sets common-mode output voltage
14
EN
Inverting outputs
Non-inverting outputs
ENABLE
Typical Performance Curves
20
GAIN (dB)
VS=±5V
15 RLD=1kΩ
CLD=0pF
RF=422Ω
10
5
AV=2
0
-5
AV=5
-10
-15
100K
1M
10M
100M
1G
FREQUENCY (Hz)
FIGURE 1. EL5178 FREQUENCY RESPONSE FOR VARIOUS RF
FIGURE 3. EL5178 FREQUENCY RESPONSE FOR VARIOUS
CLD
5
FIGURE 2. EL5178 FREQUENCY RESPONSE FOR VARIOUS
GAIN
FIGURE 4. EL5178 FREQUENCY RESPONSE FOR VARIOUS
RLD
FN7491.1
March 8, 2005
EL5178, EL5378
Typical Performance Curves
FIGURE 5. EL5178 FREQUENCY RESPONSE FOR VARIOUS
VOPP
FIGURE 6. EL5378 FREQUENCY RESPONSE FOR VARIOUS RF
20
GAIN (dB)
VS=±5V
15 RLD=1kΩ
CLD=0pF
RF=422Ω
10
AV=2
5
0
-5
AV=5
-10
-15
100K
1M
10M
100M
1G
FREQUENCY (Hz)
FIGURE 7. EL5378 FREQUENCY RESPONSE FOR VARIOUS
GAIN
FIGURE 8. EL5378 FREQUENCY RESPONSE FOR VARIOUS
CLD
FIGURE 9. EL5378 FREQUENCY RESPONSE FOR VARIOUS
RLD
FIGURE 10. VOLTAGE AND CURRENT NOISE vs FREQUENCY
6
FN7491.1
March 8, 2005
EL5178, EL5378
Typical Performance Curves
FIGURE 11. CMRR vs FREQUENCY
FIGURE 12. DIFFERENTIAL PSRR vs FREQUENCY
IMPEDANCE (Ω)
100
10
0
0.1
10K
100K
1M
10M
100M
FREQUENCY (Hz)
FIGURE 13. OUTPUT IMPEDANCE vs FREQUENCY
FIGURE 15. TOTAL HARMONIC DISTORTION vs
DIFFERENTIAL OUTPUT SWING
7
FIGURE 14. EL5378 CHANNEL SEPARATION
FIGURE 16. TOTAL HARMONIC DISTORTION vs FREQUENCY
FN7491.1
March 8, 2005
EL5178, EL5378
Typical Performance Curves
VIN
VIN
200mV/DIV
1V/DIV
VOUT
VOUT
5ns/DIV
10ns/DIV
FIGURE 17. SMALL SIGNAL TRANSIENT RESPONSE
FIGURE 18. LARGE SIGNAL TRANSIENT RESPONSE
VOUT
2V/DIV
EN
4V/DIV
VOUT
2V/DIV
EN
4V/DIV
100ns/DIV
400ns/DIV
FIGURE 19. EL5378 ENABLED RESPONSE
JEDEC JESD51-7 HIGH EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
POWER DISSIPATION (W)
1.6
1.4
1.583W
1.4
QSOP28
θJA=79°C/W
1.2 1.136W
1 1.087W
0.8
SO8
θJA=110°C/W
MSOP8
θJA=115°C/W
0.6
POWER DISSIPATION (W)
1.8
FIGURE 20. EL5378 DISABLED RESPONSE
0.4
0.2
0
0
25
75 85 100
50
125
150
AMBIENT TEMPERATURE (°C)
FIGURE 21. PACKAGE POWER DISSIPATION vs AMBIENT
TEMPERATURE
8
JEDEC JESD51-3 LOW EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
1.2 1.263W
QSOP28
θJA=99°C/W
1
781mW
0.8
SO8
θJA=160°C/W
607mW
0.6
MSOP8
θJA=206°C/W
0.4
0.2
0
0
25
50
75 85 100
125
150
AMBIENT TEMPERATURE (°C)
FIGURE 22. PACKAGE POWER DISSIPATION vs AMBIENT
TEMPERATURE
FN7491.1
March 8, 2005
Connection Diagrams
EL5178
RF1
422Ω
IN+
REF
RG
845Ω
9
RS2
50Ω
RS2
50Ω
CL1
5pF
-5V
1 FBP
OUT 8
2 INP
VSN 7
3 REF
VSP 6
4 FBN
OUTB 5
OUT
RLD
1kΩ
CL2
5pF
+5V
RF2
OUTB
422Ω
EL5378
+5V
OUT1 28
INP1
2 INP1
FBP1 27
INN1
3 INN1
FBN1 26
REF1
4 REF1
OUT1B 25
5 NC
VSP 24
INP2
6 INP2
VSN 23
INN2
7 INN2
OUT2 22
REF2
8 REF2
FBP2 21
9 NC
FBN2 20
INP3
10 INP3
OUT2B 19
INN3
11 INN3
OUT3 18
12 REF3
FBP3 17
13 NC
FBN3 16
14 EN
OUT3B 15
REF3
RSP1
50Ω
RSN1
50Ω
RSR1
50Ω
RSP2
50Ω
RSN2
50Ω
RSR2
50Ω
RSP3
50Ω
RSN3
50Ω
RSR3
50Ω
ENABLE
RF
-5V
422Ω
RG
845Ω
RF
422Ω
RLD1
1kΩ
RF
422Ω
RG
845Ω
RF
422Ω
RF
422Ω
RG
845Ω
RF
422Ω
RLD2
1kΩ
RLD3
1kΩ
CL1
CL1B
CL2
CL2B
CL3
CL3B
5pF
5pF
5pF
5pF
5pF
5pF
EL5178, EL5378
1 NC
FN7491.1
March 8, 2005
EL5178, EL5378
Simplified Schematic
VS+
R1
IN+
IN-
R3
R2
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 EL5178 and EL5378 are wide bandwidth, low power
and single/differential ended to differential output amplifiers.
The EL5178 is a single channel differential amplifier. Since
the IN- pin and REF pin are tired together internally, the
EL5178 can be used as a single ended to differential
converter. The EL5378 is a triple channel differential
amplifier. The EL5378 have a separate IN- pin and REF pin
for each channel. It can be used as single/differential ended
to differential converter. The EL5178 and EL5378 are
internally compensated for closed loop gain of 1 of greater.
Connected in gain of 2 and driving a 1kΩ differential load,
the EL5178 and EL5378 have a -3dB bandwidth of 700MHz.
Driving a 200Ω differential load at gain of 2, the bandwidth is
about 320MHz. The EL5378 is available with a power down
feature to reduce the power while the amplifier is disabled.
Input, Output, and Supply Voltage Range
The EL5178 and EL5378 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 -4.3V 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 3.7V. 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 EL5178, 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 EL5178 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
EL5378 have 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 EL5178 and EL5378 can swing from -3.8V
to +3.8V at 1kΩ differential load at ±5V supply. As the load
resistance becomes lower, the output swing is reduced.
10
FN7491.1
March 8, 2005
EL5178, EL5378
Driving Capacitive Loads and Cables
The gain setting for EL5378 is:
The EL5178 and EL5378 can drive 23pF differential
capacitor in parallel with 200Ω differential load with less than
5dB of peaking at gain of 2. 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 2, 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-
RG
VREF
V O+
IN+
INREF
V O-
FBN
RF2
FIGURE 23.
Choice of Feedback Resistor and Gain Bandwidth
Product
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 EL5178 and EL5378 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 the
gains other than 1, optimum response is obtained with RF
between 500Ω to 1kΩ.
The EL5178 and EL5378 have a gain bandwidth product of
350MHz 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 EL5378 only)
The EL5378 can be disabled and placed its outputs in a high
impedance state. The turn off time is about 1.2µs and the
turn on time is about 130ns. 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 EN 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 EL5178 and EL5378 have internal short circuit
protection. Its typical short circuit current is ±60mA. 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 EL5178 and
EL5378. 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.
The maximum power dissipation allowed in a package is
determined according to:
Gain × BW = 300MHz
T JMAX – T AMAX
PD MAX = -------------------------------------------Θ JA
11
FN7491.1
March 8, 2005
EL5178, EL5378
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
ILOAD = Load current
i = Number of channels
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.
By setting the two PDMAX equations equal to each other, we
can solve the output current and RLD to avoid the device
overheat.
Typical Applications
RF
FBP
50
TWISTED PAIR
IN+
IN+
RT
RG
INREF
EL5178/
EL5378
50
IN-
ZO = 100Ω
FBN
EL5175/
EL5375
VO
REF
RF
RFR
RGR
FIGURE 24. TWISTED PAIR CABLE RECEIVER
As the signal is transmitted through a cable, the high
frequency signal will be attenuated. One way to compensate
this loss is to boost the high frequency gain at the receiver
side.
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EL5178, EL5378
RF
GAIN
(dB)
FBP
RT
75
RGC
VO+
IN+
RG
IN-
CL
REF
VO-
FBN
RF
2R
DC Gain = 1 + ----------FRG
fL
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 25. TRANSMIT EQUALIZER
MSOP Package Outline Drawing
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FN7491.1
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EL5178, EL5378
SO Package Outline Drawing
14
FN7491.1
March 8, 2005
EL5178, EL5378
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
15
FN7491.1
March 8, 2005