DATASHEET

EL2160
®
Data Sheet
September 26, 2001
FN7051
180MHz Current Feedback Amplifier
Features
The EL2160 is a current feedback
operational amplifier with -3dB
bandwidth of 130MHz at a gain of +2.
Built using the Elantec proprietary monolithic
complementary bipolar process, this amplifier uses current
mode feedback to achieve more bandwidth at a given gain
than a conventional voltage feedback operational amplifier.
• 130MHz 3dB bandwidth (AV=+2)
The EL2160 is designed to drive a double terminated 75Ω
coax cable to video levels. Differential gain and phase are
excellent when driving both loads of 500Ω (<0.01%/<0.01°)
and double terminated 75Ω cables (0.025%/0.1°).
The amplifier can operate on any supply voltage from 4V
(±2V) to 33V (±16.5V), yet consume only 8.5mA at any supply voltage. Using industry-standard pinouts, the EL2160 is
available in 8-pin PDIP and SO packages, as well as a 16-pin
SO (0.300”) package. All are specified for operation over the
full -40°C to +85°C temperature range. For dual and quad
applications, please see the EL2260/EL2460 datasheet.
• 180MHz 3dB bandwidth (AV=+1)
• 0.01% differential gain, RL=500Ω
• 0.01° differential phase, RL=500Ω
• Low supply current, 8.5mA
• Wide supply range, ±2V to ±15V
• 80mA output current (peak)
• Low cost
• 1500V/µs slew rate
• Input common mode range to within 1.5V of supplies
• 35ns settling time to 0.1%
Applications
• Video amplifiers
• Cable drivers
Ordering Information
• RGB amplifiers
PART NUMBER
PACKAGE
TAPE &
REEL
PKG. NO.
• Test equipment amplifiers
EL2160CN
8-Pin PDIP
-
MDP0031
• Current to voltage converters
EL2160CS-T7
8-Pin SO
7”
MDP0027
EL2160CS-T13
8-Pin SO
13”
MDP0027
16-Pin SO (0.300”)
-
MDP0027
13”
MDP0027
EL2160CM
EL2160CM-T13 16-Pin SO (0.300”)
Pinouts
EL2160
[16-PIN SO (0.300”)]
TOP VIEW
NC 1
16 NC
NC 2
15 NC
-IN 3
14 VS+
+
NC 4
13 NC
+IN 5
12 OUT
NC 6
11 NC
VS- 7
10 NC
NC 8
9 NC
1
EL2160
(8-PIN PDIP, SO)
TOP VIEW
NC 1
-IN 2
+IN 3
VS- 4
8 NC
+
7 VS+
6 OUT
5 NC
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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EL2160
Absolute Maximum Ratings (TA = 25°C)
Voltage between VS+ and VS- . . . . . . . . . . . . . . . . . . . . . . . . . .+33V
Voltage between +IN and -IN . . . . . . . . . . . . . . . . . . . . . . . . . . . .±6V
Current into +IN or -IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA
Internal Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . See Curves
Operating Ambient Temperature Range . . . . . . . . . .-40°C to +85°C
Operating Junction Temperature
Plastic Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C
Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50mA
Storage Temperature Range . . . . . . . . . . . . . . . . . .-65°C to +150°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
Open-Loop DC Electrical Specifications
VS = ±15V, RL = 150Ω, TA = 25°C unless otherwise specified.
LIMITS
PARAMETER
DESCRIPTION
CONDITIONS
TEMP
MIN
TYP
MAX
UNIT
25°C
2
10
mV
Full
10
VOS
Input Offset Voltage
TC VOS
Average Offset Voltage Drift (Note 1)
+IIN
+Input Current
VS = ±5V, ±15V
25°C
0.5
5
µA
-IIN
-Input Current
VS = ±5V, ±15V
25°C
5
25
µA
CMRR
Common Mode Rejection Ratio (Note 2)
VS = ±5V, ±15V
25°C
-ICMR
-Input Current Common Mode Rejection (Note 2) VS = ±5V, ±15V
25°C
PSRR
Power Supply Rejection Ratio (Note 3)
25°C
-IPSR
-Input Current Power Supply Rejection (Note 3)
25°C
ROL
Transimpedance (Note 4)
VS = ±5V, ±15V
50
55
0.2
75
µV/°C
dB
5
95
0.2
µA/V
dB
5
µA/V
VS = ±15V
RL = 400Ω
25°C
500
2000
kΩ
VS = ±5V
RL = 150Ω
25°C
500
1800
kΩ
1.5
3.0
MΩ
+RIN
+Input Resistance
25°C
+CIN
+Input Capacitance
25°C
2.5
pF
CMIR
Common Mode Input Range
VS = ±15V
25°C
±13.5
V
VS = ±5V
25°C
±3.5
V
RL = 400Ω
VS =±15V
25°C
±13.5
V
RL = 150Ω
VS =±15V
25°C
±12
V
RL = 150Ω
VS =±5V
25°C
±3.0
±3.7
V
VS = ±5V,
25°C
60
100
150
mA
VO
ISC
Output Voltage Swing
Output Short Circuit Current (Note 5)
±12
VS = ±15V
IS
Supply Current
VS = ±15V
25°C
8.5
12.0
mA
VS = ±5V
25°C
6.4
9.5
mA
NOTES:
1. Measured from TMIN to TMAX
2. VCM = ±10V for VS = ±15V and TA = 25°C, VCM = ±3V for VS = ±5V and TA = 25°C
3. The supplies are moved from ±2.5V to ±15V
4. VOUT = ±7V for VS = ±15V, and VOUT = ±2V for VS = ±5V
5. A heat sink is required to keep junction temperature below absolute maximum when an output is shorted
2
EL2160
Closed-Loop AC Electrical Specifications
VS = ±15V, AV = +2, RF = 560Ω, RL = 150Ω, TA = 25°C unless otherwise noted.
LIMITS
PARAMETER
BW
SR
DESCRIPTION
-3dB Bandwidth (Note 1)
Slew Rate (Note 1)(Note 2)
CONDITIONS
MIN
TYP
MAX
UNIT
VS = ±15V, AV = +2
130
MHz
VS = ±15V, AV = +1
180
MHz
VS = ±5V, AV = +2
100
MHz
VS = ±5V, AV = +1
110
MHz
1500
V/µs
1500
V/µs
2.7
ns
3.2
ns
RL = 400Ω
RF = 1kΩ, RG = 110Ω
RL = 400Ω
t R , tF
Rise Time, Fall Time (Note 1)
tPD
Propagation Delay (Note 1)
OS
Overshoot (Note 1)
VOUT = ±500mV
0
%
tS
0.1% Settling Time (Note 1)
VOUT = ±10V
AV = -1, RL = 1k
35
ns
dG
Differential Gain (Note 1)(Note 3)
RL = 150Ω
0.025
%
RL = 500Ω
0.006
%
RL = 150Ω
0.1
°
RL = 500Ω
0.005
°
dP
Differential Phase (Note 1)(Note 3)
VOUT = ±500mV
1000
NOTES:
1. All AC tests are performed on a “warmed up” part, except for Slew Rate, which is pulse tested
2. Slew Rate is with VOUT from +10V to -10V and measured at the 25% and 75% points
3. DC offset from -0.714V through +0.714V, AC amplitude 286mVP-P, f = 3.58MHz
3
EL2160
Typical Performance Curves
Non-Inverting Frequency
Response (Gain)
Inverting Frequency
Response (Gain)
Non-Inverting Frequency
Response (Phase)
Inverting Frequency
Response (Phase)
Frequency Response
for Various RL
Frequency Response for
Various RF and RG
R
3dB Bandwidth vs Supply
Voltage for AV = -1
4
Peaking vs Supply Voltage
for AV = -1
3dB Bandwidth vs
Temperature for AV = - 1
EL2160
Typical Performance Curves
3dB Bandwidth vs Supply
Voltage for AV = +1
(Continued)
Peaking vs Supply Voltage
for AV = +1
3dB Bandwidth vs Temperature
for AV = +1
3dB Bandwidth vs Supply
Voltage for AV = +2
Peaking vs Supply Voltage
for AV = +2
3dB Bandwidth vs Temperature
for AV = +2
3dB Bandwidth vs Supply
Voltage for AV = +10
Peaking vs Supply Voltage
for AV = +10
5
3dB Bandwidth vs Temperature
for AV = +10
EL2160
Typical Performance Curves
(Continued)
Frequency Response
for Various CL
Frequency Response
for Various CIN-
2nd and 3rd Harmonic
Distortion vs Frequency
Transimpedance (ROL)
vs Frequency
Closed-Loop Output
Impedance vs Frequency
6
PSRR and CMRR
vs Frequency
Voltage and Current Noise
vs Frequency
Transimpedance (ROL)
vs Die Temperature
EL2160
Typical Performance Curves
Offset Voltage
vs Die Temperature
(4 Samples)
(Continued)
Supply Current
vs Die Temperature
Supply Current
vs Supply Voltage
+Input Resistance
vs Die Temperature
Input Current
vs Die Temperature
+Input Bias Current
vs Input Voltage
Output Voltage Swing
vs Die Temperature
Short Circuit Current
vs Die Temperature
PSRR & CMRR
vs Die Temperature
7
EL2160
Typical Performance Curves
Differential Gain
vs DC Input Voltage,
RL = 150
Differential Gain
vs DC Input Voltage,
RL = 500
Slew Rate
vs Supply Voltage
8
(Continued)
Differential Phase
vs DC Input Voltage,
RL = 150
Differential Phase
vs DC Input Voltage,
RL = 500
Slew Rate
vs Temperature
Small Signal
Pulse Response
Large Signal
Pulse Response
Settling Time
vs Settling Accuracy
EL2160
Typical Performance Curves
(Continued)
Long Term Settling Error
Package Power Dissipation vs Ambient Temp.
JEDEC JESD51-3 Low Effective Thermal Conductivity Test
Board
1.6
1.344W
Power Dissipation (W)
1.4
1.2 1.250W
SO16 (0.300”)
θJA=93°C/W
1
PDIP8
θJA=100°C/W
0.8
781mW
0.6
SO8
θJA=160°C/W
0.4
0.2
0
0
25
50
75 85 100
Ambient Temperature (°C)
Burn-In Circuit
EL2160
9
125
150
EL2160
Differential Gain and Phase Test Circuit
Simplified Schematic (One Amplifier)
Applications Information
Product Description
The EL2160 is a current mode feedback amplifier that offers
wide bandwidth and good video specifications at a
moderately low supply current. It is built using Elantec's
proprietary complimentary bipolar process and is offered in
industry standard pin-outs. Due to the current feedback
architecture, the EL2160 closed-loop 3dB bandwidth is
dependent on the value of the feedback resistor. First the
desired bandwidth is selected by choosing the feedback
10
resistor, RF, and then the gain is set by picking the gain
resistor, RG. The curves at the beginning of the Typical
Performance Curves section show the effect of varying both
RF and RG. The 3dB bandwidth is somewhat dependent on
the power supply voltage. As the supply voltage is
decreased, internal junction capacitances increase, causing
a reduction in closed loop bandwidth. To compensate for
this, smaller values of feedback resistor can be used at lower
supply voltages.
EL2160
Power Supply Bypassing and Printed Circuit
Board Layout
As with any high frequency device, good printed circuit board
layout is necessary for optimum performance. Ground plane
construction is highly recommended. Lead lengths should be
as short as possible, below ¼”. The power supply pins must
be well bypassed to reduce the risk of oscillation. A 1.0µF
tantalum capacitor in parallel with a 0.01µF ceramic
capacitor is adequate for each supply pin.
For good AC performance, parasitic capacitances should be
kept to a minimum, especially at the inverting input (see
Capacitance at the Inverting Input section). This implies
keeping the ground plane away from this pin. Carbon
resistors are acceptable, while use of wire-wound resistors
should not be used because of their parasitic inductance.
Similarly, capacitors should be low inductance for best
performance. Use of sockets, particularly for the SO
package, should be avoided. Sockets add parasitic
inductance and capacitance which will result in peaking and
overshoot.
Bandwidth vs Temperature
Whereas many amplifier's supply current and consequently
3dB bandwidth drop off at high temperature, the EL2160 was
designed to have little supply current variations with
temperature. An immediate benefit from this is that the 3dB
bandwidth does not drop off drastically with temperature.
With VS = ±15V and AV = +2, the bandwidth only varies from
150MHz to 110MHz over the entire die junction temperature
range of 0°C < T < 150°C.
Supply Voltage Range
The EL2160 has been designed to operate with supply
voltages from ±2V to ±15V. Optimum bandwidth, slew rate,
and video characteristics are obtained at higher supply
voltages. However, at ±2V supplies, the 3dB bandwidth at
AV = +2 is a respectable 70MHz. The following figure is an
oscilloscope plot of the EL2160 at ±2V supplies, AV = +2,
RF = RG = 560Ω, driving a load of 150Ω, showing a clean
±600mV signal at the output.
Capacitance at the Inverting Input
Due to the topology of the current feedback amplifier, stray
capacitance at the inverting input will affect the AC and
transient performance of the EL2160 when operating in the
non-inverting configuration. The characteristic curve of gain
vs. frequency with variations of CIN- emphasizes this effect.
The curve illustrates how the bandwidth can be extended to
beyond 200MHz with some additional peaking with an
additional 2pF of capacitance at the VIN- pin for the case of
AV = +2. Higher values of capacitance will be required to
obtain similar effects at higher gains.
In the inverting gain mode, added capacitance at the
inverting input has little effect since this point is at a virtual
ground and stray capacitance is therefore not “seen” by the
amplifier.
Feedback Resistor Values
The EL2160 has been designed and specified with
RF = 560Ω for AV = +2. This value of feedback resistor yields
extremely flat frequency response with little to no peaking
out to 130MHz. As is the case with all current feedback
amplifiers, wider bandwidth, at the expense of slight peaking,
can be obtained by reducing the value of the feedback
resistor. Inversely, larger values of feedback resistor will
cause rolloff to occur at a lower frequency. By reducing RF to
430Ω, bandwidth can be extended to 170MHz with under
1dB of peaking. Further reduction of RF to 360Ω increases
the bandwidth to 195MHz with about 2.5dB of peaking. See
the curves in the Typical Performance Curves section which
show 3dB bandwidth and peaking vs. frequency for various
feedback resistors and various supply voltages.
11
If a single supply is desired, values from +4V to +30V can be
used as long as the input common mode range is not
exceeded. When using a single supply, be sure to either 1)
DC bias the inputs at an appropriate common mode voltage
and AC couple the signal, or 2) ensure the driving signal is
within the common mode range of the EL2160.
Settling Characteristics
The EL2160 offers superb settling characteristics to 0.1%,
typically in the 35ns to 40ns range. There are no aberrations
created from the input stage which often cause longer
settling times in other current feedback amplifiers. The
EL2160 is not slew rate limited, therefore any size step up to
±10V gives approximately the same settling time.
As can be seen from the Long Term Settling Error curve, for
AV = +1, there is approximately a 0.035% residual which
tails away to 0.01% in about 40µs. This is a thermal settling
error caused by a power dissipation differential (before and
after the voltage step). For AV = -1, due to the inverting
mode configuration, this tail does not appear since the input
stage does not experience the large voltage change as in the
non-inverting mode. With AV = -1, 0.01% settling time is
slightly greater than 100ns.
EL2160
Power Dissipation
The EL2160 amplifier combines both high speed and large
output current drive capability at a moderate supply current
in very small packages. It is possible to exceed the maximum
junction temperature allowed under certain supply voltage,
temperature, and loading conditions. To ensure that the
EL2160 remains within its absolute maximum ratings, the
following discussion will help to avoid exceeding the
maximum junction temperature.
packages. The curves assume worst case conditions of
TA = +85°C and IS = 11mA.
Supply Voltage vs RLOAD for
Various VOUT (8-Pin SO Package)
The maximum power dissipation allowed in a package is
determined by its thermal resistance and the amount of
temperature rise according to:
T JMAX – T AMAX
P DMAX = -------------------------------------------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:
Supply Voltage vs RLOAD for
Various VOUT (PDIP Package)
V OUT
P DMAX = 2 × V S + ( V S – V OUT ) × ---------------RL
where IS is the supply current. (To be more accurate, the
quiescent supply current flowing in the output driver
transistor should be subtracted from the first term because,
under loading and due to the class AB nature of the output
stage, the output driver current is now included in the second
term.)
In general, an amplifier's AC performance degrades at
higher operating temperature and lower supply current.
Unlike some amplifiers, the EL2160 maintains almost
constant supply current over temperature so that AC
performance is not degraded as much over the entire
operating temperature range. Of course, this increase in
performance doesn't come for free. Since the current has
increased, supply voltages must be limited so that maximum
power ratings are not exceeded.
The EL2160 consumes typically 8.5mA and maximum
11.0mA. The worst case power in an IC occurs when the
output voltage is at half supply, if it can go that far, or its
maximum values if it cannot reach half supply. If we set the
two PDMAX equations equal to each other, and solve for VS,
we can get a family of curves for various loads and output
voltages according to:
R L × ( T MAX -T AMAX )
- + ( V OUT ) ÷ [ ( 2 × I S × R L ) + V OUT ]
V S = -------------------------------------------------------θ JA
The following curves show supply voltage (±VS) vs RLOAD
for various output voltage swings for the 2 different
12
The curves do not include heat removal or forcing air, or the
simple fact that the package will probably be attached to a
circuit board, which can also provide some form of heat
removal. Larger temperature and voltage ranges are
possible with heat removal and forcing air past the part.
Current Limit
The EL2160 has an internal current limit that protects the
circuit in the event of the output being shorted to ground.
This limit is set at 100mA nominally and reduces with
junction temperature. At a junction temperature of 150°C, the
current limits at about 65mA. If the output is shorted to
ground, the power dissipation could be well over 1W. Heat
removal is required in order for the EL2160 to survive an
indefinite short.
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 EL2160 from the capacitive cable and allow
extensive capacitive drive. However, other applications may
have high capacitive loads without termination resistors. In
these applications, an additional small value (5Ω–50Ω)
resistor in series with the output will eliminate most peaking.
EL2160
The gain resistor, RG, can be chosen to make up for the gain
loss created by this additional series resistor at the output.
EL2160 Macromodel
* Revision A, November 1993
* AC Characteristics used CIN- (pin 2) = 1 pF; RF = 560Ω
* Connections:
+input
*
|
-input
*
|
|
+Vsupply
*
|
|
|
-Vsupply
*
|
|
|
|
output
*
|
|
|
|
|
.subckt EL2160/EL 3 2 7 4 6
*
* Input Stage
*
e1 10 0 3 0 1.0
vis 10 9 0V
h2 9 12 vxx 1.0
r1 2 11 130
l1 11 12 25nH
iinp 3 0 0.5µA
iinm 2 0 5µA
r12 3 0 2Meg
*
* Slew Rate Limiting
*
h1 13 0 vis 600
r2 13 14 1K
d1 14 0 dclamp
d2 0 14 dclamp
*
* High Frequency Pole
*
*e2 30 0 14 0 0.00166666666
l3 30 17 0.43µH
c5 17 0 0.27pF
r5 17 0 500
*
* Transimpedance Stage
*
g1 0 18 17 0 1.0
ro1 18 0 2Meg
cdp 18 0 2.285pF
*
* Output Stage
*
q1 4 18 19 qp
q2 7 18 20 qn
q3 7 19 21 qn
q4 4 20 22 qp
r7 21 6 4
r8 22 6 4
ios1 7 19 2mA
ios2 20 4 2mA
*
* Supply Current
*
ips 7 4 3mA
*
13
EL2160
* Error Terms
*
ivos 0 23 2mA
vxx 23 0 0V
e4 24 0 3 0 1.0
e5 25 0 7 0 1.0
e6 26 0 4 0 1.0
r9 24 23 562
r10 25 23 1K
r11 26 23 1K
*
* Models
*
.model qn npn (is=5e-15 bf=100 tf=0.1ns)
.model qp pnp (is=5e-15 bf=100 tf=0.1ns)
.model dclamp d (is=1e-30 ibv=0.266 bv=2.24 n=4)
.ends
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14