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Número de pieza | OPA2680 | |
Descripción | Dual Wideband / Voltage Feedback OPERATIONAL AMPLIFIER With Disable | |
Fabricantes | Burr-Brown | |
Logotipo | ||
Hay una vista previa y un enlace de descarga de OPA2680 (archivo pdf) en la parte inferior de esta página. Total 21 Páginas | ||
No Preview Available ! OPA2680
®
OPA2680
OPA2680
TM Dual Wideband, Voltage Feedback
OPERATIONAL AMPLIFIER With Disable
FEATURES
q WIDEBAND +5V OPERATION: 220MHz (G = 2)
q HIGH OUTPUT CURRENT: 150mA
q OUTPUT VOLTAGE SWING: ±4.0V
q HIGH SLEW RATE: 1800V/µs
q LOW SUPPLY CURRENT: 6.4mA/Ch.
q LOW DISABLED CURRENT: 300µA/Ch.
q ENABLE/DISABLE TIME: 25ns/100ns
APPLICATIONS
q VIDEO LINE DRIVING
q xDSL LINE DRIVER/RECEIVER
q HIGH SPEED IMAGING CHANNELS
q ADC BUFFERS
q PORTABLE INSTRUMENTS
q TRANSIMPEDANCE AMPLIFIERS
q ACTIVE FILTERS
DESCRIPTION
The OPA2680 represents a major step forward in unity
gain stable, voltage feedback op amps. A new internal
architecture provides slew rate and full power band-
width previously found only in wideband current feed-
back op amps. A new output stage architecture delivers
high currents with a minimal headroom requirement.
These combine to give exceptional single supply opera-
tion. Using a single +5V supply, the OPA2680 can
deliver a 1V to 4V output swing with over 100mA drive
current and 150MHz bandwidth. This combination of
features makes the OPA2680 an ideal RGB line driver
or single supply ADC input driver.
The OPA2680’s low 6.4mA/ch. supply current is pre-
cisely trimmed at 25°C. This trim, along with low tem-
perature drift, guarantees lower maximum supply current
than competing products. System power may be reduced
further using the optional disable control pin (SO-14
package only). Leaving this disable pin open, or holding
it high, will operate the OPA2680N normally. If pulled
low, the OPA2680N supply current drops to less than
600µA while the output goes into a high impedance state.
OPA2680 RELATED PRODUCTS
Voltage Feedback
Current Feedback
Fixed Gain
SINGLES
OPA680
OPA681
OPA682
DUALS
OPA2680
OPA2681
OPA2682
TRIPLES
OPA3680
OPA3681
OPA3682
1.5kΩ
200Ω
+2.5V
+5V 0.1µF
+1.5V
800Ω
1/2
OPA2680
50Ω
3.2kΩ
1.6kΩ
1.5kΩ
1/2
OPA2680
1.6kΩ
50Ω
2.5VCM
±1VDIFF
+5V
0.1µF
+3.5V
+1.5V
REFB
REFT
0.1µF
IN
10pF
ADS822
10-Bit
40MSPS
Clock
400Ω
VIN
0V to +1V
400Ω
Single-Supply, DC-Coupled, Single-to-Differential ADC Driver
50Ω
IN
10pF
nternational Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111
Twx: 910-952-1111 • Internet: http://www.burr-brown.com/ • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132
©1997 Burr-Brown Corporation
PDS-1433C
Printed in U.S.A. October, 1999
1 page TYPICAL PERFORMANCE CURVES: VS = ±5V
At TA = +25°C, G = +2, RF = 402Ω, and RL = 100Ω, unless otherwise noted. See Figure 1.
SMALL-SIGNAL FREQUENCY RESPONSE
6
3 VO = 0.5Vp-p
G = +1
RF = 25Ω
0
–3 G = +2
–6
–9 G = +5
–12
–15
G = +10
–18
–21
–24
0.5
10
Frequency (MHz)
100
500
15
12
9
6
3
0
–3
–6
–9
–12
–15
0.5
LARGE-SIGNAL FREQUENCY RESPONSE
VO = 1Vp-p
VO = 2Vp-p
VO = 7Vp-p
VO = 4Vp-p
10
Frequency (MHz)
100
500
400
300
200
100
0
–100
–200
–300
–400
SMALL-SIGNAL PULSE RESPONSE
G = +2
VO = 0.5Vp-p
Time (5ns/div)
LARGE-SIGNAL PULSE RESPONSE
+4
+3 G = +2
VO = 5Vp-p
+2
+1
0
–1
–2
–3
–4
Time (5ns/div)
LARGE-SIGNAL DISABLE/ENABLE RESPONSE
VDIS
5.0
4.0
2.0
0
2.0 Output Voltage
1.6
1.2
0.8
G = +2
0.4 VIN = +1V
0
Each Channel
SO-14 Package
Only
Time (50ns/div)
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
1
CHANNEL-TO-CHANNEL CROSSTALK
10
Frequency (MHz)
100
®
5 OPA2680
5 Page APPLICATIONS INFORMATION
WIDEBAND VOLTAGE FEEDBACK OPERATION
The OPA2680 provides an exceptional combination of high
output power capability in a dual, wideband, unity gain
stable voltage feedback op amp using a new high slew rate
input stage. Typical differential input stages used for voltage
feedback op amps are designed to steer a fixed-bias current
to the compensation capacitor, setting a limit to the achiev-
able slew rate. The OPA2680 uses a new input stage which
places the transconductance element between two input
buffers, using their output currents as the forward signal. As
the error voltage increases across the two inputs, an increas-
ing current is delivered to the compensation capacitor. This
provides very high slew rate (1800V/µs) while consuming
relatively low quiescent current (6.4mA/ch.). This excep-
tional full power performance comes at the price of a slightly
higher input noise voltage than alternative architectures. The
4.8nV/√Hz input voltage noise for the OPA2680 is excep-
tionally low for this type of input stage.
Figure 1 shows the DC-coupled, gain of +2, dual power
supply circuit configuration used as the basis of the ±5V
Specifications and Typical Performance Curves. This is for
one channel. The other channel is connected similarly. For
test purposes, the input impedance is set to 50Ω with a
resistor to ground and the output impedance is set to 50Ω
with a series output resistor. Voltage swings reported in the
specifications are taken directly at the input and output pins,
while output powers (dBm) are at the matched 50Ω load. For
the circuit of Figure 1, the total effective load will be 100Ω
|| 804Ω. The disable control line (SO-14 package only) is
typically left open to guarantee normal amplifier operation.
Two optional components are included in Figure 1. An
additional resistor (175Ω) is included in series with the non-
inverting input. Combined with the 25Ω DC source resis-
tance looking back towards the signal generator, this gives an
input bias current cancelling resistance that matches the
200Ω source resistance seen at the inverting input (see the
DC Accuracy and Offset Control section). In addition to the
usual power supply decoupling capacitors to ground, a 0.1µF
capacitor is included between the two power supply pins. In
practical PC board layouts, this optional-added capacitor will
typically improve the 2nd harmonic distortion performance
by 3dB to 6dB.
Figure 2 shows the AC-coupled, gain of +2, single supply
circuit configuration which is the basis of the +5V Specifi-
cations and Typical Performance Curves. Though not a “rail-
to-rail” design, the OPA2680 requires minimal input and
output voltage headroom compared to other very wideband
voltage feedback op amps. It will deliver a 3Vp-p output
swing on a single +5V supply with >150MHz bandwidth.
The key requirement of broadband single-supply operation is
to maintain input and output signal swings within the useable
voltage ranges at both the input and the output. The circuit
of Figure 2 establishes an input midpoint bias using a simple
resistive divider from the +5V supply (two 698Ω resistors).
Separate networks would be required at each input. The
input signal is then AC-coupled into the midpoint voltage
bias. The input voltage can swing to within 1.5V of either
supply pin, giving a 2Vp-p input signal range centered
between the supply pins. The input impedance matching
resistor (59Ω) used for testing is adjusted to give a 50Ω input
load when the parallel combination of the biasing divider
network is included. Again, an additional resistor (50Ω in
this case) is included directly in series with the non-inverting
input. This minimum recommended value provides part of
the DC source resistance matching for the non-inverting
input bias current. It is also used to form a simple parasitic
pole to roll off the frequency response at very high frequen-
cies (>500MHz) using the input parasitic capacitance. The
gain resistor (RG) is AC-coupled, giving the circuit a DC
gain of +1, which puts the input DC bias voltage (2.5V) on
the output as well. The output voltage can swing to within
1V of either supply pin while delivering >100mA output
+5V
0.1µF
6.8µF
+
50Ω Source
175Ω
VI 50Ω
VD
1/2
OPA2680
DIS
VO 50Ω
50Ω Load
0.1µF
RF
402Ω
+5V
+VS
698Ω
+
0.1µF
6.8µF
0.1µF
50Ω
DIS
VI
698Ω
VD
1/2
VO 100Ω
59Ω OPA2680
VS/2
RF
402Ω
RG
402Ω
+ 6.8µF
0.1µF
RG
402Ω
0.1µF
–5V
FIGURE 1. DC-Coupled, G = +2, Bipolar Supply, Specifi- FIGURE 2. AC-Coupled, G = +2, Single Supply Specifica-
cation and Test Circuit.
tion and Test Circuit.
®
11 OPA2680
11 Page |
Páginas | Total 21 Páginas | |
PDF Descargar | [ Datasheet OPA2680.PDF ] |
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