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PDF OPA680 Data sheet ( Hoja de datos )
| Número de pieza | OPA680 | |
| Descripción | Wideband / Voltage Feedback OPERATIONAL AMPLIFIER With Disable TM | |
| Fabricantes | Burr-Brown | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de OPA680 (archivo pdf) en la parte inferior de esta página. Total 21 Páginas | ||
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®
OPA680
OPA680
OPA680
OPA680
TM Wideband, Voltage Feedback
OPERATIONAL AMPLIFIER With Disable
FEATURES
q WIDEBAND +5V OPERATION: 220MHz (G = 2)
q UNITY GAIN STABLE: 400MHz (G = 1)
q HIGH OUTPUT CURRENT: 150mA
q OUTPUT VOLTAGE SWING: ±4.0V
q HIGH SLEW RATE: 1800V/µs
q LOW SUPPLY CURRENT: 6.4mA
q LOW DISABLED CURRENT: 300µA
q ENABLE/DISABLE TIME: 25ns/100ns
APPLICATIONS
q VIDEO LINE DRIVER
q xDSL LINE DRIVER/RECEIVER
q HIGH SPEED IMAGING CHANNELS
q ADC BUFFERS
q PORTABLE INSTRUMENTS
q TRANSIMPEDANCE AMPLIFIERS
q ACTIVE FILTERS
DESCRIPTION
The OPA680 represents a major step forward in unity gain
stable, voltage feedback op amps. A new internal architec-
ture provides slew rate and full power bandwidth previously
found only in wideband current feedback op amps. A new
output stage architecture delivers high currents with a mini-
mal headroom requirement. These combine to give excep-
tional single supply operation. Using a single +5V supply,
the OPA680 can deliver a 1V to 4V output swing with over
100mA drive current and 150MHz bandwidth. This combi-
nation of features makes the OPA680 an ideal RGB line
driver or single supply ADC input driver.
The OPA680’s low 6.4mA supply current is precisely
trimmed at 25°C. This trim, along with low temperature
drift, guarantees lower maximum supply current than com-
peting products. System power may be reduced further using
the optional disable control pin. Leaving this disable pin
open, or holding it high, will operate the OPA680 normally.
If pulled low, the OPA680 supply current drops to less than
300µA while the output goes to a high impedance state. This
feature may be used for either power savings or to imple-
ment video MUX applications.
OPA680 RELATED PRODUCTS
Voltage Feedback
Current Feedback
Fixed Gain
SINGLES
OPA680
OPA681
OPA682
DUALS
OPA2680
OPA2681
OPA2682
TRIPLES
OPA3680
OPA3681
OPA3682
0.1µF 400Ω
0.5Vp-p 0.1µF
VIN
50Ω
+5V
1.2kΩ
DIS
40Ω
OPA680
2Vp-p
1.15kΩ
Clock
+5V
3kΩ
+3.5V
+VS REFT
Analog
Input
22pF
ADS822
10-Bit
40MSPS
+2.5V
CM
0.1µF
0.1µF
Single-Supply, High Speed, 10-Bit Digitzer
Gnd REFB
3kΩ
+1.5V
0.1µF
International 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-11426E
OPA680Printed 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
2.0
1.6
0.8
0.4 G = +2
VIN = +1V
0
Output Voltage
Time (50ns/div)
6.0
4.0
2.0
0
DISABLED FEEDTHROUGH vs FREQUENCY
–45
–50 VDIS = 0
–55
–60
–65
–70
Forward
Reverse
–75
–80
–85
–90
–95
1
10
Frequency (MHz)
100
®
5 OPA680
5 Page 
APPLICATIONS INFORMATION
WIDEBAND VOLTAGE FEEDBACK OPERATION
The OPA680 provides an exceptional combination of high
output power capability with a 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 OPA680 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). This exceptional
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 OPA680 is exception-
ally 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. 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 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 resistance looking back towards the signal genera-
tor, 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 OPA680 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).
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 to
form a bandlimiting pole. The gain resistor (RG) is AC-
coupled, giving the circuit a DC gain of +1, which puts the
input DC bias voltage (2.5V) at the output as well. The
+5V
0.1µF
6.8µF
+
50Ω Source
175Ω
VI 50Ω
OPA680
DIS
50Ω Load
VO 50Ω
+5V
+VS
50Ω Source
0.1µF
VI 59Ω
698Ω
+
0.1µF
6.8µF
50Ω DIS
698Ω OPA680
VO 100Ω
VS/2
0.1µF
RG
402Ω
RF
402Ω
+ 6.8µF
–5V
0.1µF
RG
402Ω
0.1µF
RF
402Ω
FIGURE 1. DC-Coupled, G = +2, Bipolar Supply, Specifi-
cation and Test Circuit.
FIGURE 2. AC-Coupled, G = +2, Single Supply, Specifica-
tion and Test Circuit.
®
11 OPA680
11 Page | ||
| Páginas | Total 21 Páginas | |
| PDF Descargar | [ Datasheet OPA680.PDF ] | |
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