NSC CLC5802IM Dual low-noise, voltage feedback op amp Datasheet

CLC5802
Dual Low-Noise, Voltage Feedback Op Amp
General Description
Features
The CLC5802 is a dual op amp that offers a traditional
voltage-feedback topology featuring unity-gain stability. Low
noise and very low harmonic distortion combine to form a
very wide dynamic-range op amp that operates within a
power supply range of 5V to 12V.
Each of the CLC5802’s closely matched channels provides a
140MHz unity-gain bandwidth with a very low input voltage
noise density (4nV/
). Low 2nd/3rd harmonic distortion
(−69/−66dBc) as well as high channel-to-channel isolation
(−61dB) make the CLC5802 a perfect wide dynamic-range
amplifier for I/Q channels and other application which require
low distortion and matching. With its fast and accurate settling (18ns to 0.1%), the CLC5802 is also a excellent choice
for wide-dynamic range, anti-aliasing filters to buffer the inputs of hi-resolution analog-to-digital converters. Combining
the CLC5802 two tightly-matched amplifiers in a single
eight-pin SOIC reduces cost and board space for many composite amplifier applications such as active filters, differential
line drivers/receivers, fast peak detectors and instrumentation amplifiers.
(TA = 25˚C, VS = ± 5V, RL = 100Ω, Typical unless specified).
n Wide unity-gain bandwidth: 140MHz
n Ultra-low noise: 4nV/
, 2pA/
n Low distortion: −69/−66dBc (5MHz)
n Settling time: 18ns to 0.1%
n High output current: ± 70mA
n Supply voltage range: 5V to 12V
Applications
n
n
n
n
n
n
n
General purpose dual op amp
Low noise active filters
Low noise integrators
High-speed detectors
Diff-in/diff-out instrumentation amp
I/Q channel amplifiers
Driver/receiver for transmission systems
Equivalent Input Noise
DS101341-16
Typical Application
Full Duplex Transmission
DS101341-28
© 2000 National Semiconductor Corporation
DS101341
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CLC5802 Dual Low-Noise, Voltage Feedback Op Amp
May 2000
CLC5802
Connection Diagram
8-Pin SOIC
DS101341-2
Top View
Ordering Information
Package
8-pin SOIC
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Part Number
Packaging
Marking
Transport Media
NSC
Drawing
CLC5802IM
CLC5802IMX
CLC5802IM
Rails
M08A
CLC5802IM
2.5k Tape and Reel
2
Storage Temperature
Lead Temperature (soldering 10 sec)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Operating Rating(Note 1)
± 7V
(Note 3)
± VCC
± 10V
+125˚C
Supply Voltage
Short Circuit Current
Common-Mode Input Voltage
Differential Input Voltage
Maximum Junction Temperature
−65˚C to +150˚C
+300˚C
Thermal Resistance (θJC)
40˚C/W
Thermal Resistance (θJA)
115˚C/W
Temperature Range
−40˚C to +85˚C
Supply Voltage Range
5V to 12V
Electrical Characteristics
(TA = +25˚C, VCC = ± 5V, AV = +2V/V, Rf = 100Ω, Rg = 100Ω, RL = 100Ω; unless specified).
Symbol
Parameter
Conditions
Typ
+25˚C
Min/Max Ratings
(Note 2)
+25˚C
0˚C to
+70˚C
Units
−40˚C
to
+85˚C
Frequency Domain Response
GBW
Gain Bandwidth Product
VOUT < 0.5VPP
120
90
SSBW
−3dB Bandwidth (AV = +1)
VOUT < 0.5VPP
140
110
−3dB Bandwidth (AV = +2)
VOUT < 0.5VPP
75
50
LSBW
−3dB Bandwidth
VOUT < 5.0VPP
40
25
GFP
Gain Flatness Peaking
DC to 200MHz, VOUT < 0.5
VPP
0.0
0.6
dB
GFR
Gain Flatness Rolloff
DC to 20MHz, VOUT < 0.5
VPP
0.05
0.5
dB
LPD
Linear Phase Deviation
DC to 20MHz
0.2
1.0
Deg
MHz
Time Domain Response
TRS
Rise and Fall Time
1V step
6
8
ns
TSS
Settling Time
2V step to 0.1%
18
22
ns
OS
Overshoot
1V step
1
5
%
SR
Slew Rate
5V step
450
275
V/µs
Distortion And Noise Response
HD2
2nd Harmonic Distortion
1VPP, 5MHz
−69
−57
dBc
HD3
3rd Harmonic Distortion
1VPP, 5MHz
−66
−54
dBc
VN
Equivalent Input Noise Voltage
1MHz to 100MHz
4.0
4.5
nV/
ICN
Equivalent Input Noise Current
1MHz to 100MHz
2.0
3.0
pA/
CT
Crosstalk
Input referred, 10MHz
−61
−58
dB
Static, DC Performance
AOL
Open-Loop Gain
60
56
50
50
dB
VIO
Input Offset Voltage (Note 4)
DC
± 1.0
± 2.0
± 3.0
± 3.5
mV
DVIO
Offset Voltage Average Drift
5
–
15
20
µV/˚C
IB
Input Bias Current (Note 4)
1.5
25
40
65
µA
DIB
Bias Current Average Drift
150
–
600
700
nA/˚C
IIO
Input Offset Current
0.3
3
5
5
µA
DIIO
Offset Current Average Drift
5
–
25
50
nA/˚C
PSRR
Power Supply Rejection Ratio
DC
63
57
55
55
dB
CMRR
Common Mode Rejection Ratio
DC
60
54
52
52
dB
ICC
Supply Current (Note 4)
Per Channel, RL = ∞
11
12
13
15
mA
3
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CLC5802
Absolute Maximum Ratings (Note 1)
CLC5802
Electrical Characteristics
(Continued)
(TA = +25˚C, VCC = ± 5V, AV = +2V/V, Rf = 100Ω, Rg = 100Ω, RL = 100Ω; unless specified).
Symbol
Parameter
Conditions
Typ
Min/Max Ratings
(Note 2)
Units
+25˚C
+25˚C
0˚C to
+70˚C
−40˚C
to
+85˚C
Common-Mode
500
250
125
125
kΩ
Differential-Mode
200
50
25
25
kΩ
Miscellaneous Performance
RINC
Input Resistance
RIND
CINC
Input Capacitance
CIND
Common-Mode
2.0
3.0
3.0
3.0
pF
Differential-Mode
2.0
3.0
3.0
3.0
pF
0.2
Ω
ROUT
Output Resistance
Closed Loop
0.05
0.1
VO
Output Voltage Range
RL = ∞
± 3.6
± 3.4
± 3.7
± 70
± 3.5
± 3.2
± 3.5
± 50
VOL
RL = 100Ω
CMIR
Input Voltage Range
IO
Output Current
Common-Mode
0.2
± 3.3
± 2.6
± 3.3
± 40
± 3.3
± 1.3
± 3.3
± 20
V
V
V
mA
Note 1: “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the devices
should be operated at these limits. The table of “Electrical Characteristics” specifies conditions of device operation. Operating Ratings indicate conditions for which
the device is intended to be functional, but specific performance is not guaranteed,
Note 2: Min/max ratings are based on product characterization and simulation. Individual parameters are tested as noted. Outgoing quality levels are determined
from tested parameters.
Note 3: Output is short circuit protected to ground, however maximum reliability is obtained if output current does not exceed 160mA.
Note 4: 100% tested at +25˚C.
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4
(TA = 25˚C, VCC = ± 5V, Rg = 26.1Ω, Rf = 499Ω, RL = 100Ω,
unless otherwise specified).
Non-Inverting Frequency Response
Inverting Frequency Response
DS101341-3
Frequency Response vs. Load Resistance
DS101341-4
Frequency Response vs. Output Amplitude
DS101341-5
Frequency Response vs. Capacitive Load
DS101341-6
Gain Flatness & Linear Phase Deviation
DS101341-8
DS101341-7
5
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CLC5802
Typical Performance Characteristics
CLC5802
Typical Performance Characteristics
(TA = 25˚C, VCC = ± 5V, Rg = 26.1Ω, Rf = 499Ω, RL = 100Ω,
unless otherwise specified).. (Continued)
Maximum Output Voltage vs. Load
Channel-to-Channel Crosstalk
DS101341-9
Open-Loop Gain & Phase
DS101341-10
2nd and 3rd Harmonic Distortion
DS101341-11
2nd Harmonic Distortion vs. Output Voltage
DS101341-12
3rd Harmonic Distortion vs. Output Voltage
DS101341-13
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DS101341-14
6
(TA = 25˚C, VCC = ± 5V, Rg = 26.1Ω, Rf = 499Ω, RL = 100Ω,
unless otherwise specified).. (Continued)
Closed-Loop Output Resistance
Equivalent Input Noise
DS101341-16
DS101341-15
2-Tone, 3rd order Intermodulation Intercept
Pulse Response (VOUT = 100mV)
DS101341-18
DS101341-17
Pulse Response (VOUT = 2V)
Settling Time vs. Capacitive Load
DS101341-19
DS101341-20
7
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CLC5802
Typical Performance Characteristics
CLC5802
Typical Performance Characteristics
(TA = 25˚C, VCC = ± 5V, Rg = 26.1Ω, Rf = 499Ω, RL = 100Ω,
unless otherwise specified).. (Continued)
Short-Term Settling Time
CMRR and PSRR
DS101341-21
Typical DC Errors vs. Temperature
DS101341-22
Output Voltage vs. Output Sourcing Current
DS101341-23
DS101341-37
Output Voltage vs. Output Sinking Current
DS101341-38
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8
Low Noise Design
(B1). If the coax cable is lossless and Rf equals Rg, receiver
A2 (B2) will then reject the signals from driver A1 (B1) and
pass the signals from driver B1 (A1).
Ultimate low noise performance from circuit designs using
the CLC5802 requires the proper selection of external resistors. By selecting appropriate low-valued resistors for Rf and
Rg, amplifier circuits using the CLC5802 can achieve output
noise that is approximately the equivalent voltage input
noise of 4nV/
multiplied by the desired gain (AV).
Each amplifier in the CLC5802 has an equivalent input noise
resistance which is optimum for matching source impedances of approximately 2k. Using a transformer, any source
can be matched to achieve the lowest noise design.
For even lower noise performance than the CLC5802, consider the CLC425, CLC426 or CLC5801 at 1.05, 1.6 and
2nV/
, respectively.
DC Bias Currents and Offset Voltages
Cancellation of the output offset voltage due to input bias
currents is possible with the CLC5802. This is done by making the resistance seen from the inverting and non-inverting
inputs equal. Once done, the residual output offset voltage
will be the input offset voltage (VOS) multiplied by the desired
gain (AV). Application Note OA-7 offers several solutions to
further reduce the output offset.
Output and Supply Considerations
With ± 5V supplies, the CLC5802 is capable of a typical output swing of ± 3.6V under a no-load condition. Additional output swing is possible with slightly higher supply voltages. For
loads of less than 50Ω, the output swing will be limited by the
CLC5802’s output current capability, typically 70mA.
Output settling time when driving capacitive loads can be improved by the use of a series output resistor. See the plot labeled “Settling Time vs. Capacitive Load” in the Typical Performance Characteristics section.
Layout
Proper power supply bypassing is critical to insure good high
frequency performance and low noise. De-coupling capacitors of 0.1µF should be placed as close as possible to the
power supply pins. The use of surface mounted capacitors is
recommended due to their low series inductance.
A good high frequency layout will keep power supply and
ground traces away from the inverting input and output pins.
Parasitic capacitance from these nodes to ground causes
frequency response peaking and possible circuit oscillation.
See OA-15 for more information. National suggests the
CLC730038 (through-hole) or the CLC730036 (SOIC) dual
op amp evaluation board as a guide for high frequency layout and as an aid in device evaluation.
Full Duplex Digital or Analog Transmission
Simultaneous transmission and reception of analog or digital
signals over a single coaxial cable or twisted-pair line can reduce cabling requirements. The CLC5802’s wide bandwidth
and high common-mode rejection in a differential amplifier
configuration allows full duplex transmission of video, telephone, control and audio signals.
In the circuit shown in Figure 1, one of the CLC5802’s amps
is used as a “driver” and the other as a difference “receiver”
amplifier. The output impedance of the “driver” is essentially
zero. The two R’s are chosen to match the characteristic impedance of the transmission line. The “driver” op amp gain
can be selected for unity or greater.
Receiver amplifier A2 (B2) is connected across R and forms
a differential amplifier for the signals transmitted by driver A1
DS101341-28
FIGURE 1.
The output of the receiver amplifier will be:
(1)
Care must be given to layout and component placement to
maintain a high frequency common-mode rejection. The plot
of Figure 2 show the simultaneous reception of signals transmitted at 1MHz and 10MHz.
DS101341-25
FIGURE 2.
Five Decade Integrator
A composite integrator, shown in Figure 3, uses the
CLC5802 dual op amp to increase the circuits usable frequency range of operation. The transfer function of this circuit is:
(2)
DS101341-27
FIGURE 3.
9
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CLC5802
Application Information
CLC5802
Application Information
(Continued)
A resistive divider made from the 143Ω and 60.4Ω resistors
was chosen to reduce the loop-gain and stabilize the network. The CLC5802 composite integrator provides integration over five decades of operation. R and C set the integrator’s gain. Figure 4 shows the frequency and phase
response of the circuit in Figure 3 with R = 44.2Ω and C =
360pF.
DS101341-31
FIGURE 6.
A current source, built around Q1, provides the necessary
bias current for the second amplifier and prevents saturation
when power is applied. The resistor, R, closes the loop while
diode D2 prevents negative saturation when VIN is less than
VC. A MOS-type switch (not shown) can be used to reset the
capacitor’s voltage.
The maximum speed of detection is limited by the delay of
the op amp and the diodes. The use of Schottky diodes will
provide faster response.
Adjustable or Bandpass Equalizer
A “boost” equalizer can be made with the CLC5802 by summing a bandpass response with the input signal, as shown in
Figure 7.
DS101341-29
FIGURE 4.
K: R2/(R1 + R2)
A0: Op amp low Frequency open loop gain
Positive Peak Detector
The CLC5802’s dual amplifiers can be used to implement a
unity-gain peak detector circuit as shown in Figure 5.
DS101341-32
FIGURE 7.
The overall transfer function is shown in Equation (3).
DS101341-30
FIGURE 5.
(3)
To build a boost circuit, use the design Equation 4 and 5.
The acquisition speed of this circuit is limited by the dynamic
resistance of the diode when charging Chold. A plot of the circuit’s performance is shown in Figure 6 with a 1MHz sinusoidal input.
(4)
(5)
Select R2 and C using Equation (4). Use reasonable values
for high frequency circuits - R2 between 10Ω and 5kΩ, C between 10pF and 2000pF. Use Equation (5) to determine the
parallel combination of Ra and Rb. Select Ra and Rb by either the 10Ω to 5kΩ criteria or by other requirements based
on the impedance VIN is capable of driving. Finish the design
by determining the value of K from Equation (6).
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10
CLC5802
Application Information
(Continued)
(6)
Figure 8 shows an example of the response of the circuit of
Figure 7, where fO is 2.3MHz. The component values are as
follows: Ra = 2.1kΩ, Rb = 68.5Ω, R2 = 4.22kΩ, R = 500Ω,
KR = 50Ω, C = 120pF.
DS101341-36
FIGURE 8.
11
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CLC5802 Dual Low-Noise, Voltage Feedback Op Amp
Physical Dimensions
inches (millimeters) unless otherwise noted
8-Pin SOIC
NS Package Number M08A
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