XR1008, XR2008
0.5mA, 75MHz Rail-to-Rail Amplifiers
General Description
The XR1008 (single) and XR2008 (dual) are rail-to-rail output amplifiers that
offer superior dynamic performance with 75MHz small signal bandwidth
and 50V/μs slew rate. The XR1008 and XR2008 amplifiers consume only
505μA of supply current per channel and are designed to operate from a
supply range of 2.5V to 5.5V (±1.25 to ±2.75).
The combination of low power, high output current drive, and rail-to-rail
performance make the XR1008 and XR2008 well suited for battery-powered
metering and test equipment.
The combination of low cost and high performance make these amplifiers
suitable for high volume industrial applications such as ultrasonic heat
meters, water meters and other applications requiring high speed and low
power.
FE ATURE S
■ 505μA supply current
■ 75MHz bandwidth
■ Input voltage range with 5V supply:
-0.3V to 3.8V
■ Output voltage range with 5V supply:
0.07V to 4.86V
■ 50V/μs slew rate
■ 12nV/√Hz input voltage noise
■ 15mA linear output current
■ Fully specified at 2.7V and 5V supplies
A P P LI CATION S
■ Portable/battery-powered applications
■ Mobile communications, cell phones,
pagers
■ ADC buffer
■ Active filters
■ Portable test instruments
■ Signal conditioning
■ Medical equipment
■ Portable medical instrumentation
■ Flow meters
Ordering Information - back page
Frequency Response vs. Temperature
Typical Application
+2.7
Magnitude (1dB/div)
6.8μF
+
In
+
0.1μF
Out
XR1008
RIN
ROUT
Rf
Rg
0.01
0.1
1
10
100
Frequency (MHz)
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exar.com/XR1008
Rev 1B
XR1008, XR2008
Absolute Maximum Ratings
Operating Conditions
Stresses beyond the limits listed below may cause
permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect
device reliability and lifetime.
Supply Voltage Range ...................................................2.5 to 5.5V
Operating Temperature Range ...............................-40°C to 125°C
Junction Temperature ........................................................... 150°C
Storage Temperature Range...................................-65°C to 150°C
Lead Temperature (Soldering, 10s) ......................................260°C
VS ..................................................................................... 0V to 6V
VIN ............................................................ -VS - 0.5V to +VS +0.5V
Package Thermal Resistance
Continuous Output Current ..................................-30mA to +30mA
θJA (TSOT-5) .....................................................................215°C/W
θJA (SOIC-8) .....................................................................150°C/W
θJA (MSOP-8) .................................................................. 200°C/W
Package thermal resistance (θJA), JEDEC standard, multi-layer
test boards, still air.
ESD Protection
XR1008 (HBM) .........................................................................2kV
XR2008 (HBM) ......................................................................2.5kV
ESD Rating for HBM (Human Body Model).
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exar.com/XR1008
Rev 1B
XR1008, XR2008
Electrical Characteristics at +2.7V
TA = 25°C, VS = +2.7V, Rf = Rg = 1kΩ, RL = 1kΩ to VS/2; G = 2; unless otherwise noted.
Symbol
Parameter
Conditions
Min
Typ
Max
Units
Frequency Domain Response
UGBWSS
Unity Gain -3dB Bandwidth
G = +1, VOUT = 0.05Vpp, Rf = 0
65
MHz
BWSS
-3dB Bandwidth
G = +2, VOUT < 0.2Vpp
30
MHz
BWLS
Large Signal Bandwidth
G = +2, VOUT = 2Vpp
12
MHz
GBWP
Gain Bandwidth Product
G = +11, VOUT = 0.2Vpp
28
MHz
Time Domain Response
tR, tF
Rise and Fall Time
VOUT = 0.2V step; (10% to 90%)
7.5
ns
tS
Settling Time to 0.1%
VOUT = 1V step
60
ns
OS
Overshoot
VOUT = 1V step
10
%
SR
Slew Rate
G = -1, 2V step
40
V/μs
Distortion/Noise Response
HD2
2nd Harmonic Distortion
1MHz, VOUT = 1Vpp
-67
dBc
HD3
3rd Harmonic Distortion
1MHz, VOUT = 1Vpp
-72
dBc
THD
Total Harmonic Distortion
1MHz, VOUT = 1Vpp
65
dB
en
Input Voltage Noise
>10kHz
12
nV/√Hz
DC Performance
VIO
Input Offset Voltage
0
mV
dVIO
Average Drift
10
μV/°C
IB
Input Bias Current
1.2
μA
dIB
Average Drift
3.5
nA/°C
IOS
Input Offset Current
30
nA
PSRR
Power Supply Rejection Ratio
DC
66
dB
AOL
Open Loop Gain
VOUT = VS / 2
98
dB
IS
Supply Current
per channel
470
μA
60
Input Characteristics
RIN
Input Resistance
CIN
Input Capacitance
CMIR
Common Mode Input Range
CMRR
Common Mode Rejection Ratio
Non-inverting
9
MΩ
1.5
pF
-0.3 to
1.5
V
74
dB
RL = 1kΩ to VS / 2
0.09 to
2.53
V
RL = 10kΩ to VS / 2
0.05 to
2.6
V
DC, VCM = 0V to VS - 1.5V
Output Characteristics
VOUT
Output Voltage Swing
IOUT
Output Current
±15
mA
ISC
Short Circuit Current
±30
mA
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exar.com/XR1008
Rev 1B
XR1008, XR2008
Electrical Characteristics at +5V
TA = 25°C, VS = +5V, Rf = Rg = 1kΩ, RL = 1kΩ to VS/2; G = 2; unless otherwise noted.
Symbol
Parameter
Conditions
Min
Typ
Max
Units
Frequency Domain Response
UGBWSS
Unity Gain -3dB Bandwidth
G = +1, VOUT = 0.05Vpp, Rf = 0
75
MHz
BWSS
-3dB Bandwidth
G = +2, VOUT < 0.2Vpp
35
MHz
BWLS
Large Signal Bandwidth
G = +2, VOUT = 2Vpp
15
MHz
GBWP
Gain Bandwidth Product
G = +11, VOUT = 0.2Vpp
33
MHz
Time Domain Response
tR, tF
Rise and Fall Time
VOUT = 0.2V step; (10% to 90%)
6
ns
tS
Settling Time to 0.1%
VOUT = 1V step
60
ns
OS
Overshoot
VOUT = 1V step
12
%
SR
Slew Rate
G = -1, 2V step
50
V/μs
Distortion/Noise Response
HD2
2nd Harmonic Distortion
1MHz, VOUT = 2Vpp
-64
dBc
HD3
3rd Harmonic Distortion
1MHz, VOUT = 2Vpp
-62
dBc
THD
Total Harmonic Distortion
1MHz, VOUT = 2Vpp
60
dB
en
Input Voltage Noise
>10kHz
12
nV/√Hz
DC Performance
VIO
Input Offset Voltage
dVIO
Average Drift
IB
Input Bias Current
-5
-1
5
mV
10
-3.5
1.2
dIB
Average Drift
3.5
IOS
Input Offset Current
30
PSRR
Power Supply Rejection Ratio
DC
60
AOL
Open Loop Gain
VOUT = VS / 2
65
IS
Supply Current
per channel
μV/°C
3.5
nA/°C
350
66
nA
dB
80
505
μA
dB
620
μA
Input Characteristics
RIN
Input Resistance
CIN
Input Capacitance
CMIR
Common Mode Input Range
CMRR
Common Mode Rejection Ratio
Non-inverting
DC, VCM = 0V to VS - 1.5V
9
MΩ
1.5
pF
-0.3 to
3.8
V
65
74
dB
0.2 to
4.65
0.13 to
4.73
V
0.08 to
4.84
V
Output Characteristics
RL = 1kΩ to VS / 2
VOUT
Output Voltage Swing
RL = 10kΩ to VS / 2
IOUT
Output Current
±15
mA
ISC
Short Circuit Current
±30
mA
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exar.com/XR1008
Rev 1B
XR1008, XR2008
XR1008 Pin Configurations
XR1008 Pin Assignments
TSOT-5
TSOT-5
OUT
1
-Vs
2
+IN
3
+Vs
5
+
-IN
4
SOIC-8
NC
Pin Name
Description
1
OUT
Output
2
-VS
Negative supply
3
+IN
Positive input
4
-IN
Negative input
5
+VS
Positive supply
SOIC-8
NC
8
1
-IN
2
-
7
+Vs
+IN
3
+
6
OUT
-Vs
Pin No.
NC
5
4
Pin No.
Pin Name
Description
1
NC
No Connect
2
-IN
Negative input
3
+IN
Positive input
4
-VS
Negative supply
5
NC
No Connect
6
OUT
Output
7
+VS
Positive supply
8
NC
No Connect
XR2008 Pin Configuration
XR2008 Pin Assignments
SOIC-8 / MSOP-8
SOIC-8 / MSOP-8
OUT1
1
2
-
+IN1
3
+
-Vs
4
© 2014 Exar Corporation
+
Pin Name
1
OUT1
Description
Output, channel 1
+Vs
2
-IN1
Negative input, channel 1
7
OUT2
3
+IN1
Positive input, channel 1
4
-VS
6
-IN2
5
+IN2
Positive input, channel 2
6
-IN2
Negative input, channel 2
7
OUT2
8
+VS
8
-IN1
Pin No.
5
+IN2
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Negative supply
Output, channel 2
Positive supply
exar.com/XR1008
Rev 1B
XR1008, XR2008
Typical Performance Characteristics
TA = 25°C, VS = +5V, Rf = Rg = 1kΩ, RL = 1kΩ to VS/2; G = 2; unless otherwise noted.
Inverting Frequency Response at VS = 5V
Normalized Magnitude (1dB/div)
Normalized Magnitude (1dB/div)
Non-Inverting Frequency Response at VS = 5V
G=1
Rf = 0
G=2
Rf = 1k1
G = 10
Rf = 1k1
G=5
Rf = 1k1
0.1
1
10
0.1
100
Frequency (MHz)
Normalized Magnitude (1dB/div)
Normalized Magnitude (2dB/div)
G=2
Rf = 1k1
G = 10
Rf = 2k1
G=5
Rf = 1k1
10
G = -5
Rf = 1k1
G = -1
Rf = 1k1
1
10
0.1
100
Frequency (MHz)
G = -1
Rf = 1k1
G = -2
Rf = 1k1
G = -10
Rf = 1k1
G = -5
Rf = 1k1
1
10
Frequency Response vs RL
RL = 1k1
Magnitude (1dB/div)
Magnitude (1dB/div)
CL = 10pF
Rs = 01
CL = 20pF
Rs = 1001
CL = 50pF
Rs = 1001
+
-
Rs
CL
1k1
100
Frequency (MHz)
Frequency Response vs CL
CL = 100pF
Rs = 1001
100
Inverting Frequency Response at VS = 2.7V
G=1
Rf = 0
1
G = -10
Rf = 1k1
Frequency (MHz)
Non-Inverting Frequency Response at VS = 2.7V
0.1
G = -2
Rf = 1k1
RL
RL = 10k1
RL = 1001
1k1
0.1
1
10
100
0.1
Frequency (MHz)
© 2014 Exar Corporation
1
10
100
Frequency (MHz)
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exar.com/XR1008
Rev 1B
XR1008, XR2008
Typical Performance Characteristics
TA = 25°C, VS = +5V, Rf = Rg = 1kΩ, RL = 1kΩ to VS/2; G = 2; unless otherwise noted.
Frequency Response vs. VOUT
Open Loop Gain & Phase vs. Frequency
90
Open Loop Gain (dB)
80
Vo = 2Vpp
Vo = 4Vpp
Gain
70
60
50
40
Phase
30
0
20
-45
10
-90
0
-135
-10
0.1
1
10
100
100
1k
10k
Frequency (MHz)
1M
10M
-180
100M
3rd Harmonic Distortion vs VOUT
-20
-20
-30
-30
-40
-40
Distortion (dB)
Distortion (dBc)
100k
Frequency (Hz)
2nd Harmonic Distortion vs VOUT
-50
-60
1MHz
-70
500kHz
-80
-50
-60
500kHz
-70
1MHz
100kHz
-80
100kHz
-90
-90
0.5
1
1.5
2
0.5
2.5
Output Amplitude (Vpp)
-20
1.0
1.5
2.0
2.5
Output Amplitude (Vpp)
2nd & 3rd Harmonic Distortion at VS = 2.7V
Frequency Response vs. Temperature
Vo = 1Vpp
3rd
RL = 1501
-40
3rd
RL = 1k1
Magnitude (1dB/div)
-30
Distortion (dBc)
Open Loop Phase (deg)
Magnitude (1dB/div)
Vo = 1Vpp
-50
-60
2nd
RL = 1k1
-70
2nd
RL = 1501
-80
-90
0
1
2
3
4
0.01
5
Frequency (MHz)
© 2014 Exar Corporation
0.1
1
10
100
Frequency (MHz)
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exar.com/XR1008
Rev 1B
XR1008, XR2008
Typical Performance Characteristics
TA = 25°C, VS = +5V, Rf = Rg = 1kΩ, RL = 1kΩ to VS/2; G = 2; unless otherwise noted.
CMRR
PSRR
0
0
-10
-10
-20
-20
PSRR (dB)
CMRR (dB)
-30
-40
-50
-60
-70
-30
-40
-50
-60
-80
-70
-90
-100
-80
100
1k
10k
100k
1M
10M
100
100M
Frequency (Hz)
Output Swing
1k
10k
100k
1M
10M
100M
Frequency (Hz)
Output Voltage vs. Output Current
3
Output Voltage (0.5V/div)
Output Voltage (0.6V/div)
2.7
0
-3
0
50
Time (1+s/div)
Output Voltage (20mV/div)
Small Signal Pulse Response at VS = 5V
Time (10ns/div)
© 2014 Exar Corporation
-50
Output Current (10mA/div)
Output Voltage (20mV/div)
Small Signal Pulse Response at VS = 2.7V
0
Time (10ns/div)
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exar.com/XR1008
Rev 1B
XR1008, XR2008
Typical Performance Characteristics
TA = 25°C, VS = +5V, Rf = Rg = 1kΩ, RL = 1kΩ to VS/2; G = 2; unless otherwise noted.
Large Signal Pulse Response at VS = 5V
Input Voltage Noise
Voltage Noise (nV/3Hz)
Output Voltage (0.5V/div)
70
60
50
40
30
20
10
0
0.0001
Time (10ns/div)
© 2014 Exar Corporation
0.001
0.01
0.1
1
10
Frequency (MHz)
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exar.com/XR1008
Rev 1B
XR1008, XR2008
Application Information
+Vs
6.8μF
General Description
The XR1008 family are a single supply, general purpose,
voltage-feedback amplifiers fabricated on a complementary
bipolar process. The XR1008 offers 75MHz unity gain
bandwidth, 50V/μs slew rate, and only 505μA supply current.
It features a rail-to-rail output stage and is unity gain stable.
Input
0.1μF
+
Output
RL
0.1μF
Figures 1, 2, and 3 illustrate typical circuit configurations for
non-inverting, inverting, and unity gain topologies for dual
supply applications. They show the recommended bypass
capacitor values and overall closed loop gain equations.
Figure 4 shows the typical non-inverting gain circuit for
single supply applications.
6.8μF
Figure 3: Unity Gain Circuit
The common mode input range extends to 300mV below
ground in single supply operation. Exceeding these values
will not cause phase reversal. However, if the input voltage
exceeds the rails by more than 0.5V, the input ESD devices
will begin to conduct.
+Vs
6.8μF
+
The design uses a Darlington output stage. The output
stage is short circuit protected and offers “soft” saturation
protection that improves recovery time.
In
+
-
6.8μF
Out
Rg
Figure 4: Single Supply Non-Inverting Gain Circuit
0.1μF
+
0.1μF
Rf
+Vs
Input
G=1
-Vs
Output
-
For optimum response at a gain of +2, a feedback resistor
of 1kΩ is recommended. Figure 5 illustrates the XR1008
frequency response with both 1kΩ and 2kΩ feedback
resistors.
RL
0.1μF
Rg
6.8μF
-Vs
Rf
G = 1 + (Rf/Rg)
Figure 1: Typical Non-Inverting Gain Circuit
G=2
RL = 1kΩ
Magnitude (1dB/div)
+Vs
6.8μF
R1
Input
Rg
0.1μF
+
Rf = 2kΩ
Rf = 1kΩ
Output
RL
0.1μF
6.8μF
-Vs
0.1
Rf
1
10
100
Frequency (MHz)
Figure 5: Frequency Response vs. Rf
G = - (Rf/Rg)
For optimum input offset
voltage set R1 = Rf || Rg
Figure 2: Typical Inverting Gain Circuit
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exar.com/XR1008
Rev 1B
XR1008, XR2008
Power Dissipation
Power dissipation should not be a factor when operating
under the stated 1kΩ load condition. However, applications
with low impedance, DC coupled loads should be analyzed
to ensure that maximum allowed junction temperature is
not exceeded. Guidelines listed below can be used to verify
that the particular application will not cause the device to
operate beyond it’s intended operating range.
Assuming the load is referenced in the middle of the power
rails or Vsupply/2.
The XR1008 is short circuit protected. However, this may not
guarantee that the maximum junction temperature (+150°C)
is not exceeded under all conditions. Figure 6 shows the
maximum safe power dissipation in the package vs. the
ambient temperature for the packages available.
1.5
Maximum Power Dissipation (W)
Maximum power levels are set by the absolute maximum
junction rating of 150°C. To calculate the junction
temperature, the package thermal resistance value ThetaJA
(θJA) is used along with the total die power dissipation.
TJunction = TAmbient + (θJA × PD)
Where TAmbient is the temperature of the working
environment.
In order to determine PD, the power dissipated in the load
needs to be subtracted from the total power delivered by the
supplies.
SOIC-8
1
0.5
MSOP-8
TSOT-5
0
-40
-20
0
20
40
60
80
100
120
Ambient Temperature (°C)
PD = Psupply - Pload
Figure 6. Maximum Power Derating
Supply power is calculated by the standard power equation.
Psupply = Vsupply × IRMSsupply
Vsupply = VS+ - VSPower delivered to a purely resistive load is:
Pload = ((Vload)RMS2)/Rloadeff
The effective load resistor (Rloadeff) will need to include the
effect of the feedback network. For instance,
Driving Capacitive Loads
Increased phase delay at the output due to capacitive loading
can cause ringing, peaking in the frequency response, and
possible unstable behavior. Use a series resistance, RS,
between the amplifier and the load to help improve stability
and settling performance. Refer to Figure 7.
Rloadeff in Figure 3 would be calculated as:
Input
+
RL || (Rf + Rg)
-
These measurements are basic and are relatively easy to
perform with standard lab equipment. For design purposes
however, prior knowledge of actual signal levels and load
impedance is needed to determine the dissipated power.
Here, PD can be found from
PD = PQuiescent + PDynamic - Pload
Quiescent power can be derived from the specified IS values
along with known supply voltage, Vsupply. Load power can
be calculated as above with the desired signal amplitudes
using:
Rs
Rf
Output
CL
RL
Rg
Figure 7. Addition of RS for Driving Capacitive Loads
Table 1 provides the recommended RS for various capacitive
loads. The recommended RS values result in approximately