OPA1612
OPA1611
Burr-BrownAudio
Pre-Output Driver OUT
V-
V+
IN-
IN+
OPA1611
OPA1612
www.ti.com
SBOS450B –JULY 2009–REVISED JULY 2011
™
High-Performance, Bipolar-Input
AUDIO OPERATIONAL AMPLIFIERS
Check for Samples: OPA1611,OPA1612
1FEATURES DESCRIPTION
The OPA1611 (single) and OPA1612 (dual)
23•SUPERIOR SOUND QUALITY bipolar-input operational amplifiers achieve very low
•ULTRALOW NOISE: 1.1nV/√Hz at 1kHz 1.1nV/√Hz noise density with an ultralow distortion of
•ULTRALOW DISTORTION: 0.000015% at 1kHz. The OPA1611 and OPA1612
0.000015% at 1kHz offer rail-to-rail output swing to within 600mV with a
•HIGH SLEW RATE: 27V/μs2kΩload, which increases headroom and maximizes
dynamic range. These devices also have a high
•WIDE BANDWIDTH: 40MHz (G = +1) output drive capability of ±30mA.
•HIGH OPEN-LOOP GAIN: 130dB
•UNITY GAIN STABLE These devices operate over a very wide supply range
of ±2.25V to ±18V, on only 3.6mA of supply current
•LOW QUIESCENT CURRENT: per channel. The OPA1611 and OPA1612 op amps
3.6mA PER CHANNEL are unity-gain stable and provide excellent dynamic
•RAIL-TO-RAIL OUTPUT behavior over a wide range of load conditions.
•WIDE SUPPLY RANGE: ±2.25V to ±18V The dual version features completely independent
•SINGLE AND DUAL VERSIONS AVAILABLE circuitry for lowest crosstalk and freedom from
interactions between channels, even when overdriven
APPLICATIONS or overloaded.
•PROFESSIONAL AUDIO EQUIPMENT Both the OPA1611 and OPA1612 are available in
•MICROPHONE PREAMPLIFIERS SO-8 packages and are specified from –40°C to
•ANALOG AND DIGITAL MIXING CONSOLES +85°C. SoundPlus™
•BROADCAST STUDIO EQUIPMENT
•AUDIO TEST AND MEASUREMENT
•HIGH-END A/V RECEIVERS
1Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2SoundPlus is a trademark of Texas Instruments Incorporated.
3All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date. Copyright ©2009–2011, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
1
2
3
4
8
7
6
5
NC(1)
V+
OUT
NC(1)
NC(1)
-IN
+IN
V-
1
2
3
4
8
7
6
5
V+
OUTB
-INB
+INB
OUTA
-INA
+INA
V-
A
B
OPA1611
OPA1612
SBOS450B –JULY 2009–REVISED JULY 2011
www.ti.com
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
ABSOLUTE MAXIMUM RATINGS(1)
Over operating free-air temperature range (unless otherwise noted). VALUE UNIT
Supply Voltage VS= (V+) –(V–) 40 V
Input Voltage (V–)–0.5 to (V+) + 0.5 V
Input Current (All pins except power-supply pins) ±10 mA
Output Short-Circuit(2) Continuous
Operating Temperature (TA)–55 to +125 °C
Storage Temperature (TA)–65 to +150 °C
Junction Temperature (TJ) 200 °C
Human Body Model (HBM) 3000 V
ESD Ratings Charged Device Model (CDM) 1000 V
Machine Model (MM) 200 V
(1) Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may
degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond
those specified is not supported.
(2) Short-circuit to VS/2 (ground in symmetrical dual supply setups), one amplifier per package.
PACKAGE INFORMATION(1)
PRODUCT PACKAGE-LEAD PACKAGE DESIGNATOR PACKAGE MARKING
TI OPA
OPA1611 SO-8 D 1611A
TI OPA
OPA1612 SO-8 D 1612A
(1) For the most current package and ordering information see the Package Option Addendum at the end of this document, or see the TI
web site at www.ti.com.
PIN CONFIGURATIONS
D PACKAGE D PACKAGE
OPA1611, SO-8 OPA1612, SO-8
(TOP VIEW) (TOP VIEW)
(1) NC denotes no internal connection. Pin can be left floating or connected to any voltage between (V–) and (V+).
2Copyright ©2009–2011, Texas Instruments Incorporated
OPA1611
OPA1612
www.ti.com
SBOS450B –JULY 2009–REVISED JULY 2011
ELECTRICAL CHARACTERISTICS: VS=±2.25V to ±18V
At TA= +25°C and RL= 2kΩ, unless otherwise noted. VCM = VOUT = midsupply, unless otherwise noted.
Boldface limits apply over the specified temperature range, TA=–40°C to +85°C. OPA1611AI, OPA1612AI
PARAMETER CONDITIONS MIN TYP MAX UNIT
AUDIO PERFORMANCE
0.000015 %
Total Harmonic Distortion + THD+N G = +1, f = 1kHz, VO= 3VRMS
Noise –136 dB
Intermodulation Distortion IMD G = +1, VO= 3VRMS 0.000015 %
SMPTE/DIN Two-Tone, 4:1 (60Hz and 7kHz) –136 dB
0.000012 %
DIM 30 (3kHz square wave and 15kHz sine wave) –138 dB
0.000008 %
CCIF Twin-Tone (19kHz and 20kHz) –142 dB
FREQUENCY RESPONSE
Gain-Bandwidth Product GBW G = 100 80 MHz
G = 1 40 MHz
Slew Rate SR G = –1 27 V/μs
Full Power Bandwidth(1) VO= 1VPP 4 MHz
Overload Recovery Time G = –10 500 ns
Channel Separation (Dual) f = 1kHz –130 dB
NOISE
Input Voltage Noise f = 20Hz to 20kHz 1.2 μVPP
Input Voltage Noise Density(2) enf = 10Hz 2 nV/√Hz
f = 100Hz 1.5 nV/√Hz
f = 1kHz 1.1 1.5 nV/√Hz
Input Current Noise Density Inf = 10Hz 3 pA/√Hz
f = 1kHz 1.7 pA/√Hz
OFFSET VOLTAGE
Input Offset Voltage VOS VS=±15V ±100 ±500 μV
over Temperature(2) dVOS/dT 1 4 μV/°C
vs Power Supply PSRR VS=±2.25V to ±18V 0.1 1 μV/V
INPUT BIAS CURRENT
Input Bias Current IBVCM = 0V ±60 ±250 nA
over Temperature(2) 350 nA
Input Offset Current IOS VCM = 0V ±25 ±175 nA
INPUT VOLTAGE RANGE
Common-Mode Voltage VCM (V–) + 2 (V+) –2 V
Range
Common-Mode Rejection CMRR (V–) + 2V ≤VCM ≤(V+) –2V 110 120 dB
Ratio
INPUT IMPEDANCE
Differential 20k || 8 Ω|| pF
Common-Mode Ω|| pF
109|| 2
(1) Full-power bandwidth = SR/(2π × VP), where SR = slew rate.
(2) Specified by design and characterization.
Copyright ©2009–2011, Texas Instruments Incorporated 3
OPA1611
OPA1612
SBOS450B –JULY 2009–REVISED JULY 2011
www.ti.com
ELECTRICAL CHARACTERISTICS: VS=±2.25V to ±18V (continued)
At TA= +25°C and RL= 2kΩ, unless otherwise noted. VCM = VOUT = midsupply, unless otherwise noted.
Boldface limits apply over the specified temperature range, TA=–40°C to +85°C. OPA1611AI, OPA1612AI
PARAMETER CONDITIONS MIN TYP MAX UNIT
OPEN-LOOP GAIN
Open-Loop Voltage Gain AOL (V–) + 0.2V ≤VO≤(V+) –0.2V, RL= 10kΩ114 130 dB
AOL (V–) + 0.6V ≤VO≤(V+) –0.6V, RL= 2kΩ110 114 dB
OUTPUT
Voltage Output VOUT RL= 10kΩ, AOL ≥114dB (V–) + 0.2 (V+) –0.2 V
RL= 2kΩ, AOL ≥110dB (V–) + 0.6 (V+) –0.6 V
Output Current IOUT See Figure 27 mA
Open-Loop Output ZOSee Figure 28 Ω
Impedance
Short-Circuit Current ISC +55/–62 mA
Capacitive Load Drive CLOAD See Typical Characteristics pF
POWER SUPPLY
Specified Voltage VS±2.25 ±18 V
Quiescent Current IQIOUT = 0A 3.6 4.5 mA
(per channel)
over Temperature(3) 5.5 mA
TEMPERATURE RANGE
Specified Range –40 +85 °C
Operating Range –55 +125 °C
Thermal Resistance θJA
SO-8 150 °C/W
(3) Specified by design and characterization.
4Copyright ©2009–2011, Texas Instruments Incorporated
20nV/div
Time(1s/div)
VoltageNoiseDensity(nV/ )ÖHz
CurrentNoiseDensity(pA/ )ÖHz
0.1
Frequency(Hz)
100k101 100 1k 10k
100
10
1
CurrentNoiseDensity
VoltageNoiseDensity
30
25
20
15
10
5
0
Output Voltage (V )
PP
10k 100k 1M 10M
Frequency (Hz)
V = 2.25V
S±
V = 5V
S±
V = 15V
S±Maximum output
voltage range
without slew-rate
induced distortion
140
120
100
80
60
40
20
0
20
40
-
-
180
160
140
120
100
80
60
40
20
0
Gain(dB)
Phase(degrees)
100 1k 10k 100k 1M 10M 100M
Frequency(Hz)
Phase
Gain
25
20
15
10
5
0
5
10
15
20
25-
-
-
-
-
Gain(dB)
100k 1M 10M 100M
Frequency(Hz)
G=+10
G=+1
G= 1-
OPA1611
OPA1612
www.ti.com
SBOS450B –JULY 2009–REVISED JULY 2011
TYPICAL CHARACTERISTICS
At TA= +25°C, VS=±15V, and RL= 2kΩ, unless otherwise noted.
INPUT VOLTAGE NOISE DENSITY AND
INPUT CURRENT NOISE DENSITY vs FREQUENCY 0.1Hz TO 10Hz NOISE
Figure 1. Figure 2.
VOLTAGE NOISE vs SOURCE RESISTANCE MAXIMUM OUTPUT VOLTAGE vs FREQUENCY
Figure 3. Figure 4.
GAIN AND PHASE vs FREQUENCY CLOSED-LOOP GAIN vs FREQUENCY
Figure 5. Figure 6.
Copyright ©2009–2011, Texas Instruments Incorporated 5
0.01
0.001
0.0001
0.00001
-
-
-
-
80
100
120
140
Total Harmonic Distortion + Noise (dB)
Total Harmonic Distortion + Noise (%)
20 100 1k 10k 20k
Frequency (Hz)
R = 600W
SOURCE
R = 300W
SOURCE
R = 150W
SOURCE
R = 0W
SOURCE
V = 3V
BW = 80kHz
OUT RMS
OPA1611
+15V
-15V RL
RSOURCE
0.0001
0.00001
-
-
120
140
Total Harmonic Distortion + Noise (%)
Total Harmonic Distortion + Noise (dB)
10 100 1k 10k 20k
Frequency (Hz)
V = 3V
BW = 80kHz
OUT RMS
G = +1, R = 600W
L
G = +1, R = 2k
G = 1, R = 600
L
L
W
- W
G = 1, R = 2k
G = +10, R = 600
G = +10, R = 2k
- W
W
W
L
L
L
0.001
0.0001
0.00001
Total Harmonic Distortion + Noise (%)
-
-
-
100
120
140
Total Harmonic Distortion + Noise (dB)
10 100 1k 10k 100k
Frequency (Hz)
V = 3V
BW > 500kHz
OUT RMS
G = +1, R = 600W
L
G = +1, R = 2k
G = 1, R = 600
L
L
W
- W
G = 1, R = 2k
G = +11, R = 600
G = +11, R = 2k
- W
W
W
L
L
L
0.01
0.001
0.0001
0.00001
Total Harmonic Distortion + Noise (%)
Total Harmonic Distortion + Noise (dB)
-
-
-
-
80
100
120
140
10 100 1k 10k 100k
Frequency (Hz)
R = 600W
SOURCE
R = 300W
SOURCE
R = 150W
SOURCE
R = 0W
SOURCE
V = 3V
BW > 500kHz
OUT RMS
OPA1611
+15V
-15V RL
RSOURCE
0.01
0.001
0.0001
0.00001
0.000001
Total Harmonic Distortion + Noise (%)
-
-
-
-
-
80
100
120
140
160
Total Harmonic Distortion + Noise (dB)
0.01 0.1 1 10 20
Output Amplitude (V )
RMS
1kHz Signal
BW = 80kHz
R = 0
SOURCE W
G = +1, R = 600W
L
G = +1, R = 2k
G = 1, R = 600
L
L
W
- W
G = 1, R = 2k
G = +10, R = 600
G = +10, R = 2k
- W
W
W
L
L
L
0.01
0.001
0.0001
0.00001
0.000001
Intermodulation Distortion (%)
-
-
-
-
-
80
100
120
140
160
Intermodulation Distortion (dB)
0.1 1 10 20
Output Amplitude (V )
RMS
SMPTE/DIN
Two-Tone
4:1 (60Hz and 7kHz)
CCIF Twin-Tone
(19kHz and 20kHz)
DIM30
(3kHz square wave
and 15kHz sine wave)
G = +1
OPA1611
OPA1612
SBOS450B –JULY 2009–REVISED JULY 2011
www.ti.com
TYPICAL CHARACTERISTICS (continued)
At TA= +25°C, VS=±15V, and RL= 2kΩ, unless otherwise noted.
THD+N RATIO vs FREQUENCY THD+N RATIO vs FREQUENCY
Figure 7. Figure 8.
THD+N RATIO vs FREQUENCY THD+N RATIO vs FREQUENCY
Figure 9. Figure 10.
INTERMODULATION DISTORTION vs
THD+N RATIO vs OUTPUT AMPLITUDE OUTPUT AMPLITUDE
Figure 11. Figure 12.
6Copyright ©2009–2011, Texas Instruments Incorporated
-
-
-
-
-
-
-
-
-
-
80
90
100
110
120
130
140
150
160
170
180-
Channel Separation (dB)
10
Frequency (Hz)
100k
100 1k 10k
V = 15V±
S
V = 3.5V
OUT RMS
G = +1
R = 2kW
L
R = 600W
L
L
R = 5kW
1 10
Frequency(Hz)
100M10k100 1k 100k 1M 10M
-PSRR
+PSRR
CMRR
160
140
120
100
80
60
40
20
0
Common-ModeRejectionRatio(dB)
Power-SupplyRejectionRatio(dB)
20mV/div
Time (0.1 s/div)m
G = +1
C = 50pF
L
+15V
-15V CL
RL
OPA1611
Time (0.1 s/div)m
20mV/div
G = 1
C = 50pF
-
L
+15V
-15V
RF=2kWRI=2kW
CF=5.6pF
CL
OPA1611
2V/div
Time (0.5 s/div)m
G = +1
C = 50pF
R = 2k
L
LW
R = 0W
F
R = 75W
F
See ,
section
Applications Information
Input Protection
2V/div
Time (0.5 s/div)m
G = 1
C = 50pF
R = 2k
-
W
L
L
OPA1611
OPA1612
www.ti.com
SBOS450B –JULY 2009–REVISED JULY 2011
TYPICAL CHARACTERISTICS (continued)
At TA= +25°C, VS=±15V, and RL= 2kΩ, unless otherwise noted.
CHANNEL SEPARATION vs FREQUENCY CMRR AND PSRR vs FREQUENCY (Referred to Input)
Figure 13. Figure 14.
SMALL-SIGNAL STEP RESPONSE SMALL-SIGNAL STEP RESPONSE
(100mV) (100mV)
Figure 15. Figure 16.
LARGE-SIGNAL STEP RESPONSE LARGE-SIGNAL STEP RESPONSE
Figure 17. Figure 18.
Copyright ©2009–2011, Texas Instruments Incorporated 7
25
20
15
10
5
0
Overshoot (%)
0 100 200 300 400 500 600 700 800 900 1000
Capacitive Load (pF)
G = 1-
R = 0W
S
R = 50W
S
R = 25W
S
OPA1611
R =
I2kW
RS
CL
CF= 5.6pF
RF= 2kW
+15V
-15V
50
40
30
20
10
0
Overshoot (%)
0 100 200 300 400 500 600
Capacitive Load (pF)
G = +1
R = 0W
S
R = 50W
S
R = 25W
S
+15V
-15V
RS
CL
OPA1611
RL
1.0
0.8
0.6
0.4
0.2
0
0.2
0.4
0.6
0.8
1.0
-
-
-
-
-
AOL ( V/V)m
-40 -15 10 35 60 85
Temperature ( C)
°
2kW
10kW
80
70
60
50
40
30
20
10
0
10
20
-
-
I IOSB and (nA)
-18 -12 -6 0 6 12 18
Common-Mode Voltage (V)
-IB
+IB
IOS
V = 18V
S±
Common-Mode Range
5.0
4.5
4.0
3.5
3.0
2.5
2.0
IQ(mA)
-40 -15 10 35 60 85
Temperature ( C)°
OPA1611
OPA1612
SBOS450B –JULY 2009–REVISED JULY 2011
www.ti.com
TYPICAL CHARACTERISTICS (continued)
At TA= +25°C, VS=±15V, and RL= 2kΩ, unless otherwise noted.
SMALL-SIGNAL OVERSHOOT SMALL-SIGNAL OVERSHOOT
vs CAPACITIVE LOAD (100mV Output Step) vs CAPACITIVE LOAD (100mV Output Step)
Figure 19. Figure 20.
OPEN-LOOP GAIN vs TEMPERATURE IBAND IOS vs TEMPERATURE
Figure 21. Figure 22.
IBAND IOS vs COMMON-MODE VOLTAGE QUIESCENT CURRENT vs TEMPERATURE
Figure 23. Figure 24.
8Copyright ©2009–2011, Texas Instruments Incorporated
4.0
3.9
3.8
3.7
3.6
3.5
3.4
3.3
3,2
3.1
3.0
048 12 16 20 24 28 32 36
SupplyVoltage(V)
IQ(mA)
SpecifiedSupply-VoltageRange
75
70
65
60
55
50
45
40
35
30
ISC (mA)
-50 -25 0 25 50 75 100 125
Temperature ( C)
°
+ISC
-ISC
Z ( )W
O
10
10k
0.1
Frequency(Hz)
100M
1
100 1k 10k
10
100
1k
100k 10M
1M
15
14
13
OutputVoltage(V)
-
-
-
13
14
15
0 10 20 30 40 50
OutputCurrent(mA)
+85 C°
+25 C°
-40 C°
V = 15V
Dualversionwith
bothchannels
drivensimultaneously
S±
OPA1611
OPA1612
www.ti.com
SBOS450B –JULY 2009–REVISED JULY 2011
TYPICAL CHARACTERISTICS (continued)
At TA= +25°C, VS=±15V, and RL= 2kΩ, unless otherwise noted.
QUIESCENT CURRENT vs SUPPLY VOLTAGE SHORT-CIRCUIT CURRENT vs TEMPERATURE
Figure 25. Figure 26.
OPEN-LOOP OUTPUT IMPEDANCE vs
OUTPUT VOLTAGE vs OUTPUT CURRENT FREQUENCY
Figure 27. Figure 28.
Copyright ©2009–2011, Texas Instruments Incorporated 9
Pre-Output Driver OUT
V-
V+
IN-
IN+
OPA1611
OPA1612
SBOS450B –JULY 2009–REVISED JULY 2011
www.ti.com
APPLICATION INFORMATION
applications do not require equal positive and
The OPA1611 and OPA1612 are unity-gain stable, negative output voltage swing. With the OPA161x
precision op amps with very low noise; these devices series, power-supply voltages do not need to be
are also free from output phase reversal. Applications equal. For example, the positive supply could be set
with noisy or high-impedance power supplies require to +25V with the negative supply at –5V.
decoupling capacitors close to the device
power-supply pins. In most cases, 0.1μF capacitors In all cases, the common-mode voltage must be
are adequate. Figure 29 shows a simplified internal maintained within the specified range. In addition, key
schematic of the OPA1611. parameters are assured over the specified
temperature range of TA=–40°C to +85°C.
Parameters that vary with operating voltage or
OPERATING VOLTAGE temperature are shown in the Typical Characteristics.
The OPA161x series op amps operate from ±2.25V
to ±18V supplies while maintaining excellent
performance. The OPA161x series can operate with
as little as +4.5V between the supplies and with up to
+36V between the supplies. However, some
Figure 29. OPA1611 Simplified Schematic
10 Copyright ©2009–2011, Texas Instruments Incorporated
VOLTAGE NOISE SPECTRAL DENSITY
vs SOURCE RESISTANCE
10k
1k
100
10
1
100 1k 10k 100k 1M
Source Resistance, R ( )W
S
Resistor
Noise
E = e
O n S
+ (i R ) + 4kTR
n S
2 2 2
RS
EO
Total Output
Voltage Noise
Voltage Noise Spectral Density, EO(nV/ )Hz?
OPA1611 Output
RF
Input
-
+
RI
OPA1611
OPA1612
www.ti.com
SBOS450B –JULY 2009–REVISED JULY 2011
INPUT PROTECTION current noise is negligible, and voltage noise
generally dominates. The low voltage noise of the
The input terminals of the OPA1611 and the OPA161x series op amps makes them a good choice
OPA1612 are protected from excessive differential for use in applications where the source impedance is
voltage with back-to-back diodes, as Figure 30 less than 1kΩ.
illustrates. In most circuit applications, the input
protection circuitry has no consequence. However, in The equation in Figure 31 shows the calculation of
low-gain or G = +1 circuits, fast ramping input signals the total circuit noise, with these parameters:
can forward bias these diodes because the output of •en= Voltage noise
the amplifier cannot respond rapidly enough to the •In= Current noise
input ramp. This effect is illustrated in Figure 17 of •RS= Source impedance
the Typical Characteristics. If the input signal is fast •k = Boltzmann’s constant = 1.38 ×10–23 J/K
enough to create this forward bias condition, the input
signal current must be limited to 10mA or less. If the •T = Temperature in degrees Kelvin (K)
input signal current is not inherently limited, an input
series resistor (RI) and/or a feedback resistor (RF)
can be used to limit the signal input current. This
input series resistor degrades the low-noise
performance of the OPA1611 and is examined in the
following Noise Performance section. Figure 30
shows an example configuration when both
current-limiting input and feedback resistors are used.
Figure 31. Noise Performance of the OPA1611 in
Unity-Gain Buffer Configuration
Figure 30. Pulsed Operation
BASIC NOISE CALCULATIONS
NOISE PERFORMANCE Design of low-noise op amp circuits requires careful
Figure 31 shows the total circuit noise for varying consideration of a variety of possible noise
source impedances with the op amp in a unity-gain contributors: noise from the signal source, noise
configuration (no feedback resistor network, and generated in the op amp, and noise from the
therefore no additional noise contributions). feedback network resistors. The total noise of the
circuit is the root-sum-square combination of all noise
The OPA1611 (GBW = 40MHz, G = +1) is shown components.
with total circuit noise calculated. The op amp itself
contributes both a voltage noise component and a The resistive portion of the source impedance
current noise component. The voltage noise is produces thermal noise proportional to the square
commonly modeled as a time-varying component of root of the resistance. Figure 31 plots this function.
the offset voltage. The current noise is modeled as The source impedance is usually fixed; consequently,
the time-varying component of the input bias current select the op amp and the feedback resistors to
and reacts with the source resistance to create a minimize the respective contributions to the total
voltage component of noise. Therefore, the lowest noise.
noise op amp for a given application depends on the
source impedance. For low source impedance,
Copyright ©2009–2011, Texas Instruments Incorporated 11
R1
R2
EO
R1
R2
EO
RS
VS
RS
VS
NoiseinNoninvertingGainConfiguration
NoiseinInvertingGainConfiguration
Noiseattheoutput:
E =
O
2
Wheree = Ö
S S
4kTR ´=thermalnoiseofRS
2
1+ R2
R1
e +e
n1 2 n2 S S
+e +(i R ) +e +(inR )
2 2 2 2 2 2
1+ R2
R1
R2
R1
e = Ö
1 1
4kTR ´=thermalnoiseofR1
2
1+ R2
R1
e = Ö
2 2 2
4kTR =thermalnoiseofR
Noiseattheoutput:
E =
O
2
Wheree = 4kTRÖ
S S ´=thermalnoiseofRS
2
1+ R2
R +R
1 S
e +e
n 1 2 n 2 S
+e +(i R ) +e
2 2 2 2 2
R2
R +R
1 S
R2
R +R
1 S
e = 4kTRÖ
1 1 ´=thermalnoiseofR1
e = 4kTRÖ
2 2 2
=thermalnoiseofR
OPA1611
OPA1612
SBOS450B –JULY 2009–REVISED JULY 2011
www.ti.com
Figure 32 illustrates both inverting and noninverting The current noise of the op amp reacts with the
op amp circuit configurations with gain. In circuit feedback resistors to create additional noise
configurations with gain, the feedback network components. The feedback resistor values can
resistors also contribute noise. generally be chosen to make these noise sources
negligible. The equations for total noise are shown for
both configurations.
For the OPA161x series op amps at 1kHz, en= 1.1nV/√Hz and in= 1.7pA/√Hz.
Figure 32. Noise Calculation in Gain Configurations
12 Copyright ©2009–2011, Texas Instruments Incorporated
R2
OPA1611
R1
Signal Gain = 1+
Distortion Gain = 1+
R3V = 3V
O RMS
Generator
Output
Analyzer
Input
Audio Precision
System Two(1)
with PC Controller
Load
SIG.
GAIN
DIST.
GAIN R1R2R3
¥
4.99kW
1kW
4.99kW
10W
49.9W
1
-1
101
101
R2
R1
R2
R II R
1 3
+10 110 549W4.99kW49.9W
OPA1611
OPA1612
www.ti.com
SBOS450B –JULY 2009–REVISED JULY 2011
TOTAL HARMONIC DISTORTION Validity of this technique can be verified by
MEASUREMENTS duplicating measurements at high gain and/or high
frequency where the distortion is within the
The OPA161x series op amps have excellent measurement capability of the test equipment.
distortion characteristics. THD + Noise is below Measurements for this data sheet were made with an
0.00008% (G = +1, VO= 3VRMS, BW = 80kHz) Audio Precision System Two distortion/noise
throughout the audio frequency range, 20Hz to analyzer, which greatly simplifies such repetitive
20kHz, with a 2kΩload (see Figure 7 for measurements. The measurement technique can,
characteristic performance). however, be performed with manual distortion
measurement instruments.
The distortion produced by OPA1611 series op amps
is below the measurement limit of many commercially
available distortion analyzers. However, a special test CAPACITIVE LOADS
circuit (such as Figure 33 shows) can be used to The dynamic characteristics of the OPA1611 and
extend the measurement capabilities. OPA1612 have been optimized for commonly
Op amp distortion can be considered an internal error encountered gains, loads, and operating conditions.
source that can be referred to the input. Figure 33 The combination of low closed-loop gain and high
shows a circuit that causes the op amp distortion to capacitive loads decreases the phase margin of the
be 101 times (or approximately 40dB) greater than amplifier and can lead to gain peaking or oscillations.
that normally produced by the op amp. The addition As a result, heavier capacitive loads must be isolated
of R3to the otherwise standard noninverting amplifier from the output. The simplest way to achieve this
configuration alters the feedback factor or noise gain isolation is to add a small resistor (RSequal to 50Ω,
of the circuit. The closed-loop gain is unchanged, but for example) in series with the output.
the feedback available for error correction is reduced This small series resistor also prevents excess power
by a factor of 101, thus extending the resolution by dissipation if the output of the device becomes
101. Note that the input signal and load applied to the shorted. Figure 19 and Figure 20 illustrate graphs of
op amp are the same as with conventional feedback Small-Signal Overshoot vs Capacitive Load for
without R3. The value of R3should be kept small to several values of RS. Also, refer to Applications
minimize its effect on the distortion measurements. Bulletin AB-028 (literature number SBOA015,
available for download from the TI web site) for
details of analysis techniques and application circuits.
(1) For measurement bandwidth, see Figure 7 through Figure 12.
Figure 33. Distortion Test Circuit
Copyright ©2009–2011, Texas Instruments Incorporated 13
OPA1611
OPA1612
SBOS450B –JULY 2009–REVISED JULY 2011
www.ti.com
POWER DISSIPATION It is helpful to have a good understanding of this
basic ESD circuitry and its relevance to an electrical
OPA1611 and OPA1612 series op amps are capable overstress event. Figure 34 illustrates the ESD
of driving 2kΩloads with a power-supply voltage up circuits contained in the OPA161x series (indicated
to ±18V. Internal power dissipation increases when by the dashed line area). The ESD protection circuitry
operating at high supply voltages. Copper leadframe involves several current-steering diodes connected
construction used in the OPA1611 and OPA1612 from the input and output pins and routed back to the
series op amps improves heat dissipation compared internal power-supply lines, where they meet at an
to conventional materials. Circuit board layout can absorption device internal to the operational amplifier.
also help minimize junction temperature rise. Wide This protection circuitry is intended to remain inactive
copper traces help dissipate the heat by acting as an during normal circuit operation.
additional heat sink. Temperature rise can be further
minimized by soldering the devices to the circuit An ESD event produces a short duration,
board rather than using a socket. high-voltage pulse that is transformed into a short
duration, high-current pulse as it discharges through
a semiconductor device. The ESD protection circuits
ELECTRICAL OVERSTRESS are designed to provide a current path around the
Designers often ask questions about the capability of operational amplifier core to prevent it from being
an operational amplifier to withstand electrical damaged. The energy absorbed by the protection
overstress. These questions tend to focus on the circuitry is then dissipated as heat.
device inputs, but may involve the supply voltage pins When an ESD voltage develops across two or more
or even the output pin. Each of these different pin of the amplifier device pins, current flows through one
functions have electrical stress limits determined by or more of the steering diodes. Depending on the
the voltage breakdown characteristics of the path that the current takes, the absorption device
particular semiconductor fabrication process and may activate. The absorption device internal to the
specific circuits connected to the pin. Additionally, OPA1611 triggers when a fast ESD voltage pulse is
internal electrostatic discharge (ESD) protection is impressed across the supply pins. Once triggered, it
built into these circuits to protect them from quickly activates and clamps the ESD pulse to a safe
accidental ESD events both before and during voltage level.
product assembly.
14 Copyright ©2009–2011, Texas Instruments Incorporated
RF
Op-Amp
Core
RI
RL
V(1)
IN
ID
-In
Out
+In
ESD Current-
Steering Diodes
Edge-Triggered ESD
Absorption Circuit
+VS
+V
-V
-VS
OPA1611
OPA1611
OPA1612
www.ti.com
SBOS450B –JULY 2009–REVISED JULY 2011
When the operational amplifier connects into a circuit direct current path is established between the +VS
such as the one Figure 34 shows, the ESD protection and –VSsupplies. The power dissipation of the
components are intended to remain inactive and not absorption device is quickly exceeded, and the
become involved in the application circuit operation. extreme internal heating destroys the operational
However, circumstances may arise where an applied amplifier.
voltage exceeds the operating voltage range of a Another common question involves what happens to
given pin. Should this condition occur, there is a risk the amplifier if an input signal is applied to the input
that some of the internal ESD protection circuits may while the power supplies +VSand/or –VSare at 0V.
be biased on, and conduct current. Any such current Again, it depends on the supply characteristic while at
flow occurs through steering diode paths and rarely 0V, or at a level below the input signal amplitude. If
involves the absorption device. the supplies appear as high impedance, then the
Figure 34 depicts a specific example where the input operational amplifier supply current may be supplied
voltage, VIN, exceeds the positive supply voltage by the input source via the current steering diodes.
(+VS) by 500mV or more. Much of what happens in This state is not a normal bias condition; the amplifier
the circuit depends on the supply characteristics. If most likely will not operate normally. If the supplies
+VScan sink the current, one of the upper input are low impedance, then the current through the
steering diodes conducts and directs current to +VS. steering diodes can become quite high. The current
Excessively high current levels can flow with level depends on the ability of the input source to
increasingly higher VIN. As a result, the datasheet deliver current, and any resistance in the input path.
specifications recommend that applications limit the If there is an uncertainty about the ability of the
input current to 10mA. supply to absorb this current, external zener diodes
If the supply is not capable of sinking the current, VIN may be added to the supply pins as shown in
may begin sourcing current to the operational Figure 34. The zener voltage must be selected such
amplifier, and then take over as the source of positive that the diode does not turn on during normal
supply voltage. The danger in this case is that the operation. However, its zener voltage should be low
voltage can rise to levels that exceed the operational enough so that the zener diode conducts if the supply
amplifier absolute maximum ratings. In extreme but pin begins to rise above the safe operating supply
rare cases, the absorption device triggers on while voltage level.
+VSand –VSare applied. If this event happens, a
(1) VIN = +VS+ 500mV.
Figure 34. Equivalent Internal ESD Circuitry and Its Relation to a Typical Circuit Application
Copyright ©2009–2011, Texas Instruments Incorporated 15
I L+
OUT
AudioDAC
withDifferential
Current
Outputs OPA1611
8200pF
100W
I L-
OUT
OPA1611
0.1 Fm
2200pF
820W
0.1 Fm
2700pF
-VA
( 15V)-
+VA
(+15V)
680W620W
330W
-VA
( 15V)-
+VA
(+15V)
0.1 Fm
0.1 Fm
330W2700pF
OPA1611
0.1 Fm
2200pF
820W
0.1 Fm
-VA
( 15V)-
+VA
(+15V) 680W620W
LCh
Output
OPA1611
OPA1612
SBOS450B –JULY 2009–REVISED JULY 2011
www.ti.com
APPLICATION CIRCUIT
Figure 35. Audio DAC Post Filter (I/V Converter and Low-Pass Filter)
16 Copyright ©2009–2011, Texas Instruments Incorporated
OPA1611
OPA1612
www.ti.com
SBOS450B –JULY 2009–REVISED JULY 2011
REVISION HISTORY
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision A (August, 2009) to Revision B Page
•Revised Features list items ................................................................................................................................................... 1
•Updated front-page figure ..................................................................................................................................................... 1
•Added max specification for input voltage noise density at f = 1kHz ................................................................................... 3
•Corrected typo in footnote 1 for Electrical Characteristics .................................................................................................... 3
•Revised Figure 4 ................................................................................................................................................................... 5
•Updated Figure 7 .................................................................................................................................................................. 6
•Changed Figure 9 ................................................................................................................................................................. 6
•Revised Figure 11 ................................................................................................................................................................. 6
•Corrected typo in Figure 15 .................................................................................................................................................. 7
•Updated Figure 29 .............................................................................................................................................................. 10
•Revised table in Figure 33 .................................................................................................................................................. 13
•Revised fourth paragraph of Electrincal Overstress section ............................................................................................... 14
Copyright ©2009–2011, Texas Instruments Incorporated 17
PACKAGE OPTION ADDENDUM
www.ti.com 22-Jun-2011
Addendum-Page 1
PACKAGING INFORMATION
Orderable Device Status (1) Package Type Package
Drawing Pins Package Qty Eco Plan (2) Lead/
Ball Finish MSL Peak Temp (3) Samples
(Requires Login)
OPA1611AID ACTIVE SOIC D 8 75 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
OPA1611AIDR ACTIVE SOIC D 8 2500 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
OPA1612AID ACTIVE SOIC D 8 75 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
OPA1612AIDR ACTIVE SOIC D 8 2500 Green (RoHS
& no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device Package
Type Package
Drawing Pins SPQ Reel
Diameter
(mm)
Reel
Width
W1 (mm)
A0
(mm) B0
(mm) K0
(mm) P1
(mm) W
(mm) Pin1
Quadrant
OPA1611AIDR SOIC D 8 2500 330.0 12.4 6.4 5.2 2.1 8.0 12.0 Q1
OPA1612AIDR SOIC D 8 2500 330.0 12.4 6.4 5.2 2.1 8.0 12.0 Q1
PACKAGE MATERIALS INFORMATION
www.ti.com 14-Jul-2012
Pack Materials-Page 1
*All dimensions are nominal
Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
OPA1611AIDR SOIC D 8 2500 367.0 367.0 35.0
OPA1612AIDR SOIC D 8 2500 367.0 367.0 35.0
PACKAGE MATERIALS INFORMATION
www.ti.com 14-Jul-2012
Pack Materials-Page 2
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