Datasheet OPA2342UA, OPA342UA-2K5, OPA4342EA, OPA4342PA, OPA4342EA-2K5 Datasheet (Burr Brown)
...Page 1
Low Cost, Low Power, Rail-to-Rail
OPERA TIONAL AMPLIFIERS
Micro
Amplifier
™
Series
© 1999 Burr-Brown Corporation PDS-1485B Printed in U.S.A. June, 2000
®
FEATURES
● LOW QUIESCENT CURRENT: 150µA typ
● RAIL-TO-RAIL INPUT
● RAIL-TO-RAIL OUTPUT (within 1mV)
● SINGLE SUPPLY CAPABILITY
● LOW COST
●
Micro
SIZE PACKAGE OPTIONS:
SOT23-5
MSOP-8
TSSOP-14
● BANDWIDTH: 1MHz
● SLEW RATE: 1V/µs
● THD + NOISE: 0.006%
APPLICATIONS
● COMMUNICATIONS
● PCMCIA CARDS
● DATA ACQUISITION
● PROCESS CONTROL
● AUDIO PROCESSING
● ACTIVE FILTERS
● TEST EQUIPMENT
● CONSUMER ELECTRONICS
DESCRIPTION
The OPA342 series rail-to-rail CMOS operational
amplifiers are designed for low cost, low power,
miniature applications. They are optimized to operate
on a single supply as low as 2.5V with an input
common-mode voltage range that extends 300mV
beyond the supplies.
Rail-to-rail input/output and high-speed operation make
them ideal for driving sampling Analog-to-Digital Converters (ADC). They are also well suited for general
purpose and audio applicaitons and providing I/V conversion at the output of Digital-to-Analog Converters
(DAC). Single, dual and quad versions have identical
specs for design flexibility.
The OPA342 series offers excellent dynamic response
with a quiescent current of only 250µA max. Dual and
quad designs feature completely independent circuitry
for lowest crosstalk and freedom from interaction.
OPA342
OPA2342
OPA4342
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
For most current data sheet and other product
information, visit www.burr-brown.com
®
OPA342
OPA342
OPA2342
OPA4342
OPA4342
SINGLE DUAL QUAD
PACKAGE OPA342 OPA2342 OPA4342
SOT23-5 ✔
MSOP-8 ✔
SO-8 ✔✔
TSSOP-14 ✔
SO-14 ✔
DIP-14 ✔
SPICE MODEL available at www.burr-brown.com.
Page 2
2
®
OPA342, 2342, 4342
SPECIFICATIONS: VS = 2.7V to 5.5V
At TA = +25°C, RL = 10kΩ connected to VS/ 2 and V
OUT
= VS/ 2, unless otherwise noted.
Boldface limits apply over the temperature range, T
A
= –40°C to +85°C.
OPA342NA, UA
OPA2342EA, UA
OPA4342EA, UA, PA
PARAMETER CONDITION MIN TYP MAX UNITS
OFFSET VOLTAGE
Input Offset Voltage V
OS
VCM = VS/2 ±1 ±6mV
T
A
= –40°C to +85°C ±1 ±6mV
vs Temperature dV
OS
/dT ±3 µV/°C
vs Power Supply PSRR V
S
= 2.7V to 5.5V, V
CM
< (V+) -1.8V 30 200 µV/V
T
A
= –40°C to +85°CV
S
= 2.7V to 5.5V, V
CM
< (V+) -1.8V 250 µV/V
Channel Separation, dc 0.2 µV/V
f = 1kHz 132 dB
INPUT BIAS CURRENT
Input Bias Current I
B
±0.2 ±10 pA
T
A
= –40°C to +85°C See Typical Curve pA
Input Offset Current I
OS
±0.2 ±10 pA
NOISE
Input Voltage Noise, f = 0.1Hz to 50kHz 8 µVrms
Input Voltage Noise Density, f = 1kHz e
n
30 nV/√Hz
Current Noise Density, f = 1kHz i
n
0.5 fA/√Hz
INPUT VOLTAGE RANGE
Common-Mode Voltage Range V
CM
–0.3 (V+) + 0.3 V
Common-Mode Rejection Ratio CMRR V
S
= +5.5V, –0.3V < VCM < (V+) - 1.8 76 88 dB
T
A
= –40°C to +85°CV
S
= +5.5V, –0.3V < VCM < (V+) - 1.8 74 dB
Common-Mode Rejection Ratio CMRR V
S
= +5.5V, –0.3V < VCM < 5.8V 66 78 dB
T
A
= –40°C to +85°CV
S
= +5.5V, –0.3V < VCM < 5.8V 64 dB
Common-Mode Rejection Ratio CMRR V
S
= +2.7V, –0.3V < VCM < 3V 62 74 dB
T
A
= –40°C to +85°CV
S
= +2.7V, –0.3V < VCM < 3V 60 dB
INPUT IMPEDANCE
Differential 10
13
|| 3 Ω || pF
Common-Mode 10
13
|| 6 Ω || pF
OPEN-LOOP GAIN
Open-Loop Voltage Gain A
OLRL
= 100kΩ, 10mV < VO < (V+) – 10mV 104 124 dB
T
A
= –40°C to +85°CR
L
= 100kΩ, 10mV < VO < (V+) – 10mV 100 dB
R
L
= 5kΩ, 400mV < VO < (V+) – 400mV 96 114 dB
T
A
= –40°C to +85°CR
L
= 5kΩ, 400mV < VO < (V+) – 400mV 90 dB
FREQUENCY RESPONSE C
L
= 100pF
Gain-Bandwidth Product GBW G = 1 1 MHz
Slew Rate SR 1 V/µs
Settling Time, 0.1% V
S
= 5.5V, 2V Step 5 µs
0.01% V
S
= 5.5V, 2V Step 8 µs
Overload Recovery Time V
IN
• G = V
S
2.5 µs
Total Harmonic Distortion + Noise, f = 1kHz
THD+N VS = 5.5V, VO = 3Vp-p
(1)
, G = 1 0.006 %
OUTPUT
Voltage Output Swing from Rail
(2)
RL = 100kΩ, AOL ≥ 96dB 1 mV
R
L
= 100kΩ, AOL ≥ 104dB 3 10 mV
T
A
= –40°C to +85°CR
L
= 100kΩ, AOL ≥ 100dB 10 mV
R
L
= 5kΩ, A
OL
≥ 96dB 20 400 mV
T
A
= –40°C to +85°CR
L
= 5kΩ, AOL ≥ 90dB 400 mV
Short-Circuit Current I
SC
Per Channel ±15 mA
Capacitive Load Drive C
LOAD
See Typical Curve
POWER SUPPLY
Specified Voltage Range V
S
2.7 5.5 V
Operating Voltage Range 2.5 to 5.5 V
Quiescent Current (per amplifier) I
Q
IO = 0A 150 250 µA
T
A
= –40°C to +85°C 300 µA
TEMPERATURE RANGE
Specified Range –40 +85 °C
Operating Range –55 +125 °C
Storage Range –65 +150 °C
Thermal Resistance
θ
JA
SOT23-5 Surface Mount 200 °C/W
MSOP-8 Surface Mount 150 °C/W
SO-8 Surface Mount 150 °C/W
TSSOP-14 Surface Mount 100 °C/W
SO-14 Surface Mount 100 °C/W
DIP-14 100 °C/W
NOTE: (1) V
OUT
= 0.25V to 3.25V. (2) Output voltage swings are measured between the output and power-supply rails.
Page 3
3
®
OPA342, 2342, 4342
PACKAGE SPECIFIED
DRAWING TEMPERATURE PACKAGE ORDERING TRANSPORT
PRODUCT PACKAGE NUMBER RANGE MARKING NUMBER
(1)
MEDIA
OPA342NA SOT23-5 331 –40°C to +85°C B42 OPA342NA/250 Tape and Reel
"""""OPA342NA /3K Tape and Reel
OPA342UA SO-8 182 –40°C to +85°C OPA342UA OPA342UA Rails
"""""OPA342UA /2K5 Tape and Reel
OPA2342EA MSOP-8 337 –40°C to +85°C C42 OPA2342EA /250 Tape and Reel
"""""OPA2342EA /2K5 Tape and Reel
OPA2342UA SO-8 182 –40°C to +85°C OPA2342UA OPA2342UA Rails
"""""OPA2342UA/2K5 Tape and Reel
OPA4342EA TSSOP-14 357 –40°C to +85°C OPA4342EA OPA4342EA/250 Tape and Reel
"""""OPA4342EA /2K5 Tape and Reel
OPA4342UA SO-14 235 –40°C to +85°C OPA4342UA OPA4342UA Rails
"""""OPA4342UA/2K5 Tape and Reel
OPA4342PA DIP-14 010 –40°C to +85°C OPA4342PA OPA4342PA Rails
NOTE: (1) Models with a slash (/) are available only in Tape and Reel in the quantities indicated (e.g., /3K indicates 3000 devices per reel). Ordering 3000 pieces
of “OPA342NA/3K” will get a single 3000-piece Tape and Reel.
PACKAGE/ORDERING INFORMATION
Supply Voltage, V+ to V- ................................................................... 7.5V
Signal Input Terminals, Voltage
(2)
..................... (V–) –0.5V to (V+) +0.5V
Current
(2)
.................................................... 10mA
Output Short-Circuit
(3)
.............................................................. Continuous
Operating Temperature ..................................................–55°C to +125°C
Storage Temperature ..................................................... –65°C to +150°C
Junction Temperature ...................................................................... 150°C
Lead Temperature (soldering, 10s) ................................................. 300°C
ESD Tolerance (Human Body Model) ............................................ 4000V
NOTES: (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. Functional operation of the device at these conditions, or beyond the specified operating
conditions, is not implied. (2) Input terminals are diode-clamped to the power
supply rails. Input signals that can swing more than 0.5V beyond the supply
rails should be current-limited to 10mA or less. (3) Short-circuit to ground,
one amplifier per package.
ABSOLUTE MAXIMUM RATINGS
(1)
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Burr-Brown
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.
Page 4
4
®
OPA342, 2342, 4342
TYPICAL PERFORMANCE CURVES
At TA = +25°C, VS = +5V, and RL = 10kΩ connected to VS/2, unless otherwise noted.
POWER SUPPLY AND COMMON-MODE
REJECTION RATIO vs FREQUENCY
10
Rejection Ratio (dB)
Frequency (Hz)
100 1k 10k 100k
100
80
60
40
20
10
+PSRR
CMRR
–PSRR
CHANNEL SEPARATION vs FREQUENCY
100
Channel Separation (dB)
Frequency (Hz)
1k 10k 100k 1M
140
120
100
80
60
Dual and quad devices.
G = 1, all channels.
Quad measured channel
A to D or B to C—other
combinations yield improved
rejection.
VOLTAGE AND CURRENT NOISE
SPECTRAL DENSITY vs FREQUENCY
1
Voltage Noise (nV/√Hz)
Frequency (Hz)
10 100 1k 10k 100k 1M 10M
10000
1000
100
10
Current Noise (fA/√Hz)
100
10
1
0.1
V
N
I
N
TOTAL HARMONIC DISTORTION + NOISE
vs FREQUENCY
20
THD+N (%)
Frequency (Hz)
100 1k 10k 20k
1
0.1
0.010
0.001
OPEN-LOOP GAIN/PHASE vs FREQUENCY
0.1 1
Gain (dB)
0
30
60
90
120
150
180
Phase (°)
Frequency (Hz)
10 100 1k 10k 100k 1M 10M
120
100
80
60
40
20
0
Gain
Phase
MAXIMUM OUTPUT VOLTAGE vs FREQUENCY
10k
Maximum Output Voltage (Vp-p)
Frequency (Hz)
100k 1M
6
5
4
3
2
1
0
VS = +2.7V
VS = +5.5V
VS = +5V
Page 5
5
®
OPA342, 2342, 4342
TYPICAL PERFORMANCE CURVES (Cont.)
At TA = +25°C, VS = +5V, and RL = 10kΩ connected to VS/2, unless otherwise noted.
OPEN-LOOP GAIN, COMMON-MODE REJECTION RATIO,
AND POWER SUPPLY REJECTION vs TEMPERATURE
A
OL
–75
A
OL
, CMRR, PSRR (dB)
Temperature (°C)
–25 0 25–50 50 12575 100 150
140
120
100
80
60
40
20
0
CMRR
PSRR
INPUT BIAS CURRENT vs TEMPERATURE
–75
Input Bias Current (pA)
Temperature (°C)
–25 0 25–50 10050 75 125
10000
1000
100
10
1
0.1
QUIESCENT CURRENT AND
SHORT-CIRCUIT CURRENT vs TEMPERATURE
–75 –50 0
Quiescent Current (µA)
Temperature (°C)
25 50 100
I
Q
+I
SC
–I
SC
75–25 125
200
175
150
135
100
75
50
25
0
Short-Circuit Current (mA)
40
35
30
25
20
15
10
5
0
SLEW RATE vs TEMPERATURE
–75
Slew Rate (V/µs)
Temperature (°C)
250
–SR
+SR
7550–25–50 100 125
1.2
1
0.8
0.6
0.4
0.2
0
INPUT BIAS CURRENT
vs COMMON-MODE VOLTAGE
–1
Input Bias Current (pA)
Common-Mode Voltage (V)
012 4356
6
4
2
0
–2
–4
–6
V+
Supply
V–
Supply
Input voltage ≤ –0.3V
can cause op amp output
to lock up. See text.
QUIESCENT CURRENT AND
SHORT-CIRCUIT CURRENT vs SUPPLY VOLTAGE
Quiescent Current (µA)
Supply Voltage (V)
23456
+I
SC
–I
SC
I
Q
160
155
150
145
140
Short-Circuit Current (mA)
20
15
10
5
0
Page 6
6
®
OPA342, 2342, 4342
TYPICAL PERFORMANCE CURVES (Cont.)
At TA = +25°C, VS = +5V, and RL = 10kΩ connected to VS/2, unless otherwise noted.
OUTPUT VOLTAGE SWING vs OUTPUT CURRENT
0
Output Voltage (V)
Output Current (mA)
5
≈≈
10 15 20
V+
(V+) – 1
(V+) – 2
2
1
0
85°C
25°C
–40°C
85°C
25°C
–40°C
OPEN-LOOP GAIN vs OUTPUT VOLTAGE SWING
120
110
100
90
80
Open-Loop Gain (dB)
Output Voltage Swing from Rail (mV)
120 100 80 60 40 20 0
RL = 5kΩ
RL = 100kΩ
OFFSET VOLTAGE
PRODUCTION DISTRIBUTION
Percent of Amplifiers (%)
Offset Voltage (mV)
–6
–5.4
–4.8
–4.2
–3.6–3–2.4
–1.8
–1.2
–0.6
0
0.6
1.2
1.8
2.433.6
4.2
4.8
5.4
6
24
20
16
12
8
4
0
Typical production
distribution of
packaged units.
OFFSET VOLTAGE DRIFT
PRODUCTION DISTRIBUTION
Percent of Amplifiers (%)
Offset Voltage Drift (µV/°C)
18
16
14
12
10
8
6
4
2
0
Typical production
distribution of
packaged units.
–10
–9–8–7–6–5–4–3–2–1
012345678
9
10
Quiescent Current (µA)
QUIESCENT CURRENT
PRODUCTION DISTRIBUTION
24
20
16
12
8
4
0
Percent of Amplifiers (%)
<0
<25
<50
<75
<100
<125
<150
<175
<200
<225
<250
SETTLING TIME vs CLOSED-LOOP GAIN
1
Settling Time (µs)
Closed-Loop Gain (V/V)
10 100
0.01%
0.1%
1000
400
350
300
250
200
150
100
50
0
Page 7
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®
OPA342, 2342, 4342
TYPICAL PERFORMANCE CURVES (Cont.)
At TA = +25°C, VS = +5V, and RL = 10kΩ connected to VS/2, unless otherwise noted.
SMALL-SIGNAL OVERSHOOT vs LOAD CAPACITANCE
1
Small-Signal Overshoot (%)
Load Capacitance (pF)
10 100 1k 10k
G = –1
G = –5
50
45
40
35
30
25
20
15
10
5
0
G = +5
G = +1
5µs/div
LARGE-SIGNAL STEP RESPONSE
G = +1, R
L
= 10kΩ, CL = 100pF
1V/div
5µs/div
SMALL-SIGNAL STEP RESPONSE
G = +1, R
L
= 10kΩ, CL = 100pF
20mV/div
Page 8
8
®
OPA342, 2342, 4342
APPLICATIONS INFORMATION
OPA342 series op amps are unity gain stable and can operate
on a single supply, making them highly versatile and easy to
use.
Rail-to-rail input and output swing significantly increases
dynamic range, especially in low supply applications. Figure
1 shows the input and output waveforms for the OPA342 in
unity-gain configuration. Operation is from VS = +5V with
a 10kΩ load connected to VS/2. The input is a 5Vp-p
sinusoid. Output voltage is approximately 4.997Vp-p.
Power supply pins should be by passed with 0.01pF ceramic
capacitors.
OPERATING VOLTAGE
OPA342 series op amps are fully specified and guaranteed
from +2.7V to +5.5V. In addition, many specifications apply
from –40ºC to +85ºC. Parameters that vary significantly
with operating voltages or temperature are shown in the
Typical Performance Curves.
RAIL-TO-RAIL INPUT
The input common-mode voltage range of the OPA342
series extends 300mV beyond the supply rails. This is
achieved with a complementary input stage—an N-channel
input differential pair in parallel with a P-channel differential pair (see Figure 2). The N-channel pair is active for input
voltages close to the positive rail, typically (V+) – 1.3V to
300mV above the positive supply, while the P-channel pair
is on for inputs from 300mV below the negative supply to
approximately (V+) –1.3V. There is a small transition region, typically (V+) – 1.5V to (V+) – 1.1V, in which both
pairs are on. This 400mV transition region can vary 300mV
with process variation. Thus, the transition region (both
stages on) can range from (V+) – 1.8V to (V+) – 1.4V on the
low end, up to (V+) – 1.2V to (V+) – 0.8V on the high end.
Within the 400mV transition region PSRR, CMRR, offset
voltage, offset drift, and THD may be degraded compared to
operation outside this region. For more information on
designing with rail-to-rail input op amps, see Figure 3
“Design Optimization with Rail-to-Rail Input Op Amps.”
FIGURE 2. Simplified Schematic.
V
BIAS1
V
BIAS2
VIN+
VIN–
Class AB
Control
Circuitry
V
O
V–
(Ground)
V+
Reference
Current
FIGURE 1. Rail-to-Rail Input and Output.
5µs/div
1V/div
Output (inverted on scope)
Input
G = +1, VS = +5V
5V
0V
Page 9
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®
OPA342, 2342, 4342
COMMON-MODE REJECTION
The CMRR for the OPA342 is specified in several ways so
the best match for a given application may be used. First, the
CMRR of the device in the common-mode range below the
transition region (VCM < (V+) – 1.8V) is given. This specification is the best indicator of the capability of the device
when the application requires use of one of the differential
input pairs. Second, the CMRR at VS = 5.5V over the entire
common-mode range is specified. Third, the CMRR at VS =
2.7V over the entire common-mode range is provided. These
last two values include the variations seen through the
transition region.
INPUT VOLTAGE BEYOND THE RAILS
If the input voltage can go more than 0.3V below the
negative power supply rail (single-supply ground), special
precautions are required. If the input voltage goes sufficiently negative, the op amp output may lock up in an
inoperative state. A Schottky diode clamp circuit will prevent this—see Figure 4. The series resistor prevents excessive current (greater than 10mA) in the Schottky diode and
in the internal ESD protection diode, if the input voltage can
exceed the positive supply voltage. If the signal source is
limited to less than 10mA, the input resistor is not required.
RAIL-TO-RAIL OUTPUT
A class AB output stage with common-source transistors is
used to achieve rail-to-rail output. This output stage is
capable of driving 600Ω loads connected to any potential
between V+ and ground. For light resistive loads (> 50kΩ),
the output voltage can typically swing to within 1mV from
supply rail. With moderate resistive loads (2kΩ to 50kΩ),
the output can swing to within a few tens of milli-volts from
the supply rails while maintaining high open-loop gain. See
the typical performance curve “Output Voltage Swing vs
Output Current.”
V
O
V
IN
V
B
V+
Non-Inverting Gain
V
CM
= V
IN
V
O
V
B
V
IN
V+
Inverting Amplifier
V
CM
= V
B
V
O
V
IN
V+
G = 1 Buffer
V
CM
= VIN = V
O
FIGURE 3. Design Optimization with Rail-to-Rail Input Op Amps.
Rail-to-rail op amps can be used in virtually any op amp
configuration. To achieve optimum performance, however, applications using these special double-input-stage
op amps may benefit from consideration of their special
behavior.
In many applications, operation remains within the common-mode range of only one differential input pair.
However some applications exercise the amplifier through
the transition region of both differential input stages.
Although the two input stages are laser trimmed for
excellent matching, a small discontinuity may occur in
this transition. Careful selection of the circuit configuration, signal levels and biasing can often avoid this transition region.
DESIGN OPTIMIZATION WITH RAIL-TO-RAIL INPUT OP AMPS
With a unity-gain buffer, for example, signals will traverse
this transition at approximately 1.3V below V+ supply
and may exhibit a small discontinuity at this point.
The common-mode voltage of the non-inverting amplifier is equal to the input voltage. If the input signal always
remains less than the transition voltage, no discontinuity
will be created. The closed-loop gain of this configuration can still produce a rail-to-rail output.
Inverting amplifiers have a constant common-mode voltage equal to VB. If this bias voltage is constant, no
discontinuity will be created. The bias voltage can generally be chosen to avoid the transition region.
FIGURE 4. Input Current Protection for Voltages Exceed-
ing the Supply Voltage.
1kΩ
OPA342
10mA max
V+
V
IN
V
OUT
I
OVERLOAD
IN5818
Schottky diode is required only
if input voltage can go more
than 0.3V below ground.
CAPACITIVE LOAD AND STABILITY
The OPA342 in a unity-gain configuration can directly drive
up to 250pF pure capacitive load. Increasing the gain enhances the amplifier’s ability to drive greater capacitive
loads. See the typical performance curve “Small-Signal
Page 10
10
®
OPA342, 2342, 4342
Overshoot vs Capacitive Load.” In unity-gain configurations, capacitive load drive can be improved by inserting a
small (10Ω to 20Ω) resistor, RS, in series with the output, as
shown in Figure 5. This significantly reduces ringing while
maintaining dc performance for purely capacitive loads.
However, if there is a resistive load in parallel with the
capacitive load, a voltage divider is created, introducing a dc
error at the output and slightly reducing the output swing.
The error introduced is proportional to the ratio RS/RL, and
is generally negligible.
FIGURE 6. OPA342 in Noninverting Configuration Driving ADS7822.
FIGURE 7. Speech Bandpass Filtered Data Acquisition System.
DRIVING A/D CONVERTERS
The OPA342 series op amps are optimized for driving
medium-speed sampling ADCs. The OPA342 op amps buffer
the ADC’s input capacitance and resulting charge injection
while providing signal gain.
Figures 6 shows the OPA342 in a basic noninverting con-
figuration driving the ADS7822. The ADS7822 is a 12-bit,
micro-power sampling converter in the MSOP-8 package.
When used with the low-power, miniature packages of the
OPA342, the combination is ideal for space-limited, lowpower applications. In this configuration, an RC network at
the ADC’s input can be used to filter charge injection.
Figure 7 shows the OPA2342 driving an ADS7822 in a
speech bandpass filtered data acquisition system. This small,
low-cost solution provides the necessary amplification and
signal conditioning to interface directly with an electret
microphone. This circuit will operate with VS = +2.7V to
+5V with less than 500µA quiescent current.
FIGURE 5. Series Resistor in Unity-Gain Configuration
Improves Capacitive Load Drive.
10Ω to
20Ω
OPA342
V+
V
IN
V
OUT
R
S
R
L
C
L
C
3
33pF
V
+
GND
3
1
8
4
5
6
7
–IN
+IN
2
C
2
DCLOCK
Serial
Interface
1000pF
R
1
1.5kΩ
R
4
20kΩ
R
5
20kΩ
R
6
100kΩ
R
8
150kΩ
R
9
510kΩ
R
7
51kΩ
D
OUT
V
REF
V+ = +2.7V to 5V
CS/SHDN
C
1
1000pF
Electret
Microphone
(1)
G = 100
Passband 300Hz to 3kHz
R
3
1MΩ
R
2
1MΩ
NOTE: (1) Electret microphone
powered by R
1
.
ADS7822
12-Bit A/D
1/2
OPA2342
1/2
OPA2342
ADS7822
12-Bit A/D
DCLOCK
D
OUT
CS/SHDN
OPA342
+5V
V
IN
V+
2
+In
3
–In
V
REF
8
4GND
Serial
Interface
1
0.1µF 0.1µF
7
6
5
NOTE: A/D Input = 0 to V
REF
VIN = 0V to 5V for
0V to 5V output.
RC network filters high frequency noise.
500Ω
3300pF
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