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Электронный компонент: AD8515AKS

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REV. B
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
www.analog.com
Fax: 781/326-8703
2003 Analog Devices, Inc. All rights reserved.
a
AD8515
1.8 V Low Power CMOS Rail-to-Rail
Input/Output Operational Amplifier
FEATURES
Single-Supply Operation: 1.8 V to 5 V
Offset Voltage: 6 mV Max
Space-Saving SOT-23 and SC70 Packages
Slew Rate: 2.7 V/ s
Bandwidth: 5 MHz
Rail-to-Rail Input and Output Swing
Low Input Bias Current: 2 pA Typ
Low Supply Current @ 1.8 V: 450 A Max
APPLICATIONS
Portable Communications
Portable Phones
Sensor Interfaces
Laser Scanners
PCMCIA Cards
Battery-Powered Devices
New Generation Phones
Personal Digital Assistants
PIN CONFIGURATION
GENERAL DESCRIPTION
The AD8515 is a rail-to-rail amplifier that can operate from a
single-supply voltage as low as 1.8 V.
The AD8515 single amplifier, available in SOT-23-5L and
SC70-5L packages, is small enough to be placed next to sensors,
reducing external noise pickup.
The AD8515 is a rail-to-rail input and output amplifier with a
gain bandwidth of 5 MHz and typical offset voltage of 1 mV
from a 1.8 V supply. The low supply current makes these parts
ideal for battery-powered applications. The 2.7 V/
ms slew rate
makes the AD8515 a good match for driving ASIC inputs, such
as voice codecs.
The AD8515 is specified over the extended industrial tempera-
ture range (40
C to +125C).
5-Lead SC70 and SOT-23
(KS and RT Suffixes)
1
2
3
5
4
IN
+IN
V+
OUT
AD8515
V
REV. B
2
AD8515SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
Parameter
Symbol
Condition
Min
Typ
Max
Unit
INPUT CHARACTERISTICS
Offset Voltage
V
OS
V
CM
= V
S
/2
1
6
mV
40
C < T
A
< +125
C
8
mV
Input Bias Current
I
B
V
S
= 1.8 V
2
30
pA
40
C < T
A
< +85
C
600
pA
40
C < T
A
< +125
C
8
nA
Input Offset Current
I
OS
1
10
pA
40
C < T
A
< +125
C
300
pA
Input Voltage Range
0
1.8
V
Common-Mode Rejection Ratio CMRR
0 V
V
CM
1.8 V
50
dB
Large Signal Voltage Gain
A
VO
R
L
= 100 k
W, 0.3 V V
OUT
1.5 V
110
400
V/mV
Offset Voltage Drift
DV
OS
/
DT
4
mV/C
OUTPUT CHARACTERISTICS
Output Voltage High
V
OH
I
L
= 100
mA, 40C < T
A
< +125
C
1.79
V
I
L
= 750
mA, 40C < T
A
< +125
C
1.77
V
Output Voltage Low
V
OL
I
L
= 100
mA, 40C < T
A
< +125
C
10
mV
I
L
= 750
mA, 40C < T
A
< +125
C
30
mV
Short Circuit Limit
I
SC
20
mA
POWER SUPPLY
Supply Current/Amplifier
I
SY
V
OUT
= V
S
/2
300
450
mA
40
C < T
A
< +125
C
500
mA
DYNAMIC PERFORMANCE
Slew Rate
SR
R
L
= 10 k
W
2.7
V/
ms
Gain Bandwidth Product
GBP
5
MHz
NOISE PERFORMANCE
Voltage Noise Density
e
n
f = 1 kHz
22
nV/
Hz
f = 10 kHz
20
nV/
Hz
Current Noise Density
i
n
f = 1 kHz
0.05
pA/
Hz
(V
S
= 1.8 V, V
CM
= V
S
/2, T
A
= 25 C, unless otherwise noted.)
Specifications subject to change without notice.
REV. B
AD8515
3
ELECTRICAL CHARACTERISTICS
Parameter
Symbol
Condition
Min
Typ
Max
Unit
INPUT CHARACTERISTICS
Offset Voltage
V
OS
V
CM
=V
S
/2
1
6
mV
40
C < T
A
< +125
C
8
mV
Input Bias Current
I
B
V
S
= 3.0 V
2
30
pA
40
C < T
A
< +85
C
600
pA
40
C < T
A
< +125
C
8
nA
Input Offset Current
I
OS
1
10
pA
40
C < T
A
< +125
C
300
pA
Input Voltage Range
0
3
V
Common-Mode Rejection Ratio CMRR
0 V
V
CM
3.0 V
54
dB
Large Signal Voltage Gain
A
VO
R
L
= 100 k
W, 0.3 V V
OUT
2.7 V
250
1,000
V/mV
Offset Voltage Drift
DV
OS
/
DT
4
mV/C
OUTPUT CHARACTERISTICS
Output Voltage High
V
OH
I
L
= 100
mA, 40C < T
A
< +125
C
2.99
V
I
L
= 750
mA, 40C < T
A
< +125
C
2.98
V
Output Voltage Low
V
OL
I
L
= 100
mA, 40C < T
A
< +125
C
10
mV
I
L
= 750
mA, 40C < T
A
< +125
C
20
mV
POWER SUPPLY
Power Supply Rejection Ratio
PSRR
V
S
= 1.8 V to 5.0 V,
40
C < T
A
< +125
C
65
85
dB
Supply Current/Amplifier
I
SY
V
OUT
= V
S
/2
300
450
mA
40
C < T
A
< +125
C
500
mA
DYNAMIC PERFORMANCE
Slew Rate
SR
R
L
= 10 k
W
2.7
V/
ms
Gain Bandwidth Product
GBP
5
MHz
NOISE PERFORMANCE
Voltage Noise Density
e
n
f = 1 kHz
22
nV/
Hz
f = 10 kHz
20
nV/
Hz
Current Noise Density
i
n
f = 1 kHz
0.05
pA/
Hz
(V
S
= 3.0 V, V
CM
= V
S
/2, T
A
= 25 C, unless otherwise noted.)
Specifications subject to change without notice.
REV. B
4
AD8515
ELECTRICAL CHARACTERISTICS
Parameter
Symbol
Condition
Min
Typ
Max
Unit
INPUT CHARACTERISTICS
Offset Voltage
V
OS
V
CM
=V
S
/2
1
6
mV
40
C < T
A
< +125
C
8
mV
Input Bias Current
I
B
V
S
= 5.0 V
5
30
pA
40
C < T
A
< +85
C
600
pA
40
C < T
A
< +125
C
8
nA
Input Offset Current
I
OS
1
10
pA
40
C < T
A
< +125
C
300
pA
Input Voltage Range
0
5.0
V
Common-Mode Rejection Ratio CMRR
0 V
V
CM
5.0 V
60
75
dB
Large Signal Voltage Gain
A
VO
R
L
= 100 k
W, 0.3 V V
OUT
4.7 V
500
2,000
V/mV
Offset Voltage Drift
DV
OS
/
DT
4
mV/C
OUTPUT CHARACTERISTICS
Output Voltage High
V
OH
I
L
= 100
mA, 40C < T
A
< +125
C
4.99
V
I
L
= 750
mA, 40C < T
A
< +125
C
4.98
V
Output Voltage Low
V
OL
I
L
= 100
mA, 40C < T
A
< +125
C
10
mV
I
L
= 750
mA, 40C < T
A
< +125
C
20
mV
POWER SUPPLY
Power Supply Rejection Ratio
PSRR
V
S
= 1.8 V to 5.0 V,
40
C < T
A
< +125
C
65
82
dB
Supply Current/Amplifier
I
SY
V
OUT
= V
S
/2
350
500
mA
40
C < T
A
< +125
C
600
mA
DYNAMIC PERFORMANCE
Slew Rate
SR
R
L
= 10 k
W
2.7
V/
ms
Gain Bandwidth Product
GBP
5
MHz
NOISE PERFORMANCE
Voltage Noise Density
e
n
f = 1 kHz
22
nV/
Hz
f = 10 kHz
20
nV/
Hz
Current Noise Density
i
n
f = 1 kHz
0.05
pA/
Hz
(V
S
= 5.0 V, V
CM
= V
S
/2, T
A
= 25 C, unless otherwise noted.)
Specifications subject to change without notice.
REV. B
AD8515
5
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although the
AD8515 features proprietary ESD protection circuitry, permanent damage may occur on devices
subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended
to avoid performance degradation or loss of functionality.
ABSOLUTE MAXIMUM RATINGS
*
(T
A
= 25
C, unless otherwise noted.)
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 V
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND to V
S
Differential Input Voltage . . . . . . . . . . . . . . . . . .
6 V or V
S
Output Short-Circuit Duration
to GND . . . . . . . . . . . . . . . . . . . . Observe Derating Curves
Storage Temperature Range
KS and RT Packages . . . . . . . . . . . . . . . . 65
C to +150C
Operating Temperature Range
AD8515 . . . . . . . . . . . . . . . . . . . . . . . . . . 40
C to +125C
Junction Temperature Range
KS and RT Packages . . . . . . . . . . . . . . . . 65
C to +150C
Lead Temperature Range (Soldering, 60 sec) . . . . . . . . 300
C
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those listed in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
Package Type
JA
*
JC
Unit
5-Lead SOT-23 (RT)
230
146
C/W
5-Lead SC70 (KS)
376
126
C/W
*
q
JA
is specified for worst-case conditions, i.e.,
q
JA
is specified for device sol-
dered in circuit board for surface-mount packages.
ORDERING GUIDE
Model
Temperature Range
Package Description
Package Option
AD8515ART
40C to +125C
5-Lead SOT-23
RT-5
AD8515AKS
40C to +125C
5-Lead SC70
KS-5
REV. B
6
AD8515Typical Performance Characteristics
BANDWIDTH (MHz)
450
400
200
4.65
4.95
4.70
SUPPLY CURRENT (
A)
4.75
4.80
4.85
4.90
350
300
250
V
S
= 2.5V
TPC 1. Supply Current vs. Bandwidth
450
400
0
SUPPL
Y CURRENT (
A)
200
150
100
50
300
250
350
SUPPLY VOLTAGE (V)
6
1
2
3
4
5
0
TPC 2. Supply Current vs. Supply Voltage
TEMPERATURE ( C)
500
300
50
150
I
SY
(
A)
25
50
75
125
400
350
25
0
100
450
V
S
= 5V
TPC 3. I
SY
vs. Temperature
BANDWIDTH
6
0
4.65
4.95
SUPPLY VOLTAGE (V)
4.70
4.75
4.85
5
4
2
4.80
1
3
4.90
TPC 4. Supply Voltage vs. Bandwidth
LOAD CURRENT (mA)
160
140
0
0
20
5
D
OUTPUT VOLTAGE (mV)
10
15
80
60
40
20
120
100
V
OL
V
OH
V
S
= 2.5V
TPC 5. Output Voltage to Supply Rail vs. Load Current
270
225
180
180
135
90
45
0
45
90
135
PHASE Degrees
FREQUENCY (Hz)
1k
50M
10k
1M
10M
100k
80
80
60
40
20
0
20
40
60
100
120
GAIN (dB)
GAIN
PHASE
V
S
= 2.5V
AMPLITUDE = 20mV
TPC 6. Gain and Phase vs. Frequency
REV. B
AD8515
7
FREQUENCY (Hz)
10k
30M
100k
A
CL
(dB)
1M
10M
120
100
80
80
60
40
20
0
20
40
60
V
S
= 2.5V
G = 100
G = 10
G = 1
TPC 7. A
CL
vs. Frequency
FREQUENCY (Hz)
120
80
60
10k
100M
100k
CMRR (dB)
1M
10M
40
0
20
40
80
20
60
100
V
S
= 2.5V
AMPLITUDE = 50mV
TPC 8. CMRR vs. Frequency
FREQUENCY (Hz)
100
10M
1k
PSRR (dB)
10k
100k
1M
120
100
60
80
60
40
20
10
0
20
40
V
S
= 2.5V
AMPLITUDE = 50mV
+PSRR
PSRR
TPC 9. PSRR vs. Frequency
TEMPERATURE ( C)
96
76
50
150
PSRR (dB)
50
84
80
0
100
92
88
V
S
= 2.5V
TPC 10. PSRR vs. Temperature
V
OS
(mV)
430
0
6.24
4.27
NUMBER OF AMPLIFIERS
2.29
0.32
1.66
3.63
86
172
258
344
V
S
= 2.5V
TPC 11. V
OS
Distribution
FREQUENCY (Hz)
150
1k
10M
OUTPUT IMPEDANCE (
)
50
10k
100k
1M
0
100
GAIN = 100
GAIN = 10
GAIN = 1
V
S
= 2.5V
TPC 12. Output Impedance vs. Frequency
REV. B
AD8515
8
TEMPERATURE ( C)
15
25
16
50
150
I
SC
(mA)
0
50
21
20
18
100
17
19
23
24
22
I
SC
+I
SC
V
S
= 5V
TPC 13. I
SC
vs. Temperature
FREQUENCY (Hz)
0
0
0
VO
LTA
G
E
(
1
3
V/DIV)
0
0
0
0
0
0
V
S
= 2.5V
TPC 14. Voltage Noise Density
TIME (1s/DIV)
0
0
0
0
0
0
VO
LTA
GE (200mV/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 2.5V
GAIN = 100k
TPC 15. Input Voltage Noise
TIME (200 s/DIV)
0
0
0
0
0
0
VO
LTA
GE (2V/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 2.5V
V
IN
= 6.4V
V
OUT
V
IN
TPC 16. No Phase Reversal
TIME (1 s/DIV)
0
0
0
0
0
0
VO
LTA
GE (100mV/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 2.5V
C
L
= 50pF
V
IN
= 200mV
TPC 17. Small Signal Transient Response
TIME (1 s/DIV)
0
0
0
0
0
0
VO
LTA
GE (100mV/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 2.5V
C
L
= 500pF
V
IN
= 200mV
TPC 18. Small Signal Transient Response
REV. B
AD8515
9
TIME (1 s/DIV)
0
0
0
0
0
0
VO
LTA
GE (1V/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 2.5V
C
L
= 300pF
V
IN
= 4V
TPC 19. Large Signal Transient Response
TIME (2 s/DIV)
0
0
0
0
0
0
VO
LTA
G
E
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 1.5V
GAIN = 40
V
IN
= 100mV
V
IN
V
OUT
100mV
0V
0V
2V
TPC 20. Saturation Recovery
TIME (2 s/DIV)
0
0
0
0
0
0
VO
LTA
G
E
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 1.5V
GAIN = 40
V
IN
= 100mV
100mV
0V
2V
0V
V
IN
V
OUT
TPC 21. Saturation Recovery
FREQUENCY (Hz)
10k
100M
100k
CMRR (dB)
1M
10M
120
100
80
80
60
40
20
0
20
40
60
V
S
= 1.5V
AMPLITUDE = 50mV
TPC 22. CMRR vs. Frequency
TIME (1 s/DIV)
0
0
0
0
0
0
VO
LTA
GE (100mV/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 0.9V
C
L
= 50pF
V
IN
= 200mV
TPC 23. Small Signal Transient Response
FREQUENCY (Hz)
10k
30M
100k
GAIN (dB)
1M
10M
120
100
80
80
60
40
20
0
20
40
60
PHASE (Degrees)
270
225
180
180
135
90
45
0
45
90
135
V
S
= 0.9V
AMPLITUDE = 20mV
TPC 24. Gain and Phase vs. Frequency
REV. B
AD8515
10
FREQUENCY (Hz)
200
1k
10M
OUTPUT IMPEDANCE
(
)
50
10k
100k
1M
0
100
GAIN = 100
GAIN = 10
GAIN = 1
V
S
= 0.9V
150
TPC 25. Output Impedance vs. Frequency
TIME (200 s/DIV)
0
0
0
0
0
0
VO
LTA
GE (1V/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 0.9V
V
IN
= 3.2V
V
IN
V
OUT
TPC 26. No Phase Reversal
TEMPERATURE ( C)
11
3
50
150
V
OL
(mV)
50
7
5
0
100
9
V
S
= 5V
I
L
= 750 A
TPC 27. V
OL
vs. Temperature
TEMPERATURE ( C)
4.995
4.990
50
150
V
OH
(V)
50
4.994
4.992
0
100
4.991
4.993
V
S
= 5V
I
L
= 750 A
TPC 28. V
OH
vs. Temperature
TEMPERATURE ( C)
80
65
77
71
68
74
50
150
CMRR (dB)
50
0
100
V
S
= 5V
TPC 29. CMRR vs. Temperature
REV. B
AD8515
11
FUNCTIONAL DESCRIPTION
The AD8515, offered in space-saving SOT-23 and SC70 pack-
ages, is a rail-to-rail input and output operational amplifier that
can operate at supply voltages as low as 1.8 V. This product is
fabricated using 0.6 micron CMOS to achieve one of the best power
consumption to speed ratios (i.e., bandwidth) in the industry. With a
small amount of supply current (less than 400
mA), a wide unity
gain bandwidth of 4.5 MHz is available for signal processing.
The input stage consists of two parallel, complementary, differential
pairs of PMOS and NMOS. The AD8515 exhibits no phase rever-
sal as the input signal exceeds the supply by more than 0.6 V.
Currents into the input pin must be limited to 5 mA or less by
the use of external series resistance(s). The AD8515 has a very
robust ESD design and can stand ESD voltages of up to 4,000 V.
Power Consumption vs. Bandwidth
One of the strongest features of the AD8515 is the bandwidth
stability over the specified temperature range while consuming
small amounts of current. This effect is shown in TPC 1 through
TPC 3. This product solves the speed/power requirements for
many applications. The wide bandwidth is also stable even when
operated with low supply voltages. TPC 4 shows the relationship
between the supply voltage versus the bandwidth for the AD8515.
The AD8515 is ideal for battery-powered instrumentation and
handheld devices since it can operate at the end of discharge
voltage of most popular batteries. Table I lists the nominal and
end of discharge voltages of several typical batteries.
Table I. Typical Battery Life Voltage Range
End of Discharge
Battery
Nominal Voltage (V)
Voltage (V)
Lead-Acid
2
1.8
Lithium
2.63.6
1.72.4
NiMH
1.2
1
NiCd
1.2
1
Carbon-Zinc
1.5
1.1
DRIVING CAPACITIVE LOADS
Most amplifiers have difficulty driving large capacitive loads.
Additionally, higher capacitance at the output can increase the
amount of overshoot and ringing in the amplifier's step response
and could even affect the stability of the device. This is due to the
degradation of phase margin caused by additional phase lag from
the capacitive load. The value of capacitive load that an amplifier
can drive before oscillation varies with gain, supply voltage, input
signal, temperature, and other parameters. Unity gain is the most
challenging configuration for driving capacitive loads. The AD8515
is capable of driving large capacitive loads without any external
compensation. The graphs in Figures 1a and 1b show the amplifier's
capacitive load driving capability when configured in unity gain of +1.
The AD8515 is even capable of driving higher capacitive loads
in inverting gain of 1, as shown in Figure 2.
TIME (1 s/DIV)
0
0
0
0
0
0
VO
LTA
GE (100mV/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 2.5V
C
L
= 50pF
GAIN = +1
Figure 1a. Capacitive Load Driving @ C
L
= 50 pF
TIME (1 s/DIV)
0
0
0
0
0
0
VO
LTA
GE (100mV/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 2.5V
C
L
= 500pF
GAIN = +1
Figure 1b. Capacitive Load Driving @ C
L
= 500 pF
TIME (1 s/DIV)
0
0
0
0
0
0
VO
LTA
GE (100mV/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
S
= 0.9V
C
L
= 800pF
GAIN = 1
Figure 2. Capacitive Load Driving @ C
L
= 800 pF
REV. B
AD8515
12
Full Power Bandwidth
The slew rate of an amplifier determines the maximum frequency
at which it can respond to a large input signal. This frequency
(known as full power bandwidth, FPBW) can be calculated
from the equation
FPBW
SR
V
PEAK
=
2
p
for a given distortion. The FPBW of AD8515 is shown in Figure 3
to be close to 200 kHz.
TIME (2 s/DIV)
0
0
0
0
0
0
VO
LTA
GE (2V/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
IN
V
OUT
Figure 3. Full Power Bandwidth
A MICROPOWER REFERENCE VOLTAGE GENERATOR
Many single-supply circuits are configured with the circuit biased
to one-half of the supply voltage. In these cases, a false ground
reference can be created by using a voltage divider buffered by
an amplifier. Figure 4 shows the schematic for such a circuit. The
two 1 M
W resistors generate the reference voltages while drawing
only 0.9
mA of current from a 1.8 V supply. A capacitor connected
from the inverting terminal to the output of the op amp provides
compensation to allow for a bypass capacitor to be connected at
the reference output. This bypass capacitor helps establish an ac
ground for the reference output.
0.9V TO 2.5V
AD8515
1
3
2
C2
0.022 F
R4
100
C1
1 F
V
V+
1.8V TO 5V
U1
R2
1M
C3
1 F
R1
1M
R3
10k
Figure 4. Micropower Voltage Reference Generator
A 100 kHz Single-Supply Second Order Band-Pass Filter
The circuit in Figure 5 is commonly used in portable applications
where low power consumption and wide bandwidth are required.
This figure shows a circuit for a single-supply band-pass filter
with a center frequency of 100 kHz. It is essential that the op
amp has a loop gain at 100 kHz in order to maintain an accurate
center frequency. This loop gain requirement necessitates the
choice of an op amp with a high unity gain crossover frequency,
such as the AD8515. The 4.5 MHz bandwidth of the AD8515
is sufficient to accurately produce the 100 kHz center frequency,
as the response in Figure 6 shows. When the op amp's bandwidth
is close to the filter's center frequency, the amplifier's internal
phase shift causes excess phase shift at 100 kHz, which alters
the filter's response. In fact, if the chosen op amp has a bandwidth
close to 100 kHz, the phase shift of the op amps will cause the
loop to oscillate.
A common-mode bias level is easily created by connecting the
noninverting input to a resistor divider consisting of two resistors
connected between VCC and ground. This bias point is also
decoupled to ground with a 1
mF capacitor.
f
R
C
f
R
C
H
R
R
VCC
V
V
L
H
=
=
= +
=
-
1
2
1
1
1
2
1
1
1
2
1
1 8
5
0
p
p
.
where:
f
L
is the low 3 db frequency.
f
H
is the high 3 db frequency.
H
0
is the midfrequency gain.
VOUT
AD8515
1
3
4
C6
10pF
V
V+
VCC
U9
R6
1M
R8
1M
R2
20k
R5
2k
R1
5k
C1
2nF
V11
400mV
VCC
C3
1 F
0
0
Figure 5. Second Order Band-Pass Filter
FREQUENCY (Hz)
2
0
1k
100M
10k
OUTPUT V
O
L
T
A
GE
( V)
100k
1M
10M
1
Figure 6. Frequency Response of the Band-Pass Filter
REV. B
AD8515
13
Wien Bridge Oscillator
The circuit in Figure 7 can be used to generate a sine wave, one
of the most fundamental waveforms. Known as a Wien Bridge
oscillator, it has the advantage of requiring only one low power
amplifier. This is an important consideration, especially for battery-
operated applications where power consumption is a critical
issue. To keep the equations simple, the resistor and capacitor
values used are kept equal. For the oscillation to happen, two
conditions have to be met. First, there should be a zero phase
shift from the input to the output, which will happen at the
oscillation frequency of
F
R
C
OSC
=
1
2
10
10
p
Second, at this frequency, the ratio of VOUT to the voltage at
+input (Pin 3) has to be 3, which means that the ratio of
R11/R12 should be greater than 2.
AD8515
1
3
2
V
V+
VCC
U10
C10
1nF
R13
1k
R11
2.05k
C9
1nF
R10
1k
R12
1k
VEE
Figure 7. Low Power Wien Bridge Oscillator
High frequency oscillators can be built with the AD8515 due to its
wide bandwidth. Using the values shown, an oscillation frequency of
130 kHz is created and is shown in Figure 8. If R11 is too low, the
oscillation might converge; if too large, the oscillation will diverge
until the output clips (V
S
=
2.5 V, F
OSC
= 130 kHz).
TIME (2 s/DIV)
0
0
0
0
0
0
VO
LTA
GE (2V/DIV)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 8. Output of Wien Bridge Oscillator
REV. B
AD8515
14
OUTLINE DIMENSIONS
5-Lead Small Outline Transistor Package [SOT-23]
(RT-5)
Dimensions shown in millimeters
PIN 1
1.60 BSC
2.80 BSC
1.90
BSC
0.95 BSC
1
3
4
5
2
0.22
0.08
0.55
0.45
0.35
10
5
0
0.50
0.35
0.15 MAX
SEATING
PLANE
1.45 MAX
1.30
1.15
0.90
2.90 BSC
COMPLIANT TO JEDEC STANDARDS MO-178AA
5-Lead Thin Shrink Small Outline Transistor Package [SC70]
(KS-5)
Dimensions shown in millimeters
0.30
0.15
1.00
0.90
0.70
SEATING
PLANE
1.10 MAX
0.22
0.08
0.46
0.36
0.26
3
5
4
1
2
2.00 BSC
PIN 1
2.10 BSC
0.65 BSC
1.25 BSC
0.10 MAX
0.10 COPLANARITY
COMPLIANT TO JEDEC STANDARDS MO-203AA
REV. B
AD8515
15
Revision History
Location
Page
4/03--Data Sheet changed from REV. A to REV. B.
Change to Figure 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2/03--Data Sheet changed from REV. 0 to REV. A.
Added new SC70 Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Universal
Changes to FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Changes to GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Changes to PIN CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Changes to SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Changes to ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Changes to ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Changes to TPC 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Changes to TPC 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Changes to TPC 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Changes to TPC 27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Changes to TPC 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Added new TPC 29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Changes to FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Updated to OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
C0302404/03(B)
16