LTC6910-2ITS8#TRMPBF [Linear]
LTC6910 - Digitally Controlled Programmable Gain Amplifiers in SOT-23; Package: SOT; Pins: 8; Temperature Range: -40°C to 85°C;型号: | LTC6910-2ITS8#TRMPBF |
厂家: | Linear |
描述: | LTC6910 - Digitally Controlled Programmable Gain Amplifiers in SOT-23; Package: SOT; Pins: 8; Temperature Range: -40°C to 85°C 放大器 光电二极管 |
文件: | 总26页 (文件大小:330K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
LTC6910-1/
LTC6910-2/LTC6910-3
Digitally Controlled
Programmable
Gain Amplifiers in SOT-23
FeaTures
DescripTion
The LTC®6910 family are low noise digitally program-
mable gain amplifiers (PGAs) that are easy to use and
occupy very little PC board space. The inverting gain is
adjustable using a 3-bit digital input to select gains of 0,
1, 2, 5, 10, 20, 50 and 100V/V in the LTC6910-1; 0, 1, 2,
4, 8, 16, 32 and 64V/V in the LTC6910-2; and 0, 1, 2, 3,
4, 5,6 and 7V/V in the LTC6910-3.
n
3-Bit Digital Gain Control in Three Gain-Code
Options
n
Rail-to-Rail Input Range
n
Rail-to-Rail Output Swing
n
Single or Dual Supply: 2.7V to 10.5V Total
n
11MHz Gain Bandwidth Product
n
Input Noise Down to 8nV/√Hz
n
System Dynamic Range to 120dB
The LTC6910-Xs are inverting amplifiers with rail-to-rail
output. When operated with unity gain, they will also
process rail-to-rail input signals. A half-supply refer-
ence generated internally at the AGND pin supports single
power supply applications. Operating from single or split
supplies from 2.7V to 10.5V, the LTC6910-X family is
offered in an 8-lead SOT-23 package.
n
Input Offset Voltage: 1.5mV
n
8-Pin Low Profile (1mm) SOT-23
(ThinSOT™) Package
applicaTions
n
Data Acquisition Systems
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
ThinSOT is a trademark of Analog Devices, Inc. All other trademarks are the property of their
respective owners. Protected by U.S. patents, including 6121908.
n
Dynamic Gain Changing
n
Automatic Ranging Circuits
Automatic Gain Control
n
Typical applicaTion
Single Supply Programmable Amplifier
Frequency Response (LTC6910-1)
+
50
V
V
= 10V, V = 5mV
IN RMS
S
2.7V TO 10.5V
GAIN OF 100 (DIGITAL INPUT 111)
0.1µF
40
30
DIGITAL INPUTS GAIN IN VOLTS/VOLT
G2 G1 G0 6910-1 6910-2 6910-3
GAIN OF 50 (DIGITAL INPUT 110)
8
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
0
0
4
–1
–1
–1
–2
–3
–4
–5
–6
–7
GAIN OF 20 (DIGITAL INPUT 101)
GAIN OF 10 (DIGITAL INPUT 100)
GAIN OF 5 (DIGITAL INPUT 011)
3
1
–2
–5
–10
–20
–50
–100
–2
20
10
V
V
= GAIN • V
OUT IN
LTC6910-X
IN
–4
2
–8
5
–16
–32
–64
AGND
1µF OR LARGER
6
7
GAIN OF 2 (DIGITAL INPUT 010)
GAIN OF 1 (DIGITAL INPUT 001)
G2 G1 G0
6910 TA01
0
PIN 2 (AGND) PROVIDES BUILT-IN HALF-SUPPLY
REFERENCE WITH INTERNAL RESISTANCE OF 5k.
AGND CAN ALSO BE DRIVEN BY A SYSTEM ANALOG
GROUND REFERENCE NEAR HALF SUPPLY
–10
100
1k
10k
100k
1M
10M
FREQUENCY (Hz)
6910 TA01b
6910123fb
1
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
absoluTe MaxiMuM raTings
pin conFiguraTion
(Note 1)
Total Supply Voltage (V+ to V–) ............................... 11V
Input Current...................................................... 25mA
Operating Temperature Range (Note 2)
LTC6910-1C, -2C, -3C..........................–40°C to 85°C
LTC6910-1I, -2I, -3I ............................. –40°C to 85°C
LTC6910-1H, -2H, -3H ...................... –40°C to 125°C
Specified Temperature Range (Note 3)
LTC6910-1C, -2C, -3C.......................... –40°C to 85°C
LTC6910-1I, -2I, -3I ............................. –40°C to 85°C
LTC6910-1H, -2H, -3H ...................... –40°C to 125°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
TOP VIEW
+
OUT 1
AGND 2
8 V
7 G2
6 G1
5 G0
IN 3
–
V
4
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
T
= 150°C, θ = 230°C/W
JA
JMAX
orDer inForMaTion
http://www.linear.com/product/LTC6910#orderinfo
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
TEMPERATURE RANGE
LTC6910-1CTS8#PBF
LTC6910-1ITS8#PBF
LTC6910-1HTS8#PBF
LTC6910-2CTS8#PBF
LTC6910-2ITS8#PBF
LTC6910-2HTS8#PBF
LTC6910-3CTS8#PBF
LTC6910-3ITS8#PBF
LTC6910-3HTS8#PBF
LTC6910-1CTS8#TRPBF LTB5 (6910-1)
LTC6910-1ITS8#TRPBF LTB5 (6910-1)
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
LTC6910-1HTS8#TRPBF LTB5 (6910-1)
LTC6910-2CTS8#TRPBF LTACQ (6910-2)
LTC6910-2ITS8#TRPBF
LTACQ (6910-2)
LTC6910-2HTS8#TRPBF LTACQ (6910-2)
LTC6910-3CTS8#TRPBF LTACS (6910-3)
LTC6910-3ITS8#TRPBF
LTACS (6910-3)
LTC6910-3HTS8#TRPBF LTACS (6910-3)
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/. Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
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For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
gain seTTings anD properTies
Table 1. LTC6910-1
NOMINAL
NOMINAL
NOMINAL LINEAR INPUT RANGE (V
)
P-P
INPUT
IMPEDANCE
(kΩ)
VOLTAGE GAIN
Dual 5V
Supply
Single 5V
Supply
Single 3V
Supply
G2
0
G1
0
G0
0
Volts/Volt
0
(dB)
–120
0
10
10
5
5
5
3
(Open)
0
0
1
–1
3
10
5
0
1
0
–2
6
2.5
1
1.5
0.6
0.3
0.15
0.06
0.03
0
1
1
–5
14
20
26
34
40
2
2
1
0
0
–10
–20
–50
–100
1
0.5
0.25
0.1
0.05
1
1
0
1
0.5
0.2
0.1
1
1
1
0
1
1
1
1
1
Table 2. LTC6910-2
NOMINAL
INPUT
NOMINAL
VOLTAGE GAIN
NOMINAL LINEAR INPUT RANGE (V
)
P-P
Dual 5V
Supply
Single 5V
Supply
Single 3V
Supply
IMPEDANCE
(kΩ)
G2
0
G1
0
G0
0
Volts/Volt
(dB)
–120
0
0
10
10
5
3
(Open)
10
0
0
1
–1
5
3
0
1
0
–2
6
5
2.5
1.5
5
0
1
1
–4
12
2.5
1.25
0.625
0.313
0.156
0.078
0.75
0.375
0.188
0.094
0.047
2.5
1
0
0
–8
18.1
24.1
30.1
36.1
1.25
0.625
0.313
0.156
1.25
1.25
1.25
1.25
1
0
1
–16
–32
–64
1
1
0
1
1
1
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For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
gain seTTings anD properTies
Table 3. LTC6910-3
NOMINAL
INPUT
NOMINAL
NOMINAL LINEAR INPUT RANGE (V
)
P-P
VOLTAGE GAIN
Dual 5V
Supply
Single 5V
Supply
Single 3V
Supply
IMPEDANCE
(kΩ)
G2
0
G1
0
G0
0
Volts/Volt
(dB)
–120
0
0
10
10
5
3
3
(Open)
10
0
0
1
–1
–2
–3
–4
–5
–6
–7
5
0
1
0
6
5
2.5
1.67
1.25
1
1.5
1
5
0
1
1
9.5
12
3.33
2.5
2
3.3
2.5
2
1
0
0
0.75
0.6
0.5
0.43
1
0
1
14
1
1
0
15.6
16.9
1.67
1.43
0.83
0.71
1.7
1.4
1
1
1
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For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
elecTrical characTerisTics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k
to mid-supply point, unless otherwise noted.
C, I SUFFIXES
H SUFFIX
MIN TYP MAX MIN TYP MAX
PARAMETER
CONDITIONS
UNIT
Specifications for the LTC6910-1, LTC6910-2, LTC6910-3
●
Total Supply Voltage
2.7
10.5
2.7
10.5
V
●
●
●
●
Supply Current
V = 2.7V, V = 1.35V
2
3
2
3
mA
mA
mA
mA
S
IN
V = 5V, V = 2.5V
2.4
3
3.5
4.5
4.9
2.4
3
3.5
4.5
4.9
S
IN
V = 5V, V = 0V, Pins 5, 6, 7 = –5V or 5V
S
IN
V = 5V, V = 0V, Pin 5 = 4.5V,
3.5
3.5
S
IN
Pins 6, 7 = 0.5V (Note 4)
●
●
Output Voltage Swing LOW (Note 5)
V = 2.7V, R = 10k to Mid-Supply Point
12
50
30
100
12
50
30
100
mV
mV
S
L
V = 2.7V, R = 500Ω to Mid-Supply Point
S
L
●
●
V = 5V, R = 10k to Mid-Supply Point
20
90
40
160
20
90
40
160
mV
mV
S
L
V = 5V, R = 500Ω to Mid-Supply Point
S
L
●
●
V = 5V, R = 10k to 0V
30
180
50
250
30
180
50
270
mV
mV
S
L
V = 5V, R = 500Ω to 0V
S
L
●
●
Output Voltage Swing HIGH (Note 5)
V = 2.7V, R = 10k to Mid-Supply Point
10
50
20
80
10
50
20
85
mV
mV
S
L
V = 2.7V, R = 500Ω to Mid-Supply Point
S
L
●
●
V = 5V, R = 10k to Mid-Supply Point
10
80
30
150
10
80
30
150
mV
mV
S
L
V = 5V, R = 500Ω to Mid-Supply Point
S
L
●
●
V = 5V, R = 10k to 0V
20
180
40
250
20
180
40
250
mV
mV
S
L
V = 5V, R = 500Ω to 0V
S
L
Output Short-Circuit Current (Note 6)
AGND Open-Circuit Voltage
V = 2.7V
S
27
35
27
35
mA
mA
S
V = 5V
●
V = 5V
S
2.45
2.5
2.55 2.45
2.5
2.55
V
●
●
AGND Rejection (i.e., Common Mode
Rejection or CMRR)
V = 2.7V, V
S
= 1.1V to Upper AGND Limit
= –2.5V to 2.5V
55
55
80
75
50
50
80
75
dB
dB
S
AGND
AGND
V = 5V, V
●
●
Power Supply Rejection Ratio (PSRR)
Signal Attenuation at Gain = 0 Setting
Slew Rate
V = 2.7V to 5V
60
80
60
80
dB
dB
S
Gain = 0 (Digital Inputs 000), f = 20kHz
V = 5V, V = 2.8V
–122
–122
12
16
12
16
V/µs
V/µs
S
OUT
P-P
V = 5V, V
S
= 2.8V
OUT
P-P
●
●
●
Digital Input “High” Voltage
V = 2.7V
2.43
4.5
4.5
2.43
4.5
4.5
V
V
V
S
V = 5V
S
V = 5V
S
●
●
●
Digital Input “Low” Voltage
V = 2.7V
0.27
0.5
0.5
0.27
0.5
0.5
V
V
V
S
V = 5V
S
V = 5V
S
–
+
Digital Input Leakage Current Magnitude
V ≤ (Digital Input) ≤ V
2
2
µA
6910123fb
5
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
elecTrical characTerisTics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k
to mid-supply point, unless otherwise noted.
LTC6910-1C/LTC6910-1I
LTC6910-1H
MIN
TYP MAX MIN TYP MAX
PARAMETER
CONDITIONS
UNIT
Specifications for the LTC6910-1 Only
Voltage Gain (Note 7)
●
●
V = 2.7V, Gain = 1, R = 10k
–0.05
0
0.07 –0.06
0
0.07
dB
dB
S
L
V = 2.7V, Gain = 1, R = 500Ω
–0.1 –0.02 0.06 –0.12 –0.02 0.08
5.96 6.02 6.08 5.96 6.02 6.08
13.85 13.95 14.05 13.83 13.95 14.05
S
L
●
●
V = 2.7V, Gain = 2, R = 10k
dB
dB
S
L
V = 2.7V, Gain = 5, R = 10k
S
L
●
●
V = 2.7V, Gain = 10, R = 10k
19.7 19.9 20.1 19.7 19.9 20.1
19.6 19.85 20.1 19.4 19.85 20.1
dB
dB
S
L
V = 2.7V, Gain = 10, R = 500Ω
S
L
●
●
V = 2.7V, Gain = 20, R = 10k
25.7 25.9 26.1 25.65 25.9 26.1
33.5 33.8 34.1 33.4 33.8 34.1
dB
dB
S
L
V = 2.7V, Gain = 50, R = 10k
S
L
●
●
V = 2.7V, Gain = 100, R = 10k
39
39.6 40.2 38.7 39.6 40.2
dB
dB
S
L
V = 2.7V, Gain = 100, R = 500Ω
36.4 38.5 40.1 35.4 38.5 40.1
S
L
●
●
V = 5V, Gain = 1, R = 10k
–0.05 0.07 –0.05 0.07
0
0
dB
dB
S
L
V = 5V, Gain = 1, R = 500Ω
–0.1 –0.01 0.08 –0.11 –0.01 0.08
5.96 6.02 6.08 5.955 6.02 6.08
13.8 13.95 14.1 13.75 13.95 14.1
S
L
●
●
V = 5V, Gain = 2, R = 10k
dB
dB
S
L
V = 5V, Gain = 5, R = 10k
S
L
●
●
V = 5V, Gain = 10, R = 10k
19.8 19.9 20.1 19.75 19.9 20.1
19.6 19.85 20.1 19.45 19.85 20.1
dB
dB
S
L
V = 5V, Gain = 10, R = 500Ω
S
L
●
●
V = 5V, Gain = 20, R = 10k
25.8 25.9 26.1 25.70 25.9 26.1
33.5 33.8 34.1 33.4 33.8 34.1
39.3 39.7 40.1 39.1 39.7 40.1
dB
dB
S
L
V = 5V, Gain = 50, R = 10k
S
L
●
●
V = 5V, Gain = 100, R = 10k
dB
dB
S
L
V = 5V, Gain = 100, R = 500Ω
37
38.7 40.1
36
38.7 40.1
S
L
●
●
V = 5V, Gain = 1, R = 10k
–0.05
0
0.07 –0.05
0
0.07
dB
dB
S
L
V = 5V, Gain = 1, R = 500Ω
–0.1 –0.01 0.08 –0.1 –0.01 0.08
5.96 6.02 6.08 5.96 6.02 6.08
13.80 13.95 14.1 13.80 13.95 14.1
S
L
●
●
V = 5V, Gain = 2, R = 10k
dB
dB
S
L
V = 5V, Gain = 5, R = 10k
S
L
●
●
V = 5V, Gain = 10, R = 10k
19.8 19.9 20.1 19.75 19.9 20.1
19.7 19.9 20.1 19.6 19.9 20.1
dB
dB
S
L
V = 5V, Gain = 10, R = 500Ω
S
L
●
●
V = 5V, Gain = 20, R = 10k
25.8 25.95 26.1 25.75 25.95 26.1
dB
dB
S
L
V = 5V, Gain = 50, R = 10k
33.7 33.85
39.4 39.8 40.2 39.25 39.8 40.2
37.8 39.1 40.1 37 39.1 40.1
34
33.6 33.85 34
S
L
●
●
V = 5V, Gain = 100, R = 10k
dB
dB
S
L
V = 5V, Gain = 100, R = 500Ω
S
L
●
Offset Voltage Magnitude (Internal Op Amp)
1.5
9
1.5
11
mV
(V
) (Note 8)
OS(OA)
Offset Voltage Drift (Internal Op Amp) (Note 8)
6
8
µV/°C
●
●
Offset Voltage Magnitude
Gain = 1
Gain = 10
3
1.7
15
10
3
1.7
18
12
mV
mV
(Referred to “IN” Pin) (V
)
OS(IN)
DC Input Resistance (Note 9)
DC V = 0V
Gain = 0
Gain = 1
Gain = 2
Gain = 5
Gain = 10, 20, 50, 100
IN
>100
10
5
2
1
>100
10
5
2
1
MΩ
kΩ
kΩ
kΩ
kΩ
●
●
●
●
6910123fb
6
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
elecTrical characTerisTics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k
to mid-supply point, unless otherwise noted.
LTC6910-1C/LTC6910-1I
LTC6910-1H
PARAMETER
CONDITIONS
MIN TYP
MAX MIN TYP MAX
UNIT
Specifications for LTC6910-1 Only
DC Small-Signal Output Resistance
Gain = 0
Gain = 1
Gain = 2
Gain = 5
Gain = 10
Gain = 20
Gain = 50
Gain = 100
0.4
0.7
1
1.9
3.4
6.4
15
30
0.4
0.7
1
1.9
3.4
6.4
15
30
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Gain-Bandwidth Product
Gain = 100, f = 200kHz
8
6
11
11
14
16
8
5
11
11
14
16
MHz
MHz
IN
●
Wideband Noise (Referred to Input)
f = 1kHz to 200kHz
Gain = 0 Output Noise
Gain = 1
Gain = 2
Gain = 5
Gain = 10
Gain = 20
Gain = 50
Gain = 100
3.8
10.7
7.3
5.2
4.5
4.2
3.9
3.4
3.8
10.7
7.3
5.2
4.5
4.2
3.9
3.4
µV
RMS
RMS
RMS
RMS
RMS
RMS
RMS
RMS
µV
µV
µV
µV
µV
µV
µV
Voltage Noise Density (Referred to Input)
f = 50kHz
Gain = 1
Gain = 2
24
16
12
24
16
12
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
Gain = 5
Gain = 10
Gain = 20
Gain = 50
Gain = 100
10
10
9.4
8.7
7.6
9.4
8.7
7.6
Total Harmonic Distortion
Gain = 10, f = 10kHz, V
= 1V
RMS
–90
0.003
–90
0.003
dB
%
IN
OUT
Gain = 10, f = 100kHz, V
= 1V
RMS
–77
0.014
–77
0.014
dB
%
IN
OUT
●
●
●
AGND (Common Mode) Input Voltage Range V = 2.7V
0.55
0.7
–4.3
1.6
3.65
3.5
0.7
1
–4.3
1.5
3.25
3.35
V
V
V
S
(Note 10)
V = 5V
S
V = 5V
S
6910123fb
7
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
elecTrical characTerisTics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k
to mid-supply point, unless otherwise noted.
LTC6910-2C/LTC6910-2I
LTC6910-2H
MIN TYP MAX MIN TYP MAX
PARAMETER
CONDITIONS
UNIT
Specifications for LTC6910-2 Only
Voltage Gain (Note 7)
l
l
V = 2.7V, Gain = 1, R = 10k
–0.06
0
0.08 –0.07
0
0.08
dB
dB
S
L
V = 2.7V, Gain = 1, R = 500Ω
–0.1 –0.02 0.06 –0.11 –0.02 0.06
S
L
l
l
V = 2.7V, Gain = 2, R = 10k
5.96 6.02 6.1 5.95 6.02 6.1
dB
dB
S
L
V = 2.7V, Gain = 4, R = 10k
11.9 12.02 12.12 11.9 12.02 12.12
S
L
l
l
V = 2.7V, Gain = 8, R = 10k
17.8 17.98 18.15 17.8 17.98 18.15
17.65 17.95 18.15 17.55 17.95 18.15
dB
dB
S
L
V = 2.7V, Gain = 8, R = 500Ω
S
L
l
l
V = 2.7V, Gain = 16, R = 10k
23.75 24
29.7 30
24.2 23.75 24
30.2 29.65 30
24.2
30.2
dB
dB
S
L
V = 2.7V, Gain = 32, R = 10k
S
L
l
l
V = 2.7V, Gain = 64, R = 10k
35.3 35.75 36.2 35.2 35.75 36.2
33.2 34.8 36.2 32.7 34.8 36.2
dB
dB
S
L
V = 2.7V, Gain = 64, R = 500Ω
S
L
l
l
V = 5V, Gain = 1, R = 10k
–0.06
0
0.08 –0.06
0
0.08
dB
dB
S
L
V = 5V, Gain = 1, R = 500Ω
–0.1 –0.01 0.08 –0.11 –0.01 0.08
S
L
l
l
V = 5V, Gain = 2, R = 10k
5.96 6.02 6.1 5.96 6.02 6.1
11.85 12.02 12.15 11.85 12.02 12.15
dB
dB
S
L
V = 5V, Gain = 4, R = 10k
S
L
l
l
V = 5V, Gain = 8, R = 10k
17.85 18
18.15 17.85 18 18.15
dB
dB
S
L
V = 5V, Gain = 8, R = 500Ω
17.65 17.9 18.15 17.6 17.9 18.15
S
L
l
l
V = 5V, Gain = 16, R = 10k
23.85 24
29.7 30
24.15 23.78 24 24.15
30.2 29.7 30 30.2
dB
dB
S
L
V = 5V, Gain = 32, R = 10k
S
L
l
l
V = 5V, Gain = 64, R = 10k
35.6 35.9 36.2 35.5 35.9 36.2
dB
dB
S
L
V = 5V, Gain = 64, R = 500Ω
33.8
35
36
33.2
35
36
S
L
l
l
V = 5V, Gain = 1, R = 10k
–0.05
0
0.07 –0.05
0
0.07
dB
dB
S
L
V = 5V, Gain = 1, R = 500Ω
–0.1 –0.01 0.08 –0.1 –0.01 0.08
S
L
l
l
V = 5V, Gain = 2, R = 10k
5.96 6.02
11.9 12.02 12.15 11.9 12.02 12.15
17.85 18 18.15 17.85 18 18.15
17.80 17.95 18.1 17.72 17.95 18.1
6.1
5.96 6.02
6.1
dB
dB
S
L
V = 5V, Gain = 4, R = 10k
S
L
l
l
V = 5V, Gain = 8, R = 10k
dB
dB
S
L
V = 5V, Gain = 8, R = 500Ω
S
L
l
l
V = 5V, Gain = 16, R = 10k
23.85 24
29.85 30
24.15 23.8
24 24.15
dB
dB
S
L
V = 5V, Gain = 32, R = 10k
30.15 29.78 30 30.15
S
L
l
l
V = 5V, Gain = 64, R = 10k
35.7 35.95 36.2 35.7 35.95 36.2
34.2 35.3 36.2 33.8 35.3 36.2
dB
dB
S
L
V = 5V, Gain = 64, R = 500Ω
S
L
l
Offset Voltage Magnitude (Internal Op Amp)
1.5
9
1.5
11
mV
(V
) (Note 8)
OS(OA)
l
Offset Voltage Drift (Internal Op Amp) (Note 8)
6
8
µV/°C
l
l
Offset Voltage Magnitude
Gain = 1
Gain = 8
3
2
15
10
3
2
17
12
mV
mV
(Referred to “IN” Pin) (V
)
OS(IN)
DC Input Resistance (Note 9)
DC V = 0V
Gain = 0
Gain = 1
Gain = 2
Gain = 4
Gain = 8, 16, 32, 64
IN
>100
10
5
2.5
1.25
>100
10
5
2.5
1.25
MΩ
kΩ
kΩ
kΩ
kΩ
l
l
l
l
6910123fb
8
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
elecTrical characTerisTics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k
to mid-supply point, unless otherwise noted.
LTC6910-2C/LTC6910-2I
LTC6910-2H
MIN TYP
MAX MIN TYP MAX
PARAMETER
CONDITIONS
UNIT
Specifications for LTC6910-2 Only
DC Small-Signal Output Resistance
Gain = 0
Gain = 1
Gain = 2
Gain = 4
Gain = 8
Gain = 16
Gain = 32
Gain = 64
0.4
0.7
1
1.6
2.8
5
0.4
0.7
1
1.6
2.8
5
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω
10
20
10
20
Gain-Bandwidth Product
Gain = 64, f = 200kHz
9
7
13
13
16
19
9
7
13
13
16
19
MHz
MHz
IN
l
Wideband Noise (Referred to Input)
f = 1kHz to 200kHz
Gain = 0 Output Noise
Gain = 1
Gain = 2
Gain = 4
Gain = 8
Gain = 16
Gain = 32
Gain = 64
3.8
10.7
7.3
5.3
4.6
4.2
4
3.8
10.7
7.3
5.3
4.6
4.2
4
µV
RMS
RMS
RMS
RMS
RMS
RMS
RMS
RMS
µV
µV
µV
µV
µV
µV
µV
3.6
3.6
Voltage Noise Density (Referred to Input)
f = 50kHz
Gain = 1
Gain = 2
Gain = 4
Gain = 8
Gain = 16
Gain = 32
Gain = 64
24
16
12
10.3
9.4
9
24
16
12
10.3
9.4
9
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
8.1
8.1
Total Harmonic Distortion
Gain = 8, f = 10kHz, V
= 1V
RMS
–90
0.003
–90
0.003
dB
%
IN
OUT
Gain = 8, f = 100kHz, V
= 1V
RMS
–77
0.014
–77
0.014
dB
%
IN
OUT
l
l
l
AGND (Common Mode) Input Voltage Range V = 2.7V
0.85
0.7
–4.3
1.55 0.85
1.55
3.6
3.4
V
V
V
S
(Note 10)
V = 5V
3.6
3.4
0.7
S
V = 5V
S
–4.3
6910123fb
9
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
elecTrical characTerisTics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k
to mid-supply point, unless otherwise noted.
LTC6910-3C/LTC6910-3I
LTC6910-2H
MIN
TYP MAX MIN TYP MAX
PARAMETER
CONDITIONS
UNIT
Specifications for LTC6910-3 Only
Voltage Gain (Note 7)
l
l
V = 2.7V, Gain = 1, R = 10k
–0.05
0
0.07 –0.05
0
0.09
dB
dB
S
L
V = 2.7V, Gain = 1, R = 500Ω
–0.1 –0.02 0.06 –0.11 –0.02 0.06
S
L
l
l
V = 2.7V, Gain = 2, R = 10k
5.93 6.02 6.08 5.93 6.02 6.09
dB
dB
S
L
V = 2.7V, Gain = 3, R = 10k
9.35
9.5
9.7
9.35 9.5 9.75
S
L
l
l
V = 2.7V, Gain = 4, R = 10k
11.9 11.98 12.2 11.9 11.98 12.2
11.8 11.98 12.2 11.75 11.98 12.2
dB
dB
S
L
V = 2.7V, Gain = 4, R = 500Ω
S
L
l
l
V = 2.7V, Gain = 5, R = 10k
13.85 13.92 14.05 13.8 13.92 14.05
15.4 15.5 15.6 15.4 15.5 15.6
dB
dB
S
L
V = 2.7V, Gain = 6, R = 10k
S
L
l
l
V = 2.7V, Gain = 7, R = 10k
16.7 16.85
16.55 16.8
17
16.7 16.85 17
dB
dB
S
L
V = 2.7V, Gain = 7, R = 500Ω
17 16.47 16.8
17
S
L
l
l
V = 5V, Gain = 1, R = 10k
–0.05
0
0.07 –0.05
0
0.07
dB
dB
S
L
V = 5V, Gain = 1, R = 500Ω
–0.1 –0.01 0.08 –0.1 –0.01 0.08
5.96 6.02 6.08 5.96 6.02 6.08
9.45 9.54 9.65 9.45 9.54 9.65
S
L
l
l
V = 5V, Gain = 2, R = 10k
dB
dB
S
L
V = 5V, Gain = 3, R = 10k
S
L
l
l
V = 5V, Gain = 4, R = 10k
11.85 12.02 12.15 11.85 12.02 12.15
11.8 11.95 12.15 11.75 11.95 12.15
dB
dB
S
L
V = 5V, Gain = 4, R = 500Ω
S
L
l
l
V = 5V, Gain = 5, R = 10k
13.8 13.95 14.05 13.8 13.95 14.05
15.35 15.5 15.65 15.35 15.5 15.65
dB
dB
S
L
V = 5V, Gain = 6, R = 10k
S
L
l
l
V = 5V, Gain = 7, R = 10k
16.7 16.85
16.6 16.8
17
17
16.7 16.85 17
dB
dB
S
L
V = 5V, Gain = 7, R = 500Ω
16.5 16.8
17
S
L
l
l
V = 5V, Gain = 1, R = 10k
–0.06
0
0.07 –0.06
0
0.07
dB
dB
S
L
V = 5V, Gain = 1, R = 500Ω
–0.1 –0.01 0.08 –0.12 –0.01 0.08
S
L
l
l
V = 5V, Gain = 2, R = 10k
5.96 6.02 6.08 5.96 6.02 6.08
dB
dB
S
L
V = 5V, Gain = 3, R = 10k
9.4
9.54 9.65
9.4 9.54 9.65
12.2
S
L
l
l
V = 5V, Gain = 4, R = 10k
11.85
11.8
12
12
12.2 11.85 12
dB
dB
S
L
V = 5V, Gain = 4, R = 500Ω
12.2 11.8
12
12.2
S
L
l
l
V = 5V, Gain = 5, R = 10k
13.8 13.95 14.1 13.8 13.95 14.1
15.35 15.5 15.7 15.35 15.5 15.7
16.7 16.85 17.05 16.7 16.85 17.05
dB
dB
S
L
V = 5V, Gain = 6, R = 10k
S
L
l
l
V = 5V, Gain = 7, R = 10k
dB
dB
S
L
V = 5V, Gain = 7, R = 500Ω
16.65 16.8
17
16.6 16.8
17
S
L
l
Offset Voltage Magnitude (Internal Op Amp)
1.5
8
1.5
8
mV
(V
) (Note 8)
OS(OA)
l
Offset Voltage Drift (Internal Op Amp) (Note 8)
6
8
µV/°C
l
l
Offset Voltage Magnitude
Gain = 1
Gain = 4
3
1.9
15
10
3
1.9
15
10
mV
mV
(Referred to “IN” Pin) (V
)
OS(IN)
DC Input Resistance (Note 9)
DC V = 0V
IN
Gain = 0
Gain = 1
Gain = 2
Gain = 3
Gain = 4
Gain = 5
Gain = 6
Gain = 7
>100
10
5
3.3
2.5
2
1.7
1.4
>100
10
5
3.3
2.5
2
1.7
1.4
MΩ
kΩ
kΩ
kΩ
kΩ
kΩ
kΩ
kΩ
l
l
l
l
l
l
l
6910123fb
10
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
elecTrical characTerisTics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k
to mid-supply point, unless otherwise noted.
LTC6910-3C/LTC6910-3I
LTC6910-2H
MIN
TYP MAX MIN TYP MAX
PARAMETER
CONDITIONS
UNIT
Specifications for LTC6910-3 Only
DC Small-Signal Output Resistance
Gain = 0
Gain = 1
Gain = 2
Gain = 3
Gain = 4
Gain = 5
Gain = 6
Gain = 7
0.4
0.7
1
1.3
1.6
1.9
2.2
2.5
0.4
0.7
1
1.3
1.6
1.9
2.2
2.5
Ω
Ω
Ω
Ω
Ω
Ω
Ω
Ω
l
Gain-Bandwidth Product
Gain = 7, f = 200kHz
11
11
MHz
IN
Wideband Noise (Referred to Input)
f = 1kHz to 200kHz
Gain = 0 Output Noise
Gain = 1
Gain = 2
Gain = 3
Gain = 4
Gain = 5
Gain = 6
Gain = 7
3.8
10.7
7.3
6.1
5.3
5.2
4.9
4.7
3.8
10.7
7.3
6.1
5.3
5.2
4.9
4.7
µV
RMS
RMS
RMS
RMS
RMS
RMS
RMS
RMS
µV
µV
µV
µV
µV
µV
µV
Voltage Noise Density (Referred to Input)
f = 50kHz
Gain = 1
Gain = 2
Gain = 3
Gain = 4
Gain = 5
Gain = 6
Gain = 7
24
16
14
24
16
14
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
12
12
11.6
11.2
10.5
11.6
11.2
10.5
Total Harmonic Distortion
Gain = 4, f = 10kHz, V
= 1V
RMS
–90
0.003
–90
0.003
dB
%
IN
OUT
Gain = 4, f = 100kHz, V
= 1V
RMS
–80
0.01
–80
0.01
dB
%
IN
OUT
l
l
l
AGND (Common Mode) Input Voltage Range V = 2.7V
0.85
0.7
–4.3
1.55 0.85
1.55
3.6
3.4
V
V
V
S
(Note 10)
V = 5V
3.6
3.4
0.7
S
V = 5V
S
–4.3
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 5: Output voltage swings are measured as differences between the
output and the respective supply rail.
Note 2: The LTC6910-XC and LTC6910-XI are guaranteed functional over
the operating temperature range of –40°C to 85°C. The LTC6910-XH are
guaranteed functional over the operating temperature range of –40°C to
125°C.
Note 6: Extended operation with output shorted may cause junction
temperature to exceed the 150°C limit and is not recommended.
Note 7: Gain is measured with a DC large-signal test using an output
excursion between approximately 30% and 70% of supply voltage.
Note 3: The LTC6910-XC are guaranteed to meet specified performance
from 0°C to 70°C. The LTC6910-XC are designed, characterized and
expected to meet specified performance from –40°C to 85°C but are not
tested or QA sampled at these temperatures. LTC6910-XI are guaranteed
to meet specified performance from –40°C to 85°C. The LTC6910-XH are
guaranteed to meet specified performance from –40°C to 125°C.
Note 8: Offset voltage referred to “IN” pin is (1 + 1/G) times offset
voltage of the internal op amp, where G is nominal gain magnitude. See
Applications Information.
Note 9: Input resistance can vary by approximately 30% part-to-part at a
given gain setting.
Note 10: At limits of AGND input range, open-loop gain of internal op
amp may be greater than, or as much as 15dB below, its value at nominal
AGND value.
Note 4: Operating all three logic inputs at 0.5V causes the supply current
to increase typically 0.1mA from this specification.
6910123fb
11
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
Typical perForMance characTerisTics (LTC6910-1)
LTC6910-1 Gain Shift
LTC6910-1 –3dB Bandwidth
vs Gain Setting
vs Temperature
LTC6910-1 Frequency Response
50
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0.2
0.1
0
V
= 2.5V
V
•
•
= 5mV
V
S
=
5Vꢀ V = 5mV
IN RMS
S
IN
V
V
RMS
= 2.7V
OUTPUT UNLOADED
•
•
S
GAIN OF 100
GAIN OF 50
= 5V
40
30
S
GAIN = 100
GAIN = 10
GAIN OF 20
GAIN OF 10
GAIN OF 5
•
•
20
10
GAIN = 1
GAIN OF 2
GAIN OF 1
•
•
–0.1
•
•
0
•
•
•
•
•
–10
100
–0.2
–50
0
50
100
150
1
10
100
1k
10k
100k
1M
10M
TEMPERATURE (°C)
GAIN
FREQUENCY (Hz)
6910 G02
6910 G01
6910 G03
LTC6910-1 Output Voltage Swing
vs Load Current
LTC6910-1 Power Supply
Rejection vs Frequency
LTC6910-1 Noise Density
vs Frequency
90
80
70
60
50
40
30
20
10
0
100
+V
S
V
=
2.5V
INPUT-REFERRED
S
V
S
=
2.5V
GAIN = 1
V
T
= ±±2.V
= ±.°C
+V – 0.5
S
A
125°C
25°C
S
SOURCE
+V – 1.0
S
–40°C
GAIN = 1
+SUPPLY
+V – 1.5
S
–SUPPLY
+V – 2.0
S
GAIN = 10
10
–V + 2.0
S
GAIN = 100
–V + 1.5
S
–V + 1.0
S
SINK
10
–V + 0.5
S
–V
S
1
10
FREQUENCY (kHz)
1
100
0.1
1
10
FREQUENCY (kHz)
100
1000
0.01
0.1
1
100
OUTPUT CURRENT (mA)
6910 G04
6910 G05
6910 G06
LTC6910-1 Distortion with Light
Loading (RL = 10k)
LTC6910-1 Distortion with Heavy
Loading (RL = 500Ω)
LTC6910-1 THD + Noise
vs Input Voltage
–30
–40
–50
3
1
–30
3
–20
V
V
=
OUT
2.5V
= 1V
f
= 1kHz
S
IN
S
(2.83V
)
V
=
5V
RMS
P-P
–30
–40
–50
–60
–70
–80
–90
–100
–110
–40
–50
1
THD MEASURES HD2 AND HD3
NOISE BW = 22kHz
GAIN =100
GAIN =10
GAIN SETTING = 100
GAIN SETTING = 10
0.3
0.3
–60
–70
0.1
–60
–70
0.1
GAIN =100
GAIN =10
GAIN =1
0.03
0.01
0.03
0.01
0.003
0.001
GAIN =1
–80
–80
V
V
=
OUT
2.5V
= 1V
S
–90
0.003
–90
(2.83V
P-P
)
RMS
GAIN SETTING = 1
0.1
INPUT VOLTAGE (V
THD MEASURES HD2 AND HD3
–100
0.001
–100
50
100
200
0
150
50
100
200
0
150
0.01
1
10
FREQUENCY (kHz)
FREQUENCY (kHz)
)
P-P
6910 G09
6910 G07
6910 G08
6910123fb
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LTC6910-2/LTC6910-3
(LTC6910-2)
Typical perForMance characTerisTics
LTC6910-2 Gain Shift
LTC6910-2 –3dB Bandwidth
vs Temperature
LTC6910-2 Frequency Response
vs Gain Setting
50
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0.2
0.1
0
V
= 2.5V
V
•
•
= 10mV
= 2.7V
S
V
V
=
IN
5V
S
IN
V
RMS
S
•
OUTPUT UNLOADED
= 10mV
S
RMS
V
= 5V
40
30
GAIN OF 64
GAIN OF 32
GAIN OF 16
GAIN OF 8
GAIN OF 4
GAIN OF 2
•
•
•
GAIN = 64
GAIN = 8
20
10
GAIN = 1
•
•
–0.1
GAIN OF 1
•
0
•
•
•
•
•
•
•
–10
–0.2
–50
0
50
100
150
1
10
GAIN
100
100
1k
10k
100k
1M
10M
TEMPERATURE (°C)
FREQUENCY (Hz)
6910 G11
6910 G10
6910 G12
LTC6910-2 Output Voltage Swing
vs Load Current
LTC6910-2 Power Supply
Rejection vs Frequency
LTC6910-2 Noise Density
vs Frequency
+V
90
80
70
60
50
40
30
20
10
0
100
S
V
=
2.5V
S
V
=
2.5V
INPUT-REFERRED
S
+SUPPLY
GAIN = 1
+V – 0.5
S
125°C
25°C
V
= ±±25V
= ±5°C
S
A
SOURCE
T
+V – 1.0
S
–40°C
GAIN = 1
+V – 1.5
S
–SUPPLY
+V – 2.0
S
GAIN = 8
10
–V + 2.0
S
GAIN = 64
–V + 1.5
S
–V + 1.0
S
SINK
10
–V + 0.5
S
–V
S
1
0.01
0.1
1
100
0.1
1
10
100
1000
10
FREQUENCY (kHz)
1
100
OUTPUT CURRENT (mA)
FREQUENCY (kHz)
6910 G13
6910 G14
6910 G15
LTC6910-2 Distortion with Light
Loading (RL = 10k)
LTC6910-2 Distortion with Heavy
Loading (RL = 500Ω)
LTC6910-2 THD + Noise
vs Input Voltage
–30
3
–20
–30
–40
–50
3
V
V
=
OUT
2.5V
= 1V
S
GAIN
SETTING = 64
(2.83V
)
P-P
–30
–40
–50
–60
–70
–80
–90
–100
–110
RMS
–40
–50
1
1
THD MEASURES HD2 AND HD3
GAIN = 64
GAIN = 8
0.3
0.1
0.3
–60
–70
–60
–70
0.1
GAIN = 64
GAIN
0.03
0.03
0.01
SETTING = 8
GAIN = 8
GAIN =1
GAIN =1
–80
0.01
–80
f
= 1kHz
V
V
=
OUT
2.5V
= 1V
IN
S
S
–90
0.003
–90
0.003
V
=
5V
(2.83V
P-P
)
RMS
NOISE BW = 22kHz
THD MEASURES HD2 AND HD3
GAIN SETTING = 1
–100
0.001
–100
0.001
50
100
200
0
150
0.01 0.1
1
10
50
100
200
0
150
FREQUENCY (kHz)
INPUT VOLTAGE (V
)
P-P
FREQUENCY (kHz)
6910 G18
6910 G17
6910 G16
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Typical perForMance characTerisTics (LTC6910-3)
LTC6910-3 Gain Shift
LTC6910-3 –3dB Bandwidth
vs Gain Setting
vs Temperature
LTC6910-3 Frequency Response
20
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0
0.02
0.01
0
V
= 2.5V
V
•
•
= 10mV
RMS
S
IN
V
V
GAIN OF 7 GAIN OF 6
OUTPUT UNLOADED
= 2.7V
•
•
S
=
5V
15
10
S
GAIN OF 5
GAIN OF 4
GAIN = 7
GAIN OF 3
GAIN OF 2
GAIN OF 1
•
•
GAIN = 4
5
0
•
•
•
•
GAIN = 1
•
•
–0.01
•
•
•
•
–5
V
V
= 5V
IN
S
= 10mV
RMS
–10
100
–0.02
–50
0
50
100
150
1
3
6
9 10
8
1k
10k
100k
1M
10M
2
4
5
7
TEMPERATURE (°C)
GAIN
FREQUENCY (Hz)
6910 G20
6910 G19
6910 G21
LTC6910-3 Output Voltage Swing
vs Load Current
LTC6910-3 Power Supply
Rejection vs Frequency
LTC6910-3 Noise Density
vs Frequency
+V
90
80
70
60
50
40
30
20
10
0
100
S
V
=
2.5V
INPUT-REFERRED
S
V
=
2.5V
+SUPPLY
S
GAIN = 1
V
T
=
2ꢀ.V
+V – 0.5
S
125°C
25°C
S
A
SOURCE
= 2.°C
+V – 1.0
S
–40°C
GAIN = 1
+V – 1.5
S
–SUPPLY
GAIN = 4
GAIN = 7
+V – 2.0
S
10
–V + 2.0
S
–V + 1.5
S
–V + 1.0
S
SINK
10
–V + 0.5
S
–V
S
1
0.01
0.1
1
100
1
10
FREQUENCY (kHz)
100
0.1
1
10
100
1000
OUTPUT CURRENT (mA)
FREQUENCY (kHz)
6910 G22
6910 G23
6910 G24
LTC6910-3 Distortion with Light
Loading (RL = 10k)
LTC6910-3 Distortion with Heavy
Loading (RL = 500Ω)
LTC6910-3 THD + Noise
vs Input Voltage
–30
–40
–50
3
–20
–30
3
V
V
=
OUT
2.5V
= 1V
f
= 1kHz
S
IN
S
(2.83V
)
P-P
V
=
5V
RMS
–30
–40
–50
–60
–70
–80
–90
–100
–110
1
–40
–50
1
THD MEASURES HD2 AND HD3
NOISE BW = 22kHz
GAIN SETTING = 7
GAIN SETTING = 4
0.3
0.1
0.3
GAIN = 7
GAIN = 4
–60
–70
–60
–70
0.1
GAIN = 7
GAIN = 4
0.03
0.01
0.03
0.01
0.003
0.001
GAIN =1
GAIN =1
–80
–80
V
V
=
OUT
2.5V
= 1V
S
–90
0.003
–90
(2.83V
)
P-P
RMS
THD MEASURES HD2 AND HD3
GAIN SETTING = 1
–100
0.001
–100
50
100
200
0
150
50
100
200
0.01
0.1
1
10
0
150
FREQUENCY (kHz)
INPUT VOLTAGE (V
)
P-P
FREQUENCY (kHz)
6910 G27
6910 G25
6910 G26
6910123fb
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pin FuncTions
OUT (Pin 1): Analog Output. This is the output of an inter-
nal operational amplifier and swings to near the power
supply rails (V+ and V–) as specified in the Electrical
Characteristics table. The internal op amp remains active
at all times, including the zero gain setting (digital input
000). As with other amplifier circuits, loading the out-
put as lightly as possible will minimize signal distortion
and gain error. The Electrical Characteristics table shows
performance at output currents up to 10mA and current
limits that occur when the output is shorted to mid-supply
at 2.7V and 5V supplies. Signal outputs above 10mA are
possible but current-limiting circuitry will begin to affect
amplifier performance at approximately 20mA. Long-term
operation above 20mA output is not recommended. Do
not exceed maximum junction temperature of 150°C. The
output will drive capacitive loads up to 50pF. Capacitances
higher than 50pF should be isolated by a series resistor
to preserve AC stability.
Recommended analog ground plane connection depends
on how power is applied to the LTC6910-X (Figures 1, 2,
–
and 3). Single power supply applications typically use V
for the system signal ground. The analog ground plane
–
in single-supply applications should therefore tie to V ,
and the AGND pin should be bypassed to this ground
plane by a high quality capacitor of at least 1µF (Figure 1).
The AGND pin then provides an internal analog reference
voltage at half the supply voltage (with internal resistance
of approximately 5kΩ) which is the center of the swing
range for both input and output. Dual supply applications
with symmetrical supplies (such as 5V) have a natural
system ground at zero volts, which can drive the analog
ground plane; AGND then connects directly to the ground
plane, making zero volts the input and output reference
voltage for the LTC6910-X (Figure 2). Finally, if a dual
power supply is asymmetrical, the supply ground is still
the natural ground plane voltage. To maximize signal
swing capability with an asymmetrical supply, however,
it is often desirable to refer the LTC6910-X’s analog input
and output to a voltage equidistant from the two supply
AGND (Pin 2): Analog Ground. The AGND pin is at the
midpoint of an internal resistive voltage divider, develop-
+
–
ing a potential halfway between the V and V pins, with
an equivalent series resistance to the pin of nominally
5kΩ (Figure 4). AGND is also the noninverting input of the
internal op amp, which makes it the ground reference volt-
age for the IN and OUT pins. Because of this, very “clean”
grounding is important, including an analog ground plane
surrounding the package.
+
–
rails V and V . The AGND pin will provide such a poten-
tial when open-circuited and bypassed with a capacitor
(Figure 3), just as with a single power supply, but now the
ground plane connection is different and the LTC6910-X’s
+
–
V and V pins are both isolated from this ground plane.
+
+
+
V
V
V
0.1µF
0.1µF
0.1µF
8
7
6
5
8
7
6
5
4
8
1
7
6
5
4
LTC6910-X
LTC6910-X
LTC6910-X
1
2
3
4
1
2
3
2
3
0.1µF
0.1µF
MID-SUPPLY
REFERENCE
ANALOG
GROUND
PLANE
ANALOG
GROUND
PLANE
ANALOG
GROUND
PLANE
+
V
1µF
REFERENCE
2
1µF
–
–
V
V
SINGLE-POINT
SYSTEM GROUND
SINGLE-POINT
SYSTEM GROUND
SINGLE-POINT
SYSTEM GROUND
DIGITAL GROUND PLANE
(IF ANY)
DIGITAL GROUND PLANE
(IF ANY)
DIGITAL GROUND PLANE
(IF ANY)
6910 F02
6910 F03
6910 F01
Figure 1. Single Supply
Ground Plane Connection
Figure 2. Symmetrical Dual Supply
Ground Plane Connection
Figure 3. Asymmetrical Dual
Supply Ground Plane Connection
6910123fb
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input resistance. The input may vary from rail to rail in
the “zero” gain setting but the output is insensitive to it
and remains at the AGND potential. Circuitry driving the
IN pin must consider the LTC6910-X’s input resistance
and the variation of this resistance when used at mul-
tiple gain settings. Signal sources with significant output
resistance may introduce a gain error as the source’s
output resistance and the LTC6910-X’s input resistance
form a voltage divider. This is especially true at the higher
gain settings where the input resistance is lowest.
Where AGND does not connect to a ground plane, as in
Figures 1 and 3, it is important to AC-bypass the AGND
pin. This is especially true when AGND is used as a refer-
ence voltage for other circuitry. Also, without a bypass
capacitor, wideband noise will enter the signal path from
the internal voltage divider resistors that set the DC volt-
age on AGND. This noise can reduce SNR by 3dB at high
gain settings. The resistors present a Thévenin equivalent
of approximately 5k to the AGND pin. An external capaci-
tor from AGND to the ground plane, whose impedance
is well below 5k at frequencies of interest, will suppress
this noise. A 1µF high quality capacitor is effective in sup-
pressing resistor noise for frequencies down to 1kHz.
Larger capacitors extend this suppression to propor-
tionately lower frequencies. This issue does not arise in
symmetrical dual supply applications (Figure 2) because
AGND goes directly to ground.
In single supply voltage applications at elevated gain
settings (digital input 010 or higher), it is important to
remember that the LTC6910-X’s DC ground reference for
–
both input and output is AGND, not V . With increasing
gains, the LTC6910-X’s input voltage range for unclipped
output is no longer rail-to-rail but shrinks toward AGND.
The OUT pin also swings positive or negative with respect
to AGND. At unity gain (digital input 001), both IN and
OUT voltages can swing from rail to rail (Tables 1, 2, 3).
In applications requiring an analog ground reference
other than halfway between the supply rails, the user can
override the built-in analog ground reference by tying the
AGND pin to a reference voltage within the AGND voltage
range specified in the Electrical Characteristics table. The
AGND pin will load the external reference with approxi-
mately 5k returned to the mid-supply potential. AGND
should still be capacitively bypassed to a ground plane as
G2
7
G1
6
G0
5
CMOS LOGIC
–
noted above. Do not connect the AGND pin to the V pin.
IN (Pin 3): Analog Input. The input signal to the amplifier
in the LTC6910-X is the voltage difference between the
IN and AGND pins. The IN pin connects internally to a
digitally controlled resistance whose other end is a cur-
rent summing point at the same potential as the AGND pin
(Figure 4). At unity gain (digital input 001), the value of this
input resistance is approximately 10kΩ and the IN volt-
age range is rail-to-rail (V+ to V–). At gain settings above
unity (digital input 010 or higher), the input resistance
falls. Also, the linear input voltage range falls in inverse
proportion to gain. (The higher gains are designed to
boost lower level signals with good noise performance.)
Tables 1, 2, and 3 summarize this behavior. In the “zero”
gain state (digital input 000), analog switches disconnect
the IN pin internally and this pin presents a very high
IN
3
INPUT R ARRAY
FEEDBACK R ARRAY
–
MOS-INPUT
1
OUT
OP AMP
+
10k
10k
+
–
V
V
8
2
4
6910 F04
+
–
V
AGND
V
Figure 4. Block Diagram
6910123fb
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V–, V+ (Pins 4, 8): Power Supply Pins. The V+ and V– pins
should be bypassed with 0.1µF capacitors to an adequate
analog ground plane using the shortest possible wiring.
Electrically clean supplies and a low impedance ground
are important for the high dynamic range available from
the LTC6910-X (see further details under AGND). Low
noise linear power supplies are recommended. Switching
power supplies require special care to prevent switching
noise coupling into the signal path, reducing dynamic
range.
These pins control the voltage gain from IN to OUT pins
(see Table 1, Table 2 and Table 3). Digital input code 000
causes a “zero” gain with very low output noise. In this
“zero” gain state the IN pin is disconnected internally, but
the OUT pin remains active and forced by the internal op
amp to the voltage present on the AGND pin. Note that the
voltage gain from IN to OUT is inverting: OUT and IN pins
always swing on opposite sides of the AGND potential.
The G pins are high impedance CMOS logic inputs and
must be connected (they will float to unpredictable volt-
ages if open circuited). No speed limitation is associated
with the digital logic because it is memoryless and much
faster than the analog signal path.
G0, G1, G2 (Pins 5, 6, 7): CMOS-Level Digital Gain-
Control Inputs. G2 is the most significant bit (MSB).
6910123fb
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Functional Description
moves, with finite speed, toward a differently scaled ver-
sion of the input signal. Varying the gain faster than the
output can settle produces a garbled output signal. The
LTC6910-X analog path settles with a characteristic time
constant or time scale, τ, that is roughly the standard
value for a first order band limited response:
The LTC6910 family are small outline, wideband inverting
DC amplifiers whose voltage gain is digitally program-
mable. Each delivers a choice of eight voltage gains,
controlled by the 3-bit digital inputs to the G pins, which
accept CMOS logic levels. The gain code is always mono-
tonic; an increase in the 3-bit binary number (G2 G1 G0)
causes an increase in the gain. Table 1, Table 2 and Table 3
list the nominal voltage gains for LTC6910-1, LTC6910-2
and LTC6910-3 respectively. Gain control within each
amplifier occurs by switching resistors from a matched
array in or out of a closed-loop op amp circuit using MOS
analog switches (Figure 4). Bandwidth depends on gain
setting. Curves in the Typical Performance Characteristics
section show measured frequency responses.
τ = 1 / (2 π f ),
-3dB
where f
is the –3dB bandwidth of the amplifier. For
-3dB
example, when the upper –3dB frequency is 1MHz, τ
is about 160ns. The bandwidth, and therefore τ, varies
with gain (see Frequency Response and –3dB Bandwidth
curves in Typical Performance Characteristics). After a
gain change it is the new gain value that determines the
settling time constant. Exact settling timing depends on
the gain change, the input signal and the possibility of
slew limiting at the output. However as a basic guideline,
the range of τ is 20ns to 1400ns for the LTC6910-1, 20ns
to 900ns for the LTC6910-2 and 20ns to 120ns for the
LTC6910-3. These numbers correspond to the ranges of
–3dB Bandwidth in the plots of that title under Typical
Performance Characteristics.
Digital Control
Logic levels for the LTC6910-X digital gain control inputs
(Pins 5, 6, 7) are nominally rail-to-rail CMOS. Logic 1
+
–
is V , logic 0 is V or alternatively 0V when using 5V
supplies. The part is tested with the values listed in the
Electrical Characteristics table (Digital Input “High” and
“Low” Voltages), which are 10% and 90% of full excur-
sion on the inputs. That is, the tested logic levels are
0.27V and 2.43V with a 2.7V supply, 0.5V and 4.5V levels
with 0V and 5V supply rails, and 0.5V and 4.5V logic levels
at 5V supplies. Do not attempt to drive the digital inputs
with TTL logic levels (such as HCT or LS logic), which
normally do not swing near +5V. TTL sources should be
adapted with CMOS drivers or suitable pull-up resistors
to 5V so that they will swing to the positive rail.
Offset Voltage vs Gain Setting
The electrical tables list DC offset (error) voltage at the
inputs of the internal op-amp in Figure 4, V
, which
OS(OA)
is the source of DC offsets in the LTC6910-X. The tables
also show the resulting, gain dependent offset voltage
referred to the IN pin, V . These two measures are
OS(IN)
related through the feedback/input resistor ratio, which
equals the nominal gain-magnitude setting, G:
V
OS(IN)
= (1 + 1/G) V
OS(OA)
Timing Constraints
Offset voltages at any gain setting can be inferred from
this relationship. For example, an internal offset V
Settling time in the CMOS gain-control logic is typically
several nanoseconds and faster than the analog signal
path. When amplifier gain changes, the limiting timing
is analog, not digital, because the effects of digital input
changes are observed only through the analog output
(Figure 4). The LTC6910-X’s logic is static (not latched)
and therefore lacks bus timing requirements. However, as
with any programmable-gain amplifier, each gain change
causes an output transient as the amplifier’s output
OS(OA)
of 1mV will appear referred to the IN pin as 2mV at a gain
setting G of 1, or 1.5mV at a gain setting of 2. At high
gains, V
approaches V
. (Offset voltage can
OS(OA)
OS(IN)
be of either polarity; it is a statistical parameter centered
on zero.) The MOS input circuitry of the internal op amp
in Figure 4 draws negligible input currents (unlike some
op amps), so only V
fier’s offset.
and G affect the overall ampli-
OS(OA)
6910123fb
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Offset Nulling and Drift
tightly matched, these internal 10k resistors also have
an absolute tolerance of up to 30% and a temperature
coefficient of typically –30ppm/°C.) Also, as described
under Pin Functions for AGND, a bypass capacitor C1 is
always advisable when AGND is not connected directly
to a ground plane.
Because internal op amp offset voltage VOS(OA) is gain
independent as noted above, offset trimming can be read-
ily added at the AGND pin, which drives the noninvert-
ing input of the internal op amp. Such a trim shifts the
AGND voltage slightly from the system’s analog ground
reference, where AGND would otherwise connect directly.
This is convenient when a low resistance analog ground
potential or analog ground reference exists, for the return
of a voltage divider as in Figure 5a. When adjusted for
zero DC output voltage when the LTC6910-X has zero
DC input voltage, this DC nulling will hold at other gain
settings also.
With this trim technique in place, the remaining DC off-
set sources are drifts with temperature (typically 6µV/°C
referred to VOS(OA)), shifts in the LTC6910-X’s supply
voltage divided by the PSRR factors, supply voltage
shifts coupling through the two 10k internal resistors of
Figure 4, and of course any shifts in the reference voltages
that supply +V and –V in Figure 5a.
REF
REF
Figure 5a shows the basic arrangement for dual-supply
applications. A voltage divider (R1 and R2) scales external
Figure 5b illustrates how to make an offset voltage adjust-
ment relative to the mid-supply potential in single supply
applications. Resistor values shown provide at least a
10mV adjustment range assuming the minimum values
for the internal resistors at pin 2 and a supply potential
of 5V. For single supply systems where all circuitry is DC
referenced to some other fixed bias potential, an offset
adjustment scheme is shown in Figure 5c. A low value
for R1 overrides the internal resistors at pin 2 and applies
the system DC bias to the LTC6910. Actual values for
the adjustment components depend on the magnitude of
the DC bias voltage. Offset adjustment component values
reference voltages +V
and –V
to a range equaling
REF
REF
or slightly exceeding the approximately 10mV op amp
offset-voltage range. Resistor R1 is chosen to drop the
10mV maximum trim voltage when the potentiometer
is set to either end. Thus if VREF is 5V, R1 should be
about 100Ω. Note also that the two internal 10k resistors
in Figure 4 tend to bias AGND toward the mid-point of
+
–
V and V . The external voltage divider will swamp this
effect if R1 is much less than 5kΩ. When considering the
effect of the internal 10k resistors, note that they form a
Thévenin equivalent of 5k in series with an open-circuit
shown are an example with a single 5V V supply and a
CC
+
–
voltage at the halfway potential (V + V )/ 2. (Although
1.25V system DC reference voltage.
1.25V
SYSTEM DC REFERENCE
VOLTAGE
5V
V
5V
CC
V
5V
CC
V
CC
8
8
+V
REF
R1
100Ω
17.4k
LTC6910-X
LTC6910-X
AGND
LTC6910-X
AGND
4.64k
500Ω
976Ω
R2
49.9k
2
2
2
AGND
500Ω
17.4k
20k
1µF
1µF
R1
C1
≥1µF
–V
6910 F05b
6910 F05c
6910 F05a
REF
4
4
ANALOG GROUND
REFERENCE
Figure 5a. Offset Nulling
(Dual Supplies)
Figure 5b. Offset Nulling
(Single Supply, Half Supply Reference)
Figure 5c. Offset Nulling
(Single Supply, External Reference)
6910123fb
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LTC6910-2/LTC6910-3
applicaTions inForMaTion
Analog Input and DC Levels
Note that operating the LTC6910-X in zero gain mode (dig-
ital inputs 000) open circuits the IN pin and this demands
some care if employed with a series input capacitor. When
the chip enters the zero gain mode, the opened IN pin
tends to freeze the voltage across the capacitor to the
value it held just before the zero gain state. This can place
the IN pin at or near the DC potential of a supply rail
(the IN pin may also drift to a supply potential in this
state due to small junction leakage currents). To prevent
driving the IN pin outside the supply limit and potentially
damaging the chip, avoid AC input signals in the zero
gain state with a series capacitor. Also, switching later to
a nonzero gain value will cause a transient pulse at the
output of the LTC6910-X (with a time constant set by
the capacitor value and the new LTC6910-X input resis-
tance value). This occurs because the IN pin returns to
the AGND potential and transient current flows to charge
the capacitor to a new DC drop.
As described in Tables 1, 2 and 3 and under Pin Functions,
the IN pin presents a variable input resistance returned
internally to a potential equal to that at the AGND pin
(within a small offset-voltage error). This input resistance
varies with digital gain setting, becoming infinite (open
circuit) at “zero” gain (digital input 000), and as low as
1kΩ at high gain settings. It is important to allow for this
input-resistance variation with gain, when driving
the LTC6910-X from other circuitry. Also, as the gain
increases above unity, the DC linear input-voltage range
(corresponding to rail-to-rail swing at the OUT pin) shrinks
toward the AGND potential. The output swings positive
or negative around the AGND potential (in the opposite
direction from the input, because the gain is inverting).
AC-Coupled Operation
Adding a capacitor in series with the IN pin makes the
LTC6910-X into an AC-coupled amplifier, suppressing the
source’s DC level (and even minimizing the offset voltage
from the LTC6910-X itself). No further components are
required because the input of the LTC6910-X biases itself
correctly when a series capacitor is added. The IN pin
connects to an internal variable resistor (and floats when
DC open-circuited to a well defined voltage equal to the
AGND input voltage at nonzero gain settings). The value
of this internal input resistor varies with gain setting over
a total range of about 1k to 10k, depending on version
(the rightmost columns of Table 1, Table 2 and Table 3).
Therefore, with a series input capacitor the low frequency
cutoff will also vary with gain. For example, for a low
frequency corner of 1kHz or lower, use a series capacitor
of 0.16µF or larger. A 0.16µF capacitor has a reactance
of 1kΩ at 1kHz, giving a 1kHz lower –3dB frequency for
gain settings of 10V/V through 100V/V in the LTC6910-1.
If the LTC6910-1 is operated at lower gain settings with
an 0.16µF input capacitor, the higher input resistance will
reduce the lower corner frequency down to 100Hz at a
gain setting of 1V/V. These frequencies scale inversely
with the value of the input capacitor.
SNR and Dynamic Range
The term “dynamic range” is much used (and abused)
with signal paths. Signal-to-noise ratio (SNR) is an unam-
biguous comparison of signal and noise levels, measured
in the same way and under the same operating conditions.
In a variable gain amplifier, however, further characteriza-
tion is useful because both noise and maximum signal
level in the amplifier will vary with the gain setting, in
general. In the LTC6910-X, maximum output signal is
independent of gain (and is near the full power supply
voltage, as detailed in the Swing sections of the Electrical
Characteristics table). The maximum input level falls with
increasing gain, and the input-referred noise falls as well
(as listed also in the table). To summarize the useful signal
range in such an amplifier, we define Dynamic Range (DR)
as the ratio of maximum input (at unity gain) to mini-
mum input-referred noise (at maximum gain). (These two
numbers are measured commensurately, in RMS Volts.
For deterministic signals such as sinusoids, 1VRMS
=
2.828V .) This DR has a physical interpretation as the
P-P
range of signal levels that will experience an SNR above
unity V/V or 0dB. At a 10V total power supply, DR in the
6910123fb
20
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
applicaTions inForMaTion
LTC6910-1 (gains 0V to 100V/V) is typically 120dB (the
Expanding an ADC’s Dynamic Range
ratio of a nominal 9.9VP-P, or 3.5VRMS, maximum input to
Figure 6 shows a compact data acquisition system
for wide ranging input levels. This figure combines an
LTC6910-X programmable amplifier (8-lead TSOT-23)
with an LTC1864 analog-to-digital converter (ADC) in
an 8-lead MSOP. This ADC has 16-bit resolution and a
maximum sampling rate of 250ksps. An LTC6910-1, for
example, expands the ADC’s input amplitude range by
40dB while operating from the same single 5V supply.
The 499Ω resistor and 270pF capacitor couple cleanly
between the LTC6910-X’s output and the switched-capac-
itor input of the LTC1864. The 270pF capacitor should be
an NPO or X7R type, and lead length and inductance in the
connections to the LTC1864 inputs must be minimized,
to achieve the full performance capability of this circuit.
(See LTC 1864 data sheet for further general information.)
the 3.4µV
high gain input noise). The corresponding
RMS
DR for the LTC6910-2 (gains 0V to 64V) is also 120dB;
for the LTC6910-3 (gains 0V to 7V/V) it is 117dB. The
SNR from an amplifier is the ratio of input level to input-
referred noise, and can be 110dB with the LTC6910 family
at unity gain.
Construction and Instrumentation Cautions
Electrically clean construction is important in applica-
tions seeking the full dynamic range of the LTC6910-X
amplifier. Short, direct wiring will minimize parasitic
capacitance and inductance. High quality supply bypass
capacitors of 0.1µF near the chip provide good decou-
pling from a clean, low inductance power source. But
several cm of wire (i.e., a few microhenrys of inductance)
from the power supplies, unless decoupled by substantial
capacitance (≥10µF) near the chip, can cause a high-Q
LC resonance in the hundreds of kHz in the chip’s sup-
plies or ground reference. This may impair circuit perfor-
mance at those frequencies. A compact, carefully laid out
printed circuit board with a good ground plane makes a
significant difference in minimizing distortion. Finally,
equipment to measure amplifier performance can itself
introduce distortion or noise floors. Checking for these
limits with a wire replacing the chip is a prudent routine
procedure.
At a gain setting of 10V/V in an LTC6910-1 (digital input
100) and a 250ksps sampling rate in the LTC1864, a
10kHz input signal at 60% of full scale shows a THD of
–87dB at the digital output of the ADC. 100kHz input
signals under the same conditions produce THD values
around –75dB. Noise effects (both random and quantiza-
tion) in the ADC are divided by the gain of the amplifier
when referred to VIN in Figure 4. Because of this, the
circuit can acquire a signal that is 40dB down from full
scale of 5V with an SNR of over 70dB. Such perfor-
P-P
mance from an ADC alone (70 + 40 = 110dB of useful
dynamic range at 250ksps), if available, would be far more
expensive.
1µF
5V
5V
0.1µF
LTC1864
8
4
V
V
CC
REF
+
499Ω
1
3
IN
IN
SCK
SDO
V
LTC6910-X
IN
5
–
270pF
6
7
GND CONV
2
6910 F04
AGND
1µF
GAIN
CONTROL
ADC
CONTROL
Figure 6. Expanding an ADC’s Dynamic Range
6910123fb
21
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
applicaTions inForMaTion
Low Noise AC Amplifier with Programmable Gain
and Bandwidth
upper corner frequency. The LT1884 also supports rail-
to-rail output swings over the total supply voltage range
of 2.7V to 10.5V. AC coupling through capacitor C1
establishes a fixed low frequency corner of 1Hz, which
can be adjusted by changing C1. Alternatively, shorting
C1 makes the amplifier DC coupled. (If DC gain is not
needed, however, the AC coupling suppresses several
error sources: any shifts in DC levels, low frequency
noise and all amplifier DC offset voltages other than the
low internally trimmed LT1884 offset in the integrating
amplifier. If desired, another coupling capacitor in series
with the input can relax the requirements on DC input
level as well.)
Analog data acquisition can exploit band limiting as well
as gain to suppress unwanted signals or noise. Tailoring
an analog front end to both the level and bandwidth of
each source maximizes the resulting SNR.
Figure 7 shows a block diagram and Figure 8 the practical
circuit for a low noise amplifier with gain and bandwidth
independently programmable over 100:1 ranges. One
LTC6910-X controls the gain and another controls the
bandwidth. An LT1884 dual op amp forms an integrating
lowpass loop with capacitor C2 to set the programmable
R2
C2
–
C1
V
IN
R1
–
+
–
–
+
+
GAIN CONTROL PGA
(GAIN A)
V
OUT
6910 F05
+
BANDWIDTH CONTROL PGA
(GAIN B)
GAIN = –1
1
1
V
= (GAIN A)V
BANDWIDTH
2πR1C1
OUT
IN
R2
2π
C2
(GAIN B)
Figure 7. Block Diagram of an AC Amplifier with Programmable Gain and Bandwidth
6910123fb
22
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
applicaTions inForMaTion
Measured frequency responses in Figure 8 with
LTC6910-1 PGAs demonstrate bandwidth settings of
10Hz, 100Hz and 1kHz, with digital codes at the BW inputs
of respectively 001, 100 and 111, and unity gain in each
case. By scaling C2, this circuit can serve other band-
widths, such as a maximum of 10kHz with 0.1µF using
LT1884 (gain-bandwidth product around 1MHz). Noise
floor from internal sources yields an output SNR of 76dB
with 10mV input, gain of 100 and 100Hz bandwidth;
P-P
for 100mV input, gain of 10 and 1000Hz bandwidth it
P-P
is 64dB.
+
–
+
–
V
V
V
V
V
OUT
0.1µF
0.1µF
0.1µF
0.1µF
R2
15.8k
C2
1µF
+
V
0.1µF
8
LT1884
8
C1
1
2
3
4
8
7
6
5
+
R1
15.8k
4
4
10µF
1
V
R4 15.8k
–
+
–
3
3
1
V
IN
LTC6910-1
6
LTC6910-1
6
5
5
–
+
R3
15.8k
7
7
V
2
2
0.1µF
–
V
GAIN
CONTROL
BANDWIDTH
CONTROL
GN2 GN1 GN0
BW2BW1BW0
0
0
0
1
1
1
1
0
1
1
0
0
1
1
1
0
1
0
1
0
1
GAIN = 1
BANDWIDTH 1Hz TO 10Hz
BANDWIDTH 1Hz TO 20Hz
BANDWIDTH 1Hz TO 50Hz
BANDWIDTH 1Hz TO 100Hz
BANDWIDTH 1Hz TO 200Hz
BANDWIDTH 1Hz TO 500Hz
BANDWIDTH 1Hz TO 1000Hz
0
0
0
1
1
1
1
0
1
1
0
0
1
1
1
0
1
0
1
0
1
GAIN = 2
GAIN = 5
GAIN = 10
GAIN = 20
GAIN = 50
GAIN = 100
Gain vs Frequency
10
GN2 GN1 GN0 = 001
0
–10
–20
–30
–40
–50
–60
–70
–80
BW2 BW1 BW0
1
1
1
BW2 BW1 BW0
0
0
1
BW2 BW1 BW0
1
0
0
1
10
100
1k
10k
100k
FREQUENCY (Hz)
6910 F06b
Figure 8. Low Noise AC Amplifier with Programmable Gain and Bandwidth
6910123fb
23
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
package DescripTion
Please refer to http://www.linear.com/product/LTC6910#packaging for the most recent package drawings.
TS8 Package
8-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1637 Rev A)
2.90 BSC
(NOTE 4)
0.40
MAX
0.65
REF
1.22 REF
1.4 MIN
1.50 – 1.75
(NOTE 4)
2.80 BSC
3.85 MAX 2.62 REF
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.22 – 0.36
8 PLCS (NOTE 3)
0.65 BSC
0.80 – 0.90
0.20 BSC
DATUM ‘A’
0.01 – 0.10
1.00 MAX
0.30 – 0.50 REF
1.95 BSC
TS8 TSOT-23 0710 REV A
0.09 – 0.20
(NOTE 3)
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
6910123fb
24
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
revision hisTory (Revision history begins at Rev B)
REV
DATE
DESCRIPTION
PAGE NUMBER
B
06/17 Updated Voltage Gain Specs
6, 8
6910123fb
25
For more information www.linear.com/LTC6910
LTC6910-1/
LTC6910-2/LTC6910-3
Typical applicaTion
AC-Coupled Single Supply Amplifiers
+
V
2.7V TO 10.5V
0.1µF
LTC6910-1
LTC6910-2
LTC6910-3
DIGITAL INPUTS PASSBAND LOWER –3dB
PASSBAND LOWER –3dB
PASSBAND LOWER –3dB
G2 G1 G0
GAIN
FREQ (C1 = 1µF)
GAIN
FREQ (C1 = 1µF)
GAIN
FREQ (C1 = 1µF)
8
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
–1
—
0
–1
—
0
–1
–2
–3
–4
–5
–6
–7
—
4
C1
16Hz
16Hz
16Hz
32Hz
48Hz
64Hz
80Hz
95Hz
111Hz
3
1
V
V
= GAIN • V
OUT IN
LTC6910-X
–2
32Hz
80Hz
160Hz
160Hz
160Hz
160Hz
–2
32Hz
64Hz
127Hz
127Hz
127Hz
127Hz
IN
–5
–4
–8
–16
–32
–64
2
5
–10
–20
–50
–100
AGND
1µF OR LARGER
6
7
G2 G1 G0
6910 TA02
C1 VALUE SETS LOWER CORNER FREQUENCY.
THE TABLE SHOWS THIS FREQUENCY WITH
C1 = 1µF. THIS FREQUENCY SCALES INVERSELY
WITH C1
PIN 2 (AGND) SETS DC OUTPUT VOLTAGE AND HAS
BUILT-IN HALF-SUPPLY REFERENCE WITH INTERNAL
RESISTANCE OF 5k. AGND CAN ALSO BE DRIVEN BY A
SYSTEM ANALOG GROUND REFERENCE NEAR HALF SUPPLY
Frequency Response, LTC6910-1
Frequency Response, LTC6910-2
Frequency Response, LTC6910-3
50
40
30
20
10
0
20
G2, G1, G0 = 110
G2, G1, G0 = 111
G2, G1, G0 = 111
G2, G1, G0 = 110
G2, G1, G0 = 111
40
15
G2, G1, G0 = 110
G2, G1, G0 = 101
G2, G1, G0 = 100
G2, G1, G0 = 101
G2, G1, G0 = 100
G2, G1, G0 = 011
G2, G1, G0 = 010
G2, G1, G0 = 001
30
10
G2, G1, G0 = 101
G2, G1, G0 = 011
G2, G1, G0 = 100
20
5
G2, G1, G0 = 010
G2, G1, G0 = 011
10
0
G2, G1, G0 = 010
G2, G1, G0 = 001
G2, G1, G0 = 001
0
–5
V
V
= 10V
S
IN
V
= 10V, V = 5mV
IN RMS
V
= 10V, V = 5mV
= 10mV
S
S
IN RMS
RMS
1k
C1 = 1µF
C1 = 1µF
C1 = 1µF
–10
100
–10
–10
1k
10k
100k
1M
100
1k
10k
100k
1M
10
100
10k 100k
1M
10M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
6910 TA03
6910 TA04
6910 TA05
relaTeD parTs
PART NUMBER
LT®1228
DESCRIPTION
COMMENTS
100MHz Gain Controlled Transconductance Amplifier
40MHz Video Fader and Gain Controlled Amplifier
10kHz to 150kHz Digitally Controlled Filter and PGA
Dual Matched Programmable Gain Amplifier
Differential Input, Continuous Analog Gain Control
LT1251/LT1256
LTC1564
Two Input, One Output, Continuous Analog Gain Control
Continuous Time, Low Noise 8th Order Filter and 4-Bit PGA
Dual 6910 in a 10 Lead MSOP
LTC6911
LTC6915
Zero Drift Instrumentation Amplifier with Programmable Gain
Zero Drift, Digitally Programmable Gain Up to 4096 V/V
6910123fb
LT 0617 REV B • PRINTED IN USA
www.linear.com/LTC6910
26
LINEAR TECHNOLOGY CORPORATION 2002
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