LTC2446/LTC2447
24-Bit High Speed
8-Channel ∆Σ ADCs with
Selectable Multiple Reference Inputs
DESCRIPTION
FEATURES
Five Selectable Differential Reference Inputs
nn Four Differential/Eight Single-Ended Inputs
nn 4-Way MUX for Multiple Ratiometric
Measurements
nn Up to 8kHz Output Rate (External f )
O
nn Up to 4kHz Multiplexing Rate (External f )
O
nn Selectable Speed/Resolution:
2µVRMS Noise at 1.76kHz Output Rate
200nVRMS Noise at 13.8Hz Output Rate with
Simultaneous 50/60Hz Rejection
nn Guaranteed Modulator Stability and Lock-Up
Immunity for any Input and Reference Conditions
nn 0.0005% INL, No Missing Codes
nn Autosleep Enables 20µA Operation at 6.9Hz
nn 0, this bit is HIGH. If VIN is 120dB
–120
–140
–110
–120
2000000
1000000
0
DIFFERENTIAL INPUT SIGNAL FREQUENCY (Hz)
24467 F13
Figure 13. LTC2446/LTC2447
Normal Mode Rejection (Internal Oscillator)
–130
–140
64
128
If FO is grounded, fS is set by the on-chip oscillator at
1.8MHz (over supply and temperature variations). At an
OSR of 32,768, the first NULL is at fN = 55Hz and the
no latency output rate is fN/8 = 6.9Hz. At the maximum
OSR, the noise performance of the device is 280nVRMS
(LTC2446) and 200nVRMS (LTC2447) with better than
80dB rejection of 50Hz ±2% and 60Hz ±2%. Since the
OSR is large (32,768) the wide band rejection is extremely
large and the anti-aliasing requirements are simple. The
first multiple of fS occurs at 55Hz • 32,768 = 1.8MHz, see
Figure 13.
60
120
240
0
180
DIFFERENTIAL INPUT SIGNAL FREQUENCY (Hz)
24467 F11
NOTCH (fN)
*Simultaneous 50/60Hz rejection
NORMAL MODE REJECTION (dB)
NORMAL MODE REJECTION (dB)
0
OSR
47 49 51 53 55 57 59 61 63
DIFFERENTIAL INPUT SIGNAL FREQUENCY (Hz)
24467 F12
Figure 12. LTC2446/LTC2447
Normal Mode Rejection (Internal Oscillator)
For more information www.linear.com/LTC2446
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21
LTC2446/LTC2447
APPLICATIONS INFORMATION
The first NULL becomes fN = 7.04kHz with an OSR of 256
(an output rate of 880Hz) and FO grounded. While the
NULL has shifted, the sample rate remains constant. As
a result of constant modulator sampling rate, the linearity,
offset and full-scale performance remain unchanged as
does the first multiple of fS.
The sample rate fS and NULL fN, may also be adjusted by
driving the FO pin with an external oscillator. The sample
rate is fS = fEOSC/5, where fEOSC is the frequency of the
clock applied to FO. Combining a large OSR with a reduced
sample rate leads to notch frequencies fN near DC while
maintaining simple anti-aliasing requirements. A 100kHz
clock applied to FO results in a NULL at 0.6Hz plus all
harmonics up to 20kHz, see Figure 14. This is useful in
applications requiring digitalization of the DC component
of a noisy input signal and eliminates the need of placing
a 0.6Hz filter in front of the ADC.
NORMAL MODE REJECTION (dB)
1µF
28
29
30
USER SELECTABLE
REFERENCES
0.1V TO VCC
11
10
24
23
8
9
ANALOG
INPUTS
12
22
7
VCC
35
FO
OUT
LTC2446
LTC1799
REFG+
REF01+
REF67–
0.1µF
38
SCK
CH1
SDO
CH2
.
CS
CH7
BUSY
COM
GND
SET
34
SDI
CH0
..
DIV
NC
–
REF01
.
..
RSET
GND
REFG–
REF67+
V+
37
4-WIRE
SPI INTERFACE
36
2
1,4,5,6,31,32,33
24467 F15
Figure 15. Simple External Clock Source
The normal mode rejection characteristic shown in
Figure 14 is achieved by applying the output of the LTC1799
(with RSET = 100k) to the FO pin on the LTC2446/LTC2447
with SDI tied HIGH (OSR = 32768).
0
–20
–40
–60
Multiple Ratiometric and Absolute Measurements
–80
–100
–120
–140
4.5V TO 5.5V
2
4
6
10
8
0
DIFFERENTIAL INPUT SIGNAL FREQUENCY (Hz)
24467 F14
Figure 14. LTC2446/LTC2447 Normal
Mode Rejection (External Oscillator at 90kHz)
An external oscillator operating from 100kHz to 12MHz can
be implemented using the LTC1799 (resistor set SOT‑23
oscillator), see Figure 15. By floating pin 4 (DIV) of the
LTC1799, the output oscillator frequency is:
10k
fOSC =10MHz •
10 •RSET
The LTC2446/LTC2447 combine a high precision, high
speed delta-sigma converter with a versatile front-end
multiplexer. The unique no latency architecture allows
seamless changes in both input channel and reference
while the absolute accuracy ensures excellent matching
between both analog input channels and reference channels. Any set of inputs (differential or single-ended) can
perform a conversion with one of two references. For
Bridges, RTDs and other ratiometric devices, each set
of channels can perform a conversion with respect to a
unique reference voltage. For Thermocouples, voltage
sense, current sense and other absolute sensors, each set
of channels can perform a conversion with respect to a
single global reference voltage (see Figure 16). This allows
users to measure both multiple absolute and multiple ratio
metric sensors with the same device in such applications
as flow, gas chromatography, multiple RTDs or bridges,
or universal data acquisition.
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22
For more information www.linear.com/LTC2446
LTC2446/LTC2447
APPLICATIONS INFORMATION
VCC
VREF
10µF
LTC2446
VREFG+
VREFO1+
RTD
VREFO1–
CH0
CH1
REF+
VREF23+
RATIOMETRIC
RTD
VREF23–
CH2
CH3
IN+
IN–
CS
+
–
SDI
VARIABLE SPEED
RESOLUTION
24-BIT ∆Σ ADC
SDO
SCK
CH4
VREF45+
BRIDGE
CH5
REF–
VREF45–
ABSOLUTE
vs VREFG
CH6
CH7
COM
VREFG
24467 F16
Figure 16. Versatile 4-Way Multiplexer Measures Multiple Ratiometric/Absolute Sensors
Average Input Current
IREF+
The LTC2446 switches the input and reference to a 2pF
capacitor at a frequency of 1.8MHz. A simplified equivalent
circuit is shown in Figure 17. The sample capacitor for the
LTC2447 is 4pF, and its average input current is externally
buffered from the input source.
The average input and reference currents can be expressed
in terms of the equivalent input resistance of the sample
capacitor, where: Req = 1/(fSW • CEQ).
When using the internal oscillator, fSW is 1.8MHz and the
equivalent resistance is approximately 110kΩ.
VCC
RSW (TYP)
500Ω
ILEAK
VREF+
ILEAK
VCC
IIN+
ILEAK
VIN+
IIN –
ILEAK
RSW (TYP)
500Ω
CEQ
5pF
(TYP)
(CEQ = 2pF
SAMPLE CAP
+ PARASITICS)
MUX
VCC
RSW (TYP)
500Ω
ILEAK
VIN –
ILEAK
MUX
VCC
IREF –
ILEAK
VREF –
ILEAK
RSW (TYP)
500Ω
24467 F17
SWITCHING FREQUENCY
fSW = 1.8MHz INTERNAL OSCILLATOR
fSW = fEOSC/5 EXTERNAL OSCILLATOR
Figure 17. LTC2446 Input Structure
For more information www.linear.com/LTC2446
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23
LTC2446/LTC2447
APPLICATIONS INFORMATION
Input Bandwidth and Frequency Rejection
Effective Noise Bandwidth
The combined effect of the internal SINC4 digital filter
and the digital and analog auto-calibration circuits determines the LTC2446/LTC2447 input bandwidth and
rejection characteristics. The digital filter’s response can
be adjusted by setting the oversample ratio (OSR) through
the SPI interface or by supplying an external conversion
clock to the FO pin.
The LTC2446/LTC2447 has extremely good input noise
rejection from the first notch frequency all the way out to
the modulator sample rate (typically 1.8MHz). Effective
noise bandwidth is a measure of how the ADC will reject
wideband input noise up to the modulator sample rate.
The example on the following page shows how the noise
rejection of the LTC2446/LTC2447 reduces the effective
noise of an amplifier driving its input.
Table 7 lists the properties of the LTC2446/LTC2447
with various combinations of oversample ratio and clock
frequency. Understanding these properties is the key to
fine tuning the characteristics of the LTC2446/LTC2447
to the application.
Example:
If an amplifier (e.g. LT1219) driving the input of an
LTC2446/LTC2447 has wideband noise of 33nV/√Hz,
band-limited to 1.8MHz, the total noise entering the
ADC input is:
Maximum Conversion Rate
33nV/√Hz • √1.8MHz = 44.3µV.
The maximum conversion rate is the fastest possible rate
at which conversions can be performed.
When the ADC digitizes the input, its digital filter rejects
the wideband noise from the input signal. The noise reduction depends on the oversample ratio which defines
the effective bandwidth of the digital filter.
First Notch Frequency
This is the first notch in the SINC4 portion of the digital filter
and depends on the FO clock frequency and the oversample
ratio. Rejection at this frequency and its multiples (up to
the modulator sample rate of 1.8MHz) exceeds 120dB.
This is 8 times the maximum conversion rate.
At an oversample of 256, the noise bandwidth of the ADC
is 787Hz which reduces the total amplifier noise to:
33nV/√Hz • √787Hz = 0.93µV.
Table 7. Performance vs Oversample Ratio
Maximum Conversion Rate
First Notch Frequency Effective Noise BW
–3dB Point
(sps)
(Hz)
(Hz)
(Hz)
OverENOB
sample *RMS *RMS
External fO External fO
(VREF = 5V)
Ratio Noise
Internal (1× Mode) (2× Mode) Internal External fO Internal External fO Internal External fO
Noise
(OSR) LTC2446 LTC2447 LTC2446 LTC2447 Clock
(fO/x)
(fO/x)
Clock
(fO/x)
9MHz Clock
(fO/x)
Clock
(fO/x)
64
23µV
23µV
17
17
2816.35
fO/2738
fO/1458
28125
fO/320
3148
fO/2860
1696
fO/5310
128
4.5µV
3.5µV
20.1
20
1455.49
fO/5298
fO/2738
14062.5
fO/640
1574
fO/5720
848
fO/10600
256
2.8µV
2µV
20.8
21.3
740.18
fO/10418
fO/5298
7031.3
fO/1280
787
fO/11440
424
fO/21200
512
2µV
1.4µV
21.3
21.8
373.28
fO/20658
fO/10418
3515.6
fO/2560
394
fO/22840
212
fO/42500
1024
1.4µV
1µV
21.8
22.4
187.45
fO/41138
fO/20658
1757.8
fO/5120
197
fO/45690
106
fO/84900
2048
1.1µV
750nV
22.1
22.9
93.93
fO/82098
fO/41138
878.9
fO/10200
98.4
fO/91460
53
fO/170000
4096
720nV
510nV
22.7
23.4
47.01
fO/164018
fO/82098
439.5
fO/20500
49.2
fO/183000
26.5
fO/340000
8192
530nV
375nV
23.2
24
23.52
fO/327858 fO/164018
219.7
fO/41000
24.6
fO/366000
13.2
fO/679000
16384
350nV
250nV
23.8
24.4
11.76
fO/655538 fO/327858
109.9
fO/81900
12.4
fO/731000
6.6
fO/1358000
32768
280nV
200nV
24.1
24.6
5.88
fO/1310898 fO/655538
54.9
fO/163800
6.2
fO/1463000
3.3
fO/2717000
*ADC noise increases by approximately √2 when OSR is decreased by a factor of 2 for OSR 32768 to OSR 256. The ADC noise at OSR 128 and OSR 64
include effects from internal modulator quantization noise.
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24
For more information www.linear.com/LTC2446
LTC2446/LTC2447
APPLICATIONS INFORMATION
The total noise is the RMS sum of this noise with the 2µV
noise of the ADC at OSR = 256.
Automatic Offset Calibration of External
Buffers/Amplifiers
√(0.93µV)2 + (2µV)2 = 2.2µV.
The LTC2447 enables an external amplifier to be inserted
between the multiplexer output and the ADC input. This
enables one external buffer/amplifier circuit to be shared
between all nine analog inputs (eight single-ended or four
differential). The LTC2447 performs an internal offset
calibration every conversion cycle in order to remove the
offset and drift of the ADC. This calibration is performed
through a combination of front end switching and digital
processing. Since the external amplifier is placed between
the multiplexer and the ADC, it is inside the correction loop.
This results in automatic offset correction and offset drift
removal of the external amplifier.
Increasing the oversample ratio to 32768 reduces the
noise bandwidth of the ADC to 6.2Hz which reduces the
total amplifier noise to:
33nV/√Hz • √6.2Hz = 82nV.
The total noise is the RMS sum of this noise with the
200nV noise of the ADC at OSR = 32768.
√(82nV)2 + (200nV)2 = 216nV.
In this way, the digital filter with its variable oversampling
ratio can greatly reduce the effects of external noise
sources.
10
FIVE
DIFFERENTIAL
REFERENCE
INPUTS
MUX
LTC2447
ADCINP
2
OFFSETS AND 1/f NOISE
OF EXTERNAL SIGNAL
CONDITIONING CIRCUITS
ARE AUTOMATICALLY
CANCELLED
3
–
1/2 LT1368
+
ADCINN
MUX
MUXOUTP
CH0-CH6/
COM
MUXOUTN
9
SDI
REF+
HIGH
SPEED
∆Σ ADC
REF–
SCK
SDO
CS
1
0.1µF*
*LT1368 REQUIRES 0.1µF
OUTPUT COMPENSATION
CAPACITOR
(EXTERNAL AMPLIFIERS)
6
5
–
5V
8
1/2 LT1368
+
4
7
0.1µF*
0V
24467 F18
Figure 18. External Buffers Provide High Impedance Inputs and Amplifier Offsets are Cancelled
24467fb
For more information www.linear.com/LTC2446
25
LTC2446/LTC2447
APPLICATIONS INFORMATION
The LT1368 is an excellent amplifier for this function.
It has rail-to-rail inputs and outputs, and it operates on a
single 5V supply. Its open-loop gain is 1M and its input
bias current is 10nA. It also requires at least a 0.1µF load
capacitor for compensation. It is this feature that sets
it apart from other amplifiers—the load capacitor
attenuates sampling glitches from the LTC2447 ADCIN
terminal, allowing it to achieve full performance of the
ADC with high impedance at the multiplexer inputs.
Another benefit of the LT1368 is that it can be powered
from supplies equal to or greater than that of the ADC.
This can allow the inputs to span the entire absolute
maximum of GND – 0.3V to VCC + 0.3V. Using a positive
supply of 7.5V to 10V and a negative supply of –2.5 to
–5V gives the amplifier plenty of headroom over the
LTC2447 input range.
Interfacing Sensors to the LTC2447
Figure 19 shows a few of the ways that the multiple reference
inputs of the LTC2447 greatly simplify sensor interfacing.
Each of the four references is fully differential and has a
differential range of 100mV to 5V. This opens up many
possibilities for sensing voltages and currents, eliminating
much of the analog signal conditioning circuitry required
for interfacing to conventional ADCs.
Figure 19a is a standard 350Ω, voltage excited strain
gauge with sense wires for the excitation voltage. REF01+
and REF01– sense the excitation voltage at the gauge,
compensating for voltage drop along the high current
excitation supply wires. This can be a significant error,
as the excitation current is 14mA when excited with 5V.
Reference loading capacitors at the ADC are necessary to
average the reference current during sampling. Both ADC
inputs are always close to mid-reference, and hence close
to mid-supply when using 5V excitation.
Figure 19b is a novel way to interface the LTC2447 to a
bridge that is specified for constant current excitation. The
Fujikura FPM-120PG is a 120psig pressure sensor that
is not trimmed for absolute accuracy, but is temperature
compensated for low drift when excited by a constant
current source. The LTC2447’s fully differential reference
allows sensing the excitation current with a resistor in series
with the bridge excitation. Changes in ambient temperature
and supply voltage will cause the current to vary, but the
LTC2447 compensates by using the current sense voltage
as its reference. The input common mode will be slightly
higher than mid-reference, but still far enough away from
the positive supply to eliminate concerns about the buffer
amplifier’s headroom.
Figure 19c is an Omega 44018 linear output thermistor.
Two fixed resistors linearize the output from the thermistors. The recommended 5700Ω series resistor is broken
up into two 2850Ω resistors to give a differential output
centered around mid-reference. This ensures that the buffer
amplifiers have enough headroom at the negative supply.
Note that the excitation is 3V, the maximum recommended
by the manufacturer to prevent self-heating errors. The
LTC2447 senses this reference voltage.
Figure 19d shows a standard 100Ω platinum RTD. This
circuit shows how to use the LTC2447 to make a direct
resistance measurement, where the output code is the RTD
resistance divided by the reference resistance. A 500Ω
sense resistor allows measurement of resistance up to
250Ω. (A standard α = 0.00385 RTD has a resistance of
247.09Ω at 400°C.)
The LTC2446 multiplexes rail-to-rail inputs directly to the
ADC modulator and is suitable for low impedance resistive
sources such as 100Ω RTDs and 350Ω strain gauges that
are located close to the ADC. In applications where the
source resistance is high or the source is located more
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26
For more information www.linear.com/LTC2446
LTC2446/LTC2447
APPLICATIONS INFORMATION
than 5cm to 10cm from the ADC, the LTC2447 (with an
LT1368 buffer) is appropriate. The LTC2447 automatically
removes offset, drift and 1/f noise of the LT®1368. One
consideration for single supply applications is that both ADC
inputs should always be at least 100mV from the LT1368’s
supply rails. All of the applications shown in Figure 19 are
designed to keep both analog inputs far enough away from
ground and VCC so that the LT1368 can operate on the
same 5V supply as the LTC2447. Although the LT1368 has
rail-to-rail inputs and outputs, these amplifiers still need
some degree of headroom to work at the resolution level
of the LTC2447. For input signals running rail-to-rail, the
supply voltage of the LT1368 can be increased in order
to provide the extra headroom.
The LTC2446/LTC2447 reference have no such limitations —they are truly rail-to-rail, and will even operate up
to 300mV outside the supply rails. Reference terminals
may be connected directly to the ground plane or to a
reference voltage that is decoupled to the ground plane
with a 1µF or larger capacitor without any degradation of
performance provided the connection is less than 5cm
from the LTC2446/LTC2447. If the reference terminals
are sensing a point more than 5cm to 10cm away from
the ADC, the reference pins should be decoupled to the
ground plane with 1µF capacitors.
The reference terminals can also sense a resistive source
with a resistance up to 500Ω located close to the LTC2446/
LTC2447, however parasitic capacitance must be kept to
a minimum. If the sense point is more than 5cm from the
ADC, then it should be buffered. The LT1368 is also an
outstanding reference buffer. While offsets are not cancelled as in the ADC input circuit, the 200mV offset and
2mV/°C drift will not degrade the performance of most
sensors. The LT1369 is a quad version of the LT1368,
and can serve as the input buffer for an LTC2447 and two
reference buffers.
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For more information www.linear.com/LTC2446
27
LTC2446/LTC2447
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/product/LTC2446#packaging for the most recent package drawings.
UHF Package
38-Lead Plastic QFN (5mm × 7mm)
(Reference LTC DWG # 05-08-1701 Rev C)
0.70 ±0.05
5.50 ±0.05
5.15 ±0.05
4.10 ±0.05
3.00 REF
3.15 ±0.05
PACKAGE
OUTLINE
0.25 ±0.05
0.50 BSC
5.5 REF
6.10 ±0.05
7.50 ±0.05
RECOMMENDED SOLDER PAD LAYOUT
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
0.75 ±0.05
5.00 ±0.10
PIN 1 NOTCH
R = 0.30 TYP OR
0.35 × 45° CHAMFER
3.00 REF
37
0.00 – 0.05
38
0.40 ±0.10
PIN 1
TOP MARK
(SEE NOTE 6)
1
2
5.15 ±0.10
5.50 REF
7.00 ±0.10
3.15 ±0.10
(UH) QFN REF C 1107
0.200 REF 0.25 ±0.05
R = 0.125
TYP
0.50 BSC
R = 0.10
TYP
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING CONFORMS TO JEDEC PACKAGE
OUTLINE M0-220 VARIATION WHKD
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.20mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON THE TOP AND BOTTOM OF PACKAGE
24467fb
28
For more information www.linear.com/LTC2446
LTC2446/LTC2447
REVISION HISTORY
(Revision history begins at Rev B)
REV
DATE
DESCRIPTION
B
01/17
Updated Max value for fEOSC.
PAGE NUMBER
4
Updated formula for tCONV.
4
Updated Note 13.
5
Inserted Figure 4. Input Range.
13
Revised Table 7. Performance vs Oversample Ratio.
24
24467fb
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection
of its circuits
as described
herein will not infringe on existing patent rights.
For more
information
www.linear.com/LTC2446
29
LTC2446/LTC2447
TYPICAL APPLICATION
5V
5V
VREF01+
1µF
350Ω
LOAD CELL
–
+
FUJIKURA FPM-120PG
(4k TO 6k IMPEDANCE)
–
+
CH3
FULL-SCALE OUTPUT = 60mV TO 140mV
CH0
CH2
FULL-SCALE OUTPUT = 10mV
VREF23+
CH1
5V
SELECT FOR V > 2 • 140mV
AT MAXIMUM BRIDGE RESISTANCE
VREF23–
375Ω
VREF01–
1µF
GND
GND
(19a) Full-Bridge, Voltage Sense
(19b) Full-Bridge, Current Sense
5V
VREF45+
LT1790-3
1µF
2850Ω
RILIM
CH5
GND
CH7
12.4k
OMEGA 44018
LINEAR
THERMISTOR
COMPOSITE
T2
SENSOR
100Ω AT 0°C
247.09Ω AT 400°C
100Ω RTD
T1
CH6
VREF67+
CH4
THERMISTOR
2850Ω
500Ω
VREF67–
VREF45–
24467 F19
GND
GND
(19c) Half-Bridge, Voltage Sense
(19d) Half-Bridge, Current Sense
Figure 19. Muxed Inputs/References Enable Multiple Ratiometric Measurements with the Same Device
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1236A-5
Precision Bandgap Reference, 5V
0.05% Max, 5ppm/°C Drift
LT1461
Micropower Series Reference, 2.5V
0.04% Max, 3ppm/°C Max Drift
LTC1799
Resistor Set SOT-23 Oscillator
Single Resistor Frequency Set
LTC2053
Rail-to-Rail Instrumentation Amplifier
10µV Offset with 50nV/°C Drift, 2.5µVP-P Noise 0.01Hz to 10Hz
LTC2412
2-Channel, Differential Input, 24-Bit, No Latency ∆Σ ADC
0.16ppm Noise, 2ppm INL, 200µA
LTC2415
1-Channel, Differential Input, 24-Bit, No Latency ∆Σ ADC
0.23ppm Noise, 2ppm INL, 2× Speed Mode
LTC2414/LTC2418
4-/8-Channel, Differential Input, 24-Bit, No Latency ∆Σ ADC
0.2ppm Noise, 2ppm INL, 200µA
LTC2430/LTC2431
1-Channel, Differential Input, 20-Bit, No Latency ∆Σ ADC
0.56ppm Noise, 3ppm INL, 200µA
LTC2436-1
2-Channel, Differential Input, 16-Bit, No Latency ∆Σ ADC
800nVRMS Noise, 0.12LBS INL, 0.006LBS Offset, 200µA
LTC2440
1-Channel, Differential Input, High Speed/Low Noise, 24-Bit, 2µVRMS Noise at 880Hz, 200nVRMS Noise at 6.9Hz, 0.0005% INL, Up
No Latency ∆Σ ADC
to 3.5kHz Output Rate
LTC2444/LTC2445/
LTC2448/LTC2449
8-/16-Channel, Differential Input, High Speed/Low Noise,
24-Bit, No Latency ∆Σ ADC
2µVRMS Noise at 1.76kHz, 200nVRMS Noise at 13.8Hz, 0.0005% INL,
Up to 8kHz Output Rate
24467fb
30 Linear Technology Corporation
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