They operate from 2.7V to 5.5V and include an integrated
oscillator, 2ppm INL and 0.2ppm RMS noise. They use
delta-sigma technology and provide single cycle settling
time for multiplexed applications. Through a single pin,
the LTC2414/LTC2418 can be configured for better than
110dB differential mode rejection at 50Hz or 60Hz ±2%,
or they can be driven by an external oscillator for a user-
defined rejection frequency. The internal oscillator requires
no external frequency setting components.
The LTC2414/LTC2418 accept any external differential
reference voltage from 0.1V to V
CC
for flexible ratiomet-
ric and remote sensing measurement applications. They
can be configured to take 4/8 differential channels or
8/16 single-ended channels. The full-scale bipolar input
range is from –0.5V
REF
to 0.5V
REF
. The reference common
mode voltage, V
REFCM
, and the input common mode volt-
age, V
INCM
, may be independently set within GND to V
CC
.
The DC common mode input rejection is better than 140dB.
The LTC2414/LTC2418 communicate through a flexible
4-wire digital interface that is compatible with SPI and
MICROWIRE protocols.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
No Latency ½∑ is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
n
n
n
n
n
n
n
8-/16-Channel Single-Ended or 4-/8-Channel
Differential Inputs (LTC2414/LTC2418)
Low Supply Current (200µA, 4µA in Autosleep)
Differential Input and Differential Reference with
GND to V
CC
Common Mode Range
2ppm INL, No Missing Codes
2.5ppm Full-Scale Error and 0.5ppm Offset
0.2ppm Noise
No Latency: Digital Filter Settles in a Single Cycle
Each Conversion Is Accurate, Even After a New
Channel Is Selected
Single Supply 2.7V to 5.5V Operation
Internal Oscillator—No External Components
Required
110dB Min, 50Hz/60Hz Notch Filter
applicaTions
n
n
n
n
n
n
n
n
Direct Sensor Digitizer
Weight Scales
Direct Temperature Measurement
Gas Analyzers
Strain Gauge Transducers
Instrumentation
Data Acquisition
Industrial Process Control
Typical applicaTion
2.7V TO 5.5V
11
21 CH0
22 CH1
•
•
•
28 CH7
1 CH8
•
•
•
8 CH15
10 COM
12 REF
–
15
GND
REF
+
9
V
CC
F
O
SDI
SCK
SDO
CS
19
20
18
17
16
1µF
V
CC
Total Unadjusted Error
vs Input Voltage
3
2
TUE (ppm OF V
REF
)
1
0
T
A
= –45°C
= 50Hz REJECTION
= EXTERNAL OSCILLATOR
= 60Hz REJECTION
V
CC
= 5V
V
REF
= 5V
V
INCM
= V
REFCM
= 2.5V
F
O
= GND
T
A
= 25°C
THERMOCOUPLE
16-CHANNEL
MUX
+
–
DIFFERENTIAL
24-BIT ∑ ADC
4-WIRE
SPI INTERFACE
–1
–2
T
A
= 85°C
LTC2418
241418 TA01a
–3
–2.5 –2 –1.5 –1 –0.5 0 0.5 1.0 1.5 2.0 2.5
INPUT VOLTAGE (V)
2414/18 TA01b
241418fb
For more information
www.linear.com/LTC2414
1
LTC2414/LTC2418
absoluTe MaxiMuM raTings
(Notes 1, 2)
Supply Voltage (V
CC
) to GND ....................... –0.3V to 7V
Analog Input Voltage to GND ........–0.3V to (V
CC
+ 0.3V)
Reference Input Voltage to GND ...–0.3V to (V
CC
+ 0.3V)
Digital Input Voltage to GND .........–0.3V to (V
CC
+ 0.3V)
Digital Output Voltage to GND.......–0.3V to (V
CC
+ 0.3V)
Operating Temperature Range
LTC2414/LTC2418C .................................. 0°C to 70°C
LTC2414/LTC2418I ...............................–40°C to 85°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
pin conFiguraTion
TOP VIEW
NC
NC
NC
NC
NC
NC
NC
NC
V
CC
1
2
3
4
5
6
7
8
9
28 CH7
27 CH6
26 CH5
25 CH4
24 CH3
23 CH2
22 CH1
21 CH0
20 SDI
19 F
O
18 SCK
17 SDO
16 CS
15 GND
CH8
CH9
CH10
CH11
CH12
CH13
CH14
CH15
V
CC
1
2
3
4
5
6
7
8
9
TOP VIEW
28 CH7
27 CH6
26 CH5
25 CH4
24 CH3
23 CH2
22 CH1
21 CH0
20 SDI
19 F
O
18 SCK
17 SDO
16 CS
15 GND
COM 10
REF
+
11
REF
–
12
NC 13
NC 14
COM 10
REF
+
11
REF
–
12
NC 13
NC 14
GN PACKAGE
28-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 110°C/W
GN PACKAGE
28-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 110°C/W
orDer inForMaTion
LEAD FREE FINISH
LTC2414CGN#PBF
LTC2414IGN#PBF
LTC2418CGN#PBF
LTC2418IGN#PBF
TAPE AND REEL
LTC2414CGN#TRPBF
LTC2414IGN#TRPBF
LTC2418CGN#TRPBF
LTC2418IGN#TRPBF
PART MARKING*
2414
2414
2418
2418
PACKAGE DESCRIPTION
28-Lead Plastic SSOP
28-Lead Plastic SSOP
28-Lead Plastic SSOP
28-Lead Plastic SSOP
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on nonstandard lead based finish parts.
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/
2
241418fb
For more information
www.linear.com/LTC2414
LTC2414/LTC2418
The
l
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Notes 3, 4)
PARAMETER
Resolution (No Missing Codes)
Integral Nonlinearity
CONDITIONS
0.1V ≤ V
REF
≤ V
CC
, –0.5
•
V
REF
≤ V
IN
≤ 0.5
•
V
REF
(Note 5)
4.5V ≤ V
CC
≤ 5.5V, REF
+
= 2.5V, REF
–
= GND, V
INCM
= 1.25V (Note 6)
5V ≤ V
CC
≤ 5.5V, REF
+
= 5V, REF
–
= GND, V
INCM
= 2.5V (Note 6)
REF
+
= 2.5V, REF
–
= GND, V
INCM
= 1.25V (Note 6)
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
GND ≤ IN
+
= IN
–
≤ V
CC
(Note 14)
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
GND ≤ IN
+
= IN
–
≤ V
CC
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
IN
+
= 0.75
•
REF
+
, IN
–
= 0.25
•
REF
+
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
IN
+
= 0.75
•
REF
+
, IN
–
= 0.25
•
REF
+
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
IN
+
= 0.25
•
REF
+
, IN
–
= 0.75
•
REF
+
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
IN
+
= 0.25
•
REF
+
, IN
–
= 0.75
•
REF
+
4.5V ≤ V
CC
≤ 5.5V, REF
+
= 2.5V, REF
–
= GND, V
INCM
= 1.25V
5V ≤ V
CC
≤ 5.5V, REF
+
= 5V, REF
–
= GND, V
INCM
= 2.5V
REF
+
= 2.5V, REF
–
= GND, V
INCM
= 1.25V
5V ≤ V
CC
≤ 5.5V, REF
+
= 5V, V
REF
– = GND,
GND ≤ IN
–
= IN
+
≤ 5V (Note 13)
l
l
l
l
elecTrical characTerisTics
MIN
24
TYP
1
2
5
2.5
20
2.5
0.03
2.5
0.03
3
3
6
1
MAX
UNITS
Bits
ppm of V
REF
ppm of V
REF
ppm of V
REF
µV
nV/°C
14
10
Offset Error
Offset Error Drift
Positive Full-Scale Error
Positive Full-Scale Error Drift
Negative Full-Scale Error
Negative Full-Scale Error Drift
Total Unadjusted Error
l
12
ppm of V
REF
ppm of V
REF
/°C
12
ppm of V
REF
ppm of V
REF
/°C
ppm of V
REF
ppm of V
REF
ppm of V
REF
µV
RMS
Output Noise
temperature range, otherwise specifications are at T
A
= 25°C. (Notes 3, 4)
PARAMETER
Input Common Mode Rejection DC
Input Common Mode Rejection
60Hz ±2%
Input Common Mode Rejection
50Hz ±2%
Input Normal Mode Rejection
60Hz ±2%
Input Normal Mode Rejection
50Hz ±2%
Reference Common Mode
Rejection DC
Power Supply Rejection, DC
Power Supply Rejection, 60Hz ±2%
Power Supply Rejection, 50Hz ±2%
CONDITIONS
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
GND ≤ IN
–
= IN
+
≤ 5V (Note 5)
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
GND ≤ IN
–
= IN
+
≤ 5V (Notes 5, 7)
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
GND ≤ IN
–
= IN
+
≤ 5V (Notes 5, 8)
(Notes 5, 7)
(Notes 5, 8)
2.5V ≤ REF
+
≤ V
CC
, GND ≤ REF
–
≤ 2.5V,
V
REF
= 2.5V, IN
–
= IN
+
= GND (Note 5)
REF
+
= 2.5V, REF
–
= GND, IN
–
= IN
+
= GND
converTer characTerisTics
The
l
denotes specifications which apply over the full operating
MIN
l
l
l
l
l
l
TYP
140
MAX
UNITS
dB
dB
dB
130
140
140
110
110
130
140
140
140
110
120
120
dB
dB
dB
dB
dB
dB
REF
+
= 2.5V, REF
–
= GND, IN
–
= IN
+
= GND (Note 7)
REF
+
= 2.5V, REF
–
= GND, IN
–
= IN
+
= GND (Note 8)
241418fb
For more information
www.linear.com/LTC2414
3
LTC2414/LTC2418
analog inpuT anD reFerence
SYMBOL
IN
+
IN
–
V
IN
REF
+
REF
–
V
REF
C
S
(IN
+
)
C
S
(IN
–
)
C
S
(REF
+
)
C
S
(REF
–
)
I
DC_LEAK
(IN
+
)
I
DC_LEAK
(IN
–
)
I
DC_LEAK
(REF
+
)
I
DC_LEAK
(REF
–
)
PARAMETER
Absolute/Common Mode IN
+
Voltage
Absolute/Common Mode IN
–
Voltage
Input Differential Voltage Range
(IN
+
– IN
–
)
Absolute/Common Mode REF
+
Voltage
Absolute/Common Mode REF
–
Voltage
Reference Differential Voltage Range
(REF
+
– REF
–
)
IN
+
Sampling Capacitance
IN
–
Sampling Capacitance
REF
+
Sampling Capacitance
REF
–
Sampling Capacitance
IN
+
DC Leakage Current
IN
–
DC Leakage Current
REF
+
DC Leakage Current
REF
–
DC Leakage Current
Off Channel to In Channel Isolation
(R
IN
= 100Ω)
t
OPEN
I
S(OFF)
MUX Break-Before-Make Interval
Channel Off Leakage Current
CS
= V
CC
= 5.5V, IN
+
= GND
CS
= V
CC
= 5.5V, IN
–
= 5V
CS
= V
CC
= 5.5V, REF
+
= 5V
CS
= V
CC
= 5.5V, REF
–
= GND
DC
1Hz
f
S
= 15,3600Hz
2.7V ≤ V
CC
≤ 5.5V
Channel at V
CC
and GND
l
l
l
l
l
The
l
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
CONDITIONS
l
l
l
l
l
l
MIN
GND – 0.3
GND – 0.3
–V
REF
/2
0.1
GND
0.1
TYP
MAX
V
CC
+ 0.3
V
CC
+ 0.3
–V
REF
/2
V
CC
V
CC
– 0.1
V
CC
UNITS
V
V
V
V
V
V
pF
pF
pF
pF
18
18
18
18
–10
–10
–10
–10
1
1
1
1
140
140
140
70
–10
100
1
300
10
10
10
10
10
nA
nA
nA
nA
dB
dB
dB
ns
nA
DigiTal inpuT anD DigiTal ouTpuTs
SYMBOL
V
IH
V
IL
V
IH
V
IL
I
IN
PARAMETER
High Level Input Voltage
CS,
F
O
, SDI
Low Level Input Voltage
CS,
F
O
, SDI
High Level Input Voltage
SCK
Low Level Input Voltage
SCK
Digital Input Current
CS,
F
O
, SDI
Digital Input Current
SCK
C
IN
Digital Input Capacitance
CS,
F
O
, SDI
Digital Input Capacitance
SCK
V
OH
High Level Output Voltage
SDO
(Note 9)
I
O
= – 800µA
CONDITIONS
2.7V ≤ V
CC
≤ 5.5V
2.7V ≤ V
CC
≤ 3.3V
4.5V ≤ V
CC
≤ 5.5V
2.7V ≤ V
CC
≤ 5.5V
The
l
denotes specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
MIN
l
l
l
l
l
l
TYP
MAX
UNITS
V
V
2.5
2.0
0.8
0.6
2.5
2.0
0.8
0.6
–10
–10
10
10
10
10
V
V
2.7V ≤ V
CC
≤ 5.5V (Note 9)
2.7V ≤ V
CC
≤ 3.3V (Note 9)
4.5V ≤ V
CC
≤ 5.5V (Note 9)
2.7V ≤ V
CC
≤ 5.5V (Note 9)
0V ≤ V
IN
≤ V
CC
0V ≤ V
IN
≤ V
CC
(Note 9)
V
V
V
V
µA
µA
pF
pF
V
l
V
CC
–0.5
4
241418fb
For more information
www.linear.com/LTC2414
LTC2414/LTC2418
DigiTal inpuT anD DigiTal ouTpuTs
SYMBOL
V
OL
V
OH
V
OL
I
OZ
PARAMETER
Low Level Output Voltage
SDO
High Level Output Voltage
SCK
Low Level Output Voltage
SCK
Hi-Z Output Leakage
SDO
CONDITIONS
I
O
= 1.6mA
I
O
= – 800µA (Note 10)
I
O
= 1.6mA (Note 10)
l
l
l
l
The
l
denotes specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
MIN
TYP
MAX
0.4
V
CC
– 0.5
0.4
–10
10
UNITS
V
V
V
µA
The
l
denotes specifications which apply over the full operating temperature range,
otherwise specifications are at T
A
= 25°C. (Note 3)
SYMBOL
V
CC
I
CC
PARAMETER
Supply Voltage
Supply Current
Conversion Mode
Sleep Mode
Sleep Mode
CS
= 0V (Note 12)
CS
= V
CC
(Note 12)
CS
= V
CC
, 2.7V ≤ V
CC
≤ 3.3V (Note 12)
CONDITIONS
l
l
l
power requireMenTs
MIN
2.7
TYP
MAX
5.5
UNITS
V
µA
µA
µA
200
4
2
300
10
TiMing characTerisTics
SYMBOL
f
EOSC
t
HEO
t
LEO
t
CONV
PARAMETER
External Oscillator Frequency Range
External Oscillator High Period
External Oscillator Low Period
Conversion Time
The
l
denotes specifications which apply over the full operating temperature
