No Latency: Digital Filter Settles in a Single Cycle
Single Supply 2.7V to 5.5V Operation
Internal Oscillator
Six Addresses Available and One Global Address for
Synchronization
Available in a Tiny (3mm
×
3mm)
10-Lead DFN Package
Direct Sensor Digitizer
Weight Scales
Direct Temperature Measurement
Strain Gauge Transducers
Instrumentation
Industrial Process Control
DVMs and Meters
applicaTions
n
n
n
n
n
n
n
Typical applicaTion
V
CC
0.1µF
10k
SENSE
10k
0.1µF
V
IN–
I
DIFF
= 0
REF
+
LTC2485
GND
REF
–
V
CC
1µF
SCL
SDA
CA0/f
0
CA1
2485 TA01a
+FS Error vs R
SOURCE
at IN
+
and IN
–
V
CC
= 5V
60 V
REF
= 5V
V
IN+
= 3.75V
V
IN–
= 1.25V
40
f
O
= GND
20 T
A
= 25°C
0
–20
–40
–60
–80
1
10
1k
R
SOURCE
(Ω)
100
10k
100k
2485 TA01b
80
+FS ERROR (ppm)
V
IN+
2-WIRE
I
2
C INTERFACE
6 ADDRESSES
C
IN
= 1µF
2485fd
For more information
www.linear.com/LTC2485
1
LTC2485
absoluTe MaxiMuM raTings
(Notes 1, 2)
pin conFiguraTion
TOP VIEW
REF
+
REF
–
IN
+
Supply Voltage (V
CC
) to GND ...................... – 0.3V to 6V
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
LTC2485C .................................................... 0°C to 70°C
LTC2485I .................................................– 40°C to 85°C
Storage Temperature Range .................. –65°C to 125°C
1
2
3
4
5
11
V
CC
10 CA0/f
0
9 CA1
8 GND
7 SDA
6 SCL
IN
–
DD PACKAGE
10-LEAD (3mm
×
3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 43°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
LTC2485CDD#PBF
LTC2485IDD#PBF
TAPE AND REEL
LTC2485CDD#TRPBF
LTC2485IDD#TRPBF
PART MARKING*
LBST
LBST
PACKAGE DESCRIPTION
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead (3mm
×
3mm) Plastic DFN
TEMPERATURE RANGE
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.
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/
The
l
denotes the 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
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
elecTrical characTerisTics (norMal speeD)
CONDITIONS
0.1 ≤ V
REF
≤ V
CC
, –FS ≤ V
IN
≤ +FS (Note 5)
5V ≤ V
CC
≤ 5.5V, V
REF
= 5V, V
IN(CM)
= 2.5V (Note 6)
2.7V ≤ V
CC
≤ 5.5V, V
REF
= 2.5V, V
IN(CM)
= 1.25V (Note 6)
2.5V ≤ V
REF
≤ V
CC
, GND ≤ IN
+
= IN
–
≤ V
CC
(Note 13)
2.5V ≤ V
REF
≤ V
CC
, GND ≤ IN
+
= IN
–
≤ V
CC
2.5V ≤ V
REF
≤ V
CC
, IN
+
= 0.75V
REF
, IN
–
= 0.25V
REF
2.5V ≤ V
REF
≤ V
CC
, IN
+
= 0.75V
REF
, IN
–
= 0.25V
REF
2.5V ≤ V
REF
≤ V
CC
, IN
–
= 0.75V
REF
, IN
+
= 0.25V
REF
2.5V ≤ V
REF
≤ V
CC
, IN
–
= 0.75V
REF
, IN
+
= 0.25V
REF
5V ≤ V
CC
≤ 5.5V, V
REF
= 2.5V, V
IN(CM)
= 1.25V (Note 6)
5V ≤ V
CC
≤ 5.5V, V
REF
= 5V, V
IN(CM)
= 2.5V (Note 6)
2.7V ≤ V
CC
≤ 5.5V, V
REF
= 2.5V, V
IN(CM)
= 1.25V (Note 6)
5V ≤ V
CC
≤ 5.5V, V
REF
= 5V, GND ≤ IN
–
= IN
+
≤ V
CC
(Note 12)
T
A
= 27°C
MIN
●
●
●
TYP
2
1
0.5
10
MAX
10
2.5
25
UNITS
Bits
ppm of V
REF
ppm of V
REF
µV
nV/°C
ppm of V
REF
ppm of V
REF
/°C
ppm of V
REF
ppm of V
REF
/°C
ppm of V
REF
ppm of V
REF
ppm of V
REF
µV
RMS
24
●
0.1
●
25
0.1
15
15
15
0.6
390
450
Output Noise
Internal PTAT Signal
mV
2
2485fd
For more information
www.linear.com/LTC2485
LTC2485
elecTrical characTerisTics (2x speeD)
PARAMETER
Resolution (No Missing Codes)
Integral Nonlinearity
Offset Error
Offset Error Drift
Positive Full-Scale Error
Positive Full-Scale Error Drift
Negative Full-Scale Error
Negative Full-Scale Error Drift
Output Noise
The
l
denotes the specifications which apply over
the full operating temperature range, otherwise specifications are at T
A
= 25°C. (Notes 3, 4)
CONDITIONS
0.1 ≤ V
REF
≤ V
CC
, –FS ≤ V
IN
≤ +FS (Note 5)
5V ≤ V
CC
≤ 5.5V, V
REF
= 5V, V
IN(CM)
= 2.5V (Note 6)
2.7V ≤ V
CC
≤ 5.5V, V
REF
= 2.5V, V
IN(CM)
= 1.25V (Note 6)
2.5V ≤ V
REF
≤ V
CC
, GND ≤ IN
+
= IN
–
≤ V
CC
(Note 13)
2.5V ≤ V
REF
≤ V
CC
, GND ≤ IN
+
= IN
–
≤ V
CC
2.5V ≤ V
REF
≤ V
CC
, IN
+
= 0.75V
REF
, IN
–
= 0.25V
REF
2.5V ≤ V
REF
≤ V
CC
, IN
+
= 0.75V
REF
, IN
–
= 0.25V
REF
2.5V ≤ V
REF
≤ V
CC
, IN
–
= 0.75V
REF
, IN
+
= 0.25V
REF
2.5V ≤ V
REF
≤ V
CC
, IN
–
= 0.75V
REF
, IN
+
= 0.25V
REF
5V ≤ V
CC
≤ 5.5V, V
REF
= 5V, GND ≤ IN
–
= IN
+
≤ V
CC
●
●
●
●
●
MIN
24
TYP
2
1
0.5
100
MAX
10
2
25
UNITS
Bits
ppm of V
REF
mV
nV/°C
ppm of V
REF
ppm of V
REF
/°C
ppm of V
REF
ppm of V
REF
/°C
µV
RMS
0.1
25
0.1
0.84
converTer characTerisTics
PARAMETER
Input Common Mode Rejection DC
Input Common Mode Rejection
50Hz ± 2%
Input Common Mode Rejection
60Hz ±2%
Input Normal Mode Rejection
50Hz ±2%
Input Normal Mode Rejection
60Hz ±2%
Input Normal Mode Rejection
50Hz/60Hz ±2%
Reference Common Mode Rejection DC
Power Supply Rejection DC
Power Supply Rejection, 50Hz ±2%
Power Supply Rejection, 60Hz ±2%
CONDITIONS
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Notes 3, 4)
MIN
●
●
●
●
●
●
●
TYP
MAX
UNITS
dB
dB
dB
2.5V ≤ V
REF
≤ V
CC
, GND ≤ IN
–
= IN
+
≤ V
CC
(Note 5)
2.5V ≤ V
REF
≤ V
CC
, GND ≤ IN
–
= IN
+
≤ V
CC
(Note 5)
2.5V ≤ V
REF
≤ V
CC
, GND ≤ IN
–
= IN
+
≤ V
CC
(Note 5)
2.5V ≤ V
REF
≤ V
CC
, GND ≤ IN
–
= IN
+
≤ V
CC
(Notes 5, 7)
2.5V ≤ V
REF
≤ V
CC
, GND ≤ IN
–
= IN
+
≤ V
CC
(Notes 5, 8)
2.5V ≤ V
REF
≤ V
CC
, GND ≤ IN
–
= IN
+
≤ V
CC
(Notes 5, 9)
2.5V ≤ V
REF
≤ V
CC
, GND ≤ IN
–
= IN
+
≤ V
CC
(Note 5)
V
REF
= 2.5V, IN
–
= IN
+
= GND
V
REF
= 2.5V, IN
–
= IN
+
= GND (Notes 7, 9)
V
REF
= 2.5V, IN
–
= IN
+
= GND (Notes 8, 9)
140
140
140
110
110
87
120
140
120
120
120
120
120
dB
dB
dB
dB
dB
dB
dB
analog inpuT anD reFerence
SYMBOL
IN
+
IN
–
FS
LSB
V
IN
V
REF
PARAMETER
Absolute/Common Mode IN
+
Voltage
Absolute/Common Mode IN
–
Voltage
Full-Scale of the Differential Input (IN
+
– IN
–
)
Least Significant Bit of the Output Code
Input Differential Voltage Range (IN
+
– IN
–
)
Reference Voltage Range (REF
+
– REF
–
)
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
CONDITIONS
MIN
GND – 0.3V
GND – 0.3V
●
●
●
●
TYP
MAX
V
CC
+ 0.3V
V
CC
+ 0.3V
UNITS
V
V
V
0.5V
REF
FS/2
24
–FS
0.1
+FS
V
CC
V
V
2485fd
For more information
www.linear.com/LTC2485
3
LTC2485
analog inpuT anD reFerence
SYMBOL
C
S
(IN
+
)
C
S
(IN
–
)
C
S
(V
REF
)
I
DC_LEAK
(IN
+
)
I
DC_LEAK
(IN
–
)
I
DC_LEAK
(V
REF
)
PARAMETER
IN
+
Sampling Capacitance
IN
–
Sampling Capacitance
V
REF
Sampling Capacitance
IN
+
DC Leakage Current
IN
–
DC Leakage Current
REF
+
, REF
–
DC Leakage Current
Sleep Mode, IN
+
= GND
Sleep Mode, IN
–
= GND
Sleep Mode, V
REF
= V
CC
●
●
●
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
CONDITIONS
MIN
TYP
11
11
11
–10
–10
–100
1
1
1
10
10
100
MAX
UNITS
pF
pF
pF
nA
nA
nA
i
2
c DigiTal inpuTs anD DigiTal ouTpuTs
SYMBOL
V
IH
V
IL
V
IL(CA1)
V
IH(CA0/f0,CA1)
R
INH
R
INL
R
INF
I
I
V
HYS
V
OL
t
OF
t
SP
I
IN
C
I
C
B
C
CAX
V
IH(EXT,OSC)
V
IL(EXT,OSC)
PARAMETER
High Level Input Voltage
Low Level Input Voltage
Low Level Input Voltage for Address Pin
High Level Input Voltage for Address Pins
Resistance from CA0/f
0
, CA1 to V
CC
to Set
Chip Address Bit to 1
Resistance from CA1 to GND to Set Chip
Address Bit to 0
Resistance from CA0/f
0
, CA1 to V
CC
or
GND to Set Chip Address Bit to Float
Digital Input Current
Hysteresis of Schmitt Trigger Inputs
Low Level Output Voltage SDA
Output Fall Time from V
IHMIN
to V
ILMAX
Input Spike Suppression
Input Leakage
Capacitance for Each I/O Pin
Capacitance Load for Each Bus Line
External Capacitive Load On-Chip Address
Pins (CA0/f
0
,CA1) for Valid Float
High Level CA0/f
0
External Oscillator
Low Level CA0/f
0
External Oscillator
2.7V ≤ V
CC
< 5.5V
2.7V ≤ V
CC
< 5.5V
0.1V
CC
≤ V
IN
≤ V
CC
(Note 5)
I = 3mA
CONDITIONS
The
l
denotes the specifications which apply over
the full operating temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
MIN
●
●
●
●
●
●
●
●
TYP
MAX
0.3V
CC
0.05V
CC
UNITS
V
V
V
V
kΩ
kΩ
MΩ
0.7V
CC
0.95V
CC
10
10
2
–10
0.05V
CC
10
0.4
20+0.1C
B
250
50
1
10
400
10
V
CC
– 0.5V
0.5
µA
V
V
ns
ns
µA
pF
pF
pF
V
V
●
●
●
●
●
●
●
●
●
Bus Load C
B
10pF to 400pF (Note 14)
power requireMenTs
SYMBOL
V
CC
I
CC
PARAMETER
Supply Voltage
Supply Current
The
l
denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. (Note 3)
CONDITIONS
●
MIN
2.7
●
●
TYP
160
1
MAX
5.5
250
2
UNITS
V
µA
µA
Conversion Mode (Note 11)
Sleep Mode (Note 11)
4
2485fd
For more information
www.linear.com/LTC2485
LTC2485
TiMing characTerisTics
SYMBOL
f
EOSC
t
HEO
t
LEO
t
CONV_1
PARAMETER
External Oscillator Frequency Range
External Oscillator High Period
External Oscillator Low Period
Conversion Time for 1x Speed Mode
50Hz Mode
60Hz Mode
Simultaneous 50Hz/60Hz Mode
External Oscillator (Note 10)
50Hz Mode
60Hz Mode
Simultaneous 50Hz/60Hz Mode
External Oscillator (Note 10)
The
l
denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. (Note 3)
CONDITIONS
●
●
●
●
●
●
●
●
●
●
●
MIN
10
0.125
0.125
157.2
131.0
144.1
78.7
65.6
72.2
TYP
MAX
1000
100
100
UNITS
kHz
µs
µs
ms
ms
ms
ms
ms
ms
ms
ms
160.3
133.6
146.9
41036/f
EOSC
80.3
66.9
73.6
20556/f
EOSC
163.5
136.3
149.9
81.9
68.2
75.1
t
CONV_2
Conversion Time for 2x Speed Mode
i
2
c TiMing characTerisTics
SYMBOL
f
SCL
t
HD(SDA)
t
LOW
t
HIGH
t
SU(STA)
t
HD(DAT)
t
SU(DAT)
t
r
t
f
t
SU(STO)
PARAMETER
SCL Clock Frequency
Hold Time (Repeated) START Condition
LOW Period of the SCL Clock Pin
HIGH Period of the SCL Clock Pin
Set-Up Time for a Repeated START Condition
Data Hold Time
Data Set-Up Time
Rise Time for Both SDA and SCL Signals
Fall Time for Both SDA and SCL Signals
Set-Up Time for STOP Condition
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Notes 3, 15)
CONDITIONS
●
●
●
●
●
●
●
MIN
0
0.6
1.3
0.6
0.6
0
100
20+0.1C
B
20+0.1C
B
0.6
TYP
MAX
400
UNITS
kHz
µs
µs
µs
µs
0.9
300
300
µs
ns
ns
ns
µs
(Note 14)
(Note 14)
●
●
●
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
All voltage values are with respect to GND.
Note 3:
V
CC
= 2.7V to 5.5V unless otherwise specified.
V
REF
= REF
+
– REF
–
, V
REFCM
= (REF
+
+ REF
–
)/2, FS = 0.5V
REF
;
V
IN
= IN
+
– IN
–
, V
INCM
= (IN
+
+ IN
–
)/2.
Note 4:
Use internal conversion clock or external conversion clock source
with f
EOSC
= 307.2kHz unless otherwise specified.
Note 5:
Guaranteed by design, not subject to test.
Note 6:
Integral nonlinearity is defined as the deviation of a code from a
straight line passing through the actual endpoints of the transfer curve.
The deviation is measured from the center of the quantization band.
Note 7:
50Hz mode (internal oscillator) or f
EOSC
= 256kHz ±2% (external
oscillator).
Note 8:
60Hz mode (internal oscillator) or f
EOSC
= 307.2kHz ±2% (external
oscillator).
Note 9:
Simultaneous 50Hz/60Hz mode (internal oscillator) or f
EOSC
=
280kHz ±2% (external oscillator).
Note 10:
The external oscillator is connected to the CA0/f
0
pin. The
external oscillator frequency, f
EOSC
, is expressed in kHz.
Note 11:
The converter uses the internal oscillator.
Note 12:
The output noise includes the contribution of the internal
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