LTC2433-1
1
24331fa
The LTC
2433-1 is a differential input micropower 16-bit
No Latency
TM
analog-to-digital converter with an inte-
grated oscillator. It provides 0.12LSB INL and 1.45
V
RMS noise independent of V
REF
. It uses delta-sigma
technology and provides single conversion settling of the
digital filter. Through a single pin, the LTC2433-1 can be
configured for better than 87dB input differential mode
rejection at 50Hz and 60Hz
2%, or it can be driven by an
external oscillator for a user defined rejection frequency.
The internal oscillator requires no external frequency
setting components.
The converter accepts any external differential reference
voltage from 0.1V to V
CC
for flexible ratiometric and
remote sensing measurement configurations. The full-
scale differential input range is from 0.5 V
REF
to 0.5
V
REF
. The reference common mode voltage, V
REFCM
, and
the input common mode voltage, V
INCM
, may be indepen-
dently set anywhere between GND and V
CC
. The DC
common mode input rejection is better than 140dB.
The LTC2433-1 communicates through a flexible 3-wire
digital interface which is compatible with SPI and
MICROWIRE
TM
protocols.
s
Direct Sensor Digitizer
s
Weight Scales
s
Direct Temperature Measurement
s
Gas Analyzers
s
Strain-Gage Transducers
s
Instrumentation
s
Data Acquisition
s
Industrial Process Control
, LTC and LT are registered trademarks of Linear Technology Corporation.
s
16-Bit Differential ADC in a Tiny MSOP
s
Low Supply Current: 200
A, 4
A in Autosleep
s
Rail-to-Rail Differential Input/Reference
s
0.12LSB INL, No Missing Codes
s
0.16LSB Full-Scale Error and 5
V Offset
s
1.45
V RMS Noise, Independent of V
REF
s
Very Low Transition Noise: <0.02LSB
s
Operates with a Reference as Low as 100mV with
16-Bit Resolution
s
Internal Oscillator--No External Components
Required
s
87dB Min, Simultaneous 50Hz and 60Hz Notch Filter
s
Single Supply 2.7V to 5.5V Operation
s
Pin Compatible with the 20/24-Bit LTC2431/LTC2411
s
Available in 10-Lead MSOP Package
Differential Input
16-Bit No Latency
ADC
No Latency
is a trademark of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corporation.
Minimum Resolvable Signal vs V
REF
V
CC
REF
+
F
O
IN
+
IN
SCK
REF
SDO
GND
CS
1
10
4
9
3
5
6
8
7
24331 TA01
2
= EXTERNAL CLOCK SOURCE
= INTERNAL OSC/SIMULTANEOUS
50Hz/60Hz REJECTION
3-WIRE
SPI INTERFACE
1
F
(100mV)
4.9k
100
5V REF
LTC2433-1
V
REF
(V)
0
*FOR V
REF
0.5V THE RESOLUTION
IS LIMITED BY STEP SIZE
0
MINIMUM RESOLVABLE SIGNAL (
V)*
10
30
40
50
2
4
5
90
24331 TA02
20
1
3
60
70
80
APPLICATIO S
U
DESCRIPTIO
U
FEATURES
TYPICAL APPLICATIO
U
LTC2433-1
2
24331fa
(Notes 1, 2)
ORDER PART NUMBER
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
LTC2433-1C ............................................ 0
C to 70
C
LTC2433-1I ........................................ 40
C to 85
C
Storage Temperature Range ................. 65
C to 150
C
Lead Temperature (Soldering, 10 sec).................. 300
C
T
JMAX
= 125
C,
JA
= 110
C/W
LTC2433-1CMS
LTC2433-1IMS
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Resolution (No Missing Codes)
0.1V
V
REF
V
CC
, 0.5 V
REF
V
IN
0.5 V
REF
, (Note 5)
q
16
Bits
Integral Nonlinearity (Note 15)
5V
V
CC
5.5V, REF
+
= 2.5V, REF
= GND, V
INCM
= 1.25V, (Note 6)
0.06
LSB
5V
V
CC
5.5V, REF
+
= 5V, REF
= GND, V
INCM
= 2.5V, (Note 6)
q
0.12
1.25
LSB
REF
+
= 2.5V, REF
= GND, V
INCM
= 1.25V, (Note 6)
0.30
LSB
Offset Error (Note 15)
2.5V
REF
+
V
CC
, REF
= GND,
q
5
20
V
GND
IN
+
= IN
V
CC
, (Note 13)
Offset Error Drift
2.5V
REF
+
V
CC
, REF
= GND,
20
nV/
C
GND
IN
+
= IN
V
CC
Positive Full-Scale Error (Note 15)
2.5V
REF
+
V
CC
, REF
= GND,
q
0.16
1.25
LSB
IN
+
= 0.75REF
+
, IN
= 0.25 REF
+
Positive Full-Scale Error Drift
2.5V
REF
+
V
CC
, REF
= GND,
0.04
ppm of V
REF
/
C
IN
+
= 0.75REF
+
, IN
= 0.25 REF
+
Negative Full-Scale Error (Note 15)
2.5V
REF
+
V
CC
, REF
= GND,
q
0.16
1.25
LSB
IN
+
= 0.25 REF
+
, IN
= 0.75 REF
+
Negative Full-Scale Error Drift
2.5V
REF
+
V
CC
, REF
= GND,
0.04
ppm of V
REF
/
C
IN
+
= 0.25 REF
+
, IN
= 0.75 REF
+
Total Unadjusted Error
5V
V
CC
5.5V, REF
+
= 2.5V, REF
= GND, V
INCM
= 1.25V
0.20
LSB
5V
V
CC
5.5V, REF
+
= 5V, REF
= GND, V
INCM
= 2.5V
0.20
LSB
REF
+
= 2.5V, REF
= GND, V
INCM
= 1.25V, (Note 6)
0.25
LSB
Output Noise
5V
V
CC
5.5V, REF
+
= 5V, REF
= GND,
1.45
V
RMS
GND
IN
= IN
+
V
CC
, (Note 12)
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25
C. (Notes 3, 4, 6)
MS PART MARKING
LTAEY
LTAEZ
Consult LTC Marketing for parts specified with wider operating temperature ranges.
1
2
3
4
5
V
CC
REF
+
REF
IN
+
IN
10
9
8
7
6
F
O
SCK
SDO
CS
GND
TOP VIEW
MS10 PACKAGE
10-LEAD PLASTIC MSOP
ABSOLUTE AXI U RATI GS
W
W
W
U
PACKAGE/ORDER I FOR ATIO
U
U
W
ELECTRICAL CHARACTERISTICS
LTC2433-1
3
24331fa
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
IN
+
Absolute/Common Mode IN
+
Voltage
q
GND 0.3
V
CC
+ 0.3
V
IN
Absolute/Common Mode IN
Voltage
q
GND 0.3
V
CC
+ 0.3
V
V
IN
Input Differential Voltage Range
q
V
REF
/2
V
REF
/2
V
(IN
+
IN
)
REF
+
Absolute/Common Mode REF
+
Voltage
q
0.1
V
CC
V
REF
Absolute/Common Mode REF
Voltage
q
GND
V
CC
0.1
V
V
REF
Reference Differential Voltage Range
q
0.1
V
CC
V
(REF
+
REF
)
C
S
(IN
+
)
IN
+
Sampling Capacitance
6
pF
C
S
(IN
)
IN
Sampling Capacitance
6
pF
C
S
(REF
+
)
REF
+
Sampling Capacitance
6
pF
C
S
(REF
)
REF
Sampling Capacitance
6
pF
I
DC_LEAK
(IN
+
)
IN
+
DC Leakage Current
CS = V
CC
= 5V, IN
+
= GND
q
100
1
100
nA
I
DC_LEAK
(IN
)
IN
DC Leakage Current
CS = V
CC
= 5V, IN
= 5.5V
q
100
1
100
nA
I
DC_LEAK
(REF
+
)
REF
+
DC Leakage Current
CS = V
CC
= 5V, REF
+
= 5.5V
q
100
1
100
nA
I
DC_LEAK
(REF
)
REF
DC Leakage Current
CS = V
CC
= 5V, REF
= GND
q
100
1
100
nA
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25
C. (Note 3)
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25
C. (Notes 3, 4)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Common Mode Rejection DC
2.5V
REF
+
V
CC
, REF
= GND,
q
130
140
dB
GND
IN
= IN
+
V
CC
(Note 5)
Input Common Mode Rejection
2.5V
REF
+
V
CC
, REF
= GND,
q
140
dB
49Hz to 61.2Hz
GND
IN
= IN
+
V
CC
, (Notes 5, 7)
Input Normal Mode Rejection
(Note 5, 7)
q
87
dB
49Hz to 61.2Hz
Reference Common Mode
2.5V
REF
+
V
CC
, GND
REF
2.5V,
q
130
140
dB
Rejection DC
V
REF
= 2.5V, IN
= IN
+
= GND (Note 5)
Power Supply Rejection, DC
REF
+
= 2.5V, REF
= GND, IN
= IN
+
= GND
120
dB
Power Supply Rejection,
REF
+
= 2.5V, REF
= GND, IN
= IN
+
= GND, (Note 7)
120
dB
Simultaneous 50Hz/60Hz
2%
CO VERTER CHARACTERISTICS
U
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A ALOG I PUT A D REFERE CE
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LTC2433-1
4
24331fa
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
CC
Supply Voltage
q
2.7
5.5
V
I
CC
Supply Current
Conversion Mode
CS = 0V (Note 14)
q
200
300
A
Sleep Mode
CS = V
CC
(Notes 11, 14)
q
4
13
A
Sleep Mode
CS = V
CC
, 2.7V
V
CC
3.3V
2
A
(Notes 11, 14)
The
q
denotes specifications which apply over the full operating temperature range,
otherwise specifications are at T
A
= 25
C. (Note 3)
The
q
denotes specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25
C. (Note 3)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
IH
High Level Input Voltage
2.7V
V
CC
5.5V
q
2.5
V
CS, F
O
2.7V
V
CC
3.3V
2.0
V
V
IL
Low Level Input Voltage
4.5V
V
CC
5.5V
q
0.8
V
CS, F
O
2.7V
V
CC
5.5V
0.6
V
V
IH
High Level Input Voltage
2.7V
V
CC
5.5V (Note 8)
q
2.5
V
SCK
2.7V
V
CC
3.3V (Note 8)
2.0
V
V
IL
Low Level Input Voltage
4.5V
V
CC
5.5V (Note 8)
q
0.8
V
SCK
2.7V
V
CC
5.5V (Note 8)
0.6
V
I
IN
Digital Input Current
0V
V
IN
V
CC
q
10
10
A
CS, F
O
I
IN
Digital Input Current
0V
V
IN
V
CC
(Note 8)
q
10
10
A
SCK
C
IN
Digital Input Capacitance
10
pF
CS, F
O
C
IN
Digital Input Capacitance
(Note 8)
10
pF
SCK
V
OH
High Level Output Voltage
I
O
= 800
A
q
V
CC
0.5
V
SDO
V
OL
Low Level Output Voltage
I
O
= 1.6mA
q
0.4
V
SDO
V
OH
High Level Output Voltage
I
O
= 800
A (Note 9)
q
V
CC
0.5
V
SCK
V
OL
Low Level Output Voltage
I
O
= 1.6mA (Note 9)
q
0.4
V
SCK
I
OZ
Hi-Z Output Leakage
q
10
10
A
SDO
POWER REQUIRE E TS
W
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DIGITAL I PUTS A D DIGITAL OUTPUTS
U
U
LTC2433-1
5
24331fa
Note 9: The converter is in internal SCK mode of operation such that
the SCK pin is used as digital output. In this mode of operation the
SCK pin has a total equivalent load capacitance C
LOAD
= 20pF.
Note 10: The external oscillator is connected to the F
O
pin. The external
oscillator frequency, f
EOSC
, is expressed in kHz.
Note 11: The converter uses the internal oscillator.
F
O
= 0V.
Note 12: 1.45
V RMS noise is independent of V
REF
. Since the noise
performance is limited by the quantization, lowering V
REF
improves the
effective resolution.
Note 13: Guaranteed by design and test correlation.
Note 14: The low sleep mode current is valid only when CS is high.
Note 15: These parameters are guaranteed by design over the full
supply and temperature range. Automated testing procedures are
limited by the LSB step size (V
REF
/65,536).
Note 1: Absolute Maximum Ratings are those values beyond which the
life of the device may be impaired.
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; V
IN
= IN
+
IN
,
V
INCM
= (IN
+
+ IN
)/2.
Note 4: F
O
pin tied to GND or to an external conversion clock source
with f
EOSC
= 139,800Hz 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 precise analog input voltage. Maximum specifications are limited by
the LSB step size (V
REF
/2
16
) and the single shot measurement. Typical
specifications are measured from the center of the quantization band.
Note 7: F
O
= GND (internal oscillator) or f
EOSC
= 139,800Hz
2%
(external oscillator).
Note 8: The converter is in external SCK mode of operation such that
the SCK pin is used as digital input. The frequency of the clock signal
driving SCK during the data output is f
ESCK
and is expressed in kHz.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
f
EOSC
External Oscillator Frequency Range
q
2.56
2000
kHz
t
HEO
External Oscillator High Period
q
0.25
390
s
t
LEO
External Oscillator Low Period
q
0.25
390
s
t
CONV
Conversion Time
F
O
= 0V
q
143.8
146.7
149.6
ms
External Oscillator (Note 10)
q
20510/f
EOSC
(in kHz)
ms
f
ISCK
Internal SCK Frequency
Internal Oscillator (Note 9)
17.5
kHz
External Oscillator (Notes 9, 10)
f
EOSC
/8
kHz
D
ISCK
Internal SCK Duty Cycle
(Note 9)
q
45
55
%
f
ESCK
External SCK Frequency Range
(Note 8)
q
2000
kHz
t
LESCK
External SCK Low Period
(Note 8)
q
250
ns
t
HESCK
External SCK High Period
(Note 8)
q
250
ns
t
DOUT_ISCK
Internal SCK 19-Bit Data Output Time
Internal Oscillator (Notes 9, 11)
q
1.06
1.09
1.11
ms
External Oscillator (Notes 9, 10)
q
152/f
EOSC
(in kHz)
ms
t
DOUT_ESCK
External SCK 19-Bit Data Output Time
(Note 8)
q
19/f
ESCK
(in kHz)
ms
t
1
CS
to SDO Low Z
q
0
200
ns
t2
CS
to SDO High Z
q
0
200
ns
t3
CS
to SCK
(Note 9)
q
0
200
ns
t4
CS
to SCK
(Note 8)
q
50
ns
t
KQMAX
SCK
to SDO Valid
q
220
ns
t
KQMIN
SDO Hold After SCK
(Note 5)
q
15
ns
t
5
SCK Set-Up Before CS
q
50
ns
t
6
SCK Hold After CS
q
50
ns
The
q
denotes specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25
C. (Note 3)
TI I G CHARACTERISTICS
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