FEATURES
s
s
LTC2411/LTC2411-1
24-Bit No Latency
∆Σ
TM
ADC
with Differential Input and
Reference in MSOP
DESCRIPTIO
The LTC
®
2411/LTC2411-1 are 2.7V to 5.5V micropower
24-bit differential
∆Σ
analog-to-digital converters with an
integrated oscillator, 2ppm INL and 0.29ppm RMS noise.
They use delta-sigma technology and provide single cycle
settling time for multiplexed applications. Through a
single pin, the LTC2411 can be configured for better than
110dB differential mode rejection at 50Hz or 60Hz
±2%,
and the LTC2411-1 can provide better than 87dB input
differential mode rejection over the range of 49Hz to
61.2Hz, or they can be driven by an external oscillator for
a user-defined rejection frequency. The LTC2411 and
LTC2411-1 are identical when driven by an external
oscillator. The internal oscillator requires no external
frequency setting components.
The converters accept 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 – 0.5V
REF
to 0.5V
REF
.
The reference common mode voltage, V
REFCM
, and the
input common mode voltage, V
INCM
, may be indepen-
dently set anywhere within the GND to V
CC
range of the
LTC2411/LTC2411-1. The DC common mode input rejec-
tion is better than 140dB.
The LTC2411/LTC2411-1 communicate through a flexible
3-wire digital interface that is compatible with SPI and
MICROWIRE
TM
protocols.
, LTC and LT are registered trademarks of Linear Technology Corporation.
No Latency
∆Σ
is a trademark of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corporation.
s
s
s
s
s
s
s
s
s
24-Bit ADC in an MS10 Package
Low Supply Current (200µA in Conversion Mode
and 4µA in Autosleep Mode)
Differential Input and Differential Reference
with GND to V
CC
Common Mode Range
2ppm INL, No Missing Codes
4ppm Full-Scale Error and 1ppm Offset
0.29ppm Noise
No Latency: Digital Filter Settles in a Single Cycle.
Each Conversion Is Accurate, Even After an
Input Step
Single Supply 2.7V to 5.5V Operation
Internal Oscillator—No External Components
Required
110dB Min, Pin Selectable 50Hz/60Hz Notch Filter
(LTC2411)
Simultaneous 50Hz/60Hz Rejection (LTC2411-1)
APPLICATIO S
s
s
s
s
s
s
s
s
s
Direct Sensor Digitizer
Weight Scales
Direct Temperature Measurement
Gas Analyzers
Strain Gauge Transducers
Instrumentation
Data Acquisition
Industrial Process Control
6-Digit DVMs
TYPICAL APPLICATIO
2.7V TO 5.5V
1µF
1
V
CC
F
O
10
LTC2411/
LTC2411-1
REFERENCE
VOLTAGE
0.1V TO V
CC
ANALOG INPUT RANGE
–0.5V
REF
TO 0.5V
REF
2
3
4
5
6
REF
+
REF
–
IN
+
IN
–
GND
2411 TA01
V
CC
= INTERNAL OSC/50Hz REJECTION (LTC2411)
= EXTERNAL CLOCK SOURCE
= INTERNAL OSC/60Hz REJECTION (LTC2411)
= SIMULTANEOUS 50Hz/60Hz REJECTION (LTC2411-1)
BRIDGE
IMPEDANCE
100Ω TO 10kΩ
4
5
SCK
9
3-WIRE
SPI INTERFACE
SDO
CS
8
7
U
U
U
V
CC
1µF
2
IN
1
REF
+
V
CC
+
9 SCK
8 SDO
7 CS
F
O
10
2411 TA02
IN
–
3
LTC2411/
LTC2411-1
3-WIRE
SPI
INTERFACE
REF
–
GND
6
1
LTC2411/LTC2411-1
ABSOLUTE
(Notes 1, 2)
AXI U
RATI GS
PACKAGE/ORDER I FOR ATIO
Supply Voltage (V
CC
) to GND .......................– 0.3V to 7V
Analog Input Pins Voltage
to GND .................................... – 0.3V to (V
CC
+ 0.3V)
Reference Input Pins 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
LTC2411C ............................................... 0°C to 70°C
LTC2411I ............................................ – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART NUMBER
TOP VIEW
V
CC
REF
+
REF
–
IN
+
IN
–
1
2
3
4
5
10
9
8
7
6
F
O
SCK
SDO
CS
GND
LTC2411CMS
LTC2411IMS
LTC2411-1CMS
LTC2411-1IMS
MS10 PART MARKING
LTNS
LTNT
LTWV
LTNN
MS10 PACKAGE
10-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 120°C/W
Consult LTC Marketing for parts specified with wider operating temperature
ranges.
ELECTRICAL CHARACTERISTICS
PARAMETER
Resolution (No Missing Codes)
Integral Nonlinearity
CONDITIONS
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Notes 3, 4)
MIN
q
q
q
TYP
1
2
6
5
20
MAX
UNITS
Bits
ppm of V
REF
ppm of V
REF
ppm of V
REF
µV
nV/°C
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
+
= 0.75REF
+
, IN
–
= 0.25 • REF
+
2.5V
≤
REF
+
≤
V
CC
, REF
–
= GND,
IN
+
= 0.75REF
+
, 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)
24
14
20
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
q
4
0.04
12
ppm of V
REF
ppm of V
REF
/°C
q
4
0.04
3
3
6
1.45
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
2
U
W
U
U
W W
W
LTC2411/LTC2411-1
CO VERTER CHARACTERISTICS
PARAMETER
Input Common Mode Rejection DC
Input Common Mode Rejection
60Hz
±2%
(LTC2411)
Input Common Mode Rejection
50Hz
±2%
(LTC2411)
Input Common Mode Rejection
49Hz to 61.2Hz (LTC2411-1)
Input Normal Mode Rejection
60Hz
±2%
(LTC2411)
Input Normal Mode Rejection
50Hz
±2%
(LTC2411)
Input Normal Mode Rejection
49Hz to 61.2Hz (LTC2411-1)
Reference Common Mode
Rejection DC
Power Supply Rejection, DC
CONDITIONS
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Notes 3, 4)
MIN
q
q
q
q
q
q
q
q
Power Supply Rejection, 60Hz
±2%
REF
+
= 2.5V, REF
–
= GND, IN
–
= IN
+
= GND, (Note 7)
(LTC2411)
Power Supply Rejection, 50Hz
±2%
REF
+
= 2.5V, REF
–
= GND, IN
–
= IN
+
= GND, (Note 8)
(LTC2411)
Power Supply Rejection,
49Hz to 61.2Hz (LTC2411-1)
REF
+
= 2.5V, REF
–
= GND, IN
–
= IN
+
= GND, (Note 15)
A ALOG I PUT A D REFERE CE
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
The
q
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
CONDITIONS
q
q
q
q
q
q
U
U
U
U
TYP
140
MAX
UNITS
dB
dB
dB
dB
2.5V
≤
REF
+
≤
V
CC
, REF
–
= GND,
GND
≤
IN
–
= IN
+
≤
5V
2.5V
≤
REF
+
≤
V
CC
, REF
–
= GND,
GND
≤
IN
–
= IN
+
≤
5V, (Note 7)
2.5V
≤
REF
+
≤
V
CC
, REF
–
= GND,
GND
≤
IN
–
= IN
+
≤
5V, (Note 8)
2.5V < REF
+
< V
CC
, REF
–
= GND,
GND < IN
–
= IN
+
< V
CC
(Note 15)
(Note 7)
(Note 8)
(Note 15)
2.5V
≤
REF
+
≤
V
CC
, GND
≤
REF
–
≤
2.5V,
V
REF
= 2.5V, IN
–
= IN
+
= GND
REF
+
= 2.5V, REF
–
= GND, IN
–
= IN
+
= GND
130
140
140
140
110
110
87
130
140
140
dB
dB
dB
140
110
120
120
120
dB
dB
dB
dB
dB
U
MIN
GND – 0.3V
GND – 0.3V
– V
REF
/2
0.1
GND
0.1
TYP
MAX
V
CC
+ 0.3V
V
CC
+ 0.3V
V
REF
/2
V
CC
V
CC
– 0.1V
V
CC
UNITS
V
V
V
V
V
V
pF
pF
pF
pF
6
6
6
6
CS = V
CC
= 5.5V, IN
+
= GND
CS = V
CC
= 5.5V, IN
–
= GND
CS = V
CC
= 5.5V, REF
+
= 5V
CS = V
CC
= 5.5V, REF
–
= GND
q
q
q
q
–10
–10
–10
–10
1
1
1
1
10
10
10
10
nA
nA
nA
nA
3
LTC2411/LTC2411-1
DIGITAL I PUTS A D DIGITAL OUTPUTS
SYMBOL
V
IH
V
IL
V
IH
V
IL
I
IN
I
IN
C
IN
C
IN
V
OH
V
OL
V
OH
V
OL
I
OZ
PARAMETER
High Level Input Voltage
CS, F
O
Low Level Input Voltage
CS, F
O
High Level Input Voltage
SCK
Low Level Input Voltage
SCK
Digital Input Current
CS, F
O
Digital Input Current
SCK
Digital Input Capacitance
CS, F
O
Digital Input Capacitance
SCK
High Level Output Voltage
SDO
Low Level Output Voltage
SDO
High Level Output Voltage
SCK
Low Level Output Voltage
SCK
Hi-Z Output Leakage
SDO
(Note 9)
I
O
= – 800µA
I
O
= 1.6mA
I
O
= – 800µA (Note 10)
I
O
= 1.6mA (Note 10)
q
q
q
q
q
The
q
denotes specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
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
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)
q
q
q
q
q
q
POWER REQUIRE E TS
SYMBOL
V
CC
I
CC
PARAMETER
Supply Voltage
Supply Current
Conversion Mode
Sleep Mode
Sleep Mode
The
q
denotes specifications which apply over the full operating temperature range,
otherwise specifications are at T
A
= 25°C. (Note 3)
CONDITIONS
q
4
U W
U
U
MIN
2.5
2.0
TYP
MAX
UNITS
V
V
0.8
0.6
2.5
2.0
0.8
0.6
–10
–10
10
10
V
CC
– 0.5V
0.4
V
CC
– 0.5V
0.4
–10
10
10
10
V
V
V
V
V
V
µA
µA
pF
pF
V
V
V
V
µA
MIN
2.7
TYP
MAX
5.5
UNITS
V
µA
µA
µA
CS = 0V (Note 12)
CS = V
CC
(Note 12)
CS = V
CC
, 2.7V
≤
V
CC
≤
3.3V (Note 12)
q
q
200
4
2
300
10
LTC2411/LTC2411-1
TI I G 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
F
O
= 0V (LTC2411)
F
O
= V
CC
(LTC2411)
F
O
= 0V (LTC2411-1)
External Oscillator (Note 11)
Internal Oscillator (LTC2411) (Note 10)
Internal Oscillator (LTC2411-1) (Note 10)
External Oscillator (Notes 10, 11)
(Note 10)
(Note 9)
(Note 9)
(Note 9)
Internal Oscillator (LTC2411) (Notes 10, 12)
Internal Oscillator (LTC2411-1) (Notes 10, 12)
External Oscillator (Notes 10, 11)
q
q
q
q
q
q
q
q
q
q
The
q
denotes specifications which apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. (Note 3)
CONDITIONS
q
q
q
q
q
q
q
f
ISCK
D
ISCK
f
ESCK
t
LESCK
t
HESCK
t
DOUT_ISCK
t
DOUT_ESCK
t
1
t2
t3
t4
t
KQMAX
t
KQMIN
t
5
t
6
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
= 2.7 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 V
CC
or to external conversion clock
source with f
EOSC
= 153600Hz 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:
F
O
= 0V (internal oscillator) or f
EOSC
= 153600Hz
±2%
(external oscillator).
UW
MIN
2.56
0.25
0.25
TYP
MAX
2000
390
390
UNITS
kHz
µs
µs
ms
ms
ms
ms
kHz
kHz
kHz
130.86
133.53
136.20
157.03
160.23
163.44
143.78
146.71
149.64
20510/f
EOSC
(in kHz)
19.2
17.5
f
EOSC
/8
45
250
250
1.64
1.80
1.67
1.70
1.83
1.86
256/f
EOSC
(in kHz)
32/f
ESCK
(in kHz)
0
0
0
50
220
15
50
50
200
200
200
55
2000
Internal SCK Frequency
Internal SCK Duty Cycle
External SCK Frequency Range
External SCK Low Period
External SCK High Period
Internal SCK 32-Bit Data Output Time
%
kHz
ns
ns
ms
ms
ms
ms
ns
ns
ns
ns
ns
ns
ns
ns
External SCK 32-Bit Data Output Time (Note 9)
CS
↓
to SDO Low Z
CS
↑
to SDO High Z
CS
↓
to SCK
↓
CS
↓
to SCK
↑
SCK
↓
to SDO Valid
SDO Hold After SCK
↓
SCK Set-Up Before CS
↓
SCK Hold After CS
↓
(Note 5)
(Note 10)
(Note 9)
q
q
q
q
q
q
Note 8:
F
O
= V
CC
(internal oscillator) or f
EOSC
= 128000Hz
±2%
(external oscillator).
Note 9:
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.
Note 10:
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 11:
The external oscillator is connected to the F
O
pin. The external
oscillator frequency, f
EOSC
, is expressed in kHz.
Note 12:
The converter uses the internal oscillator.
F
O
= 0V or F
O
= V
CC
.
Note 13:
The output noise includes the contribution of the internal
calibration operations.
Note 14:
Guaranteed by design and test correlation.
Note 15:
F
O
= 0V (internal oscillator) or f
EOSC
= 139800Hz
±2%
(external oscillator).
5
嵌入式系统
