FEATURES
n
LTC2415/LTC2415-1
24-Bit No Latency
∆Σ
™
ADCs with Differential Input and
Differential Reference
DESCRIPTION
The
LTC
®
2415/2415-1
are micropower 24-bit differential
∆Σ analog to digital converters with integrated oscillator,
2ppm INL, 0.23ppm RMS noise and a 2.7V to 5.5V supply
range. They use delta-sigma technology and provide single
cycle settling time for multiplexed applications. Through a
single pin, the LTC2415 can be configured for better than
110dB input differential mode rejection at 50Hz or 60Hz
±2%, or it can be driven by an external oscillator for a
user defined rejection frequency. The LTC2415-1 can be
configured for better than 87dB input differential mode
rejection over the range of 49Hz to 61.2Hz (50Hz and 60Hz
±2% simultaneously). 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 re-
mote 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 independently set
anywhere within the GND to V
CC
range of the LTC2415/
LTC2415-1. The DC common mode input rejection is
better than 140dB.
The LTC2415/LTC2415-1 communicate through a flexible
3-wire digital interface which is compatible with SPI and
MICROWIRE protocols.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and C-Load
and No Latency
∆Σ
are trademarks of Linear Technology Corporation. All other trademarks are
the property of their respective owners.
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2× Speed Up Version of the LTC2410/LTC2413:
15Hz Output Rate, 50Hz or 60Hz Notch—LTC2415;
13.75Hz Output Rate, Simultaneous 50Hz/60Hz
Notch—LTC2415-1
Differential Input and Differential Reference with
GND to V
CC
Common Mode Range
2ppm INL, No Missing Codes
2.5ppm Gain Error
0.23ppm Noise
Single Conversion Settling Time for Multiplexed
Applications
Internal Oscillator—No External Components
Required
24-Bit ADC in Narrow SSOP-16 Package
(SO-8 Footprint)
Single Supply 2.7V to 5.5V Operation
Low Supply Current (200µA) and Auto
Shutdown
APPLICATIONS
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Direct Sensor Digitizer
Weight Scales
Direct Temperature Measurement
Gas Analyzers
Strain Gage Transducers
Instrumentation
Data Acquisition
Industrial Process Control
6-Digit DVMs
TYPICAL APPLICATION
2.7V TO 5.5V
1µF
2
V
CC
F
O
14
V
CC
V
CC
= INTERNAL OSC/50Hz REJECTION (LTC2415)
= EXTERNAL CLOCK SOURCE
= INTERNAL OSC/60Hz REJECTION (LTC2415)
= INTERNAL 50Hz/60Hz REJECTION (LTC2415-1)
BRIDGE
IMPEDANCE
100 TO 10k
3-WIRE
SPI INTERFACE
5
6
1µF
LTC2415/
LTC2415-1
REFERENCE
VOLTAGE
0.1V TO V
CC
ANALOG INPUT RANGE
–0.5V
REF
TO 0.5V
REF
3
4
5
6
REF
+
REF
–
IN
+
IN
–
GND
SDO
CS
12
11
SCK
13
3
IN
4
2
REF
+
V
CC
+
12 SDO
13 SCK
11 CS
F
O
14
2415 TA02
IN
–
LTC2415/
LTC2415-1
3-WIRE
SPI INTERFACE
REF
–
GND
1, 7, 8
9, 10,
15, 16
1, 7, 8, 9, 10, 15, 16
2415 TA01
2415fa
For more information
www.linear.com/LTC2415
1
LTC2415/LTC2415-1
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
GND
V
CC
REF
+
REF
–
IN
+
IN
–
GND
GND
1
2
3
4
5
6
7
8
16 GND
15 GND
14 F
O
13 SCK
12 SDO
11
CS
10 GND
9
GND
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
LTC2415C/LTC2415-1C ............................ 0°C to 70°C
LTC2415I/LTC2415-1I ..........................–40°C to 85°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
GN PACKAGE
16-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 95°C/W
ORDER INFORMATION
LEAD FREE FINISH
LTC2415CGN#PBF
LTC2415IGN#PBF
LTC2415-1CGN#PBF
LTC2415-1IGN#PBF
TAPE AND REEL
LTC2415CGN#TRPBF
LTC2415IGN#TRPBF
LTC2415-1CGN#TRPBF
LTC2415-1IGN#TRPBF
PART MARKING
2415
2415I
24151
24151I
PACKAGE DESCRIPTION
16-Lead Plastic SSOP
16-Lead Plastic SSOP
16-Lead Plastic SSOP
16-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.
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/
ELECTRICAL CHARACTERISTICS
PARAMETER
Resolution (No Missing Codes)
Integral Nonlinearity
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
1
2
5
0.5
20
MAX
UNITS
Bits
ppm of V
REF
ppm of V
REF
ppm of V
REF
mV
nV/°C
0.1V ≤ V
REF
≤ V
CC
, –0.5 • V
REF
≤ V
IN
≤ 0.5 • V
REF
, (Note 5)
24
14
2
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
+
●
●
●
Offset Error
Offset Error Drift
Positive Gain Error
Positive Gain Error Drift
Negative Gain Error
2.5
0.03
2.5
12
ppm of V
REF
ppm of V
REF
/°C
12
ppm of V
REF
2415fa
2
For more information
www.linear.com/LTC2415
LTC2415/LTC2415-1
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
Negative Gain Error Drift
Output Noise
CONDITIONS
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
IN
+
= 0.25 • REF
+
, IN
–
= 0.75 • REF
+
5V ≤ V
CC
≤ 5.5V, REF
+
= 5V, REF
–
= GND,
GND ≤ IN
–
= IN
+
≤ V
CC
, (Note 13)
MIN
TYP
0.03
1.1
MAX
UNITS
ppm of V
REF
/°C
µV
RMS
ELECTRICAL CHARACTERISTICS
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
Input Common Mode Rejection DC
Input Common Mode Rejection
60Hz ±2% (LTC2415)
Input Common Mode Rejection
50Hz ±2% (LTC2415)
Input Normal Mode Rejection
60Hz ±2% (LTC2415)
Input Normal Mode Rejection
50Hz ±2% (LTC2415)
Input Common Mode Rejection
49Hz to 61.2Hz (LTC2415-1)
Input Normal Mode Rejection
49Hz to 61.2Hz (LTC2415-1)
Input Normal Mode Rejection
External Clock f
EOSC
/2560 ±14%
(LTC2415-1)
Input Normal Mode Rejection
External Clock f
EOSC
/2560 ±4%
(LTC2415-1)
Reference Common Mode
Rejection DC
Power Supply Rejection, DC
CONDITIONS
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
GND ≤ IN
–
= IN
+
≤ V
CC
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
GND ≤ IN
–
= IN
+
≤ V
CC
, (Note 7)
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
GND ≤ IN
–
= IN
+
≤ V
CC
, (Note 8)
(Note 7)
(Note 8)
2.5V ≤ REF
+
≤ V
CC
, REF
–
= GND,
F
O
= GND
External Oscillator
l
l
l
l
l
l
l
l
CONVERTER CHARACTERISTICS
MIN
130
140
140
110
110
140
87
87
TYP
140
MAX
UNITS
dB
dB
dB
140
140
dB
dB
dB
dB
dB
External Oscillator
2.5V ≤ REF
+
≤ V
CC
, GND ≤ REF
–
≤ 2.5V,
V
REF
= 2.5V, IN
–
= IN
+
= GND
REF
+
= V
CC
, REF
–
= GND, IN
–
= IN
+
= GND
l
110
140
dB
l
130
140
100
120
120
dB
dB
dB
dB
Power Supply Rejection, 60Hz ±2% REF
+
= 2.5V, REF
–
= GND, IN
–
= IN
+
= GND, (Note 7)
Power Supply Rejection, 50Hz ±2% REF
+
= 2.5V, REF
–
= GND, IN
–
= IN
+
= GND, (Note 8)
ANALOG INPUT AND REFERENCE
SYMBOL
IN
+
IN
–
V
IN
REF
+
REF
–
V
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
–
)
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
MIN
●
GND – 0.3V
●
GND – 0.3V
●
●
●
●
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
2415fa
–V
REF
/2
0.1
GND
0.1
For more information
www.linear.com/LTC2415
3
LTC2415/LTC2415-1
ANALOG INPUT AND REFERENCE
SYMBOL
C
S
(IN
+
)
C
S
(IN
–
)
C
S
(REF
+
)
C
S
(REF
–
)
I
DC_LEAK
(IN
+
)
I
DC_LEAK
(IN
–
)
PARAMETER
IN
+
Sampling Capacitance
IN
–
Sampling Capacitance
REF
+
Sampling Capacitance
REF
–
Sampling Capacitance
IN
+
DC Leakage Current
IN
–
DC Leakage Current
CS
= V
CC
, IN
+
= GND
CS
= V
CC
, IN
–
= GND
CS
= V
CC
, REF
+
= 5V
CS
= V
CC
, REF
–
= GND
●
●
●
●
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
MIN
TYP
18
18
18
18
–10
–10
–10
–10
1
1
1
1
10
10
10
10
MAX
UNITS
pF
pF
pF
pF
nA
nA
nA
nA
I
DC_LEAK
(REF
+
) REF
+
DC Leakage Current
I
DC_LEAK
(REF
–
) REF
–
DC Leakage Current
The
l
denotes the specifications which apply
over the full operating temperature range, otherwise specifications are at T
A
= 25°C. (Notes 3)
SYMBOL PARAMETER
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
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
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)
●
●
●
●
●
●
DIGITAL INPUTS AND DIGITAL OUTPUTS
MIN
2.5
2.0
TYP
MAX
UNITS
V
V
V
V
V
V
V
V
µA
µA
pF
pF
V
0.8
0.6
2.5
2.0
0.8
0.6
10
10
10
–10
–10
(Note 9)
I
O
= –800µA
I
O
= 1.6mA
I
O
= –800µA (Note 10)
I
O
= 1.6mA (Note 10)
●
●
●
●
●
10
V
CC
– 0.5
0.4
V
CC
– 0.5
0.4
–10
10
V
V
V
µA
POWER REQUIREMENTS
SYMBOL PARAMETER
V
CC
I
CC
Supply Voltage
Supply Current
Conversion Mode
Sleep Mode
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
CONDITIONS
l
MIN
2.7
TYP
MAX
5.5
UNITS
V
µA
µA
2415fa
CS
= 0V (Note 12)
CS
= V
CC
(Note 12)
l
l
200
20
300
30
4
For more information
www.linear.com/LTC2415
LTC2415/LTC2415-1
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 (LTC2415)
F
O
= 0V
F
O
= V
CC
External Oscillator (Note 11)
F
O
= 0V
External Oscillator (Note 11)
Internal Oscillator (Note 10), LTC2415
Internal Oscillator (Note 10), LTC2415-1
External Oscillator (Notes 10, 11)
(Note 10)
(Note 9)
(Note 9)
(Note 9)
Internal Oscillator (Notes 10, 12), LTC2415
Internal Oscillator (Notes 10, 12), LTC2415-1
External Oscillator (Notes 10, 11)
(Note 9)
l
l
l
l
l
l
l
l
l
l
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
l
l
l
l
l
l
l
l
MIN
2.56
0.25
0.25
65.43
78.52
71.3
TYP
MAX
500
390
390
UNITS
kHz
µs
µs
ms
ms
ms
ms
ms
kHz
kHz
kHz
66.77
68.1
80.12
81.72
10278/f
EOSC
(in kHz)
72.8
74.3
10278/f
EOSC
(in kHz)
19.2
17.5
f
EOSC
/8
Conversion Time (LTC2415-1)
f
ISCK
D
ISCK
f
ESCK
t
LESCK
t
HESCK
Internal SCK Frequency
Internal SCK Duty Cycle
External SCK Frequency Range
External SCK Low Period
External SCK High Period
45
250
250
1.64
1.80
55
2000
%
kHz
ns
ns
t
DOUT_ISCK
Internal SCK 32-Bit Data Output Time
t
DOUT_ESCK
External SCK 32-Bit Data Output Time
t
1
t2
t3
t4
t
KQMAX
t
KQMIN
t
5
t
6
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
↓
1.67
1.70
1.83
1.86
256/f
EOSC
(in kHz)
32/f
ESCK
(in kHz)
200
200
200
220
ms
ms
ms
ms
ns
ns
ns
ns
ns
ns
ns
0
0
0
50
15
50
(Note 10)
(Note 9)
(Note 5)
l
l
l
l
l
l
50
ns
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
= 2.7 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).
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:
Refer to Offset Accuracy and Drift in the Applications Information
section.
2415fa
For more information
www.linear.com/LTC2415
5
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