LINEAR TECHNOLOGY LTC2495 Technical data

LTC2495

1

2495f

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

16-Bit 8-/16-Channel

ΔΣ

ADC with PGA, Easy Drive

and I

2

C Interface

The LTC®2495 is a 16-channel (eight differential), 16-bit,
No Latency ΔΣ

TM

ADC with Easy Drive technology and a

2-wire, I

2

C interface. The patented sampling scheme elimi­nates dynamic input current errors and the shortcomings
of on-chip buffering through automatic cancellation of
differential input current. This allows large external source
impedances and rail-to-rail input signals to be directly
digitized while maintaining exceptional DC accuracy.

The LTC2495 includes programmable gain, a high accuracy
temperature sensor, and an integrated oscillator. This device
can be confi gured to measure an external signal (from com­binations of 16 analog input channels operating in single­ended or differential modes) or its internal temperature
sensor. The integrated temperature sensor offers 1/2°C
resolution and 2°C absolute accuracy. The LTC2495 can
be confi gured to provide a programmable gain from 1 to
256 in 8 steps.

The LTC2495 allows a wide common mode input range
(0V to V

CC

), independent of the reference voltage. Any
combination of single-ended or differential inputs can
be selected and the fi rst conversion, after a new channel
is selected, is valid. Access to the multiplexer output en­ables optional external amplifi ers to be shared between all
analog inputs and auto calibration continuously removes
their associated offset and drift.

Data Acquisition System with Temperature Compensation

■

Up to Eight Differential or 16 Single-Ended Inputs

■

Easy DriveTM Technology Enables Rail-to-Rail

Inputs with Zero Differential Input Current

■

Directly Digitizes High Impedance Sensors with

Full Accuracy

■

2-Wire I2C Interface with 27 Addresses Plus One

Global Address for Synchronization

■

600nV RMS Noise

■

Programmable Gain from 1 to 256

■

Integrated High Accuracy Temperature Sensor

■

GND to VCC Input/Reference Common Mode Range

■

Programmable 50Hz, 60Hz, or Simultaneous 50Hz/

60Hz Rejection Mode

■

2ppm INL, No Missing Codes

■

1ppm Offset and 15ppm Full-Scale Error

■

2x Speed/Reduced Power Mode (15Hz Using Internal

Oscillator and 80µA at 7.5Hz Output)

■

No Latency: Digital Filter Settles in a Single Cycle,

Even After a New Channel is Selected

■

Single Supply 2.7V to 5.5V Operation (0.8mW)

■

Internal Oscillator

■

Tiny 5mm × 7mm QFN Package

■

Direct Sensor Digitizer

■

Direct Temperature Measurement

■

Instrumentation

■

Industrial Process Control

Built-In High Performance Temperature Sensor

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
No Latency ∆Σ and Easy Drive are trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.

SCL

SDA

F

O

REF

+

V

CC

MUXOUT/
ADCIN

MUXOUT/
ADCIN

2.7V TO 5.5V

10µF

1.7k

COM

REF

–

16-BIT ∆Σ ADC

WITH EASY DRIVE

16-CHANNEL

MUX

TEMPERATURE

SENSOR

IN

+

IN

–

2495 TA01

2-WIRE
I

2

C INTERFACE

CH0
CH1

•

•

•

•

•

•

CH7
CH8

CH15

0.1µF

OSC

TEMPERATURE (°C)

–55 –30 –5

ABSOLUTE ERROR (°C)

5

4

3

2

1

–4

–3

–2

–1

0

12095704520

2495 TA02

–5

LTC2495

2

2495f

PACKAGE/ORDER INFORMATIONABSOLUTE MAXIMUM RATINGS

Supply Voltage (VCC) ................................... –0.3V to 6V

Analog Input Voltage

(CH0-CH15, COM) ....................–0.3V to (V

CC

+ 0.3V)

REF

+

, REF– ...............................–0.3V to (V

CC

+ 0.3V)

ADCINN, ADCINP, MUXOUTP,

MUXOUTN ................................–0.3V to (V

CC

+ 0.3V)

Digital Input Voltage ......................–0.3V to (V

CC

+ 0.3V)

Digital Output Voltage ...................–0.3V to (V

CC

+ 0.3V)
Operating Temperature Range

LTC2495C .................................................0ºC to 70ºC

LTC2495I ..............................................–40ºC to 85ºC

Storage Temperature Range ....................–65ºC to 150ºC

(Notes 1, 2)

13 14 15 16

TOP VIEW

39

UHF PACKAGE

38-LEAD (5mm × 7mm) PLASTIC QFN

17 18 19

38 37 36 35 34 33 32

24

25

26

27

28

29

30

31

8

7

6

5

4

3

2

1GND

SCL

SDA

GND

NC

GND

COM

CH0

CH1

CH2

CH3

CH4

GND

REF

–

REF

+

V

CC

MUXOUTN

ADCINN

ADCINP

MUXOUTP

CH15

CH14

CH13

CH12

CA2

CA1

CA0

FOGND

GND

GND

CH5

CH6

CH7

CH8

CH9

CH10

CH11

23

22

21

20

9

10

11

12

T

JMAX

= 125°C, θJA = 34°C/W

EXPOSED PAD (PIN #39) IS GND, MUST BE SOLDERED TO PCB

ORDER PART NUMBER QFN PART MARKING*

LTC2495CUHF
LTC2495IUHF

2495

Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/

Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
*The temperature grade is defi ned by a label on the shipping container.

LTC2495

3

2495f

ELECTRICAL CHARACTERISTICS (NORMAL SPEED)

The ● denotes the specifi cations which
apply over the full operating temperature range, otherwise specifi cations are at T

A

= 25°C. (Notes 3, 4)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Resolution (No Missing Codes) 0.1V ≤ V

REF

≤ VCC, –FS ≤ VIN ≤ +FS (Note 5) 16 Bits

Integral Nonlinearity 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
1

20 ppm of V

REF

ppm of V

REF

Offset Error 2.5V ≤ V

REF

≤ VCC, GND ≤ IN+ = IN– ≤ VCC (Note 13)

●

0.5 5 µV

Offset Error Drift 2.5V ≤ V

REF

≤ VCC, GND ≤ IN+ = IN– ≤ V

CC

10 nV/°C

Positive Full-Scale Error 2.5V ≤ V

REF

≤ VCC, IN+ = 0.75V

REF

, IN– = 0.25V

REF

●

32 ppm of V

REF

Positive Full-Scale Error Drift 2.5V ≤ V

REF

≤ VCC, IN+ = 0.75V

REF

, IN– = 0.25V

REF

0.1 ppm of V

REF

/°C

Negative Full-Scale Error 2.5V ≤ V

REF

≤ VCC, IN+ = 0.25V

REF

, IN– = 0.75V

REF

●

32 ppm of V

REF

Negative Full-Scale Error Drift 2.5V ≤ V

REF

≤ VCC, IN+ = 0.25V

REF

, IN– = 0.75V

REF

0.1 ppm of V

REF

/°C

Total Unadjusted Error 5V ≤ V

CC

≤ 5.5V, V

REF

= 2.5V, V

IN(CM)

= 1.25V

5V ≤ V

CC

≤ 5.5V, V

REF

= 5V, V

IN(CM)

= 2.5V

2.7V ≤ V

CC

≤ 5.5V, V

REF

= 2.5V, V

IN(CM)

= 1.25V

15
15
15

ppm of V

REF

ppm of V

REF

ppm of V

REF

Output Noise 2.7V < VCC < 5.5V, 2.5V ≤ V

REF

≤ VCC,

GND ≤ IN

+

= IN– ≤ VCC (Note 12)

0.6 µV

RMS

Internal PTAT Signal TA = 27°C (Note 13) 27.8 28.0 28.2 mV
Internal PTAT Temperature Coeffi cient 93.5 µV/°C
Programmable Gain

●

1 256

ELECTRICAL CHARACTERISTICS (2X SPEED)

The ● denotes the specifi cations which apply over the
full operating temperature range, otherwise specifi cations are at T

A

= 25°C. (Notes 3, 4)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Resolution (No Missing Codes) 0.1V ≤ V

REF

≤ VCC, –FS ≤ VIN ≤ +FS (Note 5) 16 Bits

Integral Nonlinearity 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
1

20 ppm of V

REF

ppm of V

REF

Offset Error 2.5V ≤ V

REF

≤ VCC, GND ≤ IN+ = IN– ≤ VCC (Note 13)

●

0.2 2 mV

Offset Error Drift 2.5V ≤ V

REF

≤ VCC, GND ≤ IN+ = IN– ≤ V

CC

100 nV/°C

Positive Full-Scale Error 2.5V ≤ V

REF

≤ VCC, IN+ = 0.75V

REF

, IN– = 0.25V

REF

●

32 ppm of V

REF

Positive Full-Scale Error Drift 2.5V ≤ V

REF

≤ VCC, IN+ = 0.75V

REF

, IN– = 0.25V

REF

0.1 ppm of V

REF

/°C

Negative Full-Scale Error 2.5V ≤ V

REF

≤ VCC, IN+ = 0.25V

REF

, IN– = 0.75V

REF

●

32 ppm of V

REF

Negative Full-Scale Error Drift 2.5V ≤ V

REF

≤ VCC, IN+ = 0.25V

REF

, IN– = 0.75V

REF

0.1 ppm of V

REF

/°C

Output Noise 5V ≤ V

CC

≤ 5.5V, V

REF

= 5V, GND ≤ IN+ = IN– ≤ V

CC

0.85 µV

RMS

Programmable Gain

●

1128

CONVERTER CHARACTERISTICS

The

●

denotes the specifi cations which apply over the full operating

temperature range, otherwise specifi cations are at T

A

= 25°C. (Note 3)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Input Common Mode Rejection DC 2.5V ≤ V

REF

≤ VCC, GND ≤ IN+ = IN– ≤ VCC (Note 5)

●

140 dB

Input Common Mode Rejection 50Hz ±2% 2.5V ≤ V

REF

≤ VCC, GND ≤ IN+ = IN– ≤ VCC (Notes 5, 7)

●

140 dB

Input Common Mode Rejection 60Hz ±2% 2.5V ≤ V

REF

≤ VCC, GND ≤ IN+ = IN– ≤ VCC (Notes 5, 8)

●

140 dB

Input Normal Mode Rejection 50Hz ±2% 2.5V ≤ V

REF

≤ VCC, GND ≤ IN+ = IN– ≤ VCC (Notes 5, 7)

●

110 120 dB

Input Normal Mode Rejection 60Hz ±2% 2.5V ≤ V

REF

≤ VCC, GND ≤ IN+ = IN– ≤ VCC (Notes 5, 8)

●

110 120 dB

Input Normal Mode Rejection 50Hz/60Hz ±2% 2.5V ≤ V

REF

≤ VCC, GND ≤ IN+ = IN– ≤ VCC (Notes 5, 9)

●

87 dB

Reference Common Mode Rejection DC 2.5V ≤ V

REF

≤ VCC, GND ≤ IN+ = IN– ≤ VCC (Note 5)

●

120 140 dB

Power Supply Rejection DC V

REF

= 2.5V, IN+ = IN– = GND 120 dB

Power Supply Rejection, 50Hz ±2%, 60Hz ±2% V

REF

= 2.5V, IN+ = IN– = GND (Notes 7, 8, 9) 120 dB

LTC2495

4

2495f

I2C INPUTS AND DIGITAL OUTPUTS

The

●

denotes the specifi cations which apply over the full

operating temperature range, otherwise specifi cations are at T

A

= 25°C. (Note 3)

ANALOG INPUT AND REFERENCE

The

●

denotes the specifi cations which apply over the full operating

temperature range, otherwise specifi cations are at T

A

= 25°C. (Note 3)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

IN

+

Absolute/Common Mode IN+ Voltage
(IN

+

Corresponds to the Selected Positive Input Channel)

GND – 0.3V V

CC

+ 0.3V V

IN

–

Absolute/Common Mode IN– Voltage
(IN

–

Corresponds to the Selected Negative Input Channel)

GND – 0.3V V

CC

+ 0.3V V

V

IN

Input Differential Voltage Range (IN+ – IN–)

●

–FS +FS V

FS Full Scale of the Differential Input (IN

+

– IN–)

●

0.5V

REF

/Gain V

LSB Least Signifi cant Bit of the Output Code

●

FS/2

16

REF

+

Absolute/Common Mode REF+ Voltage

●

0.1 V

CC

V

REF

–

Absolute/Common Mode REF– Voltage

●

GND REF+ – 0.1V V

V

REF

Reference Voltage Range (REF+ – REF–)

●

0.1 V

CC

V

CS(IN

+

)IN

+

Sampling Capacitance 11 pF

CS(IN

–

)IN

–

Sampling Capacitance 11 pF

CS(V

REF

)V

REF

Sampling Capacitance 11 pF

I

DC_LEAK(IN+)

IN+ DC Leakage Current Sleep Mode, IN+ = GND

●

–10 1 10 nA

I

DC_LEAK(IN–)

IN– DC Leakage Current Sleep Mode, IN– = GND

●

–10 1 10 nA

I

DC_LEAK(REF+)

REF+ DC Leakage Current Sleep Mode, REF+ = V

CC

●

–100 1 100 nA

I

DC_LEAK(REF–)

REF– DC Leakage Current Sleep Mode, REF– = GND

●

–100 1 100 nA

t

OPEN

MUX Break-Before-Make 50 ns

QIRR MUX Off Isolation V

IN

= 2V

P-P

DC to 1.8MHz 120 dB

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

IH

High Level Input Voltage

●

0.7V

CC

V

V

IL

Low Level Input Voltage

●

0.3V

CC

V

V

IHA

Low Level Input Voltage for Address Pins CA0, CA1, CA2

●

0.05V

CC

V

V

ILA

High Level Input Voltage for Address Pins CA0, CA1, CA2

●

0.95V

CC

V

R

INH

Resistance from CA0, CA1, CA2 to VCC to Set Chip
Address Bit to 1

●

10 kΩ

R

INL

Resistance from CA0, CA1, CA2 to GND to Set Chip
Address Bit to 0

●

10 kΩ

R

INF

Resistance from CA0, CA1, CA2 to GND or VCC to Set
Chip Address Bit to Float

●

2 MΩ

I

I

Digital Input Current (FO)

●

–10 10 µA

V

HYS

Hysteresis of Schmitt Trigger Inputs (Note 5)

●

0.05V

CC

V

V

OL

Low Level Output Voltage (SDA) I = 3mA

●

0.4 V

t

OF

Output Fall Time V

IH(MIN)

to V

IL(MAX)

Bus Load CB 10pF to
400pF (Note 14)

●

20 + 0.1C

B

250 ns

I

IN

Input Leakage (SDA/SCL) 0.1VCC ≤ VIN ≤ 0.9 • V

CC

●

1µA

C

CAX

External Capacitative Load on Chip Address Pins (CA0,
CA1, CA2) for Valid Float

●

10 pF

LTC2495

5

2495f

POWER REQUIREMENTS

The

●

denotes the specifi cations which apply over the full operating temperature

range, otherwise specifi cations are at T

A

= 25°C. (Note 3)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

CC

Supply Voltage

●

2.7 5.5 V

I

CC

Supply Current Conversion Current (Note 11)

Temperature Measurement (Note 11)
Sleep Mode (Note 11)

●

●

●

160
200

1

275
300

2

µA
µA
µA

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

f

EOSC

External Oscillator Frequency Range (Note 16)

●

10 4000 kHz

t

HEO

External Oscillator High Period

●

0.125 100 µs

t

LEO

External Oscillator Low Period

●

0.125 100 µs

t

CONV_1

Conversion Time for 1x Speed Mode 50Hz Mode

60Hz Mode
Simultaneous 50Hz/60Hz Mode
External Oscillator (Note 10)

●

●

●

157.2
131

144.1

160.3

133.6

146.9

41036/f

EOSC

(in kHz)

163.5

136.3

149.9

ms
ms
ms
ms

t

CONV_2

Conversion Time for 2x Speed Mode 50Hz Mode

60Hz Mode
Simultaneous 50Hz/60Hz Mode
External Oscillator (Note 10)

●

●

●

78.7

65.6

72.2

80.3

66.9

73.6

20556/f

EOSC

(in kHz)

81.9

68.2

75.1

ms
ms
ms
ms

DIGITAL INPUTS AND DIGITAL OUTPUTS

The

●

denotes the specifi cations which apply over the

full operating temperature range, otherwise specifi cations are at T

A

= 25°C. (Note 3)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

f

SCL

SCL Clock Frequency

●

0 400 kHz

t

HD(SDA)

Hold Time (Repeated) Start Condition

●

0.6 µs

t

LOW

Low Period of the SCL Pin

●

1.3 µs

t

HIGH

High Period of the SCL Pin

●

0.6 µs

t

SU(STA)

Set-Up Time for a Repeated Start Condition

●

0.6 µs

t

HD(DAT)

Data Hold Time

●

0 0.9 µs

t

SU(DAT)

Data Set-Up Time

●

100 ns

t

r

Rise Time for SDA Signals (Note 14)

●

20 + 0.1C

B

300 ns

t

f

Fall Time for SDA Signals (Note 14)

●

20 + 0.1C

B

300 ns

t

SU(STO)

Set-Up Time for Stop Condition

●

0.6 µs

t

BUF

Bus Free Time Between a Second Start Condition

●

1.3 µs

I2C TIMING CHARACTERISTICS

The

●

denotes the specifi cations which apply over the full operating

temperature range, otherwise specifi cations are at T

A

= 25°C. (Note 3, 15)

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: Unless otherwise specifi ed: V

CC

= 2.7V to 5.5V

V

REFCM

= V

REF

/2, FS = 0.5V

REF

/Gain

V

IN

= IN+ – IN–, V

IN(CM)

= (IN+ – IN–)/2,

where IN

+

and IN– are the selected input channels.

Note 4: Use internal conversion clock or external conversion clock source
with f

EOSC

= 307.2kHz unless otherwise specifi ed.

Note 5: Guaranteed by design, not subject to test.
Note 6: Integral nonlinearity is defi ned 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 F

O

pin. The external

oscillator frequency, f

EOSC

, is expressed in kHz.

Note 11: The converter uses its internal oscillator.
Note 12: The output noise includes the contribution of the internal

calibration operations.

Note 13: Guaranteed by design and test correlation.
Note 14: C

B

= capacitance of one bus line in pF (10pF ≤ CB ≤ 400pF).

Note 15: All values refer to V

IH(MIN)

and V

IL(MAX)

levels.

Note 16: Refer to Applications Information section for Performance vs
Data Rate graphs.

LTC2495

6

2495f

TYPICAL PERFORMANCE CHARACTERISTICS

Integral Nonlinearity
(V

CC

= 5V, V

REF

= 5V)

Integral Nonlinearity
(VCC = 5V, V

REF

= 2.5V)

Integral Nonlinearity
(V

CC

= 2.7V, V

REF

= 2.5V)

Total Unadjusted Error
(VCC = 5V, V

REF

= 5V)

Total Unadjusted Error
(V

CC

= 5V, V

REF

= 2.5V)

Total Unadjusted Error
(VCC = 2.7V, V

REF

= 2.5V)

Noise Histogram (6.8sps) Noise Histogram (7.5sps) Long-Term ADC Readings

INPUT VOLTAGE (V)

–3

INL (ppm of V

REF

)

–1

1

3

–2

0

2

–1.5 –0.5 0.5 1.5

2495 G01

2.5–2–2.5 –1 0 1 2

VCC = 5V
V

REF

= 5V

V

IN(CM)

= 2.5V

F

O

= GND

85°C

–45°C

25°C

INPUT VOLTAGE (V)

–3

INL (ppm of V

REF

)

–1

1

3

–2

0

2

–0.75 –0.25 0.25 0.75

2495 G02

1.25–1.25

VCC = 5V
V

REF

= 2.5V

V

IN(CM)

= 1.25V

F

O

= GND

–45°C, 25°C, 85°C

INPUT VOLTAGE (V)

–3

INL (ppm of V

REF

)

–1

1

3

–2

0

2

–0.75 –0.25 0.25 0.75

2495 G03

1.25–1.25

VCC = 2.7V
V

REF

= 2.5V

V

IN(CM)

= 1.25V

F

O

= GND

–45°C, 25°C, 85°C

INPUT VOLTAGE (V)

–12

TUE (ppm of V

REF

)

–4

4

12

–8

0

8

–1.5 –0.5 0.5 1.5

2495 G04

2.5–2–2.5 –1 0 1 2

VCC = 5V
V

REF

= 5V

V

IN(CM)

= 2.5V

F

O

= GND

85°C

25°C

–45°C

INPUT VOLTAGE (V)

–12

TUE (ppm of V

REF

)

–4

4

12

–8

0

8

–0.75 –0.25 0.25 0.75

2495 G05

1.25–1.25

VCC = 5V
V

REF

= 2.5V

V

IN(CM)

= 1.25V

F

O

= GND

85°C

25°C

–45°C

INPUT VOLTAGE (V)

–12

TUE (ppm of V

REF

)

–4

4

12

–8

0

8

–0.75 –0.25 0.25 0.75

2495 G06

1.25–1.25

VCC = 2.7V
V

REF

= 2.5V

V

IN(CM)

= 1.25V

F

O

= GND

85°C

25°C

–45°C

OUTPUT READING (µV)

–3

NUMBER OF READINGS (%)

8

10

12

0.6

2495 G07

6

4

–1.8 –0.6

–2.4 1.2

–1.2 0 1.8

2

0

14

10,000 CONSECUTIVE
READINGS
V

CC

= 5V

V

REF

= 5V

V

IN

= 0V

T

A

= 25°C

GAIN = 256

RMS = 0.60µV

AVERAGE = –0.69µV

OUTPUT READING (µV)

–3

NUMBER OF READINGS (%)

8

10

12

0.6

2495 G08

6

4

–1.8 –0.6

–2.4 1.2

–1.2 0 1.8

2

0

14

10,000 CONSECUTIVE
READINGS
V

CC

= 2.7V

V

REF

= 2.5V

V

IN

= 0V

T

A

= 25°C

GAIN = 256

RMS = 0.59µV

AVERAGE = –0.19µV

TIME (HOURS)

0

–5

ADC READING (µV)

–3

–1

1

10

20

30 40

2495 G09

50

3

5

–4

–2

0

2

4

60

VCC = 5V
V

REF

= 5V

V

IN

= 0V

V

IN(CM)

= 2.5V

T

A

= 25°C
RMS NOISE = 0.60µV
GAIN = 256

LTC2495

7

2495f

TYPICAL PERFORMANCE CHARACTERISTICS

RMS Noise
vs Input Differential Voltage RMS Noise vs V

IN(CM)

RMS Noise vs Temperature (TA)

RMS Noise vs V

CC

RMS Noise vs V

REF

Offset Error vs V

IN(CM)

Offset Error vs Temperature Offset Error vs V

CC

Offset Error vs V

REF

INPUT DIFFERENTIAL VOLTAGE (V)

0.4

RMS NOISE (µV)

0.6

0.8

1.0

0.5

0.7

0.9

–1.5 –0.5 0.5 1.5

2495 G10

2.5–2–2.5 –1 0 1 2

VCC = 5V
V

REF

= 5V

V

IN(CM)

= 2.5V

T

A

= 25°C

F

O

= GND

V

IN(CM)

(V)

–1

RMS NOISE (µV)

0.8

0.9

1.0

24

2495 G11

0.7

0.6

01

356

0.5

0.4

VCC = 5V
V

REF

= 5V

V

IN

= 0V

T

A

= 25°C

F

O

= GND

GAIN = 256

TEMPERATURE (°C)

–45

0.4

RMS NOISE (µV)

0.5

0.6

0.7

0.8

1.0

–30 –15 15

0304560

2495 G12

75 90

0.9

VCC = 5V
V

REF

= 5V

V

IN

= 0V

V

IN(CM)

= GND

F

O

= GND

GAIN = 256

VCC (V)

2.7

RMS NOISE (µV)

0.8

0.9

1.0

3.9 4.7

2495 G13

0.7

0.6

3.1 3.5

4.3 5.1 5.5

0.5

0.4

V

REF

= 2.5V

V

IN

= 0V

V

IN(CM)

= GND

T

A

= 25°C

F

O

= GND

GAIN = 256

V

REF

(V)

0

0.4

RMS NOISE (µV)

0.5

0.6

0.7

0.8

0.9

1.0

1234

2495 G14

5

VCC = 5V
V

IN

= 0V

V

IN(CM)

= GND

T

A

= 25°C

F

O

= GND

GAIN = 256

V

IN(CM)

(V)

–1

OFFSET ERROR (ppm of V

REF

)

0.1

0.2

0.3

24

2495 G15

0

–0.1

01

356

–0.2

–0.3

VCC = 5V
V

REF

= 5V

V

IN

= 0V

T

A

= 25°C

F

O

= GND

TEMPERATURE (°C)

–45

–0.3

OFFSET ERROR (ppm of V

REF

)

–0.2

0

0.1

0.2

–15

15

30 90

2495 G16

–0.1

–30 0

45

60

75

0.3
VCC = 5V

V

REF

= 5V

V

IN

= 0V

V

IN(CM)

= GND

F

O

= GND

V

CC

(V)

2.7

OFFSET ERROR (ppm of V

REF

)

0.1

0.2

0.3

3.9 4.7

2495 G17

0

–0.1

3.1 3.5

4.3 5.1 5.5

–0.2

–0.3

REF+ = 2.5V
REF

–

= GND

V

IN

= 0V

V

IN(CM)

= GND

T

A

= 25°C

F

O

= GND

V

REF

(V)

0

–0.3

OFFSET ERROR (ppm of V

REF

)

–0.2

–0.1

0

0.1

0.2

0.3

1234

2495 G18

5

VCC = 5V
REF

–

= GND

V

IN

= 0V

V

IN(CM)

= GND

T

A

= 25°C

F

O

= GND

LTC2495

8

2495f

TYPICAL PERFORMANCE CHARACTERISTICS

On-Chip Oscillator Frequency
vs Temperature

On-Chip Oscillator Frequency
vs V

CC

PSRR vs Frequency at V

CC

PSRR vs Frequency at V

CC

PSRR vs Frequency at V

CC

Conversion Current
vs Temperature

Sleep Mode Current
vs Temperature

Conversion Current
vs Output Data Rate

Integral Nonlinearity (2x Speed
Mode; V

CC

= 5V, V

REF

= 5V)

TEMPERATURE (°C)

–45 –30

300

FREQUENCY (kHz)

304

310

–15

30

45

2495 G19

302

308

306

150

60 75

90

VCC = 4.1V
V

REF

= 2.5V

V

IN

= 0V

V

IN(CM)

= GND

F

O

= GND

V

CC

(V)

2.5

300

FREQUENCY (kHz)

302

304

306

308

310

3.0

3.5 4.0 4.5

2495 G20

5.0 5.5

V

REF

= 2.5V

V

IN

= 0V

V

IN(CM)

= GND

F

O

= GND

T

A

= 25°C

FREQUENCY AT VCC (Hz)

1

0

–20

–40

–60

–80

–100

–120

–140

1k 100k

2495 G21

10 100

10k 1M

REJECTION (dB)

VCC = 4.1V DC
V

REF

= 2.5V

IN

+

= GND

IN

–

= GND

F

O

= GND

T

A

= 25°C

FREQUENCY AT VCC (Hz)

0

–140

REJECTION (dB)

–120

–80

–60

–40

0

20

100

140

2495 G22

–100

–20

80

180

220200

40

60

120 160

VCC = 4.1V DC ±1.4V
V

REF

= 2.5V

IN

+

= GND

IN

–

= GND

F

O

= GND

T

A

= 25°C

FREQUENCY AT VCC (Hz)

30600

–60

–40

0

30750

2495 G23

–80

–100

30650 30700 30800

–120

–140

–20

REJECTION (dB)

VCC = 4.1V DC ±0.7V
V

REF

= 2.5V

IN

+

= GND

IN

–

= GND

F

O

= GND

T

A

= 25°C

TEMPERATURE (°C)

–45

100

CONVERSION CURRENT (µA)

120

160

180

200

–15

15

30 90

2495 G24

140

–30 0

45

60

75

VCC = 5V

VCC = 2.7V

FO = GND

TEMPERATURE (°C)

–45

0

SLEEP MODE CURRENT (µA)

0.2

0.6

0.8

1.0

2.0

1.4

–15

15

30 90

2495 G25

0.4

1.6

1.8

1.2

–30 0

45

60

75

VCC = 5V

VCC = 2.7V

FO = GND

OUTPUT DATA RATE (READINGS/SEC)

0

SUPPLY CURRENT (µA)

500

450

400

350

300

250

200

150

100

80

2495 G26

20 40 60 1007010 30 50 90

VCC = 5V

VCC = 3V

V

REF

= V

CC

IN+ = GND
IN

–

= GND

F

O

= EXT OSC

T

A

= 25°C

INPUT VOLTAGE (V)

–3

INL (µV)

–1

1

3

–2

0

2

–1.5 –0.5 0.5 1.5

2495 G27

2.5–2–2.5 –1 0 1 2

VCC = 5V
V

REF

= 5V

V

IN(CM)

= 2.5V

F

O

= GND

25°C, 85°C

–45°C

LTC2495

9

2495f

TYPICAL PERFORMANCE CHARACTERISTICS

Integral Nonlinearity (2x Speed
Mode; V

CC

= 5V, V

REF

= 2.5V)

Integral Nonlinearity (2x Speed
Mode; VCC = 2.7V, V

REF

= 2.5V)

Noise Histogram
(2x Speed Mode)

RMS Noise vs V

REF

(2x Speed Mode)

Offset Error vs V

IN(CM)

(2x Speed Mode)

Offset Error vs Temperature
(2x Speed Mode)

Offset Error vs V

CC

(2x Speed Mode)

Offset Error vs V

REF

(2x Speed Mode)

INPUT VOLTAGE (V)

–3

INL (ppm OF V

REF

)

–1

1

3

–2

0

2

–0.75 –0.25 0.25 0.75

2495 G28

1.25–1.25

VCC = 5V
V

REF

= 2.5V

V

IN(CM)

= 1.25V

F

O

= GND

85°C

–45°C, 25°C

INPUT VOLTAGE (V)

–3

INL (ppm OF V

REF

)

–1

1

3

–2

0

2

–0.75 –0.25 0.25 0.75

2495 G29

1.25–1.25

VCC = 2.7V
V

REF

= 2.5V

V

IN(CM)

= 1.25V

F

O

= GND

85°C

–45°C, 25°C

OUTPUT READING (µV)

179

NUMBER OF READINGS (%)

8

10

12

186.2

2495 G30

6

4

181.4 183.8 188.6

2

0

16

14

10,000 CONSECUTIVE
READINGS
V

CC

= 5V

V

REF

= 5V

V

IN

= 0V

T

A

= 25°C

GAIN = 128

RMS = 0.85µV

AVERAGE = 0.184mV

V

REF

(V)

0

RMS NOISE (µV)

0.6

0.8

1.0

4

2495 G31

0.4

0.2

0

1

2

3

5

VCC = 5V
V

IN

= 0V

V

IN(CM)

= GND

F

O

= GND

T

A

= 25°C

GAIN = 128

V

IN(CM)

(V)

–1

180

OFFSET ERROR (µV)

182

186

188

190

200

194

1

3

4

2495 G32

184

196

198

192

0

2

5

6

VCC = 5V
V

REF

= 5V

V

IN

= 0V

F

O

= GND

T

A

= 25°C

TEMPERATURE (°C)

–45

OFFSET ERROR (µV)

200

210

220

75

2495 G33

190

180

160

–15

15

45

–30 90

0

30

60

170

240

230

VCC = 5V
V

REF

= 5V

V

IN

= 0V

V

IN(CM)

= GND

F

O

= GND

V

CC

(V)

2 2.5

0

OFFSET ERROR (µV)

100

250

3

4

4.5

2495 G34

50

200

150

3.5

5

5.5

V

REF

= 2.5V

V

IN

= 0V

V

IN(CM)

= GND

F

O

= GND

T

A

= 25°C

V

REF

(V)

0

OFFSET ERROR (µV)

190

200

210

3

5

2495 G35

180

170

160

12 4

220

230

240

VCC = 5V
V

IN

= 0V

V

IN(CM)

= GND

F

O

= GND

T

A

= 25°C

LTC2495

10

2495f

GND (Pins 1, 4, 6, 31, 32, 33, 34): Ground. Multiple
ground pins internally connected for optimum ground cur­rent fl ow and V

CC

decoupling. Connect each one of these
pins to a common ground plane through a low impedance
connection. All seven pins must be connected to ground
for proper operation.

SCL (Pin 2): Serial Clock Pin of the I

2

C Interface. The
LTC2495 can only act as a slave and the SCL pin only ac­cepts an external serial clock. Data is shifted into the SDA
pin on the rising edges of the SCL clock and output through
the SDA pin on the falling edges of the SCL clock.

SDA (Pin 3): Bidirectional Serial Data Line of the I

2

C Inter­face. In the transmitter mode (Read), the conversion result
is output through the SDA pin, while in the receiver mode
(Write), the device channel select and confi guration bits
are input through the SDA pin. The pin is high impedance
during the data input mode and is an open drain output
(requires an appropriate pull-up device to V

CC

) during the

data output mode.

NC (Pin 5): No Connect. This pin can be left fl oating or
tied to GND.

COM (Pin 7): The Common Negative Input (IN

–

) for All
Single-Ended Multiplexer Confi gurations. The voltage on
CH0-CH15 and COM pins can have any value between
GND – 0.3V to V

CC

+ 0.3V. Within these limits, the two

selected inputs (IN

+

and IN– ) provide a bipolar input range

V

IN

= (IN+ – IN–) from –0.5 • V

REF

/Gain to 0.5 • V

REF

/Gain.
Outside this input range, the converter produces unique
over-range and under-range output codes.

CH0 to CH15 (Pin 8-Pin 23): Analog Inputs. May be pro­grammed for single-ended or differential mode.

MUXOUTP (Pin 24): Positive Multiplexer Output. Connect
to the input of external buffer/amplifi er or short directly
to ADCINP.

ADCINP (Pin 25): Positive ADC Input. Connect to the
output of a buffer/amplifi er driven by MUXOUTP or short
directly to MUXOUTP.

TYPICAL PERFORMANCE CHARACTERISTICS

PSRR vs Frequency at V

CC

(2x Speed Mode)

PSRR vs Frequency at V

CC

(2x Speed Mode)

PIN FUNCTIONS

PSRR vs Frequency at V

CC

(2x Speed Mode)

FREQUENCY AT VCC (Hz)

1

0

–20

–40

–60

–80

–100

–120

–140

1k 100k

2495 G36

10 100

10k 1M

REJECTION (dB)

VCC = 4.1V DC
REF

+

= 2.5V

REF

–

= GND

IN

+

= GND

IN

–

= GND

F

O

= GND

T

A

= 25°C

FREQUENCY AT VCC (Hz)

0

–140

RREJECTION (dB)

–120

–80

–60

–40

0

20

100

140

2495 G37

–100

–20

80

180

220200

40

60

120 160

VCC = 4.1V DC ±1.4V
REF

+

= 2.5V

REF

–

= GND

IN

+

= GND

IN

–

= GND

F

O

= GND

T

A

= 25°C

FREQUENCY AT VCC (Hz)

30600

–60

–40

0

30750

2495 G38

–80

–100

30650 30700 30800

–120

–140

–20

REJECTION (dB)

VCC = 4.1V DC ±0.7V
REF

+

= 2.5V

REF

–

= GND

IN

+

= GND

IN

–

= GND

F

O

= GND

T

A

= 25°C