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LINEAR TECHNOLOGY LTC2480 Data Sheet manual specifications user guide

Summary

The LTC2480 is a high-precision 16-Bit Sigma-Delta Analog-to-Digital Converter featuring patented Easy Drive technology for zero differential input current cancellation. Ideal for connecting directly to challenging, high-impedance sensors and source types like strain gauges or weighing scales. The accompanying documentation provides complete integration guidelines, detailed electrical specifications, programmable gain settings (1–256), and advanced line frequency rejection (50/60Hz) essential for instrumentation designers building robust measurement and process control systems.

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LTC2480

16-Bit ∆Σ ADC with Easy Drive Input Current Cancellation

FEATURES DESCRIPTIO Easy Drive Technology Enables Rail-to-Rail Inputs The LTC®2480 combines a 16-bit plus sign No Latency ∆ΣTM

with Zero Differential Input Current analog-to-digital converter with patented Easy Drive TM tech- Directly Digitizes High Impedance Sensors with nology. The patented sampling scheme eliminates dynamic Full Accuracy input current errors and the shortcomings of on-chip buff- Programmable Gain from 1 to 256 ering through automatic cancellation of differential input Integrated Temperature Sensor current. This allows large external source impedances and GND to VCC Input/Reference Common Mode Range input signals, with rail-to-rail input range to be directly digi- Programmable 50Hz, 60Hz or Simultaneous tized while maintaining exceptional DC accuracy.

50Hz/60Hz Rejection Mode

The LTC2480 includes on-chip programmable gain, a

2ppm (0.25LSB) INL, No Missing Codes

temperature sensor and an oscillator. The LTC2480 can be

1ppm Offset and 15ppm Full-Scale Error

configured to provide a programmable gain from 1 to 256

Selectable 2x Speed Mode (15Hz Using Internal

in 8 steps, measure an external signal or internal tempera-

Oscillator)

ture sensor and reject line frequencies. 50Hz, 60Hz or

No Latency: Digital Filter Settles in a Single Cycle

simultaneous 50Hz/60Hz line frequency rejection can be

Single Supply 2.7V to 5.5V Operation +F ER RO (p pm

selected as well as a 2x speed-up mode.

Internal Oscillator

Available in a Tiny (3mm × 3mm) 10-Lead The LTC2480 allows a wide common mode input range DFN Package (0V to VCC) independent of the reference voltage. The reference can be as low as 100m V or can be tied directly APPLICATIO S to VCC. The LTC2480 includes an on-chip trimmed oscil- lator eliminating the need for external crystals or oscilla-

Direct Sensor Digitizer

tors. Absolute accuracy and low drift are automatically

Weight Scales

maintained through continuous, transparent, offset and

Direct Temperature Measurement

full-scale calibration.

Strain Gauge Transducers

, LTC and LT are registered trademarks of Linear Technology Corporation.

Instrumentation No Latency ∆Σ and Easy Drive are trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Industrial Process Control

Patent Pending.

DVMs and Meters

TYPICAL APPLICATIO +FS Error vs RSOURCE at IN+ and IN– VCC = 5V VCC VREF = 5V + = 3.75V VIN – = 1.25V VIN 1µF FO = GND TA = 25°C

SDI CIN = 1µF

10k IDIFF = 0 VREF VCC

VIN SDO

4-WIRE –20

SENSE 1µF LTC2480

SCK SPI INTERFACE

VIN –40

10k GND FO

2480 TA01

1k 10k 100k RSOURCE (Ω) 2480 TA04

Page Summary Contents For LINEAR TECHNOLOGY LTC2480 Data Sheet manual specifications user guide

Page 1 LTC2480 16-Bit ∆Σ ADC with Easy Drive Input Current Cancellation FEATURES DESCRIPTIO Easy Drive Technology Enables Rail-to-Rail Inputs The LTC®2480 combines a 16-bit plus sign No Latency ∆ΣTM with Zer...
Page 2 LTC2480 ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Notes 1, 2) Supply Voltage (VCC) to GND...................... –0.3V to 6V TOP VIEW ORDER PART Analog Input Voltage to GND –0.3V to (VCC + 0.3V)...
Page 3 LTC2480 ELECTRICAL CHARACTERISTICS (2x SPEED) The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. (Notes 3, 4) PARAMETER CONDITI...
Page 4 LTC2480 ALOG I PUT A D REFERE CE The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3) SYMBOL PARAMETER CONDITIONS MIN...
Page 5 LTC2480 TI G CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 3) SYMBOL PARAMETER CONDITIONS MIN TYP...
Page 6 NU BE OF EA DI NG TU (p pm IN (p pm EF EF LTC2480 TYPICAL PERFOR A CE CHARACTERISTICS Integral Nonlinearity Integral Nonlinearity Integral Nonlinearity (VCC = 5V, VREF = 5V) (VCC = 5V, VREF = 2.5V) (V...
Page 7 OF FS ET RR OR (p pm RM NO IS (µ V) RM NO IS (p pm EF EF LTC2480 TYPICAL PERFOR A CE CHARACTERISTICS RMS Noise vs Input Differential Voltage RMS Noise vs VIN(CM) RMS Noise vs Temperature (TA) 1.0 1.0 ...
Page 8 RE JE CT IO (d B) FR EQ UE NC (k Hz TA T/ EF (V LTC2480 TYPICAL PERFOR A CE CHARACTERISTICS Temperature Sensor Temperature Sensor Error On-Chip Oscillator Frequency vs Temperature vs Temperature vs Te...
Page 9 IN (p pm SU PP LY UR RE NT (µ A) LTC2480 TYPICAL PERFOR A CE CHARACTERISTICS OF FS ET RR OR (µ V) Conversion Current Integral Nonlinearity (2x Speed Integral Nonlinearity (2x Speed vs Output Data Rate...
Page 10 OF FS ET RR OR (µ V) LTC2480 TYPICAL PERFOR A CE CHARACTERISTICS RR EJ EC TI ON (d B) Offset Error vs VCC Offset Error vs VREF PSRR vs Frequency at VCC (2x Speed Mode) (2x Speed Mode) (2x Speed Mode) ...
Page 11 LTC2480 PI FU CTIO S as CS is HIGH. A LOW-to-HIGH transition on CS during the Input/Output period. In External Serial Clock Operation Data Output transfer aborts the data transfer and starts a mode, S...
Page 12 LTC2480 TI I G DIAGRA S Timing Diagram Using Internal SCK t KQMIN t KQMAX 2480 TD1 SLEEP CONVERSIONDATA IN/OUT Timing Diagram Using External SCK UU WU t5 t KQMIN t6 t KQMAX t4 2480 TD2 SLEEP CONVERSIO...
Page 13 LTC2480 APPLICATIO S I FOR ATIO While in this sleep state, power consumption is reduced by network transparently removes the differential input cur- two orders of magnitude. The part remains in the sl...
Page 14 LTC2480 APPLICATIO S I FOR ATIO CS BIT 23 BIT 21 BIT 20 BIT 19 BIT 18 BIT 4 BIT 3 BIT 2BIT 22 BIT 1 BIT 0 SDO EOC SIGDMY MSB B16 LSB GS2 GS0GS1 IM Hi-Z CONVERSION RESULT PREVIOUS CONFIGURATION BITS SD...
Page 15 LTC2480 APPLICATIO S I FOR ATIO Table 2a. The LTC2480 Performance vs GAIN in Normal Speed Mode (VCC = 5V, VREF = 5V) GAIN UNIT Input Span ±2.5 ±0.625 ±0.312 ±0.156 ±78m ±39m ±19.5m ±9.76m LSB 38.1 9.5...
Page 16 LTC2480 APPLICATIO S I FOR ATIO Output Data Format Bit 20 (fourth output bit) is the most significant bit (MSB) of the result. This bit in conjunction with Bit 21 also The LTC2480 serial output data s...
Page 17 LTC2480 APPLICATIO S I FOR ATIO from HIGH to LOW at the completion of a conversion. This signal may be used as an interrupt for an external microcontroller. Bit 23 (EOC) can be captured on the first –...
Page 18 LTC2480 APPLICATIO S I FOR ATIO Table 5. LTC2480 State Duration STATE OPERATING MODE DURATION CONVERT Internal Oscillator 60Hz Rejection 133ms, Output Data Rate ≤ 7.5 Readings/s for 1x Speed Mode 67ms...
Page 19 LTC2480 TA (m V) APPLICATIO S I FOR ATIO When using the internal temperature sensor, if the output Reference Voltage Range code is normalized to RSDO = VPTAT/VREF, the temperature The LTC2480 external...
Page 20 LTC2480 APPLICATIO S I FOR ATIO temperature dependent offset error due to the input When the device is in the sleep state, its conversion result leakage current. A 1n A input leakage current will deve...
Page 21 LTC2480 APPLICATIO S I FOR ATIO 2.7V TO 5.5V 1µF VCC FO INT/EXT CLOCK LTC2480 1REFERENCE VREF SDI VOLTAGE 0.1V TO VCC SCK 4-WIRE SPI INTERFACE ANALOG IN+ CS TEST EOC INPUT IN– GND (OPTIONAL) TEST EOC ...
Page 22 LTC2480 APPLICATIO S I FOR ATIO External Serial Clock, 3-Wire I/O begun. In applications where the processor generates 32 clock cycles, or to remain compatible with higher resolu- This timing mode uti...
Page 23 LTC2480 APPLICATIO S I FOR ATIO When testing EOC, if the conversion is complete (EOC = 0), used to shift the conversion result into external circuitry. the device will exit the low power mode during t...
Page 24 LTC2480 APPLICATIO S I FOR ATIO Whenever SCK is LOW, the LTC2480’s internal pull-up at Internal Serial Clock, 3-Wire I/O, pin SCK is disabled. Normally, SCK is not externally driven Continuous Convers...
Page 25 LTC2480 APPLICATIO S I FOR ATIO 2.7V TO 5.5V 1µF VCC FO INT/EXT CLOCK LTC2480 1REFERENCE VREF SDI 10k VOLTAGE 0.1V TO VCC SCK 3-WIRE SPI INTERFACE ANALOG IN+ CS INPUT IN– GND BIT 23 BIT 19 BIT 18 BIT ...
Page 26 LTC2480 APPLICATIO S I FOR ATIO During the conversion period, the undershoot and/or converter, substantial AC current is flowing in the loop overshoot of a fast digital signal connected to the pins ca...
Page 27 LTC2480 APPLICATIO S I FOR ATIO occurs. In this case, no errors are introduced and direct zero, the common mode input current (IIN++ IIN–)/2 is digitization of the sensor is possible. proportional to ...
Page 28 LTC2480 –F ER RO (p pm +F ER RO (p pm APPLICATIO S I FOR ATIO RSOURCE common mode input current varies proportionally with input voltage. For the case of balanced input impedances, VINCM + 0.5VIN CEXT...
Page 29 LTC2480 APPLICATIO S I FOR ATIO 2/(VREF • REQ) – (0.5 • VREF • DT)/REQ in the reference Reference Current –VIN pin current as expressed in Figure 11. When using internal In a similar fashion, the LTC2...
Page 30 LTC2480 +F ER RO (p pm –F ER RO (p pm +F ER RO (p pm APPLICATIO S I FOR ATIO VCC = 5V VREF = 5V + = 3.75V VIN FO = GND CREF = 0.01µF TA = 25°C CREF = 0.01µF CREF = 0.001µF CREF = 1µF, 10µF CREF = 100p...
Page 31 LTC2480 APPLICATIO S I FOR ATIO external oscillator), the LTC2480 output data rate can be VIN(CM) = VREF(CM) VCC = VREF = 5V increased as desired. The duration of the conversion VIN = 0V phase is 4103...
Page 32 LTC2480 OF FS ET RR OR (p pm EF RE SO LU TI ON (B IT S) RE SO LU TI ON (B IT S) APPLICATIO S I FOR ATIO TA = 25°C VCC = VREF = 5V TA = 85°C VCC = 5V, VREF = 2.5V VIN(CM) = VREF(CM) VIN(CM) = VREF(CM) ...
Page 33 LTC2480 APPLICATIO S I FOR ATIO Due to the complex filtering and calibration algorithms utilized, the converter input bandwidth is not modeled 50Hz AND very accurately by a first order filter with the...
Page 34 LTC2480 IN PU NO RM AL OD RE JE CT IO (d B) IN PU NO RM AL OD RE JE CT IO (d B) APPLICATIO S I FOR ATIO The SINC4 digital filter provides greater than 120d B nor- In 1x speed mode, the regions of low ...
Page 35 NO RM AL OD RE JE CT IO (d B) NO RM AL OD RE JE CT IO (d B) NO RM AL OD RE JE CT IO (d B) LTC2480 APPLICATIO S I FOR ATIO VCC = 5V As a result of these remarkable normal mode specifica- MEASURED DATA ...
Page 36 NO RM AL OD RE JE CT IO (d B) LTC2480 APPLICATIO S I FOR ATIO NO RM AL OD RE JE CT IO (d B) IN PU NO RM AL EJ EC TI ON (d B) VCC = 5V VCC = 5V VIN(P-P) = 5V VIN(P-P) = 5V VREF = 5V VREF = 5V VIN(P-P) ...
Page 37 LTC2480 APPLICATIO S I FOR ATIO rejection identical as that for the 1x speed mode. The meter, the cold junction temperature sensor must be at the averaging operation still keeps the output rate with t...
Page 38 LTC2480 APPLICATIO S I FOR ATIO /*** read_LTC2480() ************************************************************ This is the function that actually does all the work of talking to the LTC2480. The spi...
Page 39 LTC2480 PACKAGE DESCRIPTIO DD Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698) (2 SIDES)2.15 ±0.05 PACKAGE OUTLINE 0.50 BSC 2.38 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AN...
Page 40 LTC2480 TYPICAL APPLICATIO PIC16F73 1µF 0.1µF RC7 VDD 5V C6 ISOTHERMAL 0.1µF RC5 RC4 R2 RC3 2k REF VCC CS OSC1 SCK RC1 LTC2480 SDO RC0 OSC2 SDI RB7 D1 IN– R1 TYPE K BAT54 FO RB6 10k THERMOCOUPLE GND G...

Manual Details

Brand Linear
Pages 40
File Size 535.33 KB
Published July 16, 2026
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Frequently Asked Questions

Does the LTC2480 require external crystal oscillators?

No, it includes an on-chip trimmed oscillator, eliminating the need for external crystals or oscillation components.

What function does the Easy Drive Technology provide?

It cancels differential input current errors, enabling the direct digitization of high impedance sensors with rail-to-rail inputs.

How does the ADC handle line frequency noise?

It includes a programmable 50Hz, 60Hz or simultaneous rejection mode to filter out line frequencies while maintaining DC accuracy.

What is the single supply voltage range for operation?

The device supports single supply operation with a voltage range from $2.7V$ to $5.5V$.

Does it measure internal temperature?

Yes, it features an integrated temperature sensor that maintains absolute accuracy through continuous full-scale calibration.