Analog Devices Inc. DC955A

Overview

LTC2483 from Analog Devices (formerly Linear Technology) is a 16-bit plus sign delta-sigma analog-to-digital converter with patented Easy Drive input current cancellation, I²C interface, and integrated oscillator. It delivers 600 nV_RMS noise independent of reference voltage, ±2 ppm INL, and simultaneous 50 Hz/60 Hz line rejection - enabling direct digitization of rail-to-rail, high-impedance sensor signals in precision instrumentation.

For engineers reviewing the LTC2483 datasheet, LTC2483 pinout, LTC2483 application, or LTC2483 equivalent, this page provides verified technical context, validated pin functions, real-world use cases for strain gauges and weight scales, and two confirmed alternative ADCs with documented functional trade-offs.

Technical Context

The LTC2483 employs a third-order delta-sigma modulator with transparent auto-calibration for offset and full-scale, achieving no-latency digital filter settling in one cycle. Its Easy Drive architecture eliminates differential input current via passive sampling network cancellation - allowing direct connection to sensors with source impedances up to 100 kΩ without external buffering.

It supports single-supply operation from 2.7 V to 5.5 V, accepts reference voltages from 100 mV to V_CC, and offers six I²C addresses via CA0/F0 and CA1 pins. The internal oscillator enables 87 dB 50/60 Hz rejection; an external clock (10–4000 kHz) can be applied to CA0/F0 for custom null placement at f_EOSC/5120.

Key Specifications

Pinout & Package

Package: 10-lead (3 mm × 3 mm) plastic DFN with exposed pad (Pin 11 = GND, must be soldered to PCB). θ_JA = 43°C/W, T_JMAX = 125°C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision delta-sigma ADC applications.

Compared with ADS124S08 and MAX11200, the LTC2483 uniquely combines I²C simplicity, zero-differential-input-current operation, and hardware-based dual-line-frequency rejection - making it optimal for cost-sensitive, space-constrained industrial transmitters where sensor buffering and external clocks must be avoided.

Availability

LTC2483 is available at Aetrix Electronics and suitable for weight scales, strain gauge interfaces, direct temperature measurement systems, and industrial process controllers requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LTC2483 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LTC portfolio.

The LTC2483 belongs to Linear's precision delta-sigma ADC family, designed specifically for direct sensor digitization in industrial, instrumentation, and weigh-scale applications where input buffering, external clocks, and line-frequency interference must be eliminated at the front end.

FAQ

What is the maximum source impedance the LTC2483 can drive without accuracy loss?

The LTC2483's Easy Drive technology cancels differential input current, enabling accurate digitization with source impedances up to 100 kΩ. This is confirmed by the +FS error vs R_SOURCE plot in the datasheet (Figure TA01), which shows <±20 ppm error at 100 kΩ with V_CC = 5 V and V_REF = 5 V. For optimal performance, keep total series capacitance at IN+ and IN– below 10 pF per pin.

Does the LTC2483 require an external reference voltage?

No - the LTC2483 accepts reference voltages from 100 mV to V_CC, and the reference common-mode range is GND to V_CC. It can operate with V_REF tied directly to V_CC, eliminating the need for an external reference IC. However, for highest absolute accuracy, a precision 2.5 V or 4.096 V reference may be used; the 600 nV_RMS noise remains independent of V_REF value.

How does the LTC2483 achieve simultaneous 50 Hz and 60 Hz rejection?

The LTC2483 achieves simultaneous 50 Hz/60 Hz rejection through its on-chip digital filter architecture, which places nulls at both frequencies using the internal oscillator. As stated in the datasheet, this provides 87 dB rejection without external components. When using an external clock on CA0/F0, the null frequency shifts to f_EOSC/5120 - so a 280 kHz external clock yields simultaneous nulls at 54.7 Hz and 65.6 Hz, approximating dual-line rejection.

Can the LTC2483 operate from a 3.3 V supply?

Yes - the LTC2483 supports supply voltages from 2.7 V to 5.5 V. At V_CC = 3.3 V, it maintains full specifications including 600 nV_RMS noise, ±2 ppm INL, and 87 dB line rejection. The I²C interface remains compatible with 3.3 V logic levels (VIH = 0.7 × V_CC = 2.31 V min), and the internal oscillator operates reliably across the entire supply range.

What happens if the LTC2483 is addressed during conversion?

If the LTC2483 is addressed via I²C while in conversion state, it issues a Not-Acknowledge (NACK) by holding SDA HIGH - indicating the conversion is still in progress. The master must retry after a delay. Once conversion completes, the device enters sleep mode and responds to read requests with ACK. A new conversion starts automatically after the full 24-bit read completes or upon STOP condition.