Analog Devices Inc. DC1009A-B

Overview

LTC2488 from Analog Devices (formerly Linear Technology) is a 16-bit, 4-channel ΔΣ analog-to-digital converter with Easy Drive input current cancellation, enabling rail-to-rail, high-impedance sensor digitization without external buffering. It delivers 2 ppm INL, 1 ppm offset error, 600 nV RMS noise, and simultaneous 50 Hz/60 Hz rejection - used in precision industrial temperature monitoring and sensor signal conditioning.

For engineers reviewing the LTC2488 datasheet, LTC2488 pinout, LTC2488 application, or LTC2488 equivalent, this page provides verified technical context, validated pin functions, real-world application mappings, and confirmed alternative parts for direct sensor interface designs requiring zero-latency, no-missing-codes performance across wide common-mode ranges.

Technical Context

The LTC2488 implements a third-order delta-sigma modulator with decimating FIR filter and integrated oscillator, achieving single-cycle digital filter settling - eliminating latency even after channel reconfiguration. Its patented Easy Drive architecture cancels differential input current dynamically, allowing direct connection of sensors with source impedances up to 100 kΩ while maintaining full DC accuracy.

It supports flexible operation modes: internal SCK (38.4 kHz clock output) or external SCK (up to 4 MHz), with FO pin selecting between internal 307.2 kHz oscillator or external clock for adjustable data rate and notch tuning. Input common-mode range spans GND – 0.3 V to VCC + 0.3 V independent of reference voltage, and reference range is 0.1 V to VCC.

Key Specifications

Pinout & Package

Package: 14-lead (4 mm × 3 mm) plastic DFN with exposed pad (Pin 15 = GND). RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS124S08 and MAX11206, the LTC2488 uniquely combines 16-bit precision, zero-latency channel switching, Easy Drive input cancellation, and simultaneous 50/60 Hz rejection in a 4 mm × 3 mm DFN - making it optimal for cost- and size-constrained sensor interfaces where high-Z direct connection and robust EMI immunity are mandatory.

Availability

LTC2488 is available at Aetrix Electronics and suitable for industrial process control, portable instrumentation, and medical sensor signal conditioning requiring stable component supply, long-lifecycle support, and guaranteed traceability.

Supply support for LTC2488 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 its precision analog product lines with full documentation, reference designs, and long-term manufacturing commitment.

The LTC2488 belongs to Linear's No Latency ΔΣ ADC family, designed specifically for direct sensor digitization in space-, power-, and accuracy-constrained systems where traditional buffered ADC architectures introduce error and complexity.

FAQ

What is the maximum source impedance the LTC2488 can drive without accuracy loss?

The LTC2488 supports source impedances up to 100 kΩ with full accuracy due to its Easy Drive input current cancellation architecture. This is validated in Figure TA01b of the datasheet, showing full-scale error remains within ±20 ppm up to 100 kΩ at 25°C. For optimal performance above 10 kΩ, ensure symmetric PCB trace routing and minimize stray capacitance on IN+/IN– lines. The LTC2488 achieves this without external op-amps or buffers.

Does the LTC2488 require an external reference voltage?

No - the LTC2488 operates with either an external differential reference (REF+ and REF–) or an internally derived reference by shorting REF+ to VCC and REF– to GND. When using VCC as reference, full-scale range becomes 0.5 × VCC, and noise performance scales linearly with VREF. The LTC2488 maintains 2 ppm INL and 1 ppm offset error across the full 0.1 V to VCC reference range, as specified in the Electrical Characteristics table.

How does the LTC2488 handle channel switching and conversion validity?

The LTC2488 guarantees that the first conversion after any channel selection (via SDI) is fully valid and meets all specifications - no settling delay or dummy conversions required. This "no latency" behavior results from its single-cycle digital filter design and per-conversion auto-calibration. The LTC2488 achieves this across all combinations: differential (e.g., CH0–CH1), single-ended (e.g., CH2 vs COM), or mixed configurations, with no performance penalty.

Can the LTC2488 reject both 50 Hz and 60 Hz interference simultaneously?

Yes - the LTC2488's digital filter is designed to provide simultaneous 50 Hz and 60 Hz rejection of ≥87 dB, as confirmed in the Converter Characteristics table (Input Normal Mode Rejection 50Hz/60Hz ±2%). This is achieved through hardware-level notch placement and does not require external components or firmware configuration. The LTC2488 maintains this rejection across temperature (–40°C to 85°C) and supply voltage (2.7 V to 5.5 V), per Note 9 in the datasheet.

What is the function of the FO pin on the LTC2488?

The FO (Frequency Override) pin selects the conversion clock source: grounding FO enables the internal 307.2 kHz oscillator, while applying an external clock (10 kHz–1 MHz) overrides it to adjust data rate and tune filter nulls. The LTC2488's tCONV varies inversely with fEOSC (e.g., 144.1 ms at 307.2 kHz, ~41 ms at 1 MHz), enabling trade-offs between speed and noise. FO operation is detailed in Pin Functions (Page 8) and Applications Information (Page 11).