20-bit sigma-delta ADC at 7.5 SPS — a DC measurement part
The LTC2424CG#PBF from Analog Devices (microPOWER™ series) is a 20-bit sigma-delta ADC with a 4-channel input multiplexer, designed for precision DC or near-DC measurements where conversion speed is irrelevant but resolution matters. The 7.5 SPS sampling rate tells you everything about its intended use: weigh scales, bridge sensors, thermocouple interfaces, and other low-bandwidth instrumentation where a clean 20-bit code is worth the wait. Single-ended inputs only, SPI data interface, external reference required. Packaged in a 28-SSOP (5.30 mm width) for surface-mount assembly.
The wide range also lets it run directly from a lithium cell or a loosely regulated 5 V bus without an extra LDO. The trade-off: the analog supply noise rides straight into the sigma-delta modulator, so a clean supply rail matters more than the headline PSRR number suggests.
That locks this variant into controlled indoor environments: lab instruments, bench-top test gear, office-environment data acquisition, or medical equipment that stays climate-controlled. Not a candidate for a motor drive cabinet or an outdoor telecom enclosure. If the BOM calls for industrial temperature, you need the 'I' suffix variant (LTC2424CG#PBF is the commercial-grade 'C' version).
External reference required — budget for a precision reference
The LTC2424CG#PBF uses an external voltage reference (REF+ / REF- pins). The 20-bit resolution is only as good as the reference driving it — a clean LT1236 or similar low-drift reference is the usual pairing. No internal bandgap to fall back on; the BOM must include the reference IC and its bypass caps. That's standard for this precision tier, but it's a line item a first-time specifier can miss.
Active lifecycle, ROHS3 — no LTB pressure
The 'G' suffix indicates ROHS3-compliant, lead-free finish.