LSI/CSI LS7084N-S

LS7084N-S is a CMOS quadrature clock converter for incremental optical or magnetic encoders. It validates the phase-related A and B inputs and provides count pulses on CLK plus direction on UP/DN for an external up/down counter. The surface-mount -S version uses the same functional pin assignment as the 8-pin DIP LS7084N, but its footprint and assembly process differ.

LS7084N-S is the standard narrow-body SOIC option. The LCDChip package registry lists it as 8-SOIC (0.154 inch, 3.90 mm width). Use the manufacturer's SOIC outline, not the 300 mil DIP outline, when selecting a land pattern.

Layout checks

• Check body width, pitch and lead span against the controlled SOIC outline.
• Locate pin 1 using the top-view pin assignment and assembly marking.
• Do not reuse the LS7084N through-hole DIP footprint.

The registered 8-SOIC JPG is present locally; online page-image verification is required before publication.

The manufacturer datasheet gives the following top-view LS7084N family pin functions, applicable to the -S SOIC variant.

The connected counter should use the rising CLK edge specified by LSI/CSI.

RBIAS, selected resolution and A/B phase timing must be evaluated together; a typical value is not a guaranteed limit.

LS7084N is the manufacturer-listed DIP version with the same clock/direction function, but requires a through-hole footprint. LS7083N-S shares the 8-SOIC family package but provides separate UPCK and DNCK outputs instead of CLK and UP/DN, so the counter interface changes. LS7184N-S is a related clock/direction converter; compare its controlled datasheet, timing and ordering requirements before substitution. Exact catalog records were found for these models, but their pages are unpublished, so no internal links are inserted. None is asserted to be a drop-in replacement.

LSI/CSI lists LS7084N-S as an in-production quadrature clock decoder and identifies -S as the standard SOIC package option. Its controlled LS7083N/LS7084N datasheet supplies the pin assignment, timing tables and package references. Confirm the latest revision and order-code availability for procurement.

Confirm the full LS7084N-S order code, SOIC package, pin-1 orientation and lot traceability on receipt. Obtain application-specific compliance documentation from the supplier and validate electrical behavior against the latest manufacturer datasheet.

This summary does not replace the controlled LSI/CSI datasheet. Verify supply, MODE bias, RBIAS, A/B phase timing, CLK edge and package dimensions before design release. Stock and price are maintained separately from this technical detail.