A printhead module includes a substrate, a plurality of drop ejector arrays, and electronic circuitry. The substrate includes a butting edge extending in a first direction along the substrate. The plurality of drop ejector arrays extends substantially parallel to the butting edge of the substrate with a first drop ejector array of the plurality of drop ejector arrays being closest to the butting edge of the substrate. A portion of the electronic circuitry is disposed between the first drop ejector array and the butting edge of the substrate.