The main difference between the ISL2853x and the ISL2863x series is the former has a single-ended output while the latter has a differential output. All devices come in a 14-lead TSSOP package, the ISL2853x follows the typical three op amp configuration for an In Amp, and has an extra zero-drift op amp that can be used to buffer the reference voltage if needed, or used for any other desired task. The ISL2863x has two op amps in the output stage to provide the differential outputs, and also includes an internal buffer for the reference voltage. The differential output is best for maximum noise rejection and an increased dynamic signal range. One thing to note in the circuits are the VA+ and VA- pins. They allow access to the output of the input stage and can be used to monitor sensor health or to drive the right leg drive of an ECG circuit, among other things. The logic pins go to a logic control block that uses tri-state logic, allowing nine gain selections from two pins as opposed to the standard four pins required with binary logic.