operational amplifier - op amp rail to rail voltage follower latching up

I have selected a TS922 op amp to use in a voltage follower configuration. The specs for the TS922 in summary are:

• Rail-to-rail input and output


• Low noise: 9 nV/√Hz


• Low distortion


• High output current: 80 mA (able to drive 32 Ω loads)


• High-speed: 4 MHz, 1 V/μs


• Operating from 2.7 to 12 V


• Low input offset voltage: 900 μV max.


• Latch-up immunity

The voltage follower configuration is

Supply voltage is 5 V.

To test I am using a simple 10k pot arrangement (range v supply to gnd) to apply a voltage to the input (pin 3) with a voltmeter measuring the output on pin 1.

My issue is that the TS922 output latches up to 4.7 V if the input voltage rises above 3.6 V. If the input voltage is less than 3.6 V the TS922 behaves as a voltage follower.

To try to identify why this is happening I have tried:

• placing a light load (2k resistor) from pin 1 to ground - no effect


• grounding the inputs to the other dual amp in case there was some interaction - no effect.

Is there something I am missing?? Otherwise I suspect the markings on this device don't match what is inside.

I would ALSO appreciate any advice on other op amps which are close to the TS922. The most important specs are: - single supply 5 V. - rail to rail input/output. - high output current capability > 50 mA.

I know I can search for devices - but I am hoping someone has experience with a device that works well.

Thanks in advance