Yes, you can. Phase compensation is built in all operational amplifiers except for the S-89402/89403 to enable use at a gain of +1. The S-89402/89403 implements phase compensation to enable stabilization at a gain of 5 or more.

It’s the product of the gain and the bandwidth.

We recommend using our S-8953 series, S-892 series and S-8951 series comparator products instead. The reasons are:

1. The rise time and fall time are shorter compared with an operational amplifier with the same current consumption because phase compensation capacitance is not used.

2. The current consumption may increase if you use an operational amplifier as a comparator. For instance, if you use the S-8943 (operational amplifier) as a comparator, the current consumption may increase up to 3 to 6 µA when the output is saturated on the VDD side. We therefore recommend using the S-8953, not the S-8943.

The device will not be damaged if you leave input pins open but it makes the performance unstable.
The characteristics of the operational amplifier are also affected on the user side. Thus we recommend you to implement the following procedure.
Operational amplifier:
Set a voltage follower configuration and connect the input Vin+ to VSS.
Comparator:
Connect Vin+ to VSS and Vin− to VDD.
If, however, you want to use only one circuit of a dual product, we recommend using a single product.

The input offset current is in the order of 1pA because it flows through the gate oxide of the MOS transistor. However, it is difficult to measure it correctly because of the leakage current of the package pins or because the measurement accuracy is in the pA order. Under our test conditions, the S-891 series and S-892 series are tested whether the maximum value of the input offset current is 50 nA or less. Other mini analog products are tested whether this maximum value is 10 nA or less.

The data sheet describes that the maximum rating of the input voltage for mini analogs is VSS to VDD.
This is the range of input voltage that is guaranteed by our reliability test data.

However, the device should not be damaged even if you apply an input voltage a little outside this range. How much outside this range is allowable can be defined as follows:
As described in the data sheet there is an off-transistor (NMOS) connected between the input pins and VSS for protection against ESD. The current increases when the input voltage falls below VSS – 0.7 V when you apply a voltage of less than VSS to the input pins. With a voltage down to VSS – 0.5 V, damage should not occur.

A current pass does not exist between the input pins and VDD because there is no protection device between them. The device should not be damaged as long as the input voltage is less than VSS + 7 V when you apply a voltage of more than VDD to the input pins.

It depends on the individual product.
Please refer to our data sheet.

It depends on the invidual product. Please refer to our data sheet.