Electronic – How reliable is it to use another manufacturer’s datasheet of the same part

Generally, the primary specifications will be the same, but beware as the devil is in the details as noted by Olin.

As an example, take the LM1117.

Parts with the same base number are also made by On Semiconductor and AMS.

Looking at the datasheets, TI has this to say on stability:

The output capacitor is critical in maintaining regulator stability, and must meet the required conditions for both minimum amount of capacitance and equivalent series resistance (ESR). The minimum output capacitance required by the LM1117 is 10 μF, if a tantalum capacitor is used. Any increase of the output capacitance will merely improve the loop stability and transient response. The ESR of the output capacitor should range between 0.3 Ω to 22 Ω. In the case of the adjustable regulator, when the CADJ is used, a larger output capacitance (22-μF tantalum) is required.

AMS simply states:

Stability

The circuit design used in the AMS1117 series requires the use of an output capacitor as part of the device frequency compensation. The addition of 22μF solid tantalum on the output will ensure stability for all operating conditions. When the adjustment terminal is bypassed with a capacitor to improve the ripple rejection, the requirement for an output capacitor increases. The value of 22μF tantalum covers all cases of bypassing the adjustment terminal. Without bypassing the adjustment terminal smaller capacitors can be used with equally good results. To further improve stability and transient response of these devices larger values of output capacitor can be used.

On Semiconductor has this:

Frequency compensation for the regulator is provided by capacitor Cout and its use is mandatory to ensure output stability. A minimum capacitance value of 4.7 μF with an equivalent series resistance (ESR) that is within the limits of 33 mΩ (typ) to 2.2Ω is required. See Figures 12 and 13. The capacitor type can be ceramic, tantalum, or aluminum electrolytic as long as it meets the minimum capacitance value and ESR limits over the circuit’s entire operating temperature range. Higher values of output capacitance can be used to enhance loop stability and transient response with the additional benefit of reducing output noise.

You should note that all these statements have subtle differences for a part that is designed for the same task; other parameters in the datasheets vary as well.

This is but one type of part from the millions out there. Even the humble resistor and capacitor from various manufacturers can have differences (even though they are apparently the same type of device) that you may care about (in high reliability designs, this is definitely true).

Update.

Dim makes an excellent point on schematic notation where the generic number may not be sufficient.

In what I currently do (avionics including flight controls) we have internal part numbers which are used in the schematic; these numbers map to a single part from a single manufacturer to deal with this precise issue.

If you are using a specific manufacturers part, use that manufacturers datasheet.