SOT-23 diode help

Trying to make sense of the SOT-23 diode situation...

I find the SOT-23 package (3-pin) the best for diodes. (I think that the MELF style package is just plain silly!) But there are some confusing aspects to selecting these: I have made the wrong choice at least twice in the last few years. At least one of the errors was due to an incorrect pinout in a catalog (I really do know to check the data sheet!).

In the table below I present several single and double diodes. Note that the dual diodes “always” use pin 3 as the common. (I'm sure that there are exceptions, there always are, but this is the most common situation at least.) Similarly the singles all have the same pinout: again there are exceptions but I've found it best to stick with just the one choice.

There are many other devices, but this is a reasonable set of part numbers to consider as standard items. In fact even here, there is a fair bit of redundancy, but that should allow one to make substitutions if required.

Single diodes
Device	Pinouts	PRV	Forward V @ current	Pwr [W]	Ref. Manufacturer [marking]	Notes.
BAT54		30	0.8@ 0.1 A	0.2	Diodes Inc. [KL1]	Schottky
BAS40		40	0.5@ 0.05 A	0.35	Diodes Inc. [K43]	Schottky
BAS70		40	0.5@ 0.05 A	0.2	MCC [73]	Schottky
BAS16		75	1@ 0.05 A	0.37	Infineon [A6s]	Signal/switching diode. Philips: [A6]; DI: [KA2]--aka MMBD4148 or MMBD914
MMBD4448		75	1@ 0.1 A	0.35	MCC [KA3]	Signal diode.
BAS19		100	1@ 0.1 A	0.25	Diodes Inc. [KA8]	Signal/switching diode.
BAS21		200	1@ 0.1 A	0.25	Diodes Inc. [KT3]	Signal/switching diode.
Double diodes
Device	Pinouts	PRV	Forward V @ current	Pwr [W]	Ref. Manufacturer [marking]	Notes.
BAT54S		30	0.8@ 0.1 A	0.2	Diodes Inc. [KL4]	Schottky. Series
BAT54C		30	0.8@ 0.1 A	0.2	Diodes Inc. [KL3]	Schottky. Common Cathode
BAT54A		30	0.8@ 0.1 A	0.2	Diodes Inc. [KL2]	Schottky. Common Anode
BAS40-04		40	0.5@ 0.05 A	0.35	Diodes Inc. [K44]	Schottky. Series
BAS40-05		40	0.5@ 0.05 A	0.35	Diodes Inc. [K45]	Schottky. Common Cathode
BAS40-06		40	0.5@ 0.05 A	0.35	Diodes Inc. [K46]	Schottky. Common Anode
BAV74LT1G		50	1@ 0.1 A	0.225	ON [JA]	Signal diode. Common Cathode
BAS70-04		70	0.5@ 0.05 A	0.2	MCC [74]	Schottky. Series
BAS70-05		70	0.5@ 0.05 A	0.2	MCC [75]	Schottky. Common Cathode
BAS70-06		70	0.5@ 0.05 A	0.2	MCC [76]	Schottky. Common Anode
BAW56		70	1@ 0.05 A	0.33	Infineon [A1s]	Signal diode. Common Anode
BAV23S		200	1.25@ 0.2 A	0.35	Diodes Inc. [KL31]	Schottky. Series
BAV23C		200	1.25@ 0.2 A	0.35	Diodes Inc. [KT6]	Schottky. Common Cathode
BAV23A		200	1.25@ 0.2 A	0.35	Diodes Inc. [KT7]	Schottky. Common Anode

Some notes:

• These are the main characteristics, however, there are many other considerations which may be important for your application;
• The “Ref. Manufacturer” column reflects the data sheet I extracted the data from;
• The forward voltages were taken from data sheets, and are the 100 mA values or the 50 mA values if the former is not stated;
• The max power figures are shown under different conditions in different data sheets. In all cases the test currents and maximum forward drops will not exceed the power numbers, so if the test currents are taken as maximums then the power dissipation should be within limits;
• The BAT54 family uses a suffix letter to indicate variants: no letter is a single, 'S' stands for series, 'C' for common cathode, and 'A' for common anode;
• The BAT40 and BAT70 families, however, use a different suffix system, see the table.
• The SOT-23 package is also known as the TO-236 and SC59.

Revisions:

• Added BAV23 family. 11-Sept-2013.