SMA6501, a stepper driver?

I pulled an SMA6501 off a board from an Epson dot-matrix printer.
On the board, pins 2, 4, 7, and 9 are going to the control pins of a atepper.
While, it looks like pin 11 goes to 2 pins on the stepper.

I thought this was a way of controlling higher current with lower current.
When I connect power to pin 5, power comes out all other pins except 10, 11, and 12.
When I put ground to pin 5, all the pins are floating except 1, 3, 6, and 8(they are grounded).

It is called a “Silicon NPN, PNP Epitaxial Planer”.
Datasheet: http://datasheet.seekic.com/PdfFile/SMA/SMA6501.pdf

Printer service manual: http://www.feedroller.com/Store/Service%20Manual/Stylus%201000%20Service%20Manual.pdf

I have no clue how this drives a motor.
Please help me figure this out.

On that chip, pin 5 is ground. Pins 1 to 4 and 6 to 9 are like half a ULN2803 chip, except that it needs external series resistors when driving it from an Arduino. Pins 10 -12 are a high side driver, which you can ignore.

To use it to drive that stepper:

  • Connect pins 2,4,7,9 to the stepper exactly as they were on the board.

  • Connect each of pins 1,3,6,8 through a series resistor (1K or 2.2K will do) to a separate Arduino pin.

  • Connect pin 5 to ground.

  • Connect the remaining 2 stepper wires to the positive supply you want to use for the stepper.

Then you can use the Arduino Stepper library, in 4-pin mode.

That works. Thank you.