STK672-120-E View Datasheet(PDF) - SANYO -> Panasonic

Part Name

Description

Manufacturer

STK672-120-E

Two-Phase Stepping Motor Driver (Square Wave Drive) Output Current 2.4A

SANYO -> Panasonic 

STK672-120-E

Input Pin Functions (CMOS input levels)

Pin

Pin No.

Function

Input conditions when operating

CLOCK

9

Reference clock for motor phase current switching

Operates on the rising edge of the signal

MODE

8

Excitation mode selection

Low: 2-phase excitation

High: 1-2 phase excitation

CWB

7

Motor direction switching

Low: CW (forward)

High: CCW (reverse)

RESETB

6

System reset and A, AB, B, and BB outputs cutoff.

A reset is applied by a low level

Applications must apply a reset signal for at least 20μs when power is

first applied.

• A simple reset function is formed from D1, CO4, and RO3 in this application circuit. With the CLOCK input held low,

when the 5V supply voltage is brought up a reset is applied if the motor output phases A and BB are driven.

If the 5V supply voltage rise time is slow (over 50ms), the motor output phases A and BB may not be driven. Increase

the value of the capacitor CO4 and check circuit operation again.

• See the timing chart for the concrete details on circuit operation.

Usage Notes

• 5V system input pins

[RESETB and CLOCK (Input signal timing when power is first applied)]

As shown in the timing chart, a RESETB signal input is required by the driver to operate with the timing in which the

F1 gate is turned on first. The RESETB signal timing must be set up to have a width of at least 20μs, as shown below.

The capacitor CO4 and the resistor RO3 in the application circuit form simple reset circuit that uses the RC time

constant rising time. However, when designing the RESETB input based on CMOS levels, the application must have

the timing shown in figure 1.

Rise of the 5V supply voltage

RESETB signal input

CLOCK signal

At least 20μs

At least 10μs

Figure 1 RESETB and CLOCK Signals Input Timing

See the timing chart for details on the CLOCK, MODE, CWB, and other input pins.

[Vref <Motor current peak value setting>]

In the sample application circuit, the peak value of the motor current (IOH) is set by RO1, RO2, and VDD (5V) as

described by the formula below.

IOH

0

Figure 2 Motor Current IO Flowing into the Driver IC

IOH = Vref ÷ Rs Here, Rs is hybrid IC internal current detection resistor

Vref = (R02 ÷ (R01 + R02)) × 5V

STK672-120-E: Rs = 0.165Ω

No.6042-5/9

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