bd63847 ROHM Co. Ltd., bd63847 Datasheet - Page 7

• Manufacturer Part Number: bd63847
• Description: Micro Step 36v Stepper Motor Drivers
• Manufacturer: ROHM Co. Ltd.

© 2010 ROHM Co., Ltd. All rights reserved.
BD63847/63843EFV
www.rohm.com
○CR/ Connection terminal of CR for setting chopping frequency
○MTH/ Current decay mode-setting terminal
○NC terminal
○IC back metal
This is the terminal to set the chopping frequency of output. Please connect the external C(470p~1500pF) and
R(10k~200kΩ) between this terminal and GND. Please refer to P8.
Please interconnect from external components to GND in such a way that the interconnection does not have impedance
in common with other GND patterns. In addition, please carry out the pattern design in such ways as keeps such steep
pulses as square wave etc. away and that there is no noise plunging. Please mount the two components of C and R if
being used by PWM constant current control because normal PWM constant current control becomes impossible if CR
terminal is open or it is biased externally.
This is the terminal to set the current decay mode. Current decay mode can be optionally set according to input voltage.
Please connect to GND if using at SLOW DECAY mode.
Please avoid using with MTH terminal open because if MTH terminal is open, the input is unsettled, and then there is the
danger that PWM operation becomes unstable. Besides, please take into consideration the outflow current (max.2µA) if
inputted by resistance division when selecting the resistance value.
This terminal is unconnected electrically with IC internal circuit.
For HTSSOP-B28 package, the heat-radiating metal is mounted on IC’s back side, and on the metal the heat-radiating
treatment is performed when in use, which becomes the precondition to use, so please secure sufficiently the
heat-radiating area by surely connecting by solder with the GND plane on the board and getting as wide GND pattern as
possible. Please be careful because the allowable loss as shown in P.16 cannot be secured if not connected by solder.
Moreover, the back side metal is shorted with IC chip’s back side and becomes the GND potential, so there is the danger
of malfunction and destruction if shorted with potentials other than GND, therefore please absolutely do not design
patterns other than GND through the IC’s back side.
MTH terminal input voltage [V]
0.4~1.0
1.5~3.5
0~0.3
Current decay mode
SLOW DECAY
FAST DECAY
MIX DECAY
7/19
Technical Note
2010.4 - Rev.A