LB11946 Datasheet, PDF (13/14 Pages) Sanyo Semicon Device – PWM Current Control Stepping Motor Driver

Attached Documents
LB11946
1. Switching Off Time and Noise Canceller Time Calculations
Notes on the CR Pin Setting (switching off time and noise canceller time)
The noise canceller time (Tn) and the switching off time (Toff) are set using the following formulas.
(1) When VCC is 5 V
Noise canceller time (Tn)
Tn ≈ C × R × ln {(1.5 − RI) / (4.0 − RI)}[s]
CR pin charge current: 1.25mA
Switching off time (Toff)
Toff ≈ −C × R × ln (1.5/4.8)[s]
Component value ranges
R: 5.6kΩ to 100kΩ
C: 470pF to 2000pF
(2) When V_CC is 3.3 V
Noise canceller time (Tn)
Tn ≈ C × R × ln {(1.06 − RI) / (2.66 − RI)}[s]
CR pin charge current: 0.7 mA
Switching off time (Toff)
Toff ≈ −C × R × ln (1.06 / 3.1)[s]
CR Pin Internal Circuit Structure
VCC line
One-shot multivibrator
Blanking time circuit
CR pin
E1
2. Notes on the MD Pin
(1) If slow decay mode is set up by setting the D4 and D10 bits in the input serial data to 1, the MD pin must be shorted
to ground.
(2) If fast decay mode is set up by setting the D4 and D10 bits in the input serial data to 0, mixed decay mode can be
set with the MD pin.
When the VCC = 5V specifications are used the setting voltage range for mixed decay mode is 1.6 to 3.9V.
When the VCC = 3.3V specifications are used the setting voltage range for mixed decay mode is 1.2 to 2.5V.
If mixed decay mode will not be used with the fast decay mode setting, either:
(a) Short the MD pin to ground to select fast decay mode, or
(b) Short the MD pin to VCC to select slow decay mode.
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