UDN3625M データシートの表示（PDF） - Allegro MicroSystems
部品番号
コンポーネント説明
メーカー
UDN3625M Datasheet PDF : 8 Pages
| |||
SENSOR LOCATION
3625 AND 3626
POWERHALL®
SENSOR/DRIVERS FOR
BRUSHLESS DC MOTORS
APPLICATIONS INFORMATION
Power Dissipation. Care should be taken in evaluating the package power
dissipation of these devices. Total power dissipated by the device will consist
of power due to the internal regulator, logic and drive circuitry (ICC x VCC),
power due to the output drivers (IO x VO(SAT)), and power due to the clamp
circuitry (ICL x VCL x duty cycle).
For example:
ICC x VCC = 38 mA (max) x 14 V = 532 mW (max)
IO x VO(SAT) = 450 mA x 0.4 V (max) = 180 mW (max)
ICL x VCL x duty cycle = 450 mA x 15 V (max) x 1% = 67.5 mW (max)
Total package power dissipation = 779.5 mW (max)
Some of the power dissipated by the device (ICC x VCC) can be reduced
by inserting a Zener diode in the supply line (ZA in the figure). Note that the
voltage at the VCC pin under worst-case conditions must be greater than the
minimum operating voltage (6.5 V).
Transient Protection. A note of caution concerns negative (below ground)
excursions of the outputs. In application, the coupling of the two motor
windings can provide for just such a case. Reducing the coupling between
windings will help, but ground clamp diodes or diodes in series with the
motor windings might be required (DC or DS in the figure). Most small
brushless motors will not require these diodes.
System requirements usually utilize a diode type of reverse-polarity
protection. If series diode protection is used with an inductive load (the usual
fan application), a Zener clamp between VS and ground (ZB in the figure) is
required. The Zener voltage must be greater than the supply voltage but less
than the rated maximum allowable supply voltage.
With diode reverse-polarity protection, a high-impedance supply, or a
switched supply line, high-voltage spikes will be generated (especially with
high-current or high-inductance loads) during normal operation, coasting, or
immediately after turn-off. In these situations, a Zener clamp (ZB) from VS to
ground will be required.
Over-Current Adjust Pin. The over-current limit may be reduced from the
default value (IO MAX) by selection of an external resistor (RADJ) at the
PWM/IO ADJ pin.
Share Link: 