LB1946 查看數據表（PDF） - SANYO -> Panasonic
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LB1946 Datasheet PDF : 16 Pages
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LB1946
2. Notes on the MD pin
• 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 GND.
• If the decay mode is set up by setting the D4 and D10 bits in the input serial data to 0, 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:
Short the MD pin to GND to select fast decay mode, or
Short the MD pin to VCC to select slow decay mode.
3. Usage Notes
• Notes on the VREF pin
Since the VREF pin inputs the reference voltage used to set the current, applications must be designed so that noise
does not occur at this pin.
• Notes on the GND pins
Since this IC switches large currents, care is required with respect to the GND pins.
The PCB pattern in sections where large currents flow must be designed with low impedances and must be kept
separate from the small-signal system.
In particular, the GND terminals of the E pin sense resistor (RE) and external Schottky barrier diode GND terminals
must be located as close as possible to the IC GND. The capacitor between VCC and ground and between VBB and
GND must be as close as possible to the corresponding VCC and VBB pin in the pattern.
• Power on sequence
When turning the power systems on
VCC→logic level inputs (CLK, DATA, SET, and ST) →VREF→VBB
When turning the power systems off
VBB→VREF→logic level inputs (CLK, DATA, SET, and ST) →VCC
Note that if the power supply for the logic level inputs is on when the VCC power supply is off, a bias with an
unstable state will be applied to the protection diodes at the VCC pins, and this can cause incorrect operation.
No.7115-15/16
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