LB1871M Ver la hoja de datos (PDF) - SANYO -> Panasonic
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LB1871M Datasheet PDF : 10 Pages
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LB1871, 1871M
8. Oscillator pin
A crystal oscillator and an RC circuit is connected to the LB1871’s
OSC pin. To avoid problems when selecting the oscillator and the
capacitor and resistor values, confirm these values with the
oscillator’s manufacturer. The pnp transistor and resistor circuit
shown in the figure can be used to apply an external signal (of a
few MHz) to the OSC pin.
fin = 1 to 8 MHz
Input signal level: High level voltage: 4.0 V minimum
Low level voltage: 1.5 V maximum
It will be necessary to insert a capacitor of a certain size if there is
overshoot or undershoot in the input waveform. Contact your
Sanyo representative for more information on this point if
necessary.
VDD = 6.3 V typ. (5.8 to 6.8 V)
VDD = 5.0 V typ. (4.5 to 5.5 V)
Ra = 4.7 kΩ
Ra = 2.0 kΩ
Rb = 1.3 kΩ
Rb = 1.0 kΩ
Use the LB1871 VREG output for the VDD = 6.3 V case.
9. IC internal power dissipation calculation example (calculated at VCC = 24 V, standard ratings)
• Power dissipation due to current drain
P1 = VCC × ICC = 24 V × 22 mA = 0.53 W
• Power dissipation when a –10 mA load current is drawn from the 6.3 V fixed voltage power supply.
P2 = (VCC – VREG) × I load = 17.7 V × 10 mA = 0.18 W
• Power dissipation due to the output drive current
(When IO = 0.1 A, the inter-coil voltage V Rm = Rm × IO, and the reverse voltage = 15 V)
P3 = (IO/100) × [(VCC – 0.7 V) + ((VCC – V Rm)/2) – 0.7 V] + VCC2/16 kΩ
= 1 mA × (23.3 V + 3.8 V) + 24 V2/16 kΩ = 0.06 W
• Power dissipation due to the output transistor
(When IO = 0.1 A, the inter-coil voltage V Rm = Rm × IO, and the reverse voltage = 15 V)
P4 = (VCC – V Rm) × IO = 9 V × 0.1 A = 0.9 W
Therefore, the IC’s total power dissipation is:
In stop mode:
P = P1 + P2 = 0.71 W
In start mode (When IO = 0.1 A, the inter-coil voltage V Rm = Rm × IO, and the reverse voltage = 15 V)
P = P1 + P2 + P3 + P4 = 1.67 W
No. 4849-9/10
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