Rainbow Electronics BA6285FP User Manual

Motor driver ICs
Reversible motor driver
BA6285FS / BA6285FP
The BA6285FS and BA6285FP are reversible-motor drivers with a maximum output current of 1.0A. Two logic inputs allow four output modes: forward, reverse, stop (idling), and brake. A built-in power saving circuit suppresses current consumption when the motor is in stop mode.
Applications VCRs and audio equipment in general
Features
1) Logic and power sections have separate ground pins; this allows the IC to drive speed-variable, re­versible motors by connecting an electronic governor circuit.
2) Built-in power saving circuit suppresses the stop mode current dissipation.
Absolute maximum ratings (Ta = 25C)
3) Output voltage can be set arbitrarily with the V
4) Interfaces with TTL devices.
5) Built-in thermal shutdown circuit.
ref pin.
Recommended operating conditions (Ta = 25C)
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Motor driver ICs BA6285FS / BA6285FP
Block diagram
Pin descriptions
BA6285FS
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Motor driver ICs BA6285FS / BA6285FP
BA6285FP
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Motor driver ICs BA6285FS / BA6285FP
Input / output circuits
Electrical characteristics (unless otherwise noted, Ta = 25, V
CC = 9V, VM = 9V, VREF = 9V)
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Motor driver ICs BA6285FS / BA6285FP
Measurement circuits
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Motor driver ICs BA6285FS / BA6285FP
Circuit operation (1) Input section The four output modes are controlled by two logic inputs. Current flows from OUT1 to OUT2 when F
IN is LOW, and from OUT2 to OUT1 when RIN is HIGH
R
IN is LOW (refer to the truth table). The input circuit
and F
IN is HIGH and
can be operated by a logic circuit with a current capacity of 120 170µA. (2) Output section Current flows from OUT1 to OUT2 during forward rota­tion, and from OUT2 to OUT1 during reverse rotation.
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The output voltages V
OH [V]=VREF – VCE (sat) (PNP) – VBE (NPN)
V
OL [V]=VCE (sat) (NPN)
V
CE and VBE are functions of the output current (see elec-
V
OH and VOL are given by :
trical characteristic curves). The output current can be set with the V
REF pin.
(3) Power saving circuit All circuits are turned OFF when the F
IN and RIN input pins
are both LOW or the POWER SAVE pin is HIGH. This cir­cuit saves power during standby mode by leaving the outputs OPEN.
Motor driver ICs BA6285FS / BA6285FP
(4) Thermal shutdown circuit When the thermal shutdown circuit is activated at the chip temperature of about 175C (typical), the outputs are left OPEN. The temperature difference between the activation and deactivation settings is about 15C. When the thermal shutdown circuit is deactivated, the outputs revert to the status determined by input mode.
Application examples
BA6285FS BA6285FP
Input / output truth table
Operation notes
(1) The quality of these products have been carefully checked; however, use of the products with applied volt­ages, operating temperatures, or other parameters that exceed the absolute maximum rating given may result in the damage of the IC and the product it is used in. If the IC is damaged, the short mode and open modes cannot be specified, so if the IC is to be used in applications where parameters may exceed the absolute maximum ratings, then be sure to incorporate fuses, or other physi­cal safety measures. (2) GND potential The potential for pin 1 must be kept lower than the poten­tials of the other pins regardless of the circumstances.
(3) Input pins Voltage should never be applied to the input pins when the V
CC voltage is not applied to the IC. Similarly, when
V
CC is applied, the voltage on each input pin should be
less than V
CC and within the guaranteed range for the
electrical characteristics. (4) Back-rush voltage Depending on the ambient conditions, environment, or motor characteristics, the back-rush voltage may fluctu­ate. Be sure to confirm that the back-rush voltage will not adversely affect the operation of the IC.
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Motor driver ICs BA6285FS / BA6285FP
(5) Large current line Large currents are carried by the motor power supply and motor ground for these ICs. Therefore, the layout of the pattern of the PC board and the constants of certain parameters for external compo­nents, such as the capacitor between the power supply and ground, may cause this large output current to flow back to the input pins, resulting in output oscillation or other malfunctions. To prevent this, make sure that the PC board layout and external circuit constants cause no problems with the characteristics of these ICs. (6) Power dissipation The power dissipation will fluctuate depending on the mounting conditions of the IC and the ambient environ­ment. Make sure to carefully check the thermal design of the application where these ICs will be used. (7) Power consumption The power consumption by the IC varies widely with the power supply voltage and the output current. Give full consideration to the power dissipation rating and the thermal resistance data and transient thermal resistance data, to provide a thermal design so that none of the rat­ings for the IC are exceeded. (8) ASO Make sure that the output current and supply voltage do not exceed the ASO values. (9) Precautions for input mode switching To ensure reliability, it is recommended that the mode switching for the motor pass once through the open mode.
(10) In-rush current There are no circuits built into these ICs that prevent in­rush currents. Therefore, it is recommended to place a current limiting resistor or other physical countermea­sure. (11) Factors regarding the thermal, power supply, and motor conditions If the potential of the output pin sways greatly and goes below the potential of ground, the operation of the IC may malfunction or be adversely affected. In such a case, place a diode between the output and ground, or other measure, to prevent this. (12) HIGH level output voltage setting pin Ensure that the voltage applied to the V
REF pin does not
exceed the voltage on the motor power supply pin or the V
CC pin.
(13) The input and POWER SAVE pins have tempera­ture-dependent characteristics. T ake the temperature ef­fect into consideration when using the IC. (14) To eliminate motor noise, connect a capacitor be­tween OUT1 and GND and between OUT2 and GND. Al­ternatively, connect a capacitor between OUT1 and OUT2, and also a diode between OUT1 and GND and between OUT2 and GND (see Fig. 11).
Electrical characteristic curves
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Motor driver ICs BA6285FS / BA6285FP
External dimensions (Units: mm)
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