A3976KLB Allegro Microsystems Inc, A3976KLB Datasheet - Page 6

• Manufacturer Part Number: A3976KLB
• Manufacturer: Allegro Microsystems Inc

Specifications of A3976KLB

• Operating Current: 50mA
• Operating Temperature Classification: Commercial
• Package Type: SOIC W
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / Rohs Status: Not Compliant

Open Load Protection.
operation, diagnostic circuitry will look for a minimum
source current level after a bridge is signalled on.
Additionally, the diode flyback is monitored on the proper
output. The logic will signal a fault and disable the outputs if
it determines that the current is below the minimum level
AND no flyback is occurring. If the inductive load is too
large, the current would take too long to reach the minimal
level and a false open load would be reported. It is
recommended that the inductive load be less than 38 mH.
Short Circuit Protection.
series with V
greater than 1.1 A is detected. To prevent false overcurrent
events due to reverse recovery spikes of the clamp diodes,
the current monitor is blanked for 5µs after a high side is
signalled to turn on. If an additional input command follows
after the initial fault, the selected pair of drivers will pulse
on for the 5µs blanking duration. The short circuit fault will
remember the input state where the fault occurred and will
wait for that particular logic state after the short has been
removed before normal operation is allowed to resume.
Thermal Protection
when the junction temperature reaches 170°C typically. It is
intended only to protect the device from failures due to
excessive junction temperatures and has a hysteresis of
approximately 15°C.
Layout.
ground plane. For optimum electrical and thermal
The printed wiring board should use a heavy
BB
and ground will trip the fault circuitry if
PROTECTED MOTOR DRIVER
. Circuitry turns OFF all drivers
3976 – DUAL FULL BRIDGE
During normal PWM
Internal sense resistors in
APPLICATION NOTES
performance, the driver should be soldered directly onto the
board. The load supply terminal, V
with an electrolytic capacitor (> 47 µF is recommended)
placed as close to the device as possible.
Fault Outputs.
sink types. These turn on (go low) when there is a fault.
Each requires a pull-up resistor, rated at approximately
100 kΩ at 5 V.
Both Fault outputs are open-collector-
BB
, should be decoupled
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