A3976: Dual Full Bridge Protected Motor Driver

A3976
Dual Full Bridge Protected Motor Driver
Discontinued Product
These parts are no longer in production The device should not be
purchased for new design applications. Samples are no longer available.
Date of status change: May 1, 2006
Recommended Substitutions:
For new customers or new applications, refer to the 3980.
NOTE: For detailed information on purchasing options, contact your
local Allegro field applications engineer or sales representative.
Allegro MicroSystems, Inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan for a
product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The information
included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor
for any infringements of patents or other rights of third parties which may result from its use.
Page 1 of 6
3976
PRELIMINARY DATASHEET - 8/24/04
(Subject to change without notice)
V BB 1
2 4 V CC
ENABLE1
2
2 3 ENABLE2
PHASE1
3
2 2 PHASE2
NC
4
2 1 NC
NC
5
2 0 NC
GROUND
GROUND
n/c
OUT1A
6
7
A3976KLB
1 9 GROUND
1 8 GROUND
8
1 7 n/c
9
1 6 OUT2A
n/c 1 0
DUAL FULL BRIDGE
PROTECTED MOTOR DRIVER
The A3976 is designed to drive both windings of a bipolar stepper
motor or bidirectionally control two DC Motors. Both H-Bridges are capable
of continuous output currents of up to +/- 500 mA and operating voltages to
27V. Free wheeling, substrate isolated diodes are included for output transient
suppression when switching motors or other inductive loads. For each bridge
the PHASE input controls load current polarity by selecting the appropriate
source and sink driver pair. The ENABLE input, when held high, enables the
respective output H-bridge. When both ENABLE pins are held low the device
will enter SLEEP mode and consume less than 100µA.
1 5 n/c
FAULT1
11
1 4 FAULT2
OUT1B
12
1 3 OUT2B
ABSOLUTE MAXIMUM RATINGS
at TA = +25°C
Operating Supply Voltage, VBB .................... 27 V
Non-Operating Supply Voltage .................... 35 V
Output Current, IOUT ............................±500 mA*
Logic Supply Voltage, VCC .......................... 7.0 V
Fault Output Voltage ................................... 7.0 V
Logic Input Voltage Range,
VIN ......................... -0.3 V to VCC + 0.3 V
Package Power Dissipation (TA = +25°C), PD
A3976KLB.................................. 2.2 W
Operating Temperature Range,
TA .............................. -40°C to +125°C
Junction Temperature, TJ ......................... +150°C
Storage Temperature Range,
TS .............................. -55°C to +150°C
* Output current rating may be limited by duty cycle,
ambient temperature, and heat sinking. Under any set of
conditions, do not exceed the specified current rating or a
junction temperature of 150°C.
The A3976 is protected to ensure safe operation in harsh operating
environments and was designed specifically for automotive applications.
Protection circuitry will check for open or shorted load, motor lead short to
ground or supply, VBB overvoltage, VCC undervoltage, and thermal
shutdown. If any of these conditions are detected the outputs will be disabled
and fault information will be output to diagnostic pins FAULT1 and FAULT2.
The A3976 is supplied in a 24-lead plastic SOIC with a copper
batwing tab (suffix ‘LB’).
FEATURES
T
T
T
T
T
T
T
T
T
T
T
±500 mA Continuous Output Rating
35V Load Dump Survival
Output Short Circuit Protection
Coded Fault Diagnostic Outputs
Low Current Standby Mode
Open Load Monitor
Low Current Standby Mode
VBB Over Voltage Shutdown
Internal Thermal Shutdown Circuitry
Internal Low Parasitic Free Wheeling Diodes
Crossover Current Protection
Page 2 of 6
3976 – DUAL FULL BRIDGE
PROTECTED MOTOR DRIVER
Functional Block Diagram
(one of two bridges shown)
Input Logic
PHASE
X
0
1
ENABLE
0
1
1
OUTA
Off
Low
High
OUTB
Off
High
Low
Fault Logic
Fault Condition
Thermal Shutdown
Short to Battery or Open Load
Short to Ground
Normal Operation
FAULT1
Low
Low
High
High
FAULT2
Low
High
Low
High
Page 3 of 6
3976 – DUAL FULL BRIDGE
PROTECTED MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at TA = -40°C to +125°C, VBB = 16V, VCC = 4.5 to 5.5 V (Unless noted otherwise)
Limits
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Units
–
27
V
5.5
V
Output Drivers
Load Supply Voltage Range
VBB
Operating
6
Logic Supply Range
VCC
Operating
4.5
Output Current Limit
ICL
Outputs A or B = GROUND
0.7
1.1
–
A
Outputs A or B = VBB
0.7
1.1
–
A
VOUT = VBB
–
<1.0
50
µA
VOUT = 0 V
–
<1.0
-50
µA
Source Driver, IOUT = -350 mA
–
1.0
1.2
V
Source Driver, IOUT = -500 mA
–
1.2
1.3
Sink Driver, IOUT = +350 mA
–
0.2
0.4
V
Sink Driver, IOUT = +500 mA
–
0.4
0.6
V
IF = 500 mA (Sink / Ground Clamp)
–
1.2
1.5
V
IF = 500 mA (Source / Flyback)
–
1.55
2.0
V
ENABLE1 = ENABLE2 = High
–
7
10
mA
Sleep Mode ENABLE1 = ENABLE2 = Low
–
–
25
µA
ENABLE1 = ENABLE2 = High
–
45
50
mA
Sleep Mode, ENABLE1 = ENABLE2 = Low
–
–
75
µA
VIN(1)
0.7VCC
–
-
V
VIN(0)
–
–
.3VCC
V
Output Leakage Current
Output Saturation Voltage
Clamp Diode Forward Voltage
ICEX
VCE(SAT)
VF
(Flyback or Ground Clamp)
Control Logic
Motor Supply Current
IBB
(No Load)
Logic Supply Current
Logic Input Voltage
Logic Input Current
ICC
IIN(1)
VIN = 5 V
–
50
100
µA
IIN(0)
VIN = 0 V
–
-1.0
-2.0
µA
Page 4 of 6
3976 – DUAL FULL BRIDGE
PROTECTED MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at TA = -40°C to +125°C, VBB = 16 V, VCC = 4.5 to 5.5 V (Unless noted otherwise)
Limits
Characteristics
Symbol
Test Conditions
Min.
Typ.
Max.
Units
IF-LEAK
VF = 5 V, No Faults
-
-
10
µA
–
0.8
V
Fault Circuitry
Fault Output Leakage Current
Fault Output Voltage
VFL
Fault Output Current
IF
Output Open Load Current
Thermal Fault Temp.
Thermal Fault Hysteresis
Fault Condition Asserted, IF = 25 µA
VF = 5 V, ENABLE = High
25
50
75
µA
VBB = 12 V
–
2
–
mA
TF
–
170
–
°C
TFHYS
–
10
–
°C
27
30
33
V
I OUT-O.L.
OVLO Enable Threshold
VBB rising
OVLO Hysteresis
1.5
UVLO Enable Threshold
VCC rising
UVLO Hysteresis
V
3.5
4
4.49
V
–
400
–
mV
Timing
Open Fault to Reset Delay
trs
VBB = 12 V
–
–
25
µs
PHASE_X Delay to OPEN Fault
tof
VBB = 12 V
–
8
–
µs
PHASE_X Delay to S.C. Fault
tSC
VBB = 12 V
–
5
–
µs
ENABLE_X Delay to Fault
tof
VBB = 12 V
–
5
–
µs
Propagation Delay Times
tpd
IOUT = ±0.35A, 50%TO 90%
ENABLE ON TO SOURCE ON
–
0.3
µs
ENABLE OFF TO SOURCE OFF
–
0.4
µs
ENABLE ON TO SINK ON
–
0.3
µs
ENABLE OFF TO SINK OFF
–
0.2
µs
PHASE CHANGE TO SINK ON
–
4.0
µs
PHASE CHANGE TO SINK OFF
–
0.3
µs
PHASE CHANGE TO SOURCE ON
–
4.0
µs
PHASE CHANGE TO SOURCE OFF
–
0.4
µs
0.5
3.0
Cross Over Dead Time
tCODT
1KΩ (1k+1k) Load (VBB to OUT to GND)
6.0
µs
Page 5 of 6
3976 – DUAL FULL BRIDGE
PROTECTED MOTOR DRIVER
APPLICATION NOTES
Open Load Protection. During normal PWM
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. Internal sense resistors in
series with VBB and ground will trip the fault circuitry if
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. Circuitry turns OFF all drivers
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. The printed wiring board should use a heavy
ground plane. For optimum electrical and thermal
performance, the driver should be soldered directly onto the
board. The load supply terminal, VBB, should be decoupled
with an electrolytic capacitor (> 47 µF is recommended)
placed as close to the device as possible.
Fault Outputs. Both Fault outputs are open-collectorsink 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.
Page 6 of 6
3976 - DUAL FULL BRIDGE
PROTCTED MOTOR DRIVER
Terminal List
Name
VBB
ENABLE1
PHASE1
GROUND
OUT1A
FAULT1
OUT1B
OUT2B
FAULT2
OUT2A
PHASE2
ENABLE2
VCC
NC
Description
Motor Supply Voltage
Control Logic – Bridge 1
Control Logic – Bridge 1
Power Ground Return
Bridge 1 Output A
Diagnostic Output
Bridge 1 Output B
Bridge 2 Output B
Diagnostic Output
Bridge 2 Output A
Control Logic – Bridge 2
Control Logic – Bridge 2
Logic Supply
No Connect
SOIC - 24
1
2
3
18,19,6,7
9
11
12
13
14
16
22
23
24
4,5,8,15,17,20,21
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