3976, katalog

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3976
PRELIMINARY DATASHEET - 12/20/01
(Subject to change without notice)
DUAL FULL BRIDGE
PROTECTED MOTOR DRIVER
V
BB
1
24
V
CC
ENABLE2
ENABLE1
2
23
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 100
m
A.
PHASE1
NC
3
22
PHASE2
NC
4
21
NC
5
20
NC
GROUND
GROUND
6
7
A3976KLB
19
18
GROUND
GROUND
n/c
8
17
n/c
OUT1A
n/c
9
16
OUT2A
n/c
10
15
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.
FAULT1
OUT1B
11
14
FAULT2
OUT2B
12
13
ABSOLUTE MAXIMUM RATINGS
at T
A
= +25
°
C
Operating Supply Voltage, V
BB
....................
27 V
Non-Operating Supply Voltage ....................
35 V
Output Current, I
OUT
............................ ±
500 mA*
Logic Supply Voltage, V
CC
..........................
7.0 V
Fault Output Voltage ...................................
7.0 V
Logic Input Voltage Range,
V
IN
.........................
-0.3 V to V
CC
+ 0.3 V
Package Power Dissipation (T
A
= +25°C), P
D
The A3976 is supplied in a 24-lead plastic SOIC with a copper
batwing tab (suffix ‘LB’).
FEATURES
„ ±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
A3976KLB..................................
2.2 W
Operating Temperature Range,
T
A
..............................
-40
°
C to +125
°
C
Junction Temperature, T
J
.........................
+150
°
C
Storage Temperature Range,
T
S
..............................
-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.
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3976 – DUAL FULL BRIDGE
PROTECTED MOTOR DRIVER
Functional Block Diagram
(one of two bridges shown)
V
CC
Thermal
Shutdown
Over/Under
Voltage
Monitor
V
BB
Short to Supply
Monitor
FAULT1
Diagnostic Logic
FAULT2
T
o Bridge 2
PHASE1
OUT1A
ENABLE1
CONTROL
LOGIC
OUT1B
PHASE2
ENABLE2
OUT2A
Input Pull Down
To Bridge 2
OUT2B
GROUND
Short to Ground
Monitor
Input Logic
PHASE
ENABLE
OUTA
OUTB
X
0
Off
Off
0
1
Low
High
1
1
High
Low
Fault Logic
Fault Condition
FAULT1
FAULT2
Thermal Shutdown
Low
Low
Short to Battery or Open Load
Low
High
Short to Ground
High
Low
Normal Operation
High
High
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3976 – DUAL FULL BRIDGE
PROTECTED MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at T
A
= -40°C to +125°C, V
BB
= 16V, V
CC
= 4.5 to 5.5 V
(Unless noted otherwise)
Limits
Characteristics
Symbol
Test Conditions
Min. Typ. Max. Units
Output Drivers
Load Supply Voltage Range
V
BB
Operating
6
–
27
V
Logic Supply Range
V
CC
Operating
4.5
5.5
V
Output Current Limit
I
CL
Outputs A or B = GROUND
0.7
1.1
–
A
Outputs A or B = V
BB
0.7
1.1
–
A
Output Leakage Current
I
CEX
V
OUT
= V
BB
–
<1.0
50
µA
V
OUT
= 0 V
–
<1.0
-50
m
A
Output Saturation Voltage
V
CE(SAT)
Source Driver, I
OUT
= -350 mA
–
1.0
1.2
V
Source Driver, I
OUT
= -500 mA
–
1.2
1.3
Sink Driver, I
OUT
= +350 mA
–
0.2
0.4
V
Sink Driver, I
OUT
= +500 mA
–
0.4
0.6
V
Clamp Diode Forward Voltage
V
F
I
F
= 500 mA (Sink / Ground Clamp)
–
1.2
1.5
V
(Flyback or Ground Clamp)
I
F
= 500 mA (Source / Flyback)
–
1.55
2.0
V
Control Logic
Motor Supply Current
I
BB
ENABLE1 = ENABLE2 = High
–
7
10
mA
(No Load)
Sleep Mode ENABLE1 = ENABLE2 = Low
–
–
25
µA
Logic Supply Current
I
CC
ENABLE1 = ENABLE2 = High
–
45
50
mA
Sleep Mode, ENABLE1 = ENABLE2 = Low
–
–
75
µA
Logic Input Voltage
V
IN(1)
0.7V
CC
–
-
V
V
IN(0)
–
–
.3V
CC
V
Logic Input Current
I
IN(1)
V
IN
= 5 V
–
50
100
µA
I
IN(0)
V
IN
= 0 V
–
-1.0
-2.0
µA
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3976 – DUAL FULL BRIDGE
PROTECTED MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at T
A
= -40°C to +125°C, V
BB
= 16 V, V
CC
= 4.5 to 5.5 V
(Unless noted otherwise)
Limits
Characteristics
Symbol
Test Conditions
Min. Typ. Max. Units
Fault Circuitry
Fault Output Leakage Current
I
F-LEAK
V
F
= 5 V, No Faults
-
-
10
m
A
Fault Output Voltage
V
FL
Fault Condition Asserted, I
F
= 25
m
A
–
0.8
V
Fault Output Current
I
F
V
F
= 5 V, ENABLE = High
25
50
75
m
A
Output Open Load Current
I
OUT-O.L.
BB
= 12 V
–
2
–
mA
Thermal Fault Temp.
T
F
–
170
–
°C
Thermal Fault Hysteresis
T
FHYS
–
10
–
°C
OVLO Enable Threshold
V
BB
rising
27
30
33
V
OVLO Hysteresis
1.5
V
UVLO Enable Threshold
V
CC
rising
3.5
4
4.49
V
UVLO Hysteresis
–
400
–
mV
Timing
Open Fault to Reset Delay
t
rs
V
BB
= 12 V
–
–
25
m
s
PHASE_X Delay to OPEN Fault
t
of
V
BB
= 12 V
–
8
–
m
s
PHASE_X Delay to S.C. Fault
t
SC
V
BB
= 12 V
–
5
–
m
s
ENABLE_X Delay to Fault
t
of
V
BB
= 12 V
–
5
–
m
s
Propagation Delay Times
t
pd
I
OUT
= ±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
Cross Over Dead Time
t
CODT
1K
W
(1k+1k) Load (V
BB
to OUT to GND)
0.5
3.0
6.0
µs
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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.
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, V
BB
, should be decoupled
with an electrolytic capacitor (> 47 µF is recommended)
placed as close to the device as possible.
Short Circuit Protection.
Internal sense resistors in
series with V
BB
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 5
m
s 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.
s 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 5
m
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