A3974SEDTR Allegro Microsystems Inc, A3974SEDTR Datasheet - Page 8

• Manufacturer Part Number: A3974SEDTR
• Description: IC MOTOR DRVR PWM DUAL 44-PLCC
• Manufacturer: Allegro Microsystems Inc

Specifications of A3974SEDTR

• Applications: DC Motor Driver
• Number Of Outputs: 2
• Current - Output: ±1.5A
• Voltage - Load: 15 V ~ 50 V
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -20°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-LCC (J-Lead)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

D14 Enable Logic. This bit, in conjuction with ENABLE,
determines if the output drivers are in the chopped or on state.
D15 Phase Logic. This bit determines if the device is operat-
ing in the forward or reverse state.
D16 G
by 5 or 10.
D17 Bridge 2 Mode. This bit determines slow or mixed decay
for internal current-control operation.
D19 Test Mode. This bit is reserved for testing and should
never be changed by the user. Default (low) operates the device
in normal mode.
A3974
ENABLE1
m
D15
Range Select. This bit determines if V
0
1
0
1
0
1
D16
D17
0
1
0
1
Reverse
Forward
State
D14
0
0
1
1
Decay Mode
OUT
Divider
÷10
÷5
Mixed
Slow
H
L
Mode
Chopped
On
On
Chopped
A
FUNCTIONAL DESCRIPTION (continued)
DMOS Dual Full-Bridge PWM Motor Driver
OUT
H
L
B
REF
is divided
Word 1 Bit Assignments
D0 - D17. Identical defi nitions as Word 0, with Word 1 selected.
Data is written to Full Bridge 2.
D19 Idle Mode. The device can be placed in a low-power
“idle” mode by writing a “0” to D19. The outputs will be dis-
abled, the charge pump will be turned off, and the device will
draw a lower load supply currrent. The undervoltage monitor
circuit will remain active. D19 should be programmed high for
1 ms before attempting to enable any output driver.
Select Word 1 (D18 = 1)
Bit
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
D16
D17
D18
D19
Function
Bridge 2 blank time LSB
Bridge 2 blank time MSB
Bridge 2 off-time LSB
Bridge 2 off-time bit 1
Bridge 2 off-time bit 2
Bridge 2 off-time bit 3
Bridge 2 off-time MSB
Bridge 2 fast-decay time bit LSB
Bridge 2 fast-decay time bit 1
Bridge 2 fast-decay time bit 2
Bridge 2 fast-decay time bit MSB
Bridge 2 sync. rect. control
Bridge 2 sync. rect. control
Bridge 2 external PWM mode
Bridge 2 enable
Bridge 2 phase
Bridge 2 reference range select
Bridge 2 internal PWM mode
Word select = 1
Idle mode
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
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