3977, katalog

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3977
PRELIMINARY INFORMATION
(Subject to change without notice)
January 15, 2003
MICROSTEPPING DMOS DRIVER
WITH TRANSLATOR
A3977xED
(PLCC)
The A3977xED and A3977xLP are complete microstepping motor
drivers with built-in translator. They are designed to operate bipolar
stepper motors in full-, half-, quarter-, and eighth-step modes, with
output drive capability of 35 V and ± 2.5 A. The A3977 includes a
fixed off-time current regulator that has the ability to operate in slow-,
fast-, or mixed-decay modes. This current-decay control scheme
results in reduced audible motor noise, increased step accuracy, and
reduced power dissipation.
The translator is the key to the easy implementation of the A3977.
By simply inputting one pulse on the STEP input the motor will take
one step (full, half, quarter, or eighth depending on two logic inputs).
There are no phase-sequence tables, high-frequency control lines, or
complex interfaces to program. The A3977 interface is an ideal fit for
applications where a complex
V
BB1
NC
7
39
NC
NC
8
38
CP
2
PFD
9
37
CP
1
RC
1
10
36
V
CP
GND
11
35
GND
GND
12
34
GND
GND
13
33
GND
REF
14
÷8
REG
32
V
REG
RC
2
15
31
STEP
LOGIC
SUPPLY
16
V
DD
30
NC
P is unavailable or over-burdened.
Internal synchronous-rectification control circuitry is provided to
improve power dissipation during PWM operation.
Internal circuit protection includes thermal shutdown with hyster-
esis, under-voltage lockout (UVLO) and crossover-current protection.
Special power-up sequencing is not required.
The A3977 is supplied in a choice of two power packages, a 44-
lead plastic PLCC with copper batwing tabs (suffix ED), and a thin
(<1.2 mm), 28-lead TSSOP with an exposed thermal pad (suffix LP).
NC
17
29
NC
V
BB2
Dwg. PP-075-1
C
Load Supply Voltage, V
BB
.............
35 V
Output Current, I
OUT
..................
2.5 A
*
Logic Supply Voltage, V
DD
...........
7.0 V
Logic Input Voltage Range, V
IN
(t
w
>30 ns) ....
-0.3 V to V
DD
+ 0.3 V
(t
w
<30 ns) ..........
-1 V to V
DD
+ 1 V
Sense Voltage, V
SENSE
................
0.5 V
Reference Voltage, V
REF
.................
V
DD
Package Power Dissipation,
P
D
................................
See page 3
Operating Temperature Range, T
A
(A3977E) ...............
-40
FEATURES
±
Low r
DS(on)
Outputs, 0.45
Source, 0.36
Sink Typical
Automatic Current Decay Mode Detection/Selection
3.0 V to 5.5 V Logic Supply Voltage Range
C to +85
C
Mixed, Fast, and Slow Current Decay Modes
(A3977K) .............
-40
C to +125
C
Home Output
(A3977S) ...............
-20
C to +85
C
Synchronous Rectification for Low Power Dissipation
Junction Temperature, T
J
.........
+150
C
Internal UVLO and Thermal Shutdown Circuitry
Storage Temperature Range,
T
S
.........................
-55
C to +150
C
Crossover-Current Protection
* 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.
Always order by complete part number: the prefix ‘A’ + the basic part number
(3977) + a suffix letter to indicate operating temperature range + a two-letter
suffix to indicate package style, e.g.,
A3977SLP
.
ABSOLUTE MAXIMUM RATINGS
at T
A
= +25
2.5 A, 35 V Output Rating
3977
MICROSTEPPING DMOS DRIVER
WITH TRANSLATOR
FUNCTIONAL BLOCK DIAGRAM
LOGIC
SUPPLY
V
DD
V
REG
CP
2
CP
1
LOAD
SUPPLY
UVLO
AND
FAULT
2 V
REGULATOR
CHARGE
PUMP
V
CP
BANDGAP
REF.
SUPPLY
V
BB1
REF
DAC
SENSE
1
V
CP
DMOS H BRIDGE
+-
RC
1
OUT
1A
PWM LATCH
BLANKING
MIXED DECAY
OUT
1B
4
PWM TIMER
STEP
DIR
SENSE
1
RESET
MS
1
DMOS H BRIDGE
MS
2
HOME
V
BB2
SLEEP
OUT
2A
V
PFD
SR
OUT
2B
ENABLE
PFD
PWM TIMER
PWM LATCH
BLANKING
MIXED DECAY
RC
2
+-
SENSE
2
DAC
Dwg. FP-050-2
2
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 2002, 2003 Allegro MicroSystems, Inc.
3977
MICROSTEPPING DMOS DRIVER
WITH TRANSLATOR
A3977xLP
(TSSOP)
5.0
SENSE1
1
VBB1
28
LOAD
SUPPLY1
SUFFIX '–LP', R
θ
JA
= 28
°
C/W*
HOME
2
27
SLEEP
4.0
DIR
3
26
ENABLE
OUT1A
4
25
OUT1B
SUFFIX '–ED', R
θ
JA
= 32
C/W†
PFD
5
24
CP
2
3.0
RC1
6
23
CP1
SUFFIX '–LP',
R
θ
JA
= 33
°
C/W†
AGND
7
22
VCP
2.0
REF
8
÷8
21
PGND
RC2
9
REG
20
V
REG
LOGIC
SUPPLY
10
VDD
19
STEP
1.0
SUFFIX 'E–'
AND 'S–'
OUT2A
11
18
OUT2B
SUFFIX 'K–'
MS2
12
17
RESET
0
MS1
13
16
SR
25
50
75
100
125
150
SENSE
2
14
VBB2
15
LOAD
SUPPLY2
AMBIENT TEMPERATURE IN
C
Dwg. GP-018-2
Dwg. PP-075
Package Thermal Resistance, R
JA
A3977xLP.........................
28
C/W
*
A3977xED ........................
32
C/W
†
C/W
†
* Measured on JEDEC standard “High-K” four-layer board.
† Measured on typical two-sided PCB with three square inches
(1935 mm
2
) copper ground area.
Table 1. Microstep Resolution Truth Table
MS
1
MS
2
Resolution
L
L
Full step (2 phase)
H
L
Half step
L
H
Quarter step
H
H
Eighth step
www.allegromicro.com
3
A3977xLP.........................
33
3977
MICROSTEPPING DMOS DRIVER
WITH TRANSLATOR
ELECTRICAL CHARACTERISTICS at T
A
= +25
C, V
BB
= 35 V, V
DD
= 3.0 V to 5.5V (unless otherwise
Limits
Characteristic
Symbol Test Conditions
Min. Typ. Max. Units
Output Drivers
Load Supply Voltage Range V
BB
Operating
8.0 – 35 V
During sleep mode
0 – 35 V
Output Leakage Current I
DSS
V
OUT
= V
BB
– <1.0 20
A
V
OUT
= 0 V
– <1.0 -20
A
Output On Resistance
r
DS(on)
Source driver, I
OUT
= -2.5 A – 0.45 0.57
Sink driver, I
OUT
= 2.5 A – 0.36 0.43
Body Diode Forward Voltage V
F
Source diode, I
F
= -2.5 A – – 1.4 V
Sink diode, I
F
= 2.5 A
– – 1.4 V
Motor Supply Current
I
BB
f
PWM
< 50 kHz
– – 8.0 mA
Operating, outputs disabled – – 6.0 mA
Sleep mode
– – 20
A
Control Logic
Logic Supply Voltage Range V
DD
Operating
3.0 5.0 5.5 V
Logic Input Voltage
V
IN(1)
0.7V
DD
– – V
V
IN(0)
– – 0.3V
DD
V
Logic Input Current
I
IN(1)
V
IN
= 0.7V
DD
-20 <1.0 20
A
I
IN(0)
V
IN
= 0.3V
DD
-20 <1.0 20
A
Maximum STEP Frequency f
STEP
500* – – kHz
HOME Output Voltage
V
OH
I
OH
= -200
A
0.7V
DD
– – V
V
OL
I
OL
= 200
A
– – 0.3V
DD
V
Blank Time
t
BLANK
R
t
= 56 k
, C
t
= 680 pF 700 950 1200 ns
Fixed Off Time
t
off
R
t
= 56 k
, C
t
= 680 pF 30 38 46
s
continued next page …
4
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
noted)
3977
MICROSTEPPING DMOS DRIVER
WITH TRANSLATOR
ELECTRICAL CHARACTERISTICS at T
A
= +25
C, V
BB
= 35 V, V
DD
= 3.0 V to 5.5V (unless otherwise
Limits
Characteristic
Symbol Test Conditions
Min. Typ. Max. Units
Control Logic (cont’d)
Mixed Decay Trip Point PFDH
– 0.6V
DD
– V
PFDL
– 0.21V
DD
– V
Ref. Input Voltage Range V
REF
Operating
0 – V
DD
V
Reference Input Current I
REF
– 0
3.0
A
Gain (G
m
) Error
E
G
V
REF
= 2 V, Step = 3
– –
10 %
(note 3)
V
REF
= 2 V, Step = 5
– –
5.0 %
V
REF
= 2 V, Step = 9
– –
5.0 %
Crossover Dead Time
t
DT
SR enabled
100 475 800 ns
Thermal Shutdown Temp. T
J
– 165 –
C
Thermal Shutdown Hysteresis
T
J
– 15 –
C
UVLO Enable Threshold V
UVLO
Increasing V
DD
2.45 2.7 2.95 V
UVLO Hysteresis
V
UVLO
0.05 0.10 – V
Logic Supply Current
I
DD
f
PWM
< 50 kHz
– – 12 mA
Outputs off
– – 10 mA
Sleep mode
– – 20
A
* Operation at a step frequency greater than the specified minimum value is possible but not warranteed.
NOTES: 1. Typical Data is for design information only.
2. Negative current is defined as coming out of (sourcing) the specified device terminal.
3. E
G
= ([V
REF
/8] – V
SENSE
)/(V
REF
/8)
www.allegromicro.com
5
noted)
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