3977 Datasheet, PDF (1/18 Pages) Allegro MicroSystems – MICROSTEPPING DMOS DRIVER WITH TRANSLATOR

3977
A3977xED
(PLCC)
NC 7
6
5
4
3
2
1 44 43 42 41 40
VBB1
NC 8
PFD 9
RC1 10
PWM
TIMER
GND 11
GND 12
GND 13
REF 14
÷8
REG
RC2 15
LOGIC
SUPPLY ^{16 VDD}
NC 17
VBB2
18 19 20 21 22 23 24 25 26 27 28
39 NC
38 CP2
37 CP1
36 VCP
35 GND
34 GND
33 GND
32 VREG
31 STEP
30 NC
29 NC
Dwg. PP-075-1
ABSOLUTE MAXIMUM RATINGS
at T_A = +25°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
(A3977Kx) ............ -40°C to +125°C
(A3977Sx) .............. -20°C to +85°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.
MICROSTEPPING DMOS DRIVER
WITH TRANSLATOR
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
µP 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 hysteresis,
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-pin
plastic PLCC with copper batwing tabs (suffix ED), and a thin (<1.2 mm), 28-
pin TSSOP with an exposed thermal pad (suffix LP). The SLP package is
available in a lead-free version (100% matte tin leadframe).
FEATURES
■ ±2.5 A, 35 V Output Rating
■ Low r_DS(on) Outputs, 0.45 Ω Source, 0.36 Ω Sink Typical
■ Automatic Current Decay Mode Detection/Selection
■ 3.0 V to 5.5 V Logic Supply Voltage Range
■ Mixed, Fast, and Slow Current Decay Modes
■ Home Output
■ Synchronous Rectification for Low Power Dissipation
■ Internal UVLO and Thermal Shutdown Circuitry
■ Crossover-Current Protection
Always order by complete part number:
Part Number
A3977KED
A3977KLP
A3977SED
A3977SED-T
A3977SLP
A3977SLP-T
Package
44-pin PLCC
28-pin TSSOP
44-pin PLCC
44-pin PLCC; Lead-free
28-pin TSSOP
28-pin TSSOP; Lead-free