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A3958SLBTR-T

P1-P3P4-P6P7-P9P10-P10
Description
Designed for pulse width modulated (PWM) current control of
DC motors, the A3958 is capable of continuous output currents
to ±2 A and operating voltages to 50 V. Internal fixed off-time
PWM current-control timing circuitry can be programmed via
a serial interface to operate in slow, fast, and mixed current-
decay modes.
PHASE and ENABLE input terminals are provided for use
in controlling the speed and direction of a DC motor with
externally applied PWM-control signals. The ENABLE input
can be programmed via the serial port to PWM the bridge in
fast or slow current decay. Internal synchronous rectification
control circuitry is provided to reduce power dissipation during
PWM operation.
Internal circuit protection includes thermal shutdown with
hysteresis, and crossover-current protection. Special power-up
sequencing is not required.
The A3958 is supplied in a choice of two power packages, a
24-pin plastic DIP with exposed thermal tabs (package suffix
‘B’), and a 24-pin SOIC with internally fused pins (package
suffix ‘LB’). In both cases, the power pins are at ground potential
and need no electrical isolation. Each package type is lead (Pb)
free, with 100% matte tin leadframe.
29319.31F
Features and Benefits
▪ ±2 A, 50 V continuous output rating
▪ Low r
DS(on)
outputs (270 mΩ, typical)
▪ Programmable mixed, fast, and slow current-decay modes
▪ Serial interface controls chip functions
▪ Synchronous rectification for low power dissipation
▪ Internal UVLO and thermal-shutdown circuitry
▪ Crossover-current protection
DMOS Full-Bridge PWM Motor Driver
Functional Block Diagram
A3958
Packages:
Not to scale
Package B, 24-pin DIP
with exposed tabs
Package LB, 24-pin SOIC
with internally fused pins
CHARGE PUMP
BANDGAP
V
DD
C
REG
TSD
UNDER-
VOLTAGE &
FAULT DETECT
CHARGE
PUMP
BANDGAP
REGULATOR
V
DD
V
BB
+
LOGIC
SUPPLY
V
REG
CP1
CP
CP2
LOAD
SUPPLY
GATE DRIVE
Dwg. FP-048
SLEEP
MODE
RANGE
CONTROL LOGIC
PHASE
ENABLE
SYNC RECT MODE
SYNC RECT DISABLE
PWM MODE INT
PWM MODE EXT
PROGRAMMABLE
PWM TIMER
SENSE
R
S
FIXED OFF
BLANK
DECAY
MODE
PHASE
ENABLE
CLOCK
DATA
STROBE
RANGE
REFERENCE
BUFFER &
DIVIDER
CURRENT
SENSE
ZERO
CURRENT
DETECT
OSC
OUT
A
OUT
B
REF
SERIAL
PORT
V
REF
C
S
DMOS Full-Bridge PWM Motor Driver
A3958
2
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Copyright © 2000, 2002 Allegro MicroSystems, Inc.
Selection Guide
Part Number Packing Package
A3958SB-T* 24-pin DIP with exposed thermal tabs 15 per Tube
A3958SLBTR-T 24-pin SOICW with internally fused pins 1000 per reel
Variant is in production but has been determined to be NOT FOR NEW DESIGN. This classification indicates
that sale of the variant is currently restricted to existing customer applications. The variant should not be
purchased for new design applications because obsolescence in the near future is probable. Samples are no
longer available. Status change: May 4, 2009.
Absolute Maximum Ratings
Characteristic Symbol Notes Rating Units
Load Supply Voltage V
BB
50 V
Logic Supply Voltage V
DD
7.0 V
Input Voltage V
IN
–0.3 to V
CC
+ 0.3 V
Sense Voltage V
S
0.5 V
Reference Voltage V
REF
2.7 V
Output Current I
OUT
Output current rating may be limited by duty cycle, ambient
temperature, and heat sinking. Under any set of conditions, do
not exceed the specifi ed current rating or a junction tempera-
ture of 150°C.
±2.0 mA
Package Power Dissipation P
D
B package, per SEMI G42-88 Specification, T
A
= 25°C 3.1 W
LB package, per SEMI G42-88 Specification, T
A
= 25°C 1.6 W
Operating Ambient Temperature T
A
Range S –20 to 85 ºC
Maximum Junction Temperature T
J
(max)
Fault conditions that produce excessive junction temperature
will activate the device’s thermal shutdown circuitry. These
conditions can be tolerated but should be avoided.
150 ºC
Storage Temperature T
stg
–55 to 150 ºC
Thermal Characteristics
Characteristic Symbol Test Conditions* Value Units
Package Thermal Resistance, Junction
to Ambient
R
θJA
B Package, single-layer PCB, 1 in.
2
2-oz. exposed copper 40 ºC/W
LB Package, single-layer PCB, minimal exposed copper area 77 ºC/W
Package Thermal Resistance, Junction
to Tab
R
θJT
6 ºC/W
*Additional thermal information available on Allegro website.
50 75 100 125 150
1
0
ALLOWABLE PACKAGE POWER DISSIPATION (W)
TEMPERATURE IN oo
oo
C
4
3
2
25
R = 6.0
oC/W
QJT
SUFFIX 'B', R = 40oC/W
Q
JA
SUFFIX 'LB', R = 77oC/W
QJA
DMOS Full-Bridge PWM Motor Driver
A3958
3
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
ELECTRICAL CHARACTERISTICS at T
A
= +25°C, V
BB
= 50 V, V
DD
= 5.0 V, V
SENSE
= 0.5 V,
f
PWM
< 50 kHz (unless noted otherwise)
Limits
Characteristics Symbol Test Conditions Min. Typ. Max. Units
Output Drivers
Load Supply Voltage Range V
BB
Operating 20 – 50 V
During sleep mode 0 – 50 V
Output Leakage Current I
DSS
V
OUT
= V
BB
– <1.0 20 μA
V
OUT
= 0 V – <-1.0 -20 μA
Output On Resistance r
DS(on)
Source driver, I
OUT
= -2 A – 270 300 mΩ
Sink driver, I
OUT
= 2 A – 270 300 mΩ
Body Diode Forward Voltage V
F
Source diode, I
F
= -2 A – 1.2 1.6 V
Sink diode, I
F
= 2 A – 1.2 1.6 V
Load Supply Current I
BB
f
PWM
< 50 kHz – 4.0 7.0 mA
Charge pump on, outputs disabled – 2.0 5.0 mA
Sleep Mode – – 20 μA
Control Logic
Logic Supply Voltage Range V
DD
Operating 4.5 5.0 5.5 V
Logic Input Voltage V
IN(1)
2.0 – – V
V
IN(0)
– – 0.8 V
Logic Input Current I
IN(1)
V
IN
= 2.0 V – <1.0 20 μA
(all inputs except ENABLE)
I
IN(0)
V
IN
= 0.8 V – <-2.0 -20 μA
ENABLE Input Current I
IN(1)
V
IN
= 2.0 V – 40 100 μA
I
IN(0)
V
IN
= 0.8 V – 16 40 μA
OSC input frequency f
OSC
Operating 2.9 – 6.1 MHz
OSC input duty cycle dc
OSC
Operating 40 – 60 %
OSC input hysteresis – Operating 200 – 400 mV
Input Hysteresis – All digital inputs except OSC 50 – 100 mV
Reference Input Volt. Range V
REF
Operating 0.0 – 2.6 V
Reference Input Current I
REF
V
REF
= 2.5 V – – ±0.5 μA
Comparator Input Offset Volt. V
IO
V
REF
= 0 V – 0 ±5.0 mV
Continued next page …
P1-P3P4-P6P7-P9P10-P10

A3958SLBTR-T

Mfr. #:
Buy A3958SLBTR-T
Manufacturer:
Description:
IC MOTOR DRIVER 4.5V-5.5V 24SOIC
Lifecycle:
New from this manufacturer.
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