Allegro UDN2961W, UDN2961B Datasheet

2961

HIGH-CURRENT
HALF-BRIDGE
PRINTHEAD/MOTOR DRIVER

PRINTHEAD/MOTOR DRIVER—WITH INTERNAL

CURRENT SENSING AND CONTROL

UDN2961B

V

1

REF

IN

2

3

INPUT

ENABLE

RC

MODE

4

5

6

7

8

GROUND

GROUND

ABSOLUTE MAXIMUM RATINGS

Supply Voltage, VBB. . . . . . . . . . . . . . 45 V

Output Current, I

(t

≤ 20 µs, 10% duty cycle) . . ±4.0 A

w

Logic Supply Voltage, V
Input Voltage Range,

V

. . . . . . . . . . . . . . . -0.3 V to +7.0 V

IN

Package Power Dissipation,

P

. . . . . . . . . . . . . . . . . . . See Graph

D

Operating Temperature Range,

T

. . . . . . . . . . . . . . . . -20°C to +85°C

A

Junction Temperature, T
Storage Temperature Range,

T

. . . . . . . . . . . . . . . -55°C to +150°C

S

Output current rating may be restricted to a value
determined by system concerns and factors.
These include: system duty cycle and timing,
ambient temperature, and use of any heatsinking
and/or forced cooling. For reliable operation, the
specified maximum junction temperature should
not be exceeded.

* Fault conditions that produce excessive junction
temperature will activate device thermal shutdown
circuitry. These conditions can be tolerated, but
should be avoided.

V

BB

CURRENT­CONTROL

LOGIC

(continuous) . ±3.4 A

OUT

16

15

14

13

12

V

BB

11

10

9

V

CC

. . . . . . . . . 7.0 V

CC

. . . . . . . +150°C*

J

SINK OUT

EMITTER

NC

GROUND

GROUND

LOAD SUPPLY

SOURCE OUT

LOGIC SUPPLY

Dwg. PP-035

2961

HIGH-CURRENT HALF-BRIDGE

The UDN2961B and UDN2961W are 3.4 A half bridges designed
specifically for driving solenoid printheads, stepper motors, and dc
motors. The UDN2961B/W consists of a power source driver output,
a power sink driver output, a flyback recovery diode, internal current
sensing circuitry, and a user-selectable fixed off-time chopper circuit.

The output drivers are capable of sustaining 45 V with continuous
currents of ±3.4 A and peak transient currents of ±4 A permitted. The
outputs have been optimized for a low output saturation voltage
(typically 2.6 V total source plus sink drops at 3.4 A).

For output current control, load current is sensed internally and
limited by chopping the output driver(s) in a user-selectable fixed off­time PWM mode. The maximum output current is determined by the
user’s selection of a reference voltage. The MODE pin determines
whether the current control circuitry will chop in a slow current-decay
mode (only the source driver switching) or in a fast current-decay
mode (source and sink switching). A user-selectable blanking window
prevents false triggering of the current control circuitry during
chopping.

The UDN2961B is supplied in a 16-pin dual in-line plastic batwing
package with a copper lead-frame and heat sinkable tabs for improved
power dissipation capabilities. For higher power dissipation require­ments, the UDN2961W is supplied in a 12-pin single in-line power tab
package.

FEATURES

■ 3.4 A, 45 V Source and Sink Drivers

■ Internal Current Sensing

■ User-Selectable Fixed Off-Time PWM Current Control

■ Internal Flyback Diode

■ Low Output Saturation Voltage

■ Chip Enable

■ Fast or Slow Current-Decay Modes

■ Programmable Blanking Window

■ Internal Thermal Shutdown Circuitry

Always order by complete part number:

Part Number Package

UDN2961B 16-Pin DIP
UDN2961W 12-Pin Power-Tab SIP

Data Sheet

29318.16*

2961

HIGH-CURRENT
HALF-BRIDGE
PRINTHEAD/MOTOR DRIVER

10

SUFFIX 'W',

R = 2.0°C/W

θJT

8

SUFFIX 'B',

R = 6.0°C/W

θJT

6

4

SUFFIX 'W', R = 38°C/W

2

SUFFIX 'B', R = 43°C/W

0

ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS

25

θJA

50 75 100 125 150

θJA

TEMPERATURE IN °C

Dwg. GP-032A

R

C

MODE

ENABLE

INPUT

FUNCTIONAL BLOCK DIAGRAM

+5 V

RC

V

LOW
TRIP

CC

ONE

SHOT

FLIP­FLOP

V

REF

Q

CIRCUIT

RS

+

-

TSD

REF

V

R

CV

SENSE

2940 Ω

V

BB

SOURCE OUT

V

BB

SINK OUT

EMITTER

GROUND

UDN2961W

V

CURRENT-

V

BB

1 2 3 4 5 6 7 8 9 10 11 12

REF

V

EMITTER

GROUND

SINK OUT

CONTROL

LOGIC

V

CC

CV

R

INPUT

ENABLE

RC

MODE

SOURCE OUT

LOGIC SUPPLY

Dwg. PP-036

Dwg. FP-019A

BB

LOAD SUPPLY

115 Northeast Cutoff, Box 15036
W

Worcester, Massachusetts 01615-0036 [phone]
Copyright © 1995, 1996 Allegro MicroSystems, Inc.

2961

HIGH-CURRENT
HALF-BRIDGE
PRINTHEAD/MOTOR DRIVER

ELECTRICAL CHARACTERISTICS at T
V

= 4.75 V to 5.25 V, R

CC

= 2940 Ω (unless otherwise noted).

CV

= +25°C, V

A

= 45 V,

BB

Limits
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Output Drivers

Output Leakage Current I

Output Saturation Voltage V

Output Sustaining Voltage V

CE(SAT)

CE(sus)

Recovery Diode Leakage Current I
Recovery Diode Forward Voltage V
Motor Supply Current I

BB(on)

I

BB(off)

Output Rise Time t

Output Fall Time t

CEX

R

VEN = 0.8 V, V

= 0.8 V, V

V

EN

Source Driver, I
Source Driver, I
Sink Driver, I
Sink Driver, I
I

= ±3.4 A, L = 3 mH 45 — — V

OUT

OUT

OUT

VR = 45 V — <1.0 100 µA

F

IF = 3.4 A — — 2.0 V
VEN = 2.0 V, VIN = 0.8 V, No Load — — 70 mA
VEN = 0.8 V — — 2.5 mA

r

f

Source Driver, I
Sink Driver, I

OUT

Source Driver, I
Sink Driver, I

OUT

= 0 V — <-1.0 -100 µA

SOURCE

= 45 V — <1.0 100 µA

SINK

= -3.4 A — 1.6 2.2 V

OUT

= -3.0 A — 1.5 — V

OUT

= 3.4 A — 1.0 1.4 V
= 3.0 A — 0.9 — V

= -3.4 A — — 600 ns

OUT

= 3.4 A — — 600 ns

= -3.4 A — — 600 ns

OUT

= 3.4 A — — 600 ns

Control Logic

Logic Input Voltage V

Logic Input Current I

Reference Input Current I
Transconductance I

TRIP/VREF

Logic Supply Current I

Turn On Delay t

IN(1)

V

IN(0)

IN(1)

I

IN(0)

REF

CC

pd(on)

VIN = 5.0 V — — 10 µA
VIN = 0 V — — -1.0 mA
V

= 5.0 V — — 50 µA

REF

V

= 1.0 V 0.9 1.0 1.1 A/V

REF

= 3.2 V 0.9 1.0 1.1 A/V

V

REF

VEN = 2.0 V, VIN = 0.8 V, No Load — — 160 mA

= 0.8 V — — 15 mA

V

EN

Source Driver — — 600 ns

2.0 — — V
— — 0.8 V

Sink Driver — — 600 ns

Turn Off Delay t

pd(off)

Source Driver — — 2.0 µs
Sink Driver — — 2.0 µs

Thermal Shutdown Temperature T

Negative current is defined as coming out of (sourcing) the specified device terminal.

J

— 165 — °C

2961

HIGH-CURRENT
HALF-BRIDGE
PRINTHEAD/MOTOR DRIVER

APPLICATIONS INFORMATION

The UDN2961B/W is a high current
half-bridge designed to drive a number of
inductive loads such as printer solenoids,
stepper motors, and dc motors. Load current
is sensed internally and is controlled by
pulse-width modulating (PWM) the output
driver(s) in a fixed off-time, variable­frequency format. The peak current level is
set by the user’s selection of a reference
voltage. A slow current-decay mode
(chopping only the source driver) or a fast
current-decay mode (chopping both the
source and sink drivers) can be selected via
the MODE pin.

PWM CURRENT CONTROL

A logic low on the MODE pin sets the
current-control circuitry into the slow-decay
mode. The RS flip-flop is set initially, and
both the source driver and the sink driver are
turned ON when the INPUT pin is at a logic
low. As current in the load increases, it is
sensed by the internal sense resistor until the
sense voltage equals the trip voltage of the
comparator. At this time, the flip-flop is reset
and the source driver is turned OFF. Over the
range of V
current trip point transfer function is a direct
linear function of the reference voltage:

To ensure an accurate chop current level
(±10%), an external 2940 Ω ±1% resistor
(RCV) is used. The actual load current peak
will be slightly higher than the trip point
(especially for low-inductance loads) because
of the internal logic and switching delays
(typically 1.5 µs). After the source driver turns
OFF, the load current decays, circulating
through an external ground clamp diode, the
load, and the sink transistor. The source
driver’s OFF time (and therefore the magni­tude of the current decrease) is determined
by the one-shot’s external RC timing compo­nents:

= 0.8 V to 3.4 V, the output

REF

I

= V

TRIP

t

OFF

REF

= RC

V

SENSE

BB

DRIVE CURRENT
RECIRCULATION (SLOW-DECAY MODE)

RECIRCULATION (FAST-DECAY MODE)

V

BB

RC

Dwg. EP-037

RC/2

Dwg. WP-015

ENABLE

INPUT

MODE

LOAD

CURRENT

REF

CIRCUIT

+

-

V

I

TRIP

within the range of 20 kΩ to 100 kΩ and 100 pF to 1000 pF. When the
one-shot times out, the flip-flop is set again, the source driver is re­enabled, and the load current again is allowed to rise to the set peak
value and trip the comparator. This cycle repeats itself, maintaining the
average load current at the desired level.

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]