2987
8-CHANNEL
SOURCE DRIVER
2987
8-CHANNEL SOURCE DRIVER
WITH OVER-CURRENT PROTECTION
Providing over-current protection for each of its eight sourcing
outputs, the UDN2987A and UDN2987LW drivers are used as an
interface between standard low-level logic and relays, motors, sole-
noids, LEDs, and incandescent lamps. The device includes thermal
shutdown and output transient protection/clamp diodes for use with
sustaining voltages to 35 V.
In these drivers, each channel includes a latch to turn OFF that
channel if the maximum channel current is exceeded. All channels are
disabled if the thermal shutdown is activated. A common FAULT
output is used to indicate either chip thermal shutdown or any over-
current condition. All outputs are enabled by pulling the common OE/
R input high. When OE/R is low, all outputs are inhibited and the eight
latches are reset.
Under normal operating conditions, each of eight outputs will
source in excess of 100 mA continuously at an ambient temperature of
25°C and a supply of 35 V. The over-current fault circuit will protect
the device from short-circuits to ground with supply voltages of up to
35 V.
The inputs are compatible with 5 V and 12 V logic systems—TTL,
Schottky TTL, DTL, PMOS, and CMOS. In all cases, the output is
switched ON by an active high input level. The UDN2987A is supplied
in a 20-pin dual in-line plastic package; the UDN2987LW is supplied in
a 20-lead small-outline plastic package.
Data Sheet
29310.4A
IN 1
IN 2
IN 3
IN 4
IN 5
IN 6
IN 7
IN 8
FAULT
OE/R
1
2
3
4
5
6
7
8
9
OE
x8
OE
N
FF
20
19
18
17
16
15
14
13
12
SENSE
N
OUT 1
OUT 2
OUT 3
OUT 4
OUT 5
OUT 6
OUT 7
OUT 8
GROUND
V
S
10
11
Dwg. PP-067
Note that the UDN2987A (DIP) and the UDN2987LW
(SOIC) are electrically identical and share a common
terminal number assignment.
ABSOLUTE MAXIMUM RATINGS
at T
A
= +25°C
Driver Supply Voltage, V
S
..................... 35 V
Output Sustaining Voltage, V
CE(sus)
...... 35 V
Continuous Output Current,
I
OUT
........................................ -500 mA*
FAULT Output Voltage, V
CE
................. 35 V
FAULT Output Current, l
C
................. 30 mA
Input Voltage, V
IN
................................. 15 V
Package Power Dissipation,
P
D
........................................ See Graph
Operating Temperature Range,
T
A
................................. -20
°
C to +85
°
C
Storage Temperature Range,
T
S
............................... -55
°
C to +150
°
C
* Outputs are disabled at approximately -500 mA
per driver.
FEATURES
s
s
s
s
s
s
s
350 mA Output Source Current
Over-Current Protected
Internal Ground Clamp Diodes
Output Breakdown Voltage 35 V, Minimum
TTL, DTL, PMOS, or CMOS Compatible Inputs
Internal Thermal Shutdown
Automotive Capable
Always order by complete part number:
Part Number
UDN2987A
UDN2987LW
Package
20-Pin DIP
20-Lead Wide-Body SOIC
2987
8-CHANNEL
SOURCE DRIVER
FUNCTIONAL BLOCK DIAGRAM
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
2.5
2.0
SU
FF
IX
1.5
SU
FF
IX
'A
', R
θ
J
A
=
'LW
', R
55
°
C
/W
1.0
θ
J
A
=
70
°
C
/W
0.5
0
25
50
75
100
125
AMBIENT TEMPERATURE IN
°C
150
Dwg. GS-004A
Dwg. No. A-13,286
OVER-CURRENT FAULT SENSE
OUTPUT CURRENT WAVESHAPES
PHL
Dwg. No. A-13,292
Dwg. No. A-13,293
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1987, 1997, Allegro MicroSystems, Inc.
2987
8-CHANNEL
SOURCE DRIVER
ELECTRICAL CHARACTERISTICS at T
A
= 25
°
C, V
OE
= 2.4 V, V
S
= 35 V
(unless otherwise noted).
Characteristic
Functional Supply Range
Output Leakage Current
Output Sustaining Voltage
Output Saturation Voltage
Symbol
V
S
I
CEX
V
OUT(sus)
V
OUT(SAT)
V
IN
= 0.4 V*
I
OUT
= -350 mA, L = 2.0 mH
V
IN
= 2.4 V, I
OUT
= -100 mA
V
IN
= 2.4 V, I
OUT
= -225 mA
V
IN
= 2.4 V, I
OUT
= -350 mA
Channel Shutdown Threshold
FAULT Leakage Current
FAULT Saturation Voltage
Input Voltage
I
M
I
CEX
V
CE(SAT)
V
IN(ON)
V
IN(OFF)
Input Current
I
IN(ON)
V
IN
= 2.4 V
V
IN
= 5.0 V
V
IN
= 12 V
I
IN(OFF)
Clamp Diode Leakage Current
Clamp Diode Forward Voltage
Supply Current
I
R
V
F
I
S(ON)
I
S(OFF)
Thermal Shutdown
Thermal Hysteresis
Propagation Delay Time
T
J
∆T
J
t
PLH
t
PHL
Dead Time
*AII inputs simultaneously.
t
d
R
L
= 100Ω
R
L
= 100Ω
V
IN
= 0.4 V
V
R
= 35 V, T
A
= 70°C
I
F
= 350 mA
V
IN
= 2.4 V*, Outputs Open
V
IN
= 0.4 V*
V
IN
= 2.4 V
V
CC
= 35 V
I
C
= 30 mA
Test Conditions
Min.
7.0
—
35
—
—
—
-370
—
—
2.4
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Limits
Typ.
Max.
—
<-5.0
—
1.6
1.7
1.8
-500
<1.0
0.3
—
—
125
840
1500
—
—
1.5
13
8.0
165
15
0.3
2.0
1.0
35
-200
—
1.8
1.9
2.0
—
100
0.8
—
0.4
170
1020
1800
15
50
1.8
18
12
—
—
0.6
4.0
—
Units
V
µA
V
V
V
V
mA
µA
V
V
V
µA
µA
µA
µA
µA
V
mA
mA
°C
°C
µs
µs
µs
2987
8-CHANNEL
SOURCE DRIVER
ALLOWABLE OUTPUT CURRENT
AS A FUNCTION OF DUTY CYCLE
(UDN2987A shown, multiply by 78% for UDN2987LW)
At +25°C
APPLICATIONS INFORMATION
AND CIRCUIT DESCRIPTION
As with all power integrated circuits, the UDN2987A
and UDN2987LW have a maximum allowable output
current rating. The 500 mA rating does not imply that
operation at that value is permitted or even obtainable.
The channel output current trip point is specified as -370
mA, minimum; therefore, attempted operation at current
levels greater than -370 mA may cause a fault indication
and channel shutdown. The device is tested at a maxi-
mum of -350 mA and that is the recommended maximum
output current per driver. It provides protection for current
overloads or shorted loads up to 35 V.
All outputs are enabled by pulling the OE/R input high.
When OE/R is low or allowed to float (internal pull-down),
all outputs are inhibited and the latches are reset. Note
that the RESET pulse duration (OE/R low) should be
at least 1
µs.
This will ensure safe operation under
attempted RESET conditions with a shorted load. The
latches are also reset during power up, regardless of the
state of the OE/R input.
The load current causes a small voltage drop across
the internal low-value sense resistor. This voltage is
compared to the voltage drop across a reference resistor
with a constant current. The two resistors are matched to
eliminate errors due to manufacturing tolerances or
temperature effects. Each channel includes a comparator
and its own latch. An over-current fault (V
SENSE
> V
REF
)
will set the affected latch and shut down only that channel.
All other channels will continue to operate normally. The
latch includes a 1
µs
delay (t
d
) to prevent unwanted
triggering due to crossover currents generated when
switching inductive loads. For an abrupt short circuit, the
delay and output switching times will allow a brief,
permissable current in excess of the trip current before the
output driver is turned OFF.
A common thermal shutdown disables all outputs
if the chip temperature exceeds +165°C. At thermal
shutdown, all latches are reset. The outputs are disabled
until the chip cools down to about +150°C (thermal
hysteresis).
A common open-collector FAULT output is used to
indicate any channel over-current condition or chip
thermal shutdown.
At +50°C
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
2987
8-CHANNEL
SOURCE DRIVER
UDN2987A
Dimensions in Inches
(controlling dimensions)
0.014
0.008
20
11
0.430
0.280
0.240
MAX
0.300
BSC
1
0.070
0.045
0.100
1.060
0.980
BSC
10
0.005
MIN
0.210
MAX
0.015
MIN
0.150
0.115
0.022
0.014
Dwg. MA-001-20 in
Dimensions in Millimeters
(for reference only)
0.355
0.204
20
11
10.92
7.11
6.10
MAX
7.62
BSC
1
1.77
1.15
2.54
26.92
24.89
BSC
10
0.13
MIN
5.33
MAX
0.39
MIN
3.81
2.93
0.558
0.356
Dwg. MA-001-20 mm
NOTES: 1. Exact body and lead configuration at vendor’s option within limits shown.
2. Lead spacing tolerance is non-cumulative.
3. Lead thickness is measured at seating plane or below.
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