GENERAL DESCRIPTION (cont'd)
In a printed circuit board layout, it is suggested that
these pins, along with no connect (N/C) pins 8 and 9,
be surrounded with ground traces to prevent any
possiblecrosstalkandnoisecouplingfromothersignal
sources.
Sink Output, can be connected together to form a push-pull output
which has the combined output capabilities of both channels.
In the dual complementary output mode, each comparator can be
used to drive separate loads. Due to the complementary nature of
thetwooutputs,onlyoneoutputisactiveatanyagiventime,except
for a limited crossover time. When OUT (sink output) is active ON,
Although not required for most applications, if neces-
sary,smallvaluedcapacitorsofapproximately1000pF
can be mounted at these pins to ground to further
reduce noise. For information on customized trimming
under different biasing and power supply conditions,
please contact factory.
the OUT pin is sinking current and the OUT pin is OFF and in high
H
impedance mode. Conversely, if OUT pin is ON and sourcing
H
current, OUT pin is OFF. To configure push-pull output, simply
connect OUT (sink output) pin to OUT pin.
H
Since each voltage comparator has its own complementary out-
puts, each comparator can be configured to have a different output
type. For example, one comparator output can be connected as
Open Drain output while the other comparator can be wired as
push-pull output. If used to drive capacitive loads, the output DC
current levels are at a very low level, at essentially leakage current
levels, which can be a power saving feature.
BLOCK DIAGRAM
+
(16) V
INVERTING INPUT
-
(2) OUT
1H
-IN (3)
1
The ALD2321A/ALD2321B/ALD2321 can detect and resolve very
low voltage levels at high speed, with little or no overdrive voltage.
Compared with other voltage comparator devices that require 100
mV overdrive voltages, or multiple stage circuits that include input
preamp, etc., theALD2321A/ALD2321B/ALD2321canperformall
input to output functions in one device with minimal delay time and
with as low as a 1mV signal.
(1) OUT
1
NONINVERTING INPUT
+
+IN (4)
1
(7)
VE
12
(6)
VE
11
(5)
GND
TheALD2321A/ALD2321B/ALD2321issuppliedwith4externale-
trim pins, VE11, VE12, VE21, and VE22. These pins are used for
trimming of the voltage comparator offset voltages at the factory,
and normally should be left open unconnected. However, in some
cases these pins can be used as positive/negative feedback pins,
since these pins have a positive/negative factor on the offset
voltage. For example, see TYPICAL APPLICATIONS section
titled "Voltage Comparator With Output Feedback to Provide
Hysteresis."
INVERTING INPUT
(14) OUT
-
2H
-IN (13)
2
(15) OUT
2
NONINVERTING INPUT
+
+IN (12)
2
(10)
VE
22
(11)
VE
21
(8)
(9)
N/C
N/C
ALD2321 PIN IDENTIFICATION
PIN #
SYMBOL
FUNCTION
SIGNAL PROPAGATION
1
2
3
4
OUT
OUT
COMPARATOR 1 SINK OUTPUT
COMPARATOR 1 SOURCE OUTPUT
COMPARATOR 1 INVERTING INPUT
COMPARATOR 1 NON-INVERTING INPUT
GROUND / V- SUPPLY
OUTPUT
OUTPUT
INPUT
INPUT
-
1
1H
-IN
1
+IN
1
GND
5
6
7
8
9
10
11
12
13
14
15
16
VE
VE
N/C
N/C
- VOS E-Trim COMPARATOR 1
+ VOS E-Trim COMPARATOR 1
No Connect/Do Not connect externally
No Connect/Do Not connect externally
+VOS E-Trim COMPARATOR 2
- VOS E-Trim COMPARATOR 2
COMPARATOR 2 NON-INVERTING INPUT
COMPARATOR 2 INVERTING INPUT
COMPARATOR 2 SOURCE OUTPUT
COMPARATOR 2 SINK OUTPUT
V+ SUPPLY
INPUT
INPUT
-
11
12
-
VE
VE
+IN
INPUT
INPUT
INPUT
INPUT
OUTPUT
OUTPUT
-
22
21
2
-IN
2
OUT
OUT
V+
2H
2
ALD2321A/ALD2321B/ALD2321
Advanced Linear Devices
2 of 11
ALD [ ADVANCED LINEAR DEVICES ]
