LM13700MX National Semiconductor, LM13700MX Datasheet - Page 19

• Manufacturer Part Number: LM13700MX
• Description: IC,Operational Amplifier,DUAL,BIPOLAR,SOP,16PIN,PLASTIC
• Manufacturer: National Semiconductor

Specifications of LM13700MX

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Additional Applications
The Schmitt Trigger of Figure 22 uses the amplifier output
current into R to set the hysteresis of the comparator; thus
V
variable hysteresis.
Figure 23 shows a Tachometer or Frequency-to-Voltage con-
verter. Whenever A1 is toggled by a positive-going input, an
amount of charge equal to (V
R
current of V
of time required to charge C
I
mum high output voltage swing of the LM13700. D1 is added
to provide a discharge path for C
B
H
t
, where V
. This once per cycle charge is then balanced by the
= 2 x R x I
L
O
B
/R
and V
. Varying I
t
. The maximum F
H
represent the maximum low and maxi-
B
will produce a Schmitt Trigger with
t
H
from V
–V
L
t
IN
) C
when A1 switches low.
is limited by the amount
L
t
to V
is sourced into C
H
(Continued)
with a current of
FIGURE 21. Phase Lock Loop
FIGURE 22. Schmitt Trigger
f
and
19
The Peak Detector of Figure 24 uses A2 to turn on A1
whenever V
charges storage capacitor C to hold V
Pulling the output of A2 low through D1 serves to turn off A1
so that V
O
remains constant.
IN
becomes more positive than V
00798129
00798128
O
equal to V
O
www.national.com
. A1 then
IN
PK.