QM50HA-HB Linear Technology Corporation, QM50HA-HB Datasheet - Page 15

• Manufacturer Part Number: QM50HA-HB
• Description: MEDIUM POWER SWITCHING USE INSULATED TYPE
• Manufacturer: Linear Technology Corporation

A
Comparator Applications
Sometimes it is desirable to use an op amp as a compara-
tor. When operating the LT1211/LT1212 on a single 3.3V
or 5V supply, the output interfaces directly with most TTL
and CMOS logic.
The response time of the LT1211/LT1212 is a strong
function of the amount of input overdrive as shown in the
I S PLI I F ED S
PPLICATI
W
100
4
2
0
0
V
R
S
L
Q7
Q9
= 5V
=
20mV, 10mV, 5mV, 2mV Overdrives
LT1211 Comparator Response (+)
O
Q8
U
I
CHE
1
S
–IN
I FOR ATIO
C
U
I
W
Q1
5 s/DIV
I
2
A
Q3
Q5
TIC
W
Q4
I
3
Q6
Q2
I
4
+IN
1211/12 AI01
U
Q10
I
5
C
F
following photos. These amplifiers are unity-gain stable
op amps and not fast comparators, therefore, the logic
being driven may oscillate due to the long transition time.
The output can be speeded up by adding 20mV or more of
hysteresis (positive feedback), but the offset is then a
function of the input direction.
Q11
I
7
R
100
F
C
4
2
0
0
M
V
R
S
L
= 5V
=
20mV, 10mV, 5mV, 2mV Overdrives
LT1211 Comparator Response (–)
Q12
I
6
BIAS
C
O
5 s/DIV
LT1211/LT1212
Q13
I
8
Q14
1211/12 SS
Q15
Q16
V
OUT
V
1211/12 AI02
–
+
15