LT1116CS8 Linear Technology, LT1116CS8 Datasheet - Page 7

• Manufacturer Part Number: LT1116CS8
• Description: IC COMPARATOR 12NS SINGLE 8SOIC
• Manufacturer: Linear Technology
• Series: UltraFast™r
• Type: General Purposer

Specifications of LT1116CS8

• Number Of Elements: 1
• Output Type: CMOS, Complementary, TTL
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

V
APPLICATIO S I FOR ATIO
High Speed Adaptive Trigger Circuit
Line receivers often require an adaptive trigger to
compensate for variations in signal amplitude and DC
offsets. The circuit in Figure 3 triggers on 2mV to 200mV
signals from 100Hz to 10MHz from a single 5V rail. The
trigger level is the average of the input signal’s positive and
negative peaks stored on 0.005µF capacitors. Pairs of
NPN and PNP transistors are used instead of diodes to
temperature compensate the peak detector.
IN
5V
NPN = 2N3904
PNP = 2N3906
47µF
200Ω
CABLE
1000pF
200Ω
1kΩ
4R
U
R
100Ω
U
–
+
LT1191
A1
1kΩ
5pF
5V
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
W
Figure 3. Fast Single Supply Adaptive Trigger
50Ω
C1
100µF
+
–
LT1192
A2
1kΩ
U
5V
C2
0.1µF
5V
3kΩ
1%
3kΩ
1%
To achieve single supply operation, the input signal must
be shifted into the pre-amplifier’s common mode range.
The input amplifier A1 adds a 1V level shift, while A2
provides a gain of 20 for high frequency signals.
Capacitors C1 and C2 insure that low frequency signals
see unity gain. Bandwidth limiting in A1 and A2 does not
affect triggering because the adaptive trigger threshold
varies ratiometrically to maintain circuit output.
0.005µF
0.005µF
500pF
3MΩ
3MΩ
+
–
LT1006
A3
5V
0.1µF
500Ω
+
–
LT1116
LT1116
5V
TRIGGER
LT1116 • AI03
OUT
1116fb
7
Q
Q
–