Single/Dual, Ultra-Fast, Low-Power,
Precision TTL Comparators
MAX912/MAX913
supply pins, keeping leads short to minimize lead
inductance. For particularly noisy applications, use fer-
rite beads on the power-supply lines.
Input Slew Rate
The MAX912/MAX913 design eliminates the input slew-
rate requirement imposed on many standard compara-
tors. As long as LE is high after the maximum propaga-
tion delay and the input is greater than the compara-
tor’s total DC error, the output will be valid without oscil-
lations.
Board Layout
As with all high-speed components, careful attention to
layout is essential for best performance.
1) Use a printed circuit board with an unbroken
ground plane.
2) Pay close attention to the bandwidth of bypass
components and keep leads short.
3) Avoid sockets; solder the comparator and other
components directly to the board to minimize
unwanted parasitic inductance and capacitance.
IN+
Maximum Clock (LE) and Signal Rate
The maximum clock and signal rate is 70MHz, based
on the comparator’s rise and fall time with a 5mV over-
drive at +25°C (Figure 1). With a 20mV overdrive, the
maximum propagation delay is 12ns and the clock and
signal rate is 85MHz.
IN-
HYSTERESIS
BAND*
Q
.
.
.
.
.
. ..
.
.
.
.
.
.
WITH HYSTERESIS
IDEAL (WITHOUT HYSTERESIS)
* WHEN HYSTERESIS IS ADDED, A COMPARATOR CANNOT RESOLVE ANY INPUT SIGNAL WITHIN THE HYSTERESIS BAND.
Figure 2. Effect of Hysteresis on Input Resolution
__________________________________________________________Chip Topographies
MAX912
INB+
INA-
INB-
INA+
IN-
MAX913
IN+
V+
V+
LEB
GND
QB QB QA QA
0.080"
(2.03mm)
V-
LEA
GND
V-
0.071"
(1.80mm)
LE
GND
Q
V+
0.056"
(1.42mm)
Q
0.058"
(1.47mm)
TRANSISTOR COUNT: 197;
SUBSTRATE CONNECTED TO V-.
TRANSISTOR COUNT: 100;
SUBSTRATE CONNECTED TO V-.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
8
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© 1994 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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