MAX792LCPE Maxim Integrated, MAX792LCPE Datasheet - Page 14
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MAX792LCPE
Manufacturer Part Number
MAX792LCPE
Description
Supervisory Circuits
Manufacturer
Maxim Integrated
Series
MAX792, MAX792L, MAX792M, MAX792R, MAX792S, MAX792T, MAX820, MAX820L, MAX820M, MAX820R, MAX820S, MAX820Tr
Datasheet
1.MAX19586ETNTD.pdf
(16 pages)
Specifications of MAX792LCPE
Number Of Voltages Monitored
1
Monitored Voltage
2.75 V to 5.5 V
Undervoltage Threshold
4.5 V
Overvoltage Threshold
4.75 V
Output Type
Active High, Active Low, Push-Pull
Manual Reset
Resettable
Watchdog
Watchdog
Battery Backup Switching
No Backup
Power-up Reset Delay (typ)
280 ms
Supply Voltage - Max
5.5 V
Maximum Operating Temperature
+ 70 C
Mounting Style
Through Hole
Package / Case
PDIP N
Chip Enable Signals
Yes
Maximum Power Dissipation
842 mW
Minimum Operating Temperature
0 C
Power Fail Detection
Yes
Supply Current (typ)
150 uA
Supply Voltage - Min
2.75 V
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
MAX792LCPE+
Manufacturer:
Maxim Integrated Products
Quantity:
135
Microprocessor and Nonvolatile
Memory Supervisory Circuits
Figure 11. Alternate CE Gating
Using memory devices with both CE and CE inputs
allows the MAX792/MAX820 CE propagation delay
to be bypassed. To do this, connect CE IN to ground,
pull up CE OUT to V
input of each memory device (Figure 11). The CE input
of each memory device then connects directly to the
chip-select logic, which does not have to be gated by
the MAX792/MAX820.
µPs with bidirectional reset pins, such as the Motorola
68HC11 series, can contend with the MAX792/MAX820
RESET output. If, for example, the MAX792/MAX820 RESET
output is asserted high and the µP wants to pull it low,
indeterminate logic levels may result. To avoid this,
connect a 4.7kΩ resistor between the MAX792/MAX820
RESET output and the µP reset I/O, as in Figure 12.
Buffer the MAX792/MAX820 RESET output to other sys-
tem components.
While issuing resets to the µP during power-up, power-
down, and brownout conditions, these supervisors are
relatively immune to short-duration negative-going V
transients (glitches). It is usually undesirable to reset
the µP when V
Figure 13 shows maximum transient duration vs. reset-
comparator overdrive, for which reset pulses are not
generated. The graph was produced using negative-
14
*
MAXIMUM R
THE NUMBER OF RAMS.
MINIMUM R
______________________________________________________________________________________
Interfacing to µPs with Bidirectional
P
P
14
VALUE IS 1kΩ
VALUE DEPENDS ON
CE IN
CC
Negative-Going V
Alternative Chip-Enable Gating
MAX792
MAX820
experiences only small glitches.
GND
+5V
V
CC
3
CC
12
CE OUT
, and connect CE OUT to the CE
R
P
*
13
LINES FROM LOGIC
ACTIVE-HIGH CE
CE
CE
CE
CE
CE
CE
CE
CE
CC
Reset Inputs
Transients
RAM 1
RAM 2
RAM 3
RAM 4
CC
going V
reset threshold by the magnitude indicated (reset-
comparator overdrive). The graph shows the maximum
pulse width a negative-going V
cally have without causing a reset pulse to be issued.
As the amplitude of the transient increases (i.e., goes
farther below the reset threshold), the maximum allow-
able pulse width decreases. Typically, a V
that goes 100mV below the reset threshold and lasts for
30µs or less will not cause a reset pulse to be issued.
A 100nF bypass capacitor mounted close to the V
pin provides additional transient immunity.
Figure 12. Interfacing to µPs with Bidirectional RESET Pins
Figure 13. Maximum Transient Duration Without Causing a
Reset Pulse vs. Reset-Comparator Overdrive
V
CC
CC
MAX792
MAX820
100
GND
80
60
40
20
V
pulses, starting at 5V and ending below the
0
CC
RESET COMPARATOR OVERDRIVE, (V
3
12
RESET
10
1
100
4.7k
RESET
CC
1000
BUFFER
T
transient may typi-
GND
V
A
V
µP
CC
CC
= +25°C
TH
= 5V
- V
10,000
CC
CC
) (mV)
TO OTHER
SYSTEM RESET
INPUTS
transient
CC