Electronic Components Datasheet Search
Selected language     English  ▼


MAX807NCWE Datasheet(PDF) 11 Page - Maxim Integrated Products

Part No. MAX807NCWE
Description  Full-Featured uP Supervisory Circuit with /-1.5% Reset Accuracy
Download  16 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  MAXIM [Maxim Integrated Products]
Homepage  http://www.maxim-ic.com
Logo 

 11 page
background image
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy
______________________________________________________________________________________
11
(see the Chip-Enable Propagation Delay vs. CE OUT
Load Capacitance graph in the Typical Operating
Characteristics). The CE propagation delay is produc-
tion tested from the 50% point on CE IN to the 50%
point on CE OUT using a 50
Ω driver and 50pF of load
capacitance (Figure 8). For minimum propagation
delay, minimize the capacitive load at CE OUT and use
a low output-impedance driver.
Chip-Enable Output
In the enabled mode, the impedance of CE OUT is equiv-
alent to 75
Ω in series with the source driving CE IN. In the
disabled mode, the 75
Ω transmission gate is off and CE
OUT is actively pulled to the higher of VCC or VBATT. This
source turns off when the transmission gate is enabled.
Low-Line Comparator
The low-line comparator monitors VCC with a threshold
voltage typically 52mV above the reset threshold, with
13mV of hysteresis. Use LOW LINE to provide a non-
maskable interrupt (NMI) to the µP when power begins
to fall to initiate an orderly software shutdown routine.
In most battery-operated portable systems, reserve
energy in the battery provides ample time to complete
the shutdown routine once the low-line warning is
encountered, and before reset asserts. If the system must
contend with a more rapid VCC fall time—such as when
the main battery is disconnected, a DC-DC converter
shuts down, or a high-side switch is opened during
normal operation—use capacitance on the VCC line to
provide time to execute the shutdown routine (Figure 9).
First calculate the worst-case time required for the
system to perform its shutdown routine. Then, with the
worst-case shutdown time, the worst-case load current,
and the minimum low-line to reset threshold (VLR(min)),
calculate the amount of capacitance required to allow the
shutdown routine to complete before reset is asserted:
CHOLD = (ILOAD x tSHDN) / VLR (min)
where tSHDN is the time required for the system to com-
plete the shutdown routine, and includes the VCC to
low-line propagation delay; and where ILOAD is the cur-
rent being drained from the capacitor, VLR is the low-
line to reset threshold.
VCC
CE IN
RESET
THRESHOLD
CE OUT
RESET
RESET
26
µs
28
µs
26
µs
MAX807
CE IN
50pF
CLOAD
CE OUT
GND
VRST MAX
50
Ω DRIVER
VCC
Figure 7. Reset and Chip-Enable Timing
Figure 8. CE Propagation Delay Test Circuit
GND
VCC
TO
µP NMI
CHOLD
CHOLD > ILOAD x tSHDN
VLR
4.5V to 5.5V
LOW LINE
MAX807
REGULATOR
Figure 9. Using LOW LINE to Provide a Power-Fail Warning to
the µP




Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16 


Datasheet Download



Related Electronics Part Number

Part NumberComponents DescriptionHtml ViewManufacturer
CAT1163Supervisory Circuit with I2C Serial CMOS EEPROM Precision Reset Controller and Watchdog Timer 1 2 3 4 5 MoreCatalyst Semiconductor
TS823Microprocessor Supervisory Circuit with Watchdog Timer & Manual Reset 1 2 3 4 5 MoreTaiwan Semiconductor Company, Ltd
AAT3526MicroPower Supervisory Circuit with Manual Reset 1 2 3 4 5 MoreAdvanced Analogic Technologies
G771Two Remote Temperature Sensors with SMBus Serial Interface and System Reset Circuit 1 2 3 4 5 MoreGlobal Mixed-mode Technology Inc
MAX63165-Pin μP Supervisory Circuits with Watchdog and Manual Reset 1 2 3 4 5 MoreMaxim Integrated Products
ISL6411Triple Output Low-Noise LDO Regulator with Integrated Reset Circuit 1 2 3 4 Intersil Corporation
SMS2902Voltage Supervisory Circuit With Watchdog Timer 1 2 3 4 5 MoreSummit Microelectronics, Inc.
CAT24C161Supervisory Circuits with I2C Serial CMOS E2PROM Precision Reset Controller and Watchdog Timer 1 2 3 4 5 MoreCatalyst Semiconductor
MAX6323μP Supervisory Circuits with Windowed Min/Max Watchdog and Manual Reset 1 2 3 4 5 MoreMaxim Integrated Products
ADM823Supervisory Circuits with Watchdog and Manual Reset in 5-Lead SC70 and SOT-23 1 2 3 4 5 MoreAnalog Devices

Link URL

Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Bookmark   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com 2003 - 2017    


Mirror Sites
English : Alldatasheet.com  , Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp  |   Russian : Alldatasheetru.com
Korean : Alldatasheet.co.kr   |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com  |   Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl