Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.COM

X  

LTC1727 Datasheet(PDF) 11 Page - Linear Technology

Part # LTC1727
Description  Low Voltage Supervisorwith 27 Selectable Thresholds and Watchdog Timer
Download  16 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  LINER [Linear Technology]
Direct Link  http://www.linear.com
Logo LINER - Linear Technology

LTC1727 Datasheet(HTML) 11 Page - Linear Technology

Back Button LTC1727 Datasheet HTML 7Page - Linear Technology LTC1727 Datasheet HTML 8Page - Linear Technology LTC1727 Datasheet HTML 9Page - Linear Technology LTC1727 Datasheet HTML 10Page - Linear Technology LTC1727 Datasheet HTML 11Page - Linear Technology LTC1727 Datasheet HTML 12Page - Linear Technology LTC1727 Datasheet HTML 13Page - Linear Technology LTC1727 Datasheet HTML 14Page - Linear Technology LTC1727 Datasheet HTML 15Page - Linear Technology Next Button
Zoom Inzoom in Zoom Outzoom out
 11 / 16 page
background image
LTC2917/LTC2918
11
29178f
The reference input of the comparator is controlled by the
tolerance pin. The external resistive divider should make
the voltage at VM = 0.5V when the supply is at nominal
value. The actual threshold of VM accounts for the sup-
ply tolerance of ±1.5% guaranteed over the full operating
temperature range. The resulting tolerances are –6.5%,
–11.5%, –16.5% which correspond to 0.468V, 0.443V,
0.418V respectively.
Typically, the user will pick a value of R1 based on accept-
able current draw. Current used by the resistor divider will
be approximately:
R
V
I
1
05
= ⎛
⎝⎜
⎠⎟
.
Recommended range of R1 is 1k—1M. Higher values of
resistance exacerbate the degradation of threshold ac-
curacy due to leakage currents.
If the nominal value of the supply being monitored is
VNOM, then
R2 = R1(2VNOM – 1)
Resistor tolerances must be taken into account when
determining the overall accuracy.
Selecting the Reset Timing Capacitor
The reset timeout period can be set to one of two fixed
internal timers or set with a capacitor in order to accom-
modate a variety of applications. Connecting a capacitor,
CRT, between the RT pin and ground sets the reset timeout
period, tRST. The following formula approximates the value
of capacitor needed for a particular timeout:
CRT = tRST • 110 [pF/ms]
For example, using a standard capacitor value of 2.2nF
would give a 20ms timeout.
Figure 2 shows the desired reset timeout period as a
function of the value of the timer capacitor.
Leaving RT open with no external capacitor generates a
reset timeout of approximately 400μs. Shorting RT to VCC
generates a reset timeout of approximately 200ms.
⎯R⎯S⎯T Output Characteristics
The DC characteristics of the ⎯R⎯S⎯T pull-down strength
are shown in the Typical Performance Characteristics
section. ⎯R⎯S⎯T is an open-drain pin and thus requires an
external pull-up resistor to the logic supply. ⎯R⎯S⎯T may be
pulled above VCC, providing the voltage limits of the pin
are observed.
The open-drain of the ⎯R⎯S⎯T pin allows for wired-OR con-
nection of several LTC2917/LTC2918’s.
Watchdog
LTC2917-A/LTC2918-A
A standard watchdog function is used to ensure that the
system is in a valid state by continuously monitoring
the microprocessor’s activity. The microprocessor must
toggle the logic state of the WDI pin periodically (within
upper boundary) in order to clear the watchdog timer. If
timeout occurs, the LTC2917-A/LTC2918-A asserts ⎯R⎯S⎯T
low for the reset timeout period, issuing a system reset.
Once the reset timeout completes, ⎯R⎯S⎯T is released to go
high and the watchdog timer starts again.
During power-up, the watchdog timer remains cleared while
⎯R⎯S⎯T is asserted low. As soon as the reset timer times out,
⎯R⎯S⎯T goes high and the watchdog timer is started.
APPLICATIONS INFORMATION
Figure 2. Reset Timeout Period vs RT Capacitance
RT PIN CAPACITANCE, CRT (nF)
0.001
0.1
10
10000
0.1
0.01
1
10
100
1000
29178 F02
1
100
1000


Similar Part No. - LTC1727

ManufacturerPart #DatasheetDescription
logo
Linear Technology
LTC1727 LINER-LTC1727 Datasheet
188Kb / 16P
   Micropower Precision Triple Supply Monitors in 8-Lead MSOP and 5-Lead SOT-23 Packages
LTC1727 LINER-LTC1727 Datasheet
248Kb / 16P
   36V Nano-Current Two Input Voltage Monitor
LTC1727 LINER-LTC1727 Datasheet
156Kb / 16P
   Micropower Precision Triple Supply Monitors in 8-Lead MSOP and
LTC1727 LINER-LTC1727 Datasheet
203Kb / 16P
   Micropower Precision Triple Supply Monitors in 8-Lead MSOP and 5-Lead SOT-23 Packages
LTC1727-2.5 LINER-LTC1727-2.5 Datasheet
153Kb / 16P
   Precision Quad Supply Monitor in 6-Lead SOT-23
More results

Similar Description - LTC1727

ManufacturerPart #DatasheetDescription
logo
Linear Technology
LTC2918 LINER-LTC2918_15 Datasheet
166Kb / 16P
   Voltage Supervisor with 27 Selectable Thresholds and Watchdog Timer
LTC2917 LINER-LTC2917_15 Datasheet
166Kb / 16P
   Voltage Supervisor with 27 Selectable Thresholds and Watchdog Timer
LTC2915 LINER-LTC2915 Datasheet
143Kb / 12P
   Voltage Supervisor with 27 Selectable Thresholds
LTC2916 LINER-LTC2916_15 Datasheet
150Kb / 12P
   Voltage Supervisor with 27 Selectable Thresholds
LTC2915 LINER-LTC2915_15 Datasheet
150Kb / 12P
   Voltage Supervisor with 27 Selectable Thresholds
logo
Rohm
BD3021HFP-M ROHM-BD3021HFP-M_10 Datasheet
384Kb / 15P
   Regulator with Voltage Detector and Watchdog Timer
BD3010AFV-M ROHM-BD3010AFV-M Datasheet
561Kb / 22P
   Regulator with Voltage Detector and Watchdog Timer
BD3004HFP ROHM-BD3004HFP_06 Datasheet
1Mb / 9P
   Regulators with Voltage Detector and Watchdog Timer
BD37A19FVM ROHM-BD37A19FVM_13 Datasheet
555Kb / 18P
   Voltage Detector ICs with Watchdog Timer Built-in watchdog timer
logo
Hitachi Semiconductor
HA16103 HITACHI-HA16103 Datasheet
106Kb / 21P
   Watchdog Timer
More results


Html Pages

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


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : 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  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com