Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.COM

X  

LTC2918IDDB-B1TRMPBF Datasheet(PDF) 10 Page - Linear Technology

Part # LTC2918IDDB-B1TRMPBF
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

LTC2918IDDB-B1TRMPBF Datasheet(HTML) 10 Page - Linear Technology

Back Button LTC2918IDDB-B1TRMPBF Datasheet HTML 6Page - Linear Technology LTC2918IDDB-B1TRMPBF Datasheet HTML 7Page - Linear Technology LTC2918IDDB-B1TRMPBF Datasheet HTML 8Page - Linear Technology LTC2918IDDB-B1TRMPBF Datasheet HTML 9Page - Linear Technology LTC2918IDDB-B1TRMPBF Datasheet HTML 10Page - Linear Technology LTC2918IDDB-B1TRMPBF Datasheet HTML 11Page - Linear Technology LTC2918IDDB-B1TRMPBF Datasheet HTML 12Page - Linear Technology LTC2918IDDB-B1TRMPBF Datasheet HTML 13Page - Linear Technology LTC2918IDDB-B1TRMPBF Datasheet HTML 14Page - Linear Technology Next Button
Zoom Inzoom in Zoom Outzoom out
 10 / 16 page
background image
LTC2917/LTC2918
10
29178f
APPLICATIONS INFORMATION
Threshold Accuracy
The trip threshold for the supplies monitored is selected
by configuring the three-state input pins. When using the
adjustable input, a external resistive divider sets the trip
threshold, allowing the user complete control over the
trip point. Selection of this trip voltage is crucial to the
reliability of the system.
Any power supply has some tolerance band within which
it is expected to operate (e.g. 5V±10%). It is generally
undesirable that a supervisor issue a reset when the power
supply is inside this tolerance band. Such a “nuisance”
reset reduces reliability by preventing the system from
functioning under normal conditions.
To prevent nuisance resets, the supervisor threshold must
be guaranteed to lie outside the power supply tolerance
band. To ensure that the threshold lies outside the power
supply tolerance range, the nominal threshold must lie out-
side that range by the monitor’s accuracy specification.
All 27 of the selectable thresholds have the same relative
threshold accuracy of ±1.5% of the programmed nominal
input voltage (over the full operating temperature range).
Consider the example of monitoring a 5V supply with a 10%
tolerance. The nominal threshold internal to the LTC2917
is 11.5% below the 5V input at 4.425V. With ±1.5% ac-
curacy, the trip threshold range is 4.425V±75mV over
temperature (i.e. 10% to 13% below 5V). The monitored
system must thus operate reliably down to 4.35V or 13%
below 5V over temperature.
Glitch Immunity
The above discussion is concerned only with the DC
value of the monitored supply. Real supplies also have
relatively high-frequency variation, from sources such as
load transients, noise, and pickup. These variations should
not be considered by the monitor in determining whether
a supply voltage is valid or not. The variations may cause
spurious outputs at ⎯R⎯S⎯T, particularly if the supply voltage
is near its trip threshold.
Two techniques are used to combat spurious reset without
sacrificing threshold accuracy. First, the timeout period
helps prevent high-frequency variation whose frequency
is above 1/ tRST from appearing at the ⎯R⎯S⎯T output.
When the voltage at VM goes below the threshold, the
⎯R⎯S⎯T pin asserts low. When the supply recovers past
the threshold, the reset timer starts (assuming it is not
disabled), and ⎯R⎯S⎯T does not go high until it finishes. If
the supply becomes invalid any time during the timeout
period, the timer resets and starts a fresh when the supply
next becomes valid.
While the reset timeout is useful at preventing toggling
of the reset output in most cases, it is not effective at
preventing nuisance resets due to short glitches (due to
load transients or other effects) on a valid supply.
To reduce sensitivity to these short glitches, the comparator
has additional anti-glitch circuitry. Any transient at the input
of the comparator needs to be of sufficient magnitude and
duration tUV before it can change the monitor state.
The combination of the reset timeout and anti-glitch cir-
cuitry prevents spurious changes in output state without
sacrificing threshold accuracy.
Adjustable Input
When the monitor threshold is configured as ADJ, the
internal comparator input is connected to the pin without
a resistive divider, and the pin is high-impedance. Thus,
any desired threshold may be chosen by attaching VM to
a tap point on an external resistive divider between the
monitored supply and ground, as shown in Figure 1.
Figure 1. Setting the Trip Point Using
the Adjustable Threshold.
+
0.5V
VM
R2
R1
29178 F01
VMON


Similar Part No. - LTC2918IDDB-B1TRMPBF

ManufacturerPart #DatasheetDescription
logo
Linear Technology
LTC2918 LINER-LTC2918 Datasheet
248Kb / 16P
   36V Nano-Current Two Input Voltage Monitor
LTC2918 LINER-LTC2918 Datasheet
166Kb / 16P
   Voltage Supervisor with 27 Selectable Thresholds and Watchdog Timer
LTC2918 LINER-LTC2918_15 Datasheet
166Kb / 16P
   Voltage Supervisor with 27 Selectable Thresholds and Watchdog Timer
More results

Similar Description - LTC2918IDDB-B1TRMPBF

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