LTC295x: Pushbutton On/Off Controllers
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The document provides an overview of Linear Technology's LTC295x push button controller family for applications requiring push button on/off control. It describes the features and capabilities of various push button controllers, including adjustable on/off timers, interrupt logic, supply monitoring, and wide operating voltage ranges. Selection tables and timing comparisons are provided to differentiate the parts and identify the best fit for specific applications.
LTC295x: Pushbutton On/Off Controllers
- 1. LTC295x: Pushbutton On/Off Controllers Source: LINEAR TECHNOLOGY
- 2. Introduction Purpose Provide an overview of the LTC295x Push Button Controller family Objectives Identify push button applications Explore push button capabilities and features Differentiate push button controllers @ LTC Content: 15 pages
- 3. What is a Push Button Controller? Traditional de-bounce designs: Discrete logic, flip flops, resistors and capacitors. An onboard microprocessor and discrete comparators For high voltage multicell battery applications, a high voltage LDO is needed to drive the low voltage devices. Push Button Controllers enable control for DC/DC converters Processor interrupt logic Adjustable on/off timers Push Button Controllers easily solve the inherent bounce problem. The advantages of Push Button Controller: Wide supply voltage range Small size Low quiescent current Ease of design
- 4. LTC295x Push Button Controller
- 5. Push Button Controller Applications Portable Instrumentation Meters Portable Customer Service PDA Portable TV Clinical Analyzers Blade Servers Desktop and Notebook Computers
- 6. Selection Table Part Number Supply Voltage (V) Supply Current ON Timer OFF Timer Kill Timer Comments Package LTC2950 2.7 to 26 6µA Adj Adj 1024ms Active high or low enable outputs TSOT-8 DFN-8 LTC2951 2.7 to 26 6µA 128ms Adj Adj Active high or low enable outputs TSOT-8 DFN-8 LTC2952 2.7 to 28 25µA Adj 26ms Adj Push button power path controller with system monitoring TSSOP-20 QFN-20 LTC2953 2.7 to 27 12µA 32ms 32ms Adj Push Button Controller with Supply Monitor, UVLO and Power Fail Comparators DFN-12 LTC2954 2.7 to 26 6µA Adj 32ms Adj Interrupt logic for menu driven applications. Active high enable output (LTC2954-1), active low enable output (LTC2954-2) TSOT-8 DFN-8
- 7. LTC295051: Push Button On/Off Controllers Adjustable Push Button On/Off Timers (LTC2950) Adjustable Turn OFF timer and Kill timer (LTC2951) Low Supply Current: 6µA Wide Operating Voltage Range: 2.7V to 26V Simple Interface Allows Graceful µP Shutdown EN Output (LTC2950-1 , LTC2951-1 ) EN Output (LTC2950-2, LTC2951-2) ±10kV ESD HBM on PB Input 8-pin 2mm x 3mm DFN and ThinSOT Packages
- 8. LTC2952: Low Loss Power Path Controller with Push-Button Control and Voltage Monitoring Automatic Low Loss Switching Between DC Sources Wide Operating Voltage Range: 2.7V to 28V Low 25µA Shutdown Current Adjustable Push-Button On/Off Timers Extendable House Keeping Wait Time Prior to Shutdown 200ms Reset Delay and 1.6s Watchdog Time-Out 20 pins TSSOP and QFN (4mm × 4mm) Packages
- 9. LTC2953: Push Button Controller with Voltage Monitoring Wide Operating Voltage Range: 2.7V to 27V Push Button Control of System Power Power Fail Comparator Generates Warning UVLO Comparator Gracefully Latches Power Off Adjustable Supply Monitor with 200ms Reset Low Supply Current: 14 A 10kV ESD HBM on PB, EN/EN Pins 12-pin (3mm x 3mm) DFN Package
- 10. LTC2954: Push Button On/Off Controller with μP Interrupt Adjustable On/Off Timers Wide Operating Voltage Range: 2.7V to 26V Push Button µP Interrupt for Menu Driven Applications High Voltage EN Output (LTC2954-2) Allows Circuit Breaker Control Low Leakage EN Output (LTC2954-1) Allows DC/DC Converter Control Simple Interface Allows Graceful µP Shut Down ±10kV ESD HBM on PB Input 8-Pin 3mm × 2mm DFN and ThinSOT Packages
- 11. Turn-On Timing Comparison Table Turn On De-Bounce Time System OK Response Time LTC2950 32ms + Adjustable 512ms LTC2951 128ms 512ms LTC2952 26ms + Adjustable 400ms LTC2953 32ms 512ms LTC2954 32ms + Adjustable 512ms
- 12. Turn Off Timing Comparison Table Interrupt De-Bounce Time (Short PB Pulse) Turn Off De-Bounce Time (Long PB Pulse) Automatic Shut Down After Interrupt (KILL Timer) LTC2950 32ms + Adjustable 1024ms LTC2951 32ms + Adjustable 128ms + Adjustable LTC2952 26ms 26ms + Adjustable LTC2953 32ms 64ms + Adjustable LTC2954 32ms 64ms + Adjustable
- 13. What if the DC/DC Converter is Faulty at Power Up?
- 14. Protect Against Microcontroller Hang ups The LTC295x family always responds to the push button in some way. Initiating a power down sequence by asserting INT low and starting an internal timer automatically releases its enable pin, thus shutting off system power when the KILL pin remains high
- 15. Additional Resource For ordering LTC295x, please click the part list or Call our sales hotline For additional inquires contact our technical service hotline For more product information go to http://www.linear.com/pc/viewCategory.jsp?navId=H0,C1,C1003,C1144,C1783 Newark Farnell