LM2917 - Frequency to Voltage Converter
Datasheet Packaging Samples & Pricing Reliability Application Notes Knowledge Base

Features
•Ground referenced tachometer input interfaces directly with variable reluctance magnetic pickups
•Op amp/comparator has floating transistor output
•50 mA sink or source to operate relays, solenoids, meters, or LEDs
•Frequency doubling for low ripple
•Tachometer has built-in hysteresis with either differential input or ground referenced input
•Built-in zener on LM2917
•±0.3% linearity typical
•Ground referenced tachometer is fully protected from damage due to swings above VCC and below ground

General Description

The LM2907, LM2917 series are monolithic frequency to voltage converters with a high gain op amp/comparator designed to operate a relay, lamp, or other load when the input frequency reaches or exceeds a selected rate. More...


Applications

•Over/under speed sensing
•Frequency to voltage conversion (tachometer)
•Speedometers
•Breaker point dwell meters
•Hand-held tachometer
•Speed governors
•Cruise control
•Automotive door lock control
•Clutch control
•Horn control
•Touch or sound switches
  Typical Application
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ParametersValues
Temperature Min -40 deg C
Temperature Max 85 deg C
Function Frequency to Voltage


Typical Performance

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  Additional Resources
Application Notes


Connection Diagram

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*click for larger image



Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM2907/LM2917 Frequency to Voltage Converter 542
Kbytes		 9-Dec-08 Download

If you have trouble printing or viewing PDF file(s), see Printing Problems.


Package Availability, Models, Samples & Pricing
Part NumberPackageFactory Lead TimeModelsSamples &
Electronic
Orders		Budgetary PricingStd
Pack
Size		Package
Marking
Format
TypePinsSpec.MSL
Rating		Peak
Reflow		RoHS
Report		CAD
Symbols		WeeksQtyQty$US each
LM2917M-8SOIC NARROW8NOPB
STD		1
1		260
235		RoHS N/A Full productionN/A
Samples
Buy Now 		1K+$0.76rail
of
95		NSZXTT
LM29
17M-8
6 weeks500
LM2917MX-8SOIC NARROW8NOPB1260RoHS N/A Full productionN/A
 
Buy Now 		1K+$0.76reel
of
2500		NSZXTT
LM29
17M-8
6 weeks10000
LM2917MSOIC NARROW14NOPB
STD		1
1		260
235		RoHS N/A Full productionN/A
 
Buy Now 		1K+$0.76rail
of
55		NSUZXYTTE#
LM2917M
6 weeks1000
LM2917MXSOIC NARROW14NOPB1260RoHS N/A Full productionN/A
 
Buy Now 		1K+$0.76reel
of
2500		NSUZXYTTE#
LM2917M
6 weeks5000
LM2917N-8MDIP8NOPB
STD		1
1		NA
NA		RoHS N/A Full productionN/A
Samples
Buy Now 		1K+$0.80rail
of
40		NSUZXYTTE#
LM
2917N-8
6 weeks2000
LM2917NMDIP14NOPB
STD		1
1		NA
NA		RoHS N/A Full productionN/A
 
Buy Now 		1K+$0.80rail
of
25		NSUZXYYTTE#
LM2917N
6 weeks1000

Obsolete Versions

Obsolete PartAlternate Part or SupplierSourceLast Time Buy Date
LM2917MXEP
NONE
NATIONAL SEMICONDUCTOR
16 Nov 2008

General Description

The LM2907, LM2917 series are monolithic frequency to voltage converters with a high gain op amp/comparator designed to operate a relay, lamp, or other load when the input frequency reaches or exceeds a selected rate. The tachometer uses a charge pump technique and offers frequency doubling for low ripple, full input protection in two versions (LM2907-8, LM2917-8) and its output swings to ground for a zero frequency input.

The op amp/comparator is fully compatible with the tachometer and has a floating transistor as its output. This feature allows either a ground or supply referred load of up to 50 mA. The collector may be taken above VCC up to a maximum VCE of 28V.

The two basic configurations offered include an 8-pin device with a ground referenced tachometer input and an internal connection between the tachometer output and the op amp non-inverting input. This version is well suited for single speed or frequency switching or fully buffered frequency to voltage conversion applications.

The more versatile configurations provide differential tachometer input and uncommitted op amp inputs. With this version the tachometer input may be floated and the op amp becomes suitable for active filter conditioning of the tachometer output.

Both of these configurations are available with an active shunt regulator connected across the power leads. The regulator clamps the supply such that stable frequency to voltage and frequency to current operations are possible with any supply voltage and a suitable resistor.

Reliability Metrics

Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
LM2917MSLM04404600353250011002356520
LM2917M-8SLM04404600353250011002356520
LM2917MXSLM04404600353250011002356520
LM2917MX-8SLM04404600353250011002356520
LM2917NSLM04404600353250011002356520
LM2917N-8SLM04404600353250011002356520

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.


More Application Notes

TitleSize in Kbytes Date Click link below to Download
AN-162: AN-162 LM2907 Tachometer/Speed Switch Building Block Applications 309
Kbytes		 1-May-04 Download

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[Information as of 8-Nov-2009]