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 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. 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

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Typical Application click for larger image	Connection Diagram *click for larger image LM2907 8-Pin Package *click for larger image LM2907N 14-Pin Package
Typical Performance click for larger image

Datasheet

Title		Size	Date	Other Language
	LM2907/LM2917 Frequency to Voltage Converter	542 Kbytes	9-Dec-08

Featured Application Notes

Title		Size	Date	Other Language
	AN-1237: Application Note 1237 RSDS™ Flat Panel Display Design Guidelines Part 2	141 Kbytes	14-May-03

More Application Notes

Title		Size	Date	Other Language
	AN-97: Application Note 97 Versatile Timer Operates from Microseconds to Hours	457 Kbytes	24-Feb-99
	AN-162: AN-162 LM2907 Tachometer/Speed Switch Building Block Applications	309 Kbytes	1-May-04
	AN-607: Pulse Width Modulation A/D Conversion Techniques with COP800 Family Microcontrollers	148 Kbytes	5-Aug-95
	AN-1237: Application Note 1237 RSDS™ Flat Panel Display Design Guidelines Part 2	141 Kbytes	14-May-03

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Standard Pack Size
LM2907M-8/NOPB LM2907M-8 RoHS	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 98 AVNET-EM Worldwide 33 DIGIKEY Worldwide 261 FUTURE Worldwide 150 RS COMPONENTS Worldwide 60	$0.70 each at 1K+ pcs	rail of 95
LM2907MX-8/NOPB LM2907MX-8 RoHS	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 2500 AVNET-EM Worldwide 2500 DIGIKEY Worldwide 0	$0.70 each at 1K+ pcs	reel of 2500
LM2907M/NOPB LM2907M RoHS	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty AVNET-EM Worldwide 480 DIGIKEY Worldwide 0 FUTURE Worldwide 182 NEWARK Americas 230	$0.70 each at 1K+ pcs	rail of 55
LM2907MX/NOPB LM2907MX RoHS	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty DIGIKEY Worldwide 0 FUTURE Worldwide 1100	$0.70 each at 1K+ pcs	reel of 2500
LM2907N-8/NOPB LM2907N-8 RoHS	MDIP	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 82 BRITESTONE South Korea 16 DIGIKEY Worldwide 1497 FUTURE Worldwide 1100 NEWARK Americas 664 RS COMPONENTS Worldwide 230 TAYLOR Americas 1	$0.70 each at 1K+ pcs	rail of 40
LM2907N/NOPB LM2907N RoHS	MDIP	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 306 AVNET-EM Worldwide 516 DIGIKEY Worldwide 1128 FARNELL Europe and Asia 704 FUTURE Worldwide 1100 KEIKONG Asia Pacific 4000 NEWARK Americas 142 RS COMPONENTS Worldwide 125 RSL MICRO Asia Pacific 14675 TAYLOR Americas 5996	$0.76 each at 1K+ pcs	rail of 25

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM2907MX-8EP	NONE	NATIONAL SEMICONDUCTOR	16 Nov 2008

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM2907M	SLM	0	44046	0	0	3532500	1	1002356520
LM2907M-8	SLM	0	44046	0	0	3532500	1	1002356520
LM2907MX	SLM	0	44046	0	0	3532500	1	1002356520
LM2907MX-8	SLM	0	44046	0	0	3532500	1	1002356520
LM2907N	SLM	0	44046	0	0	3532500	1	1002356520
LM2907N-8	SLM	0	44046	0	0	3532500	1	1002356520

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.

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Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM2907MX-8EP	NONE	NATIONAL SEMICONDUCTOR	16 Nov 2008