Features • Direct replacement for SE556/NE556 • Timing from microseconds through hours • Operates in both astable and monostable modes • Replaces two 555 timers • Adjustable duty cycle • Output can source or sink 200mA • Output and supply TTL compatible • Temperature stability better than 0.005% per °C • Normally on and normally off output Description The LM556 Dual timing circuit is a highly stable controller capable of producing accurate time delays or oscillation. The 556 is a dual 555. Timing is provided by an external resistor and capacitor for each timing function. The two timers operate independently of each other sharing only VCC and ground. The circuits may be triggered and reset on falling waveforms. The output structures may sink or source 200mA. Applications • Precision timing • Pulse generation • Sequential timing • Time delay generation • Pulse width modulation • Pulse position modulation • Linear ramp generator

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Datasheet

Title		Size	Date	Other Language
	LM556 Dual Timer	216 Kbytes	29-Mar-00
	LM556 Mil-Aero Datasheet MNLM556-X	11 Kbytes

Featured Application Notes

Title		Size	Date	Other Language
	AN-694: Application Note 694 A DMOS 3A, 55V, H-Bridge: The LMD18200	408 Kbytes	26-Sep-02	日本語

More Application Notes

Title		Size	Date	Other Language
	AN-1566: Application Note 1566 Techniques for Thermal Analysis of Switching Power Supply Designs	370 Kbytes	7-Feb-07	日本語 中文
	AN-694: Application Note 694 A DMOS 3A, 55V, H-Bridge: The LMD18200	408 Kbytes	26-Sep-02	日本語

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Standard Pack Size
LM556CM/NOPB LM556CM RoHS	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 878 AVNET-EM Worldwide 44 DIGIKEY Worldwide 941 FARNELL Europe and Asia 3317 FUTURE Worldwide 770 NEWARK Americas 987 RS COMPONENTS Worldwide 240 TAYLOR Americas 29	$0.58 each at 1K+ pcs	rail of 55
LM556CMX/NOPB LM556CMX RoHS	SOIC NARROW	Full production Lead Time: 6 weeks	Distributor Region Qty DIGIKEY Worldwide 5193 FUTURE Worldwide 1100	$0.58 each at 1K+ pcs	reel of 2500
LM556CN/NOPB LM556CN RoHS	MDIP	Full production Lead Time: 6 weeks	Distributor Region Qty ARROW Worldwide 1156 AVNET-EM Worldwide 595 BRITESTONE South Korea 43 DIGIKEY Worldwide 2959 FARNELL Europe and Asia 911 FUTURE Worldwide 1100 RS COMPONENTS Worldwide 490 TAYLOR Americas 665	$0.58 each at 1K+ pcs	rail of 25
LM556 MD8 RoHS		Full production Lead Time: N/A	Contact your distributor	CALL	tray of N/A
LM556 MWC RoHS		Full production Lead Time: N/A	Contact your distributor	CALL	wafer jar of N/A

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM556J-MIL	NONE	NATIONAL SEMICONDUCTOR	03 Dec 2008

Design Tools

Reference Design

RD-168 - Ambient Light Adaptive LED Driver

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM556 MWC	SLM	0	44046	0	0	3532500	1	1002356520
LM556CM	SLM	0	44046	0	0	3532500	1	1002356520
LM556CMX	SLM	0	44046	0	0	3532500	1	1002356520
LM556CN	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.

For more information on Reliability Metrics, please click here.

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM556J-MIL	NONE	NATIONAL SEMICONDUCTOR	03 Dec 2008