UC3845A Status: ACTIVE

Current Mode PWM Controller

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Datasheet

Current Mode PWM Controller (Rev. A) (uc3845a.pdf, 984 KB)
18 Apr 2002 Download

	UC1845A	UC2845A	UC3845A
Topology	Boost, Flyback, Forward	Boost, Flyback, Forward	Boost, Buck, Flyback, Forward
Control Method	Current Mode	Current Mode	Current Mode
Duty Cycle(Max)(%)	50	50	50
PWM Outputs(#)	1	1	1
Frequency(Max)(kHz)	450	450	450
UVLO Thresholds On/Off(V)	8.4/7.6	8.4/7.6	8.4/7.6
Pin/Package	20LCCC,8CDIP	14SOIC,16SOIC,8PDIP,8SOIC	14SOIC,8PDIP,8SOIC
Regulated Outputs(#)	1	1	1
	Samples	Samples	Samples
	Inventory	Inventory	Inventory

Other qualified versions of UC3845A

Version	Part Number	Definition
Catalog	UC3845AM	TI's standard catalog product
Enhanced Product	UC1845A-EP	Supports Defense, Aerospace and Medical Applications
Military	UC1845A	QML certified for Military and Defense Applications
Space	UC1845A-SP	Radiation tolerant, ceramic packaging and qualified for use in Space-based application

Customers Who Evaluated This Product Also Evaluated

UC3845: Current-Mode PWM Controller
UC3842A: Current Mode PWM Controller
UCC2813-4: Low Power Economy BiCMOS Current Mode PWM
TPS3838K33: 220nA Supervisor with 10ms/200ms selectable delay time
TPS54310: Low Input Voltage 3A Synchronous Buck Converter with Adjustable Output Voltage
TPS5430: 5.5V to 36V Input, 3-A Step Down Converter

More Related Products

Product Information

Features

Optimized for Off-line and DC to DC Converters
Low Start Up Current (<0.5mA)
Trimmed Oscillator Discharge Current
Automatic Feed Forward Compensation
Pulse-by-Pulse Current Limiting
Enhanced Load Response Characteristics
Under-Voltage Lockout With Hysteresis
Double Pulse Suppression
High Current Totem Pole Output
Internally Trimmed Bandgap Reference
500kHz Operation
Low RO Error Amp

Description

The UC1842A/3A/4A/5A family of control ICs is a pin for pin compatible improved version of the UC3842/3/4/5 family. Providing the necessary features to control current mode switched mode power supplies, this family has the following improved features. Start up current is guaranteed to be less than 0.5mA. Oscillator discharge is trimmed to 8.3mA. During under voltage lockout, the output stage can sink at least 10mA at less than 1.2V for V_CC over 5V.

Pricing / Packaging / CAD Design Tools / Samples

			Price	Packaging			CAD Design Tools		Samples
Device	Status	Temp (^oC)	Price \| Quantity	Package \| Pins	Top Side Marking	Package QTY \| Package Carrier	Symbols	Footprints	Samples
UC3845AD	ACTIVE	0 to 70	0.80 \| 1ku	SOIC (D) \| 14	View	50 \| TUBE
UC3845AD8	ACTIVE	0 to 70	0.80 \| 1ku	SOIC (D) \| 8	View	75 \| TUBE
UC3845AD8G4	ACTIVE	0 to 70	0.80 \| 1ku	SOIC (D) \| 8	View	75 \| TUBE
UC3845AD8TR	ACTIVE	0 to 70	0.90 \| 1ku	SOIC (D) \| 8	View	2500 \| LARGE T&R	Purchase Samples
UC3845AD8TRG4	ACTIVE	0 to 70	0.90 \| 1ku	SOIC (D) \| 8	View	2500 \| LARGE T&R	Purchase Samples
UC3845ADG4	ACTIVE	0 to 70	0.80 \| 1ku	SOIC (D) \| 14	View	50 \| TUBE
UC3845ADTR	ACTIVE	0 to 70	0.90 \| 1ku	SOIC (D) \| 14	View	2500 \| LARGE T&R	Purchase Samples
UC3845ADTRG4	ACTIVE	0 to 70	0.90 \| 1ku	SOIC (D) \| 14	View	2500 \| LARGE T&R	Purchase Samples
UC3845AN	ACTIVE	0 to 70	0.80 \| 1ku	PDIP (P) \| 8	View	50 \| TUBE
UC3845ANG4	ACTIVE	0 to 70	0.80 \| 1ku	PDIP (P) \| 8	View	50 \| TUBE

* Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For higher volume price quotes,prices in local currency or delivery quotes, please contact your local Texas Instruments Sales Office or Authorized Distributor.

Inventory

	TI Inventory Status			Reported Distributor Inventory
UC3845AD	As of 8:48 AM GMT, 20 Nov 2008			As of 8:48 AM GMT, 20 Nov 2008
	In Stock	In Progress QTY \| Date	Lead Time	Region	Company	In Stock	Purchase
	0*	6950 \| 17 Dec	4 Weeks	Americas	Arrow	>1k
					Avnet	200
					DigiKey	290
					Mouser Electronics	143
					Rochester Electronics	>1k
				Asia	WPI	41
				Europe	Arrow Southern Europe	850
					Avnet-SILICA	500
					EBV Elektronik	24
					Spoerle	650
UC3845AD8	As of 8:48 AM GMT, 20 Nov 2008			As of 8:48 AM GMT, 20 Nov 2008
	In Stock	In Progress QTY \| Date	Lead Time	Region	Company	In Stock	Purchase
	0*	>10k \| 18 Dec	4 Weeks	Americas	DigiKey	974
					Mouser Electronics	>1k
					Newark	831
				Asia	WPI	750
				Europe	Arrow Northern Europe	103
					Arrow Southern Europe	900
					Avnet-SILICA	>1k
					EBV Elektronik	10
					Farnell	40
UC3845AD8G4	As of 8:48 AM GMT, 20 Nov 2008			As of 8:48 AM GMT, 20 Nov 2008
	In Stock	In Progress QTY \| Date	Lead Time	Region	Company	In Stock	Purchase
	0*	>10k \| 18 Dec	4 Weeks	Europe	EBV Elektronik	>1k
UC3845AD8TR	As of 8:48 AM GMT, 20 Nov 2008			As of 8:48 AM GMT, 20 Nov 2008
	In Stock	In Progress QTY \| Date	Lead Time	Region	Company	In Stock	Purchase
	0*	>10k \| 18 Dec	4 Weeks	Americas	Avnet	>1k
				Americas	Rochester Electronics	>1k
				Asia	WPI	>1k
				Europe	Avnet-SILICA	>1k
UC3845AD8TRG4	As of 8:48 AM GMT, 20 Nov 2008			As of 8:48 AM GMT, 20 Nov 2008
	In Stock	In Progress QTY \| Date	Lead Time	Region	Company	In Stock	Purchase
	0*	>10k \| 18 Dec	4 Weeks	Americas	Avnet	>1k
UC3845ADG4	As of 8:48 AM GMT, 20 Nov 2008			As of 8:48 AM GMT, 20 Nov 2008
	In Stock	In Progress QTY \| Date	Lead Time	Region	Company	In Stock	Purchase
	0*	6950 \| 17 Dec	4 Weeks	Americas	Avnet	50
				Europe	EBV Elektronik	100
				Europe	Farnell	191
UC3845ADTR	As of 8:48 AM GMT, 20 Nov 2008			As of 8:48 AM GMT, 20 Nov 2008
	In Stock	In Progress QTY \| Date	Lead Time	Region	Company	In Stock	Purchase
	0*	>10k \| 18 Dec	4 Weeks	None Reported View Distributors
UC3845ADTRG4	As of 8:48 AM GMT, 20 Nov 2008			As of 8:48 AM GMT, 20 Nov 2008
	In Stock	In Progress QTY \| Date	Lead Time	Region	Company	In Stock	Purchase
	0*	>10k \| 18 Dec	4 Weeks	None Reported View Distributors
UC3845AN	As of 8:48 AM GMT, 20 Nov 2008			As of 8:48 AM GMT, 20 Nov 2008
	In Stock	In Progress QTY \| Date	Lead Time	Region	Company	In Stock	Purchase
	0*	>10k \| 2 Jan	8 Weeks	Americas	Arrow	271
					Avnet	940
					DigiKey	>1k
					Mouser Electronics	941
				Europe	Arrow Northern Europe	200
					Farnell	>1k
					Spoerle	500
UC3845ANG4	As of 8:48 AM GMT, 20 Nov 2008			As of 8:48 AM GMT, 20 Nov 2008
	In Stock	In Progress QTY \| Date	Lead Time	Region	Company	In Stock	Purchase
	0*	>10k \| 2 Jan	8 Weeks	Americas	Rochester Electronics	75
	0*		8 Weeks	Europe	EBV Elektronik	100
View all Distributors

* Our information is updated daily, so please check back with us soon if this does not meet your needs. You may also contact your TI Authorized Distributor , including those listed above, for real time stock information.

** Lead time information is not available at this time. However, our information is updated daily so please check back with us soon. Please contact your preferred TI Authorized Distributor for additional information.

Quality & Lead (Pb)-Free Data

	Product Content				DPPM / MTBF / FIT Rate
Device	Eco Plan*	Lead / Ball Finish	MSL Rating / Peak Reflow	Details	Details
UC3845AD	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845AD8	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845AD8G4	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845AD8TR	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845AD8TRG4	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845ADG4	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845ADTR	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845ADTRG4	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845AN	Green (RoHS & no Sb/Br)	CU NIPDAU	N/A for Pkg Type	View	View
UC3845ANG4	Green (RoHS & no Sb/Br)	CU NIPDAU	N/A for Pkg Type	View	View

* The planned eco-friendly classification: Pb-Free (RoHS) or Pb-Free (RoHS Exempt) or Green (RoHS & no Sb/Br) - please click on the Product Content Details "View" link in the table above for the latest availability information and additional product content details.

If the information you are requesting is not available online at this time, contact one of our Product Information Centers regarding the availability of this information.

Technical Documents

Datasheets

Current Mode PWM Controller (Rev. A) (uc3845a.pdf, 984 KB)
18 Apr 2002 Download

Application Notes

Understanding Buck-Boost Power Stages in Switchmode Power Supplies (Rev. A) (slva059a.htm, 8 KB)
28 May 2002 Abstract
UCC38C42 Family of High-Speed BiCMOS Current-Mode PWM Controllers (slua257.htm, 8 KB)
07 Feb 2002 Abstract
Conditioning a Switch-mode Power Supply Current Signal Using TI Op Amps (sloa044.htm, 8 KB)
23 Mar 2000 Abstract
DN-42A Design Considerations for Transitioning from UC3842 to the New UCC3802 (slua084.htm, 8 KB)
05 Sep 1999 Abstract
U-111, Practical Considerations in Current Mode Power Supplies (slua110.htm, 8 KB)
05 Sep 1999 Abstract
DN-40 The Effects of Oscillator Discharge Current Variations on Maximum Duty (slua173.htm, 8 KB)
05 Sep 1999 Abstract
DN-30 Programmable Electronic Circuit Breaker (slua166.htm, 8 KB)
05 Sep 1999 Abstract
DN-29 UC3842A Family - Frequency Foldback Technique Provides Protection (slua165.htm, 8 KB)
05 Sep 1999 Abstract
DN-27 UC1842/UC1842A Family - Summary of Functional Differences (slua163.htm, 8 KB)
05 Sep 1999 Abstract
DN-26 UC3842A Low-Cost Start-up and Fault Protection Circuit (slua162.htm, 8 KB)
05 Sep 1999 Abstract

View Application Notes for PWM Power Supply Controllers

User Guides

View User Guides for PWM Power Supply Controllers

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