AC/DC and DC/DC Power Supplies - PWM Power Supply Controllers - UC3845

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Datasheet

Current Mode PWM Controller (Rev. C) (PDF 658 KB)
14 Jun 2007

	UC1845	UC2845	UC3845
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	14CFP, 20LCCC, 8CDIP	14SOIC, 8PDIP, 8SOIC	14SOIC, 8PDIP, 8SOIC
Regulated Outputs(#)	1	1	1
	Samples	Samples	Samples
	Inventory	Inventory	Inventory

Other qualified versions of UC3845

Version	Part Number	Definition
Military	UC1845	QML certified for Military and Defense Applications

Product Information

Features

Optimized For Off-line and DC-to-DC Converters
Low Start-Up Current (<1 mA)
Automatic Feed ForwardCompensation
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
500-kHz Operation
Low R_O Error Amp

Description

The UC1842/3/4/5 family of control devices provides the necessary features to implement off-line or dc-to-dc fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits include under-voltage lockout featuring start up current less than 1 mA, a precision reference trimmed for accuracy at the error amp input, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The output stage, suitable for driving N-Channel MOSFETs, is low in the off state.

Differences between members of this family are the under-voltage lockout thresholds and maximum duty cycle ranges.

View All Description in Datasheet

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
UC3845D	ACTIVE	0 to 70	1.05 \| 1ku	SOIC (D) \| 14	View	50 \| TUBE
UC3845D8	ACTIVE	0 to 70	1.05 \| 1ku	SOIC (D) \| 8	View	75 \| TUBE
UC3845D8G4	ACTIVE	0 to 70	1.05 \| 1ku	SOIC (D) \| 8	View	75 \| TUBE
UC3845D8TR	ACTIVE	0 to 70	0.90 \| 1ku	SOIC (D) \| 8	View	2500 \| LARGE T&R	Purchase Samples
UC3845D8TRG4	ACTIVE	0 to 70	0.90 \| 1ku	SOIC (D) \| 8	View	2500 \| LARGE T&R	Purchase Samples
UC3845DG4	ACTIVE	0 to 70	1.05 \| 1ku	SOIC (D) \| 14	View	50 \| TUBE
UC3845DTR	ACTIVE	0 to 70	0.90 \| 1ku	SOIC (D) \| 14	View	2500 \| LARGE T&R	Purchase Samples
UC3845DTRG4	ACTIVE	0 to 70	0.90 \| 1ku	SOIC (D) \| 14	View	2500 \| LARGE T&R	Purchase Samples
UC3845N	ACTIVE	0 to 70	0.90 \| 1ku	PDIP (P) \| 8	View	50 \| TUBE
UC3845NG4	ACTIVE	0 to 70	0.90 \| 1ku	PDIP (P) \| 8	View	50 \| TUBE
UC3845P	OBSOLETE	0 to 70		PDIP (P) \| 8	View			Not Available

* 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

Reported Distributor Inventory as of 9:52 AM GMT, 22 Nov 2009
Region	Company	In Stock	Purchase
TI Lead Time*: 20 WeeksUC3845D
Americas	Arrow	215
	Avnet	547
	Rochester Electronics	>1k
Europe	Abacus Polar	200
	Avnet-SILICA	>1k
	EBV Elektronik	6
	Spoerle	400
Worldwide	DigiKey	246
TI Lead Time*: 20 WeeksUC3845D8
Americas	Arrow	>1k
	Newark	227
	Rochester Electronics	>1k
Asia	Farnell Asia	287
Asia	WPI	231
Europe	Avnet-SILICA	25
TI Lead Time*: 20 WeeksUC3845D8G4
Asia	Farnell Asia	91
TI Lead Time*: 20 WeeksUC3845D8TR
None Reported View Distributors
TI Lead Time*: 20 WeeksUC3845D8TRG4
None Reported View Distributors
TI Lead Time*: 20 WeeksUC3845DG4
Asia	Farnell Asia	976
Europe	Farnell	613
Worldwide	DigiKey	Available
TI Lead Time*: 20 WeeksUC3845DTR
Worldwide	DigiKey	Available
TI Lead Time*: 20 WeeksUC3845DTRG4
Worldwide	DigiKey	Available
TI Lead Time*: 20 WeeksUC3845N
Americas	Arrow	>1k
	Avnet	>1k
	Newark	8
	Rochester Electronics	>1k
Asia	Farnell Asia	27
Asia	WPI	26
Europe	Arrow Northern Europe	50
	Avnet-SILICA	350
	EBV Elektronik	16
	Farnell	27
Worldwide	Mouser Electronics	78
TI Lead Time*: 20 WeeksUC3845NG4
Asia	Farnell Asia	353
Europe	EBV Elektronik	>1k
Europe	Farnell	301
Worldwide	Mouser Electronics	209
View all Distributors

** 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
UC3845D	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845D8	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845D8G4	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845D8TR	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845D8TRG4	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845DG4	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845DTR	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845DTRG4	Green (RoHS & no Sb/Br)	CU NIPDAU	Level-1-260C-UNLIM	View	View
UC3845N	Green (RoHS & no Sb/Br)	CU NIPDAU	N/A for Pkg Type	View	View
UC3845NG4	Green (RoHS & no Sb/Br)	CU NIPDAU	N/A for Pkg Type	View	View
UC3845P					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.

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UC3845 Status: ACTIVE

Current-Mode PWM Controller

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Other qualified versions of UC3845

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