Name: UC2854BQ
SKU: UC2854BQ
Price: 2.80115 USD
Availability: InStock

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 

 

SLUS329B − JUNE 1998 − REVISED FEBRUARY 2005

  



www.ti.com

FEATURES

Controls Boost PWM to Near-Unity Power

Factor

D Limits Line Current Distortion To < 3%

D World-Wide Operation Without Switches

D Accurate Power Limiting

D Fixed-Frequency Average Current-Mode

Control

D High Bandwidth (5 MHz), Low-Offset Current

Amplifier

D Integrated Current- and Voltage Amplifier

Output Clamps

D Multiplier Improvements: Linearity, 500 mV

Offset (Eliminates External Resistor), 0 V

to 5 V Multout Common-Mode Range

D V

REF

GOOD Comparator

D Faster and Improved Accuracy ENABLE

Comparator

D UVLO Options (16 V/10 V or 10.5 V/10 V)

D 300-µA Start-Up Supply Current

BLOCK DIAGRAM

DESCRIPTION

The UC3854A/B products are pin compatible

enhanced versions of the UC3854. Like the

UC3854, these products provide all of the

functions necessary for active power factor

corrected preregulators. The controller achieves

near unity power factor by shaping the AC input

line current waveform to correspond to the AC

input line voltage. To do this the UC3854A/B uses

average current mode control. Average current

mode control maintains stable, low distortion

sinusoidal line current without the need for slope

compensation, unlike peak current mode control.

A 1% 7.5 V reference, fixed frequency oscillator,

PWM, voltage amplifier with soft-start, line voltage

feedforward (V

RMS

squarer), input supply voltage

clamp, and over current comparator round out the

list of features.

Available in the 16-pin N (PDIP), DW (SOIC-

Wide), and J (CDIP) and 20-pin Q (PLCC)

package. See ordering information on page 3 for

availability by temperature range.

UDG−03110

ENA

VSENSE

IAC

VRMS

VCC

GND

GTDRV

2.65 V / 2.15 V

3 V

VAO

(A) 16 V / 10 V

(B) 10.5 V / 10 V

MOUT

ISENSE

CAO

OSC

RSET

PKLMT

20 V

POWER

7.5 V REF

REF

RUN

7.1 V

RUN

14 µA

MOUT

A B

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 

SLUS329B − JUNE 1998 − REVISED FEBRUARY 2005

www.ti.com

DESCRIPTION (continued)

The UC3854A/B products improve upon the UC3854 by offering a wide bandwidth, low offset current amplifier,

a faster responding and improved accuracy enable comparator, a VREF GOOD comparator, UVLO threshold

options (16 V/10 V for offline, 10.5 V/10 V for startup from an auxiliary 12 V regulator), lower startup supply

current, and an enhanced multiply/divide circuit. New features like the amplifier output clamps, improved

amplifier current sinking capability, and low offset VAC pin reduce the external component count while improving

performance. Improved common mode input range of the multiplier output/current amplifier input allow the

designer greater flexibility in choosing a method for current sensing. Unlike its predecessor, R

SET

controls only

oscillator charging current and has no effect on clamping the maximum multiplier output current. This current

is now clamped to a maximum of 2 × I

at all times which simplifies the design process and provides foldback

power limiting during brownout and extreme low line conditions.

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

ABSOLUTE MAXIMUM RATINGS

over operating free-air temperature range unless otherwise noted

(1)

UCX854A, UCX854B UNIT

Supply voltage, V

22 V

GTDRV current, I

GTDRV

Continuous 0.5 A

GTDRV Current, I

GTDRV

50% duty cycle 1.5 A

Input voltage

VSENSE, VRMS

ISENSE MOUT 11 V

Input voltage

PKLMT 5 V

Input current RSET, IAC, PKLMT, ENA 10 mA

Power dissipation 1 W

Junction temperature, T

−55 to 150

Storage temperature, T

stg

−65 to 150

°C

Lead temperature, T

sol,

1,6 mm (1/16 inch) from case for 10 seconds 300

(1)

Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only,

and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is

not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All voltages are with respect to

GND. Currents are positive into and negative out of, the specified terminal. ENA input is internally clamped to approximately 10 V.

RECOMMENDED OPERATING CONDITIONS

MIN MAX UNIT

Supply voltage, V

10 20 V

UC1854X −55 125

Operating junction temperature, T

UC2854X −40 85

°C

Operating junction temperature, T

UC3854X 0 70

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 

 

SLUS329B − JUNE 1998 − REVISED FEBRUARY 2005

www.ti.com

PACKAGE DESCRIPTION

GND

PKLMT

CAO

ISENSE

MOUT

IAC

VAO

VRMS

GTDRV

VCC

RSET

VSENSE

ENA

VREF

J, N and DW PACKAGES

(TOP VIEW)

ISENSE

CAOUT

N/C

MOUT

IAC

N/C

RSET

VSENSE

3 2 1 20 19

9 10 11 12 13

PKLMT

GND

N/C

GTDRV

VCC

VAO

VRMS

VREF

ENA

Q PACKAGE

(TOP VIEW)

N/C − No connection

ORDERING INFORMATION

UVLO

PART NUMBERS

UVLO

TURN-ON

(V)

UVLO

TURN-OFF

(V)

CDIP−16

(J)

PDIP−16

(N)

SOIC−16

(DW)

PLCC−20

(Q)

−55°C to 125°C

16 10 − − − −

−55°C to 125°C

10.5 10 UC1854BJ − − −

−40°C to 85°C

16 10 UC2854AJ UC2854AN UC2854ADW UC2854AQ

−40°C to 85°C

10.5 10 UC2854BJ UC2854BN UC2854BDW UC2854BQ

0°C to 70°C

16 10 − UC3854AN UC3854ADW −

0°C to 70°C

10.5 10 − UC3854BN UC3854BDW −

(1)

The DW and Q packages are available taped and reeled. Add TR suffix to device type (e.g. UC2854ADWTR) to order quantities of 2,000

devices per reel for the DW package and 1,000 devices per reel for the Q package.

THERMAL RESISTANCE

PACKAGED DEVICES

RESISTANCES

CDIP−16

(J)

PDIP−16

(N)

SOP−16

(DW)

PLCC−20

(Q)

(°C/W) 28

(2)

45 27 34

(°C/W) 80−120 90

(3)

50−130

(3)

43−75

(3)

(2)

data values stated are derived from MIL-STD-1835B which states “the baseline values shown are worst case (mean +2s) for a 60 × 60

mil microcircuit device silicon die and applicable for devices with die sizes up to 14,400 square mils. For device die sizes greater than

14,400 square mils use the following values, dual-in-line, 11°C/W; flat pack and pin grid array, 10°C/W.

(3)

(junction-to-ambient) applies to devices mounted to five square inch FR4 PC board with one ounce copper where noted. When

resitance range is given, lower values are for five square inch aluminum PC board. Test PWB is 0.062 inches thick and typically uses

0.635 mm trace widths for power packages and 1.3 mm trace widths for non-power packages with a 100 × 100 mil probe land are at the

end of each trace.

Part #	UC2854BQ
Description	IC PFC CTRLR AVERAGE CURR 20PLCC
Category	IC
Availability	In Stock
Qty	20

Qty	Price
1 - 4	$2.80115
5 - 8	$2.22818
9 - 12	$2.10086
13 - 16	$1.95231
17 +	$1.74011

UC2854BQ

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