Datasheet

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VREF

INV

COMP

STATUS

+VIN

EXTCLK

N/C

DRIVERB

DRIVERA

GND

N/C

DPACKAGE

(TOP VIEW)

N/C = No internal connection

UC2901-EP

www.ti.com

SLUS709A –DECEMBER 2006–REVISED MARCH 2010

ISOLATED FEEDBACK GENERATOR

Check for Samples: UC2901-EP

FEATURES

• Controlled Baseline • Internal Carrier Oscillator Usable to 5 MHz

– One Assembly/Test Site, One Fabrication • Modulator Synchronizable to an External

Site Clock

• Extended Temperature Performance of –55°C • Loop Status Monitor

to 125°C

• Enhanced Diminishing Manufacturing Sources

(DMS) Support

• Enhanced Product-Change Notification

• Qualification Pedigree

(1)

• Amplitude-Modulation System for Transformer

Coupling an Isolated Feedback Error Signal

• Low-Cost Alternative to Optical Couplers

• Internal 1% Reference and Error Amplifier

(1) Component qualification in accordance with JEDEC and

industry standards to ensure reliable operation over an

extended temperature range. This includes, but is not limited

to, Highly Accelerated Stress Test (HAST) or biased 85/85,

temperature cycle, autoclave or unbiased HAST,

electromigration, bond intermetallic life, and mold compound

life. Such qualification testing should not be viewed as

XXX

justifying use of this component beyond specified

performance and environmental limits.

DESCRIPTION

The UC2901 is designed to solve many of the problems associated with closing a feedback control loop across a

voltage isolation boundary. As a stable and reliable alternative to an optical coupler, UC2901 features an

amplitude modulation system that allows a loop error signal to be coupled with a small RF transformer or

capacitor.

The programmable, high-frequency oscillator within the UC2901 permits the use of smaller, less-expensive

transformers, which can readily be built to meet the isolation requirements of today's line-operated power

systems. As an alternative to RF operation, the external clock input to these devices allows synchronization to a

system clock or to the switching frequency of an SMPS.

An additional feature is a status monitoring circuit that provides an active low output when the sensed error

voltage is within ±10% of the reference. The DRIVERA output, DRIVERB output, and STATUS output are

disabled until the input supply has reached a sufficient level to allow proper operation of the device.

Because these devices also can be used as a DC driver for optical couplers, the benefits of 4.5 V to 40 V supply

operation, a 1% accurate reference, and a high-gain general-purpose amplifier offer advantages, even though an

AC system may not be desired.

ORDERING INFORMATION

PACKAGE

(1)

ORDERABLE PART NUMBER TOP-SIDE MARKING

–55°C to 125°C D (SOIC) UC2901MDREP UC2901MEP

(1) Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are available at

www.ti.com/sc/package.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas

Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (10 pages)

PAGE 1
UC2901-EP www.ti.
PAGE 2
UC2901-EP SLUS709A – DECEMBER 2006 – REVISED MARCH 2010 www.ti.com UC2901 SIMPLIFIED SCHEMATIC VIN 150 mV STATUS VIN 4K STATUS AMPLIFIERS 4K DRIVERB NI 150 mV DRIVERA 700 mA 700 mA INV MODULATOR VIN VIN ERROR AMPLIFIER X1 2K CT OSCILLATOR VIN 1K 3K COMP 150 mA 5K EXTCLK 10 K BIAS VREF BIAS 500 X2 BIAS 1.5-VOLT REFERENCE 1.25 V 2.
PAGE 3
UC2901-EP www.ti.com SLUS709A – DECEMBER 2006 – REVISED MARCH 2010 DISSIPATION RATING TABLE - FREE-AIR TEMPERATURE PACKAGE AIR FLOW (CFM) TA≤25°C POWER RATING DERATING FACTOR ABOVE TA = 25°C TA= 70°C POWER RATING TA= 85°C POWER RATING TA=125°C POWER RATING D 0 1000 mW 8 mW/°C 630 mW 510 mW 180 mW Electrical Characteristics over recommended operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT TA = 25°C 1.485 1.5 1.
PAGE 4
UC2901-EP SLUS709A – DECEMBER 2006 – REVISED MARCH 2010 www.ti.com 10 V VIN = 10 V OSC f = 1 Mhz TJ = 25°C Open-Loop Voltage Gain Decibels 80 0.1 mF INPUT 0.22 mF DC BIAS 60 GAIN 50 40 0 PHASE 30 45 20 90 10 135 0 180 10 10 k 100 10 k 100 k 1k Frequency - Hertz 1M 1N914 1:1 1 mH 70 Phase - Degrees 100 pF 270 pF OUTPUT 10 k 1 mH (SEE NOTE) Note: Transformer Data: N1 = N2 = 20 TAWG 26 Core = Ferroxcube 3E2A Ferrite, 0.5” O.D. Toroid Carrier Frequency = 1 Mhz Figure 1.
PAGE 5
UC2901-EP www.ti.com SLUS709A – DECEMBER 2006 – REVISED MARCH 2010 APPLICATION INFORMATION The error amplifier compensation terminal, pin 12, is intended as a source of feedback to the amplifier's inverting input at pin 11. For most applications, a series DC blocking capacitor should be part of the feedback network. The amplifier is compensated internally for unity feedback. The waveform at the driver outputs is a squarewave, with an amplitude that is proportional to the error amplifier input signal.
PAGE 6
UC2901-EP SLUS709A – DECEMBER 2006 – REVISED MARCH 2010 Primary Power and Switches www.ti.com Supply Output Power Transformer U2901 To Supply Monitor STATUS VIN -/+ 10% +/- COMP DRIVERB To PWM Controller X4 RF Coupling Transformer INV E/A + DRIVERA NI VIN 1.5 V Reference Oscillator EXTCLK CT VREF RT GND Figure 5.
PAGE 7
PACKAGE OPTION ADDENDUM www.ti.
PAGE 8
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.