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FEATURES DESCRIPTION

BLOCK DIAGRAM

UC1879

UC2879

UC3879

SLUS230B – JUNE 1998 – REVISED JUNE 2007

PHASE SHIFT RESONANT CONTROLLER

• Programmable Output Turn On Delay; Zero

The UC3879 controls a bridge power stage by phase

Delay Available

shifting the switching of one half-bridge with respect

to the other. This allows constant frequency pulse

• Compatible with Voltage Mode or Current

width modulation in combination with resonant,

Mode Topologies

zero-voltage switching for high efficiency

• Practical Operation at Switching Frequencies

performance. The UC3879 can be configured to

to 300 kHz

provide control in either voltage mode or current

• 10-MHz Error Amplifier

mode operation, with overcurrent shutdown for fast

fault protection.

• Pin Programmable Undervoltage Lockout

Independently programmable time delays provide

• Low Startup Current – 150 µ A

dead-time at the turn-on of each output stage,

• Soft Start Control

allowing time for each resonant switching interval.

• Outputs Active Low During UVLO

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 (17 pages)

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UC1879 UC2879 UC3879 www.ti.
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UC1879 UC2879 UC3879 www.ti.com SLUS230B – JUNE 1998 – REVISED JUNE 2007 DESCRIPTION (CONTINUED) With the oscillator capable of operating in excess of 600 kHz, overall output switching frequencies to 300 kHz are practical. In addition to the standard free running mode, with the CLKSYNC pin, the user may configure the UC3879 to accept an external clock synchronization signal. Alternatively, up to three units can be locked together with the operational frequency determined by the fastest device.
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UC1879 UC2879 UC3879 www.ti.
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UC1879 UC2879 UC3879 www.ti.com SLUS230B – JUNE 1998 – REVISED JUNE 2007 ELECTRICAL CHARACTERISTICS Unless specified; VC = VIN = VUVSEL = 12 V, CT = 470 pF, RT = 9.53k, RDELSETA-B = RDELSEC-D = 4.8k, CDELSETA-B = CDELSETC-D = 0.01 µF, TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Undervoltage Lockout Start threshold UVLO hysteresis Input bias, UVSEL pin VUVSEL = VIN 9 10.75 12.5 VUVSEL = Open 12.5 15.25 16.5 VUVSEL = VIN 1.15 1.75 2.15 6 7.4 VUVSEL = Open 5.
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UC1879 UC2879 UC3879 www.ti.com SLUS230B – JUNE 1998 – REVISED JUNE 2007 ELECTRICAL CHARACTERISTICS (continued) Unless specified; VC = VIN = VUVSEL = 12 V, CT = 470 pF, RT = 9.53k, RDELSETA-B = RDELSEC-D = 4.8k, CDELSETA-B = CDELSETC-D = 0.01 µF, TA = TJ.
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UC1879 UC2879 UC3879 www.ti.com SLUS230B – JUNE 1998 – REVISED JUNE 2007 ELECTRICAL CHARACTERISTICS (continued) Unless specified; VC = VIN = VUVSEL = 12 V, CT = 470 pF, RT = 9.53k, RDELSETA-B = RDELSEC-D = 4.8k, CDELSETA-B = CDELSETC-D = 0.01 µF, TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX –3 UNIT Soft Start/Reset Delay Charge current VSS = 0.5 V –20 –9 Discharge current VSS = 1 V 120 230 Restart threshold 4.3 Discharge level µA 4.
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UC1879 UC2879 UC3879 www.ti.com SLUS230B – JUNE 1998 – REVISED JUNE 2007 PIN DESCRIPTIONS CLKSYNC (Bi-directional Clock and Synchronization): Used as an output, CLKSYNC provides a clock signal. As an input, this pin provides a synchronization point. Multiple UC3879s, each with their own local oscillator frequency, may be connected together by the CLKSYNC pin, and they will synchronize to the fastest oscillator.
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UC1879 UC2879 UC3879 www.ti.com SLUS230B – JUNE 1998 – REVISED JUNE 2007 PIN DESCRIPTIONS (continued) RT (Clock/Sync Duty Cycle Set Pin): The UC3879 oscillator produces a sawtooth waveform. The rising edge is generated by connecting a resistor from RT to GND and a capacitor from CT to GND (see CT pin description). During the rising edge, the modulator has linear control of the duty cycle. The duty cycle jumps to 100% when the voltage on COMP exceeds the oscillator peak voltage.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined.
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PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant UC2879DWTR SOIC DW 20 2000 330.0 24.4 10.8 13.3 2.7 12.0 24.0 Q1 UC3879DWTR SOIC DW 20 2000 330.0 24.4 10.8 13.3 2.7 12.0 24.
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PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) UC2879DWTR SOIC DW 20 2000 367.0 367.0 45.0 UC3879DWTR SOIC DW 20 2000 367.0 367.0 45.
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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.