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FEATURES

DW PACKAGE

(TOP VIEW)

C/S SS Shutdown

B Out

GND

A Out

Sync

VREF

C/S–

C/S+

E/A+

E/A–

COMP

DESCRIPTION/ORDERING INFORMATION

UC1846-EP

CURRENT-MODE PWM CONTROLLER

SGLS329 – MAY 2006

• Controlled Baseline • Soft-Start Capability

– One Assembly/Test Site, One Fabrication • Shutdown Terminal

Site

• 500-kHz Operation

• Extended Temperature Performance of –55 ° C

to 125 ° C

• Enhanced Diminishing Manufacturing

Sources (DMS) Support

• Enhanced Product-Change Notification

• Qualification Pedigree

(1)

• Automatic Feed-Forward Compensation

• Programmable Pulse-by-Pulse Current

Limiting

• Automatic Symmetry Correction in Push-Pull

Configuration

• Enhanced Load-Response Characteristics

• Parallel Operation Capability for Modular

Power Systems

• Differential Current-Sense Amplifier With

Wide Common-Mode Range

• Double Pulse Suppression

• 500-mA (Peak) Totem-Pole Outputs

• ± 1% Bandgap Reference

• Undervoltage Lockout

(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

justifying use of this component beyond specified

performance and environmental limits.

The UC1846-EP control IC provides all of the necessary features to implement fixed-frequency, current-mode

control schemes, while maintaining a minimum external parts count. The superior performance of this technique

can be measured in improved line regulation, enhanced load-response characteristics, and a simpler,

easier-to-design control loop. Topological advantages include inherent pulse-by-pulse current-limiting capability,

automatic symmetry correction for push-pull converters, and the ability to parallel power modules, while

maintaining equal current sharing.

Protection circuitry includes built-in undervoltage lockout and programmable current limit, in addition to soft-start

capability. A shutdown function is also available, which can initiate either a complete shutdown with automatic

restart or latch the supply off.

Other features include fully latched operation, double pulse suppression, deadline adjust capability, and a ± 1%

trimmed bandgap reference.

The UC1846-EP features low outputs in the OFF state.

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 (18 pages)

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UC1846-EP CURRENT-MODE PWM CONTROLLER www.ti.
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UC1846-EP CURRENT-MODE PWM CONTROLLER www.ti.com SGLS329 – MAY 2006 ORDERING INFORMATION TA PACKAGE –55°C to 125°C ORDERABLE PART NUMBER SOIC – DW UC1846MDWREP TOP-SIDE MARKING UC1846MEP BLOCK DIAGRAM 5.1-V Reference Regulator VIN 15 2 VREF 13 VC Sync 10 RT UVLO Lockout Q Q 8 C/S− 3 Output Stage COMP X3 C/S+ 11 A Out T OSC CT F/F 9 S R Q 4 S 0.5 V 14 B Out + 0.
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UC1846-EP CURRENT-MODE PWM CONTROLLER www.ti.com SGLS329 – MAY 2006 Absolute Maximum Ratings (1) (2) MIN MAX UNIT Supply voltage (pin 15) 40 Collector supply voltage (pin 13) 40 V 500 mA Output current, source or sink (pins 11, 14) Analog inputs (pins 3, 4, 5, 6, 16) –0.
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UC1846-EP CURRENT-MODE PWM CONTROLLER www.ti.com SGLS329 – MAY 2006 Electrical Characteristics TA = –55°C to 125°C, VIN = 15 V, RT = 10 k, CT = 4.7 nF, TA = TJ (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 5.05 5.1 5.
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UC1846-EP CURRENT-MODE PWM CONTROLLER www.ti.com SGLS329 – MAY 2006 Electrical Characteristics (continued) TA = –55°C to 125°C, VIN = 15 V, RT = 10 k, CT = 4.7 nF, TA = TJ (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX 3 UNIT Current-Sense Amplifier Amplifier gain VPIN3 = 0 V, Pin 1 open (2) (3) 2.5 2.75 Maximum differential input signal (VPIN4 – VPIN3) Pin 1 open, (2) RL (pin 7) = 15 kW 1.1 1.2 Input offset voltage VPIN1 = 0.
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UC1846-EP CURRENT-MODE PWM CONTROLLER www.ti.com SGLS329 – MAY 2006 15 14 13 12 Years Estimated Life 11 10 9 8 7 6 5 4 3 2 1 0 110 115 120 125 130 Continuous TA – °C Figure 1.
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UC1846-EP CURRENT-MODE PWM CONTROLLER www.ti.com SGLS329 – MAY 2006 APPLICATION INFORMATION 7.5 mA Output deadtime is determined by the external capacitor, CT, according to the formula: ID ID * R 3.6 (kW) T τd (µs) = 145CT (µf) ID = Oscillator discharge current at 25°C is typically 7.5 mA. For large values of RT: τd (µs) ≈ 145CT (µf) 2.2 Oscillator frequency is approximated by the formula: f (kHz) ≈ RT (kW) CT (mf) T Figure 2. Oscillator Circuit VREF VREF 5 0.5 mA 6 ZS 7 Comp ZF IF < 0.
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UC1846-EP CURRENT-MODE PWM CONTROLLER www.ti.com SGLS329 – MAY 2006 Open-Loop Voltage Gain (dB) APPLICATION INFORMATION (continued) VIN = 20 V TA = 255C RL – Output Load Resistance (kW) Figure 5. Error-Amplifier Open-Logic DC Gain vs Load Resistance Figure 6.
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UC1846-EP CURRENT-MODE PWM CONTROLLER www.ti.com SGLS329 – MAY 2006 APPLICATION INFORMATION (continued) 0.5 mA 0.5 V R2 VREF − 0.5 R1 + R2 Peak current (IS) is determined by the formula: IS = 3RS Figure 7.
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UC1846-EP CURRENT-MODE PWM CONTROLLER www.ti.com SGLS329 – MAY 2006 APPLICATION INFORMATION (continued) 3 mA (latched off) 3 mA, the device Figure 8. Soft-Start and Shutdown/Restart Functions A small RC filter may be required in some applications to reduce switch transients. Differential input allows remote noise-free sensing. Figure 9.
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UC1846-EP CURRENT-MODE PWM CONTROLLER www.ti.com SGLS329 – MAY 2006 APPLICATION INFORMATION (continued) Frequency Set and Max Duty Cycle RT VREF (5-V Output) VIN (12 V) Timing Cap CT 5V 5V 0.1 mF 1 nF 4.7 nF UC1846-EP ISENSE Adjust (91 V PK) (12 V) 0.1 mF 5V Duty-Cycle Adjust 150 W 5V 150 W Current-Limit Adjust –Bypass capacitance should be low ESR and ESL type. –Short pins 6 and 7 for unity gain testing. Figure 10.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 21-Feb-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device UC1846MDWREP Package Package Pins Type Drawing SOIC DW 16 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 2000 330.0 16.4 Pack Materials-Page 1 10.85 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 10.8 2.7 12.0 16.
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PACKAGE MATERIALS INFORMATION www.ti.com 21-Feb-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) UC1846MDWREP SOIC DW 16 2000 346.0 346.0 33.
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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.