TEXAS INSTRUMENTS UCC28C4x-EP Technical data

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BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

UCC28C4x-EP

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

FEATURES

• Low Operating Current of 2.3 mA at 52 kHz

• Controlled Baseline • Fast 35 ns Cycle-by-Cycle Overcurrent

– One Assembly/Test Site, One Fabrication

Limiting

Site • ± 1 A Peak Output Current

– Extended Temperature Performance of • Rail-to-Rail Output Swings With 25 ns Rise

–55 ° C to 125 ° C and 20 ns Fall Times

• Enhanced Diminishing Manufacturing Sources • ± 1% Initial Trimmed 2.5 V Error Amplifier

(DMS) Support Reference

• Enhanced Product-Change Notification • Trimmed Oscillator Discharge Current

• Qualification Pedigree

(1)

• New Undervoltage Lockout Versions

• Enhanced Replacements for UC2842A Family • MSOP-8 Package Minimizes Board Space

With Pin-to-Pin Compatibility

• 1 MHz Operation

• 50 µ A Standby Current, 100 µ A Maximum

(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.

APPLICATIONS

• Switch Mode Power Supplies

• DC-to-DC Converters

• Board Mount Power Modules

DESCRIPTION

The UCC28C4x family are high performance current mode PWM controllers. They are enhanced BiCMOS versions with pin-for-pin compatibility to the industry standard UC284xA family and UC284x family of PWM controllers. In addition, lower startup voltage versions of 7 V are offered as UCC28C40 and UCC28C41.

Providing necessary features to control fixed frequency, peak current mode power supplies, this family offers several performance advantages. These devices offer high frequency operation up to 1 MHz with low start up and operating currents, thus minimizing start up loss and low operating power consumption for improved efficiency. The devices also feature a fast current sense to output delay time of 35 ns, and a ± 1 A peak output current capability with improved rise and fall times for driving large external MOSFETs directly.

The UCC28C4x family is offered in 8-pin package SOIC (D).

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.

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Note:Toggleflip-flopusedonlyinUCC28C41,UCC28C44,andUCC28C45.

UCC28C4x-EP BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

AVAILABLE OPTIONS

MAXIMUM UVLO

DUTY CYCLE ON/OFF

14.5 V/9 V UCC28C42MDREP

100% 8.4 V/7.6 V UCC28C43MDREP

–55 ° C to 125 ° C

7 V/6.6 V UCC28C40MDREP

14.5 V/9 V UCC28C44MDREP

50% 8.4 V/7.6 V UCC28C45MDREP

7 V/6.6 V UCC28C41MDREP

(1) D (SOIC-8) packages are available taped and reeled. Add R suffix to device type (e.g., UCC28C42DREP) to order quantities of 2500

devices per reel. Tube quantities are 75 for D packages (SOIC-8).

(2) Product Preview

FUNCTIONAL BLOCK DIAGRAM

SOIC-8

SMALL OUTLINE

(1)

(D)

(2)

(2) (2)

(2)

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UCC28C4x-EP

BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)

Supply voltage

Output current, I Output energy, capacitive load 5 µ J

Voltage rating V

Error amplifier output sink current 10 mA

Operating junction temperature range

Storage temperature range –65 150 ° C

stg

Lead temperature (soldering, 10 s) 300 ° C

(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. (2) All voltages are with respect to ground. Currents are positive into and negative out of the specified terminals. (3) Long-term high temperature storage and/or extended use at maximum recommended operating conditions may result in a reduction of

overall device life. See http://www.ti.com/ep_quality for additional information about enhanced plastic packaging.

peak ± 1 A

OUT

(1) (2)

MIN MAX UNIT

VDD 20 V Max I

30 mA

COMP, CS, FB –0.3 6.3 OUT –0.3 20 RT/CT –0.3 6.3 VREF 7

(3)

–55 150 ° C

Dissipation Ratings

PACKAGE

( ° C/W) POWER RATING ABOVE TA= 25 ° C POWER RATING POWER RATING POWER RATING

D 176 710 mW 5.68 mW/ ° C 454 mW 369 mW 142 mW

TA< 25 ° C DERATING FACTOR TA= 70 ° C TA= 85 ° C TA= 125 ° C

Recommended Operating Conditions

MIN MAX UNIT

OUT

(1)

OUT

OUT(ref

(1)

(1) It is not recommended that the device operate under conditions beyond those specified in this table for extended periods of time.

Input voltage 18 V Output voltage range 18 V Average output current 200 mA

(1)

)

Reference output current –20 mA Operating junction temperature –55 150 ° C

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ACS +

COM

,0Vv VCSv 900 mV

UCC28C4x-EP BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

Electrical Characteristics

UCC28C4x

Reference

Oscillator

Error Amplifier

VOL

PSRR Power-supply rejection ratio V

Current Sense

PSRR Power-supply rejection ratio V

Output

(1)

= 15 V

, RT= 10 k Ω , CT= 3.3 nF, C

VDD

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Output voltage, initial accuracy TA= 25 ° C , I Line regulation V Load regulation 1 mA to 20 mA 3 25 mV Temperature stability Total output variation Output noise voltage 10 Hz to 10 kHz, TA= 25 ° C 50 µ V Long term stability 1000 hours, TA= 125 ° C Output short circuit –30 –45 –55 mA

Initial accuracy

Voltage stability V Temperature stability T Amplitude RT/CT pin peak to peak 1.9 V

Discharge current

Feedback input voltage, initial accuracy V Feedback input voltage, total variation V Input bias current –0.1 –2 µ A Open-loop voltage gain V Unity gain bandwidth 1.5 MHz

Output sink current V Output source current V High-level output voltage V Low-level output voltage V

Gain

Maximum input signal V

Input bias current –0.1 –2 µ A CS to output delay 35 70 ns COMP to CS offset V

low (R

OUT

high (R

OUT

pull-down) I

DS(on)

pull-up) I

DS(on)

= 0.1 µ F and no load on the outputs, TA= TJ= –55 ° C to 125 ° C for the

= 1 mA 4.9 5 5.1 V

OUT

= 12 V to 18 V 0.2 20 mV

(2) (2)

(2)

TA= 25 ° C TA= Full Range

DD MIN

TA= 25 ° C, RT/CT = 2 V RT/CT = 2 V

COMP COMP

OUT

DD FB FB FB FB

TA= 25 ° C TA= Full Range

FB DD

SINK SOURCE

(3)

= 12 V to 18 V 0.2 2.85 %

(2)

to T

MAX

(4)

= 2.5 V, TA= 25 ° C 2.475 2.500 2.525 V = 2.5 V 2.45 2.50 2.55 V

= 2 V to 4 V 65 90 dB

= 12 V to 18 V 60 dB = 2.7 V, V = 2.3 V, V = 2.3 V, R = 2.7 V, R

(5) (6)

= 1.1 V 2 14 mA

COMP

= 5 V –0.5 –1 mA

COMP

= 15 k to GND 5 6.8 V

LOAD

= 15 k to VREF 0.1 1.1 V

LOAD

(5) (6)

< 2.4 V 0.9 1 1.1 V

= 12 V to 18 V

(2) (5)

= 0 V 1.15 V

= 200 mA 5.5 15 Ω

= 200 mA 10 25 Ω

4.82 5.18 V

50.5 53 55 kHz

50.5 57 KHz

2.85 3 3.15 V/V

2.825 3.15 V/V

0.2 0.4 mV/ ° C

7.7 8.4 9 mA

7.2 8.4 9.5 mA

70 dB

5 25 mV

1 2.5 %

(1) Adjust V (2) Not production tested.

above the start threshold before setting at 15 V.

(3) Output frequencies of the UCC28C41, UCC28C44, and UCC28C45 are one-half the oscillator frequency. (4) Oscillator discharge current is measured with RT= 10 k Ω to V (5) Parameter measured at trip point of latch with V

= 0 V.

REF

(6) Gain is defined as

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1 2 3 4

8 7 6 5

COMP

RT/CT

VREF VDD OUT GND

PDIP (P) or SOIC (D) PACKAGE

(TOP VIEW)

Electrical Characteristics (continued)

= 15 V , RT= 10 k Ω , CT= 3.3 nF, C

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Rise tIme TA= 25 ° C, C Fall time TA= 25 ° C, C

Undervoltage Lockout (UVLO)

Start threshold UCC28C43-EP, UCC28C45-EP 7.8 8.4 9 V

Minimum operating voltage UCC28C43-EP, UCC28C45-EP 7 7.6 8.2 V

PWM

Maximum duty cycle UCC28C40-EP, UCC28C44-EP, %

Minimum duty cycle 0%

Current Supply

START-UP

Start-up current V Operating supply current V

BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

= 0.1 µ F and no load on the outputs, TA= TJ= –55 ° C to 125 ° C for the UCC28C4x

VDD

= 1 nF 25 50 ns

LOAD

= 1 nF 20 40 ns

LOAD

UCC28C42-EP, UCC28C44-EP 13.5 14.5 15.5

UCC28C40-EP, UCC28C41-EP 6.5 7 7.5 UCC28C42-EP, UCC28C44-EP 8 9 10

UCC28C40-EP, UCC28C41-EP 6.1 6.6 7.1

UCC28C42-EP, UCC28C43-EP, 94 96 UCC28C45-EP, UCC28C41-EP

= UVLO start threshold (–0.5 V) 50 100 µ A

= V

= 0 V 2.3 3 mA

UCC28C4x-EP

47 48

Pin Assignments

COMP: This pin provides the output of the error amplifier for compensation. In addition, the COMP pin is

frequently used as a control port by utilizing a secondary-side error amplifier to send an error signal across the secondary-primary isolation boundary through an opto-isolator.

CS: The current-sense pin is the noninverting input to the PWM comparator. This is compared to a signal proportional to the error amplifier output voltage. A voltage ramp can be applied to this pin to run the device with a voltage mode control configuration.

FB: This pin is the inverting input to the error amplifier. The noninverting input to the error amplifier is internally trimmed to 2.5 V ± 1%.

GND: Ground return pin for the output driver stage and the logic-level controller section. OUT: The output of the on-chip drive stage. OUT is intended to directly drive a MOSFET. The OUT pin in the

UCC28C40, UCC28C42, and UCC28C43 is the same frequency as the oscillator, and can operate near 100% duty cycle. In the UCC28C41, UCC28C44, and the UCC28C45, the frequency of OUT is one-half that of the oscillator due to an internal T flipflop. This limits the maximum duty cycle to <50%.

RT/CT: Timing resistor and timing capacitor. The timing capacitor should be connected to the device ground using minimal trace length.

VDD: Power supply pin for the device. This pin should be bypassed with a 0.1 µ F capacitor with minimal trace lengths. Additional capacitance may be needed to provide hold up power to the device during startup.

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UCC28C4x-EP BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

VREF: 5-V reference. For stability, the reference should be bypassed with a 0.1 µ F capacitor to ground using

the minimal trace length possible.

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UCC28C4x-EP

BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

APPLICATION INFORMATION

This device is a pin-for-pin replacement of the bipolar UC2842 family of controllers—the industry standard PWM controller for single-ended converters. Familiarity with this controller family is assumed.

The UCC28C4x series is an enhanced replacement with pin-to-pin compatibility to the bipolar UC284x and UC284xA families. The new series offers improved performance when compared to older bipolar devices and other competitive BiCMOS devices with similar functionality. Note that these improvements discussed below generally consist of tighter specification limits that are a subset of the older product ratings, maintaining drop-in capability. In new designs these improvements can be utilized to reduce the component count or enhance circuit performance when compared to the previously available devices.

Advantages

This device increases the total circuit efficiency whether operating off-line or in dc input circuits. In off-line applications the low start-up current of this device reduces steady state power dissipation in the startup resistor, and the low operating current maximizes efficiency while running. The low running current also provides an efficiency boost in battery-operated supplies.

Low-Voltage Operation

Two members of the UCC28C4x family are intended for applications that require a lower start-up voltage than the original family members. The UCC28C40 and UCC28C41 have a turn-on voltage of 7 V typical and exhibit hysteresis of 0.4 V for a turn-off voltage of 6.6 V. This reduced start-up voltage enables use in systems with lower voltages, such as 12 V battery systems that are nearly discharged.

High-Speed Operation

The BiCMOS design allows operation at high frequencies that were not feasible in the predecessor bipolar devices. First, the output stage has been redesigned to drive the external power switch in approximately one-half the time of the earlier devices. Second, the internal oscillator is more robust, with less variation as frequency increases. In addition, the current sense to output delay has been reduced by a factor of three, to 45 ns typical. These features combine to provide a device capable of reliable high-frequency operation.

The UCC28C4x family oscillator is true to the curves of the original bipolar devices at lower frequencies, yet extends the frequency programmability range to at least 1 MHz. This allows the device to offer pin-to-pin capability where required, yet capable of extending the operational range to the higher frequencies typical of latest applications. When the original UC2842 was released in 1984, most switching supplies operated between 20 kHz and 100 kHz. Today, the UCC28C4x can be used in designs cover a span roughly ten times higher than those numbers.

Start/Run Current Improvements

The start-up current is only 60 µ A typical, a significant reduction from the bipolar device's ratings of 300 µ A (UC284xA). For operation over the temperature range of –55 ° C to 125 ° C, the UCC28C4x devices offer a maximum startup current of 100 µ A, an improvement over competitive BiCMOS devices. This allows the power-supply designer to further optimize the selection of the start-up resistor value to provide a more efficient design. In applications where low component cost overrides maximum efficiency the low run current of 2.3 mA typical may allow the control device to run directly through the single resistor to (+) rail, rather than needing a bootstrap winding on the power transformer, along with a rectifier. The start/run resistor for this case must also pass enough current to allow driving the primary switching MOSFET, which may be a few milliamps in small devices.

± 1% Initial Reference Voltage

The BiCMOS internal reference of 2.5 V has an enhanced design and utilizes production trim to allow initial accuracy of ± 1% at room temperature and ± 2% over the full temperature range. This can be used to eliminate an external reference in applications that do not require the extreme accuracy afforded by the additional device. This is very useful for nonisolated dc-to-dc applications where the control device is referenced to the same common as the output. It is also applicable in offline designs that regulate on the primary side of the isolation boundary by looking at a primary bias winding, or perhaps from a winding on the output inductor of a buck-derived circuit.

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UCC28C42

1COMP

GND

UDG-01072

REF

UCC28C4x-EP BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

APPLICATION INFORMATION (continued)

Reduced Discharge Current Variation

The original UC2842 oscillator did not have trimmed discharged current, and the parameter was not specified on the data sheet. Since many customers attempted to use the discharge current to set a crude dead-time limit, the UC2842A family was released with a trimmed discharge current specified at 25 ° C. The UCC28C4x series now offers even tighter control of this parameter, with approximately ± 3% accuracy at 25 ° C, and less than 10% variation over temperature using the UCC28C4x devices. This level of accuracy can enable a meaningful limit to be programmed, a feature not currently seen in competitive BiCMOS devices. The improved oscillator and reference also contribute to decreased variation in the peak-to-peak variation in the oscillator waveform, which is often used as the basis for slope compensation for the complete power system.

Soft-Start

Figure 1 provides a typical soft-start circuit for use with the UCC28C42. The values of R and C should be

selected to bring the COMP pin up at a controlled rate, limiting the peak current supplied by the power stage. After the soft-start interval is complete, the capacitor continues to charge to V transistor from circuit considerations.

The optional diode in parallel with the resistor forces a soft-start each time the PWM goes through UVLO and the reference (V

) goes low. Without the diode, the capacitor otherwise remains charged during a brief loss of

REF

supply or brownout, and no soft-start is enabled upon reapplication of VIN.

, effectively removing the PNP

REF

Figure 1.

Oscillator Synchronization

The UCC28C4x oscillator has the same synchronization characteristics as the original bipolar devices. Thus, the information in the application report U-100A, UC2842/3/4/5 Provides Low-Cost Current-Mode Control (SLUA143) still applies. The application report describes how a small resistor from the timing capacitor to ground can offer an insertion point for synchronization to an external clock (see Figure 2 and Figure 3 ). Figure 2 shows how the UCC28C42 can be synchronized to an external clock source. This allows precise control of frequency and dead time with a digital pulse train.

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UDG-01069

REF

RT/ C

UCC28C42 PWM

SYNCHRONIZATION CIRCUIT INPUT

ON .

LOW LOWHIGH

ON . OFF .

CLOCK

INPUT

PWM

OUT

UPPER THRESHOLD

LOWER THRESHOLD

OUTPUT A

COMBINED

UPPER THRESHOLD

LOWER THRESHOLD

VCT(ANALOG)

SYNC

(DIGITAL)

UDG−01070

BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

APPLICATION INFORMATION (continued)

Figure 2. Oscillator Synchronization Circuit

UCC28C4x-EP

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

Precautions

The absolute maximum supply voltage is 20 V, including any transients that may be present. If this voltage is exceeded, device damage is likely. This is in contrast to the predecessor bipolar devices that could survive up to 30 V. Thus, the supply pin should be decoupled as close to the ground pin as possible. Also, since no clamp is included in the device, the supply pin should be protected from external sources that could exceed the 20 V level.

Careful layout of the printed board has always been a necessity for high-frequency power supplies. As the device switching speeds and operating frequencies increase, the layout of the converter becomes increasingly important.

This 8-pin device has only a single ground for the logic and power connections. This forces the gate drive current pulses to flow through the same ground that the control circuit uses for reference. Thus, the interconnect inductance should be minimized as much as possible. One implication is to place the device (gate driver) circuitry close to the MOSFET it is driving. Note that this can conflict with the need for the error amplifier and the feedback path to be away from the noise generating components.

Circuit Applications

Figure 4 shows a typical off-line application.

Figure 3. Synchronization to an External Clock

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UDG-01071

C53

1 COMP

2 FB

3 CS

4 RT/CT

8REF

7VCC

6OUT

5GND

UCC28C44

C13

R16

R12

C12

D50

C52

D51

R10

R11

C18C1A

BR1

RT1

L50

C54

R55

R53

R56

C55

R52

SEC COMMON

12 V OUT

R50

C50

C51

R50

IC3

R54

A R

5 V OUT

AC INPUT

100 Vac - 240 Vac

EMI FILTER REQUIRED

IC2

UCC28C4x-EP BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

APPLICATION INFORMATION (continued)

Figure 4. Typical Off-Line Application

Figure 5 shows the forward converter with synchronous rectification. This application provides 48 V to 3.3 V at

10 A with over 85% efficiency, and uses the UCC28C42 as the secondary-side controller and UCC3961 as the primary-side startup control device.

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R28

100

BAR74

C26

2uF

BAR74

R14

20k40%

C16

5.6nF

C15

1uF

C14

1uF

C13

0.22uF

C12

3300pF

C11

1500pF

BZX84C15LT1

UCC28C4x

COMP

2FB3CS4

Rt/Ct

GND

OUT

Vcc

REF

C22

4.7nF

C23

680pF

C24

0.1uF

C10

2.7nF

4.7uH

C21

0.1uF

C20

470uF

C19

470uF

3r3V

PWRGND

1nF

C18

4700pF

C25

0.047uF

VinN

VinP

0.1uF

ucc3961

4FB5Rt6

Ref7AGnd

8Vs9CS10

PGnd

Out

OVS

2SD3

Vdd

UVS

470uF

10nF

0.22uF

0.1uF

470pF

100pF

1uF

C17

4700pF

TPS2832

BOOT

BTLO

HIDR

Vcc

PGND

LODR

R19

R22

100

R18

7.5k

R17

20k

R16

21.5k

R15

50k

R23

402

R24

20k

R25

20k

R12

200

R13

300

R27

4.7

R26

4.7

10k

R21

32.4k

1.2k

2.4k

1.5k

76.8k

4.7

5.1k

0.33

R10

R11

46.4k

R20

UCC28C4x-EP

BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

APPLICATION INFORMATION (continued)

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Figure 5. Forward Converter With Synchronous Rectification

Using the UCC28C42 as the Secondary-Side Controller

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DISCH

− Oscillator Discharge Current − mA

TJ − Temperature − °C

9.0

9.5

8.0

7.5

7.0

8.5

−50 −25 0 25 50 75 100 125

OSCILLATOR DISCHARGE CURRENT

TEMPERATURE

1 k

10 k

100 k

1 k 10 k 100 k

1 M

10 M

OSCILLATOR FREQUENCY

TIMING RESISTANCE AND CAPACITANCE

CT = 220 pF

CT = 4.7 nF

CT = 2.2 nF

CT = 1 nF

CT = 470 pF

RT − Timing Resistance − W

f − Frequency − Hz

Gain − (dB)

ERROR AMPLIFIER

FREQUENCY RESPONSE

1 10 100 10 k 100 k 1 M 10 M1 k

200

180

140

120

100

160

100

Phase Margin − (°)

GAIN

PHASE

MARGIN

COMP to CS OFFSET VOLTAGE (with CS = 0)

TEMPERATURE

COMP to CS

TJ − Temperature − °C

0.2

1.8

1.4

1.2

0.8

0.4

0.0

0.6

1.0

1.6

−50 −25 0 25 50 75 100 125

UCC28C4x-EP BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

APPLICATION INFORMATION (continued)

Figure 6. Figure 7.

Figure 8. Figure 9.

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REFERENCE VOLTAGE

TEMPERATURE

REF

− Reference Voltage − V

−50 −25 0 25 50 75 100 125 TJ − Temperature − °C

4.96

4.97

4.98

4.99

5.01

5.02

5.03

5.04

5.05

5.00

4.95

2.46

2.55

2.54

2.52

2.51

2.49

2.47

2.45

2.48

2.50

2.53

−50 −25 0 25 50 75 100 125

ERROR AMPLIFIER REFERENCE VOLTAGE

TEMPERATURE

EAREF

− Error Amplifier Reference Voltage − V

TJ − Temperature − °C

−200

200

150

−50

−150

100

−100

ERROR AMPLIFIER INPUT BIAS CURRENT

TEMPERATURE

BIAS

− Error Amplifier Input Bias Current − nA

TJ − Temperature − °C

−50 −25 0 25 50 75 100 125

− Reference Short Circuit Current − mA

REFERENCE SHORT-CIRCUIT CURRENT

TEMPERATURE

−55

−35

−37

−41

−45

−51

−53

−47

−49

−43

−39

−50 −25 0 25 50 75 100 125 TJ − Temperature − °C

BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

APPLICATION INFORMATION (continued)

UCC28C4x-EP

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

Figure 10. Figure 11.

Figure 12. Figure 13.

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UNDERVOLTAGE LOCKOUT

TEMPERATURE (UCC28C45)

UVLO

− UVLO Voltage − V

TJ − Temperature − °C

7.0

9.0

8.8

8.4

8.0

7.4

7.2

7.8

7.6

8.2

8.6

−50 −25 0 25 50 75 100 125

UVLO

OFF

−50 −25 0 25 50 75 100 125

UVLO

OFF

UNDERVOLTAGE LOCKOUT

TEMPERATURE (UCC28C44)

UVLO

− UVLO Voltage − V

TJ − Temperature − °C

200 k 400 k 600 k 800 k0 k 1 M

1-nF LOAD

NO LOAD

SUPPLY CURRENT

OSCILLATOR FREQUENCY

− Supply Current − mA

f − Frequency − Hz

6.3

7.3

7.2

7.0

6.8

6.5

6.4

6.7

6.6

7.1

−50 −25 0 25 50 75 100 125

6.9

UNDERVOLTAGE LOCKOUT

TEMPERATURE (UCC28C41)

UVLO

− UVLO Voltage − V

TJ − Temperature − °C

UVLO

OFF

UCC28C4x-EP BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

APPLICATION INFORMATION (continued)

Figure 14. Figure 15.

Figure 16. Figure 17.

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OUTPUT RISE TIME AND FALL TIME

TEMPERATURE

Output Rise and Fall TIme − ns

(1 nF)

−50 −25 0 25 50 75 100 125 TJ − Temperature − °C

(1 nF)

10% to 90%

VDD = 12 V

− Supply Current − mA

−50

2.1

3.0

2.9

2.7

2.6

2.4

2.2

2.0

2.3

2.5

2.8

−25 0 25 50 75 100 125

SUPPLY CURRENT

TEMPERATURE

TJ − Temperature − °C

NO LOAD

Duty Cycle − %

f − Frequency − kHz

MAXIMUM DUTY CYCLE

OSCILLATOR FREQUENCY

100

500

CT = 220 pF

CT = 1 nF

1000 1500

2000

2500

Maximum Duty Cycle − %

MAXIMUM DUTY CYCLE

TEMPERATURE

100

−50 −25 0 25 50 75 100 125

UCC28C40 UCC28C42 UCC28C43

TJ − Temperature − °C

BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

APPLICATION INFORMATION (continued)

UCC28C4x-EP

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

Figure 18. Figure 19.

Figure 20. Figure 21.

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CURRENT-SENSE THRESHOLD VOLTAGE

TEMPERATURE

CS_th

− Current Sense Threshold − V

0.90

0.95

1.00

1.05

1.10

−50 −25 0 25 50 75 100 125 TJ − Temperature − °C

MAXIMUM DUTY CYCLE

TEMPERATURE

Output Rise and Fall TIme − ns

−50 −25 0 25 50 75 100 125

UCC28C41 UCC28C44 UCC28C45

TJ − Temperature − °C

− CS to OUT Delay Time − ns

CS TO OUT DELAY TIME

TEMPERATURE

−50 −25 0 25 50 75 100 125

TJ − Temperature − °C

UCC28C4x-EP BiCMOS LOW-POWER CURRENT-MODE PWM CONTROLLERS

SGLS352B – DECEMBER 2006 – REVISED MAY 2007

APPLICATION INFORMATION (continued)

Figure 22. Figure 23.

Figure 24.

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PACKAGE OPTION ADDENDUM

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24-May-2007

PACKAGING INFORMATION

Orderable Device Status

(1)

Package

Type

Package Drawing

Pins Package

Qty

Eco Plan

UCC28C43MDREP ACTIVE SOIC D 8 2500 Green (RoHS &

no Sb/Br)

UCC28C45MDREP ACTIVE SOIC D 8 2500 Green (RoHS &

no Sb/Br)

V62/07615-01XE ACTIVE SOIC D 8 2500 Green (RoHS &

no Sb/Br)

V62/07615-02XE ACTIVE SOIC D 8 2500 Green (RoHS &

no Sb/Br)

(1)

The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in

a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device.

(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. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements

for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)

(2)

Lead/Ball Finish MSL Peak Temp

CU NIPDAU Level-1-260C-UNLIM

(3)

MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder

temperature.

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In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

Addendum-Page 1

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TEXAS INSTRUMENTS UCC28C4x-EP Technical data

Specifications and Main Features

Frequently Asked Questions

User Manual

FEATURES

APPLICATIONS

DESCRIPTION

Absolute Maximum Ratings

Dissipation Ratings

Recommended Operating Conditions

Electrical Characteristics

Pin Assignments

APPLICATION INFORMATION

Advantages

Low-Voltage Operation

High-Speed Operation

Start/Run Current Improvements

Reduced Discharge Current Variation

Soft-Start

Oscillator Synchronization

Precautions

Circuit Applications