SLUSC36B November   2015  – January 2016 UCC28881

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Switching Characteristics
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
    4. 8.4 Device Functional Modes
      1. 8.4.1 Start-Up Operation
      2. 8.4.2 Feedback and Voltage Control Loop
      3. 8.4.3 PWM Controller
      4. 8.4.4 Current Limit
      5. 8.4.5 Inductor Current Runaway Protection
      6. 8.4.6 Over Temperature Protection
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 13-V, 225-mA High-Side Buck Converter
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Input Stage (RF, D2, D3, C1, C2, L2)
          2. 9.2.1.2.2 Regulator Capacitor (CVDD)
          3. 9.2.1.2.3 Freewheeling Diode (D1)
          4. 9.2.1.2.4 Output Capacitor (CL)
          5. 9.2.1.2.5 Pre-Load Resistor (RL)
          6. 9.2.1.2.6 Inductor (L1)
          7. 9.2.1.2.7 Feedback Path (CFB, RFB1 and RFB2) and Load Resistor (RL)
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Additional UCC28881 Application Topologies
        1. 9.2.2.1 Low-Side Buck and LED Driver - Direct Feedback (Level Shifted)
        2. 9.2.2.2 High-Side Buck Converter
        3. 9.2.2.3 Non-Isolated, Low-Side Buck-Boost Converter
        4. 9.2.2.4 Non-Isolated, High-Side Buck-Boost Converter
        5. 9.2.2.5 Non-Isolated Flyback Converter
        6. 9.2.2.6 Isolated Flyback Converter
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7 Specifications

7.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted) (1) (2) (4)
MIN MAX UNIT
HVIN –0.3 700 (3) V
DRAIN Internally clamped 700 (3) V
IDRAIN Positive drain current single pulse, pulse max duration 25 μs 770 (5) mA
IDRAIN Negative drain current –700 mA
FB –0.3 6 V
VDD VDD is supplied from low impedance source –0.3 6 V
IVDD VDD is supplied from high impedance source 400 µA
TJ Junction temperature 150 °C
Lead temperature 1.6 mm (1/16 inch) from case 10 seconds 260 °C
Tstg Storage temperature range –65 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) All voltages are with respect to GND. Currents are positive into, negative out of the specified terminal. These ratings apply over the operating ambient temperature ranges unless otherwise noted.
(3) TA = 25°C
(4) The device is not rated to withstand operating conditions when multiple parameters are at or near, absolute maximum ratings.
(5) The MOSFET drain to source voltage is less than 400V

7.2 ESD Ratings

UNIT
V(ESD) Electrostatic discharge Human Body Model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins except HVIN pin (1) ±2000 V
Human Body Model (HBM) per ANSI/ESDA/JEDEC JS-001, HVIN pin (1) ±1500 V
Charged device model (CDM), per JEDEC specification JESD22-C101, all pins (2) ±500 V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

7.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
VVDD Voltage On VDD pin 5 V
VFB Voltage on FB pin –0.2 5 V
TJ Operating junction temperature –40 +125 °C

7.4 Thermal Information

THERMAL METRIC (1) UCC28881 UNIT
D (SOIC)
7 PINS
RθJA Junction-to-ambient thermal resistance 134.4 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 42.6 °C/W
RθJB Junction-to-board thermal resistance 85 °C/W
ψJT Junction-to-top characterization parameter 6.4 °C/W
ψJB Junction-to-board characterization parameter 76 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953.

7.5 Electrical Characteristics

VHVIN = 30 V, TA = TJ = –40°C to +125°C (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
VHVIN(min) Minimum Voltage to start-up 30 V
INL Internal supply current, no load FB = 1.25 V (> VFB_TH) 58 100 µA
IFL Internal supply current, full load FB = 0.75 V (> VFB_TH) 86 120 µA
ICH0 Charging VDD Cap current VVDD = 0 V, –3.8 –1.6 –0.4 mA
ICH1 Charging VDD Cap current VVDD = 4.4V, VFB = 1.25 V –3.40 –1.30 –0.25 mA
VVDD Internally regulated low Voltage supply (supplied from HVIN pin) 4.5 5.0 5.5 V
VFB_TH FB pin reference threshold 0.96 1.03 1.105 V
VVDD(on) VDD turn-on threshold VDD low-to-high 3.55 3.92 4.28 V
VVDD(off) VDD turn-off threshold VDD high-to-low 3.28 3.62 3.89 V
ΔVVDD(uvlo) VDD UVLO Hysteresis VDD high-to-low 0.27 0.345 0.39 V
DMAX Maximum Duty Cycle FB = 0.75 V 45% 55%
ILIMIT Current Limit Static, TA = –40°C 630 mA
Static, TA = 25°C 330 440 570 mA
Static, TA = 125°C 315 mA
TJ(stop) Thermal Shutdown Temperature Internal junction temperature 138.5 150 °C
TJ(hyst) Thermal Shutdown Hysteresis Internal junction temperature 37. 45 °C
BV Power MOSFET Breakdown Voltage TJ = 25°C 700 V
RDS(on) Power MOSFET On-Resistance (includes internal sense-resistor) ID = 60 mA, TJ = 25°C 14 18 Ω
ID = 60 mA, TJ = 125°C 24 30 Ω
DRAIN_ILEAKAGE Power MOSFET off state leakage current VDRAIN = 700V, TJ = 25°C 5 µA
VDRAIN = 400 V, TJ = 125°C 20 µA
HVIN_IOFF HVIN off state current VHVIN = 700 V, TJ = 25°C, VVDD = 5.8 V 4.0 7.5 36.0 µA
VHVIN = 400 V, TJ = 125°C, VVDD = 5.8 V 20 µA
VVDD(clamp) VDD clamp voltage IVDD = 250 µA 6.0 6.7 7.5 V

7.6 Switching Characteristics

over operating free-air temperature range (unless otherwise noted)
MIN TYP MAX UNIT
fSW(max) Maximum switching frequency 52 62 75 kHz
tON_MAX Maximum switch on time (current limiter not triggered), FB = 0.75 V 6.5 8.3 9.7 µs
tOFF_MIN Minimum switch off time follows every tON time, FB = 0.75 V 6.5 8.3 9.7 µs
tMIN Minimum on time 0.17 0.27 0.30 µs
tOFF(ovl) Max off time (OL condition), tOFF(ovl) = tSW – tON(max) 130 200 270 µs
tON_TO Inductor current run away protection time threshold 450 ns

7.7 Typical Characteristics

UCC28881 D301_SLUSC36_UCC28881.gif
A.
Figure 1. ILIMIT vs Temperature
UCC28881 D303_SLUSC36_UCC28881.gif
Figure 3. INL and IFL vs Temperature
UCC28881 D305_SLUSC36_UCC28881.gif
Figure 5. VVDD(on) and VVDD Hysteresis vs Temperature
UCC28881 D107_SLUSC05.gif
Figure 7. Maximum Switching Frequency vs Temperature
UCC28881 D008_SLUSC05.gif
Figure 9. tON(max) and tOFF(min) vs Temperature
UCC28881 D201_SLUSC05.gif
Figure 11. RTHJA vs Copper Area
UCC28881 D002_SLUSC36_UCC28881.gif
A.
Figure 2. ILIMIT vs Drain Current Slope
UCC28881 D104_SLUSC05.gif
Figure 4. ICH0 and ICH1 vs Temperature
UCC28881 D326_SLUSC36_UCC28881.gif
Figure 6. IDS vs VDS at 25°C and 125°C
UCC28881 D308_SLUSC36_UCC28881.gif
Figure 8. VFB_TH vs Temperature
UCC28881 D310_SLUSC36_UCC28881.gif
Figure 10. DRAIN breakdown voltage vs Temperature