SLUSFF2C September   2023  – December 2025 UCG28826 , UCG28828

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Detailed Pin Descriptions
      1. 7.3.1  HV - High Voltage Input
      2. 7.3.2  SW - Switch Node
      3. 7.3.3  GND – Ground Return
      4. 7.3.4  FLT - External Overtemperature Fault
      5. 7.3.5  FB ­­– Feedback
      6. 7.3.6  TR - Turns Ratio
      7. 7.3.7  IPK - Peak Current and Dithering
      8. 7.3.8  FCL - Frequency Clamp and Fault Response
      9. 7.3.9  CDX - CCM, Drive Strength, and X-cap Discharge
      10. 7.3.10 VCC - Input Bias
    4. 7.4 Feature Description
      1. 7.4.1  Self Bias and Auxless Sensing
      2. 7.4.2  Control Law
        1. 7.4.2.1 Valley Switching
        2. 7.4.2.2 Frequency Foldback
        3. 7.4.2.3 Burst Mode
        4. 7.4.2.4 Continuous Conduction Mode (CCM)
      3. 7.4.3  GaN HEMT Switching Capability
      4. 7.4.4  Soft Start
      5. 7.4.5  Frequency Clamp
      6. 7.4.6  Frequency Dithering
      7. 7.4.7  Slew Rate Control
      8. 7.4.8  Transient Peak Power Capability
      9. 7.4.9  X-Cap Discharge
      10. 7.4.10 Fault Protections
        1. 7.4.10.1 Brownout Protection
        2. 7.4.10.2 Short-Circuit Protection
        3. 7.4.10.3 Output Overvoltage Protection
        4. 7.4.10.4 Overpower Protection (OPP, LPS)
        5. 7.4.10.5 Overtemperature Protection
        6. 7.4.10.6 Open FB Protection
        7. 7.4.10.7 Error Codes for Protections
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input Bulk Capacitor
        2. 8.2.2.2 Transformer Primary Inductance and Turns Ratio
        3. 8.2.2.3 Output Capacitor
        4. 8.2.2.4 Selection Resistors
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

6.5 Electrical Characteristics

over operating free-air temperature range (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
BIAS SUPPLY
VVCCSHORT Threshold for reduced VCC startup current 0.65 0.9 1.2 V
IHVLO Reduced HV startup current Before VCC reaches VVCCSHORT 0.55 1 1.6 mA
IHVHI Full HV startup current After VCC exceeds VVCCSHORT 2.2 4 5.65 mA
VVCC(OFF) VCC under voltage lock out threshold Tracking with variation in other thresholds 4.9 5.1 5.3 V
VVCC(REG) VCC regulation voltage and start-up threshold Tracking with variation in other thresholds 5.6 5.8 6 V
VVCC(CHG) VCC charging trigger threshold Trigger VCC charging to VVCC(REG), Tracking with variation in other thresholds 5.4 5.6 5.8 V
IVCC Operating supply current No switching 700 µA
IVCCSLEEP Supply current in burst mode No switching 260 310 µA
IVCCFAULT Supply current when a protection is triggered 260 µA
GAN POWER TRANSISTOR
RDSON Drain-source on-resistance TJ = 25 °C, UCG28824 270 350 mΩ
RDSON Drain-source on-resistance TJ = 25 °C, UCG28826, UCG28828 170 220 mΩ
COSS Output capacitance VSW = 400V, UCG28824 28 pF
COSS Output capacitance VSW = 400V, UCG28826, UCG28828 40 pF
GAN GATE DRIVER
Turn-on dV/dt For SW node, VDS = 325V, Option 1 10 V/ns
Turn-on dV/dt  For SW node, VDS = 325V, Option 2 7 V/ns
Turn-on dV/dt  For SW node, VDS = 325V, Option 3 5 V/ns
PEAK CURRENT CONTROL
IPKMAX Maximum peak current, UCG28824 Option 1 1.9 2.05 A
Option 2 2.1 2.25
Option 3 2.4 2.55
IPKMAX Maximum peak current, UCG28826, UCG28828 Option 1 2.65 2.8 3 A
Option 2 2.95 3.1 3.3
Option 3 3.35 3.5 3.7
IPKMAX/IPKMIN Maximum to minimum peak current ratio Option 1 4
Option 2 3
TSS Soft start time 4 ms
FEEDBACK CONTROL
RFB FB pull-up resistor 60 kΩ
VFBOPEN Open FB Pin voltage 3.3 3.45 V
VBST_OFF Burst-off threshold Turn-off switching 250 mV
VBST_ON Burst-on threshold Resume burst switching 300 mV
VBST_EX Burst mode exit threshold Exit to frequency foldback 500 mV
fMIN,CLAMP Minimum frequency clamp During normal operation 23 25 kHz
During soft start 10
TSWMAX Maximum time period 40 43 µs
TONMAX Maximum on time 17 19 µs
fMAX,CLAMP Frequency clamp Option 1 140 kHz
Option 2 100
Option 3 250
Option 4 500
TDDCM DCM ring fixed timer From last seen DCM ring valley, UCG28826, UCG28828 3.75 µs
EMI DITHERING
fc Carrier frequency UCG28826-3 only 390 Hz
fc Carrier frequency 6.25 kHz
IDither,max Carrier amplitude % of instantaneous peak currents, Option 1 ±6.25 %
% of instantaneous peak currents, Option 2 ±12.5
PROTECTIONS
VTH_BI Brown-in threshold
UCG28826-1,UCG28826-3, UCG28826-4, UCG28828-1, UCG28828-2, UCG28824-1

DC level		 106 112 118 V
VTH_BI Brown-in threshold
UCG28826-5

DC level		 89 94 99 V
VTH_BO Brown-out threshold
UCG28826-1, UCG28226-3, UCG28826-4, UCG28828-1, UCG28828-2, UCG28824-1

DC level		 93 98 103 V
VTH_BO Brown-out threshold
UCG28826-5

DC level		 76 80 84 V
TDBO Brown-out delay time 60 ms
IFLT FLT pin source current 75 µA
VTH_OTP FLT threshold voltage Triggers external overtemperature fault 0.58 0.6 0.62 V
TIFLTON IFLT on time 260 µs
TIFLTperiod IFLT time period 10 ms
NFLTTSD Number of external IFLT cycles Before fault is triggered 3
RSW SW pin impedance 8.2 9.5 MΩ
VOVP OVP detection threshold UCG28826-4

VOUT threshold		 14.5 16 17.5 V
VOVP OVP detection threshold UCG28826-1, UCG28826-3, UCG28826-5, UCG28828-1, UCG28828-2, UCG28824-1

VOUT threshold		 23 25 27 V
Internal overtemperature protection shut down threshold Temperature increasing 150 °C
Internal overtemperature protection hysteresis Temperature reducing 10 °C
TRETRY Auto-retry time 1 s
POPPL Over power protection threshold, low UCG28824-1, triggers after 4.2s 61 69 78 W
POPPL Over power protection threshold, low UCG28826-1, UCG28826-3, triggers after 4.2s 89 100 114 W
POPPL Over power protection threshold UCG28826-4, triggers after 4.2s 71 80 92 W
POPPL Over power protection threshold, low UCG28826-5, UCG28828-1, UCG28828-2

Disabled		 W
POPPH Over power protection threshold, high UCG28824-1, triggers after 120ms 87 97.5 111 W
POPPH Over power protection threshold, high UCG28826-1, UCG28826-3,  UCG28826-4, UCG28826-5

Triggers after 120ms		 125 140 160 W
POPPH Over power protection threshold, high UCG28828-1, UCG28828-2

Triggers after 120ms		 169 190 216 W
ILPS LPS fault output current threshold UCG28824-1, input referred, triggers after 4.2s 4.4 5.2 6 A
ILPS LPS fault output current threshold UCG28826-1, UCG28826-3, UCG28826-4

Input referred, triggers after 4.2s		 6.3 7.5 8.65 A
ILPS LPS fault output current threshold UCG28826-5, UCG28828-1, UCG28828-2

Disabled		 A
ISCP Short Circuit Protection Primary current threshold, UCG28824 3.1 A
ISCP Short Circuit Protection Primary current threshold, UCG28826, UCG28828 4.5 A
Short Circuit Protection Number of cycles 3
tSCP Short-circuit response time 140 ns
VINOVP Input OVP trigger threshold UCG28828-2, trigger protection and stop switching, AC input 315 V
X CAP DISCHARGE
IACDET Line removal detection current Current sink from HV pin 1.5 2 2.5 mA
IXDIS X-cap discharge Current  3.8 5 6.2 mA
TXDIS X-cap discharge Time  CXCAP = 1µF 1 s