SLUSEX2A September 2025 – September 2025 UCC27734 , UCC27735
PRODUCTION DATA
- 1
- 1 Features
- 2 Applications
- 3 Description
- 4 Pin Configuration and Functions
- 5 Specifications
-
6 Detailed Description
- 6.1 Overview
- 6.2 Functional Block Diagram
- 6.3
Feature Description
- 6.3.1 Input Stages and Interlock
- 6.3.2 Enable Function (UCC277x5 Only)
- 6.3.3 Undervoltage Lockout (UVLO)
- 6.3.4 Level Shifter
- 6.3.5 Output Stage
- 6.3.6 Low Propagation Delays and Tightly Matched Outputs
- 6.3.7 HS Node dV/dt
- 6.3.8 Split Grounds (COM and VSS)
- 6.3.9 Operation Under Negative HS Voltage Condition
- 6.4 Device Functional Modes
-
7 Application and Implementation
- 7.1 Application Information
- 7.2
Typical Application
- 7.2.1 Design Requirements
- 7.2.2
Detailed Design Procedure
- 7.2.2.1 Selecting HI and LI Low Pass Filter Components (RHI, RLI, CHI, CLI)
- 7.2.2.2 Selecting Bootstrap Capacitor (CBOOT)
- 7.2.2.3 Selecting VDD Bypass Capacitor (CVDD)
- 7.2.2.4 Selecting Bootstrap Resistor (RBOOT)
- 7.2.2.5 Selecting Gate Resistor RHO/RLO
- 7.2.2.6 Selecting Bootstrap Diode
- 7.2.2.7 Estimate the UCC2773x Power Losses
- 7.2.2.8 Application Example Schematic Note
- 7.2.3 Application Curves
- 7.3 Power Supply Recommendations
- 7.4 Layout
- 8 Device and Documentation Support
- 9 Revision History
- 10Mechanical, Packaging, and Orderable Information
6.3.5 Output Stage
The UCC2773x device output stage features a unique architecture on the pull up structure which delivers the highest peak-source current when it is most needed during the Miller plateau region of the power-switch turn on transition (when the power switch drain or collector voltage experiences dV/dt). The output stage pull-up structure features a P-Channel MOSFET and an additional N-Channel MOSFET in parallel. The function of the N-Channel MOSFET is to provide a brief boost in the peak sourcing current enabling fast turn on. This is accomplished by briefly turning-on the N-Channel MOSFET during a narrow instant when the output is changing state from low to high.
The ROH parameter (see Figure 5-12) is a DC measurement and it is representative of the on-resistance of the P-Channel device only. This is because the N-Channel device is held in the off state in DC condition and is turned on only for a narrow instant when output changes state from low to high.
The effective resistance of the UCC2773x pull-up stage during the turn-on instant is much lower than what is represented by ROH parameter.
The pull-down structure in the UCC2773x is simply composed of a N-Channel MOSFET. The ROL parameter (see Figure 5-13), which is also a DC measurement, is representative of the impedance of the pull-down stage in the device.
Each output stage in the UCC2773x is capable of supplying 3.5A peak source and 4A peak sink current pulses. The output voltage swings between (VDD and COM) and (HB and HS) providing rail-to-rail operation.
Figure 6-4 Output
Stage Structure