ZHCSQT5 July 2022 TPS7A57
PRODUCTION DATA
- 1 特性
- 2 应用
- 3 说明
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Output Voltage Setting and Regulation
- 7.3.2 Low-Noise, Ultra-High Power-Supply Rejection Ratio (PSRR)
- 7.3.3 Programmable Soft-Start (NR/SS Pin)
- 7.3.4 Precision Enable and UVLO
- 7.3.5 Charge Pump Enable and BIAS Rail
- 7.3.6 Power-Good Pin (PG Pin)
- 7.3.7 Active Discharge
- 7.3.8 Thermal Shutdown Protection (TSD)
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1
Application Information
- 8.1.1 Precision Enable (External UVLO)
- 8.1.2 Undervoltage Lockout (UVLO) Operation
- 8.1.3 Dropout Voltage (VDO)
- 8.1.4 Input and Output Capacitor Requirements (CIN and COUT)
- 8.1.5 Recommended Capacitor Types
- 8.1.6 Soft-Start, Noise Reduction (NR/SS Pin), and Power-Good (PG Pin)
- 8.1.7 Optimizing Noise and PSRR
- 8.1.8 Adjustable Operation
- 8.1.9 Load Transient Response
- 8.1.10 Current Limit and Foldback Behavior
- 8.1.11 Charge Pump Operation
- 8.1.12 Sequencing
- 8.1.13 Power-Good Functionality
- 8.1.14 Output Impedance
- 8.1.15 Paralleling for Higher Output Current and Lower Noise
- 8.1.16 Current Mode Margining
- 8.1.17 Voltage Mode Margining
- 8.1.18 Power Dissipation (PD)
- 8.1.19 Estimating Junction Temperature
- 8.1.20 TPS7A57EVM-081 Thermal Analysis
- 8.2 Typical Application
- 8.3 Power Supply Recommendations
- 8.4 Layout
- 8.1
Application Information
- 9 Device and Documentation Support
- 10Mechanical, Packaging, and Orderable Information
8.1.12 Sequencing
There is no sequencing requirement between IN, BIAS, and EN. CP_EN is an analog signal and must be connected to either IN, BIAS, or GND.
As with devices having an internal MUX and charge pump, a false PG can be triggered during shutdown if the BIAS rail is faster than the IN rail to discharge.
As shown in Figure 8-12, when the bias rail decreases below VUVLO(BIAS), the internal MUX between IN and BIAS switches over and the LDO is fully powered from the IN rail.
When the BIAS rail goes below UVLO(BIAS) with the IN rail greater than 1.1 V with the charge pump enabled, the LDO may restart because IN is still a valid condition for operations.
Figure 8-12 Total Quiescent Current vs
BIAS