ZHCSHN0A February 2018 – April 2018 TPSM84424
PRODUCTION DATA.
- 1 特性
- 2 應用
- 3 說明
- 4 修訂歷史記錄
- 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 Adjusting the Output Voltage
- 7.3.2 Switching Frequency (RT)
- 7.3.3 Synchronization (CLK)
- 7.3.4 Output On/Off Enable (EN)
- 7.3.5 Input Capacitor Selection
- 7.3.6 Output Capacitor Selection
- 7.3.7 TurboTrans (TT)
- 7.3.8 Undervoltage Lockout (UVLO)
- 7.3.9 Soft Start (SS/TR)
- 7.3.10 Sequencing (SS/TR)
- 7.3.11 Power Good (PGOOD)
- 7.3.12 Safe Start-up into Pre-Biased Outputs
- 7.3.13 Overcurrent Protection
- 7.3.14 Thermal Shutdown
- 7.4 Device Functional Modes
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文檔支持
- 12機械、封裝和可訂購信息
7.3.7 TurboTrans (TT)
The TPSM84424 includes the TurboTrans feature which optimizes the transient response of the converter while simultaneously reducing the quantity of external output capacitors required to meet a target voltage deviation specification. A TurboTrans resistor, RTT, is required between the TT pin and AGND to properly set the response of the TPSM84424 based on the amount and type of output capacitors. The value of RTT can be calculated using Equation 3. In order to calculate the RTT value, a TurboTrans constant, KTT, is required. See Table 5 for the KTT value when using only ceramic output capacitors. See Table 6 for the KTT value when using a combination of ceramic and polymer output capacitors. Applications operating from input voltages above 14 V, must reduce the calculated RTT value by 20%. Also, the value of CO used in Equation 3 is the total effective output capacitance, which takes into account the effects of applied voltage and temperature.
Table 5. KTT Values (Ceramic Only Output Capacitors)
| VOUT (V) | 1 - < 1.2 | 1.2 - < 1.5 | 1.5 - < 1.8 | 1.8 - < 2 | 2 - < 2.5 | 2.5 - < 3.3 | 3.3 - < 7.5 | 7.5 - 10 |
|---|---|---|---|---|---|---|---|---|
| KTT | 1 | 1.12 | 1.4 | 1.5 | 1.65 | 1.8 | 2.0 | 2.25 |
Table 6. KTT Values (Ceramic + Polymer Output Capacitors)
| VOUT (V) | 0.6 - < 0.7 | 0.7 - < 0.9 | 0.9 - < 1 | 1 - < 2.5 | 2.5 - < 3.3 | 3.3 - < 5 | 5 - < 6 | 6 - < 7.5 | 7.5 - 10 |
|---|---|---|---|---|---|---|---|---|---|
| KTT | 0.6 | 0.65 | 0.7 | 0.6 | 0.72 | 0.9 | 1.2 | 1.5 | 1.8 |