Datasheet HT75Hxx (Holtek) - 15

HT75Hxx Application Information
When using the HT75Hxx regulators, it is important that the following application points are noted if correct operation is to be achieved.
Power-on Considerations
In order to suppress the output overshooting phenomenon, the rising time of input supply is suggested greater than 1ms. Adding an input resistor RS which is acting like a low-pass filter, it can slow down the rising time of the input supply in the VIN terminal, as shown below. RS VIN V V OUT CC VOUT
LDO
C1 C2 ILOAD GND Common Common The maximum RS is limited by ILOAD(MAX) and VDROPOUT. It be calculated by the following equation. RS≤VCC–VDROPOUT ILOAD(MAX) Once the RS value is selected, the minimum value of C1 can be calculated by the following equation: C1≥ 1ms 2.2RS
OCP and OTP Protections
The HT75Hxx implements the over current protection and over junction temperature protection to prevent IC damage even if the output is shorted to ground. When the output is shorted to ground, the output current will be clamped to IOCP2 and the junction temperature will rise. Once the junction temperature exceeds 150°C, the HT75Hxx will shut down the power component to prevent thermal damage. The protection will be released when the junction temperature falls to 120°C. There are 2 levels of over current protection threshold existing in the HT75Hxx. Once the output voltage is greater than 0.7V, the OCP limit current is set to IOCP1. Otherwise then the output voltage is less than 0.7V, the OCP current folds back to IOCP2 in order to slow down the junction temperature rises even if the output terminal is shorted to ground.
Fast Output Discharging Function
When CE=‘L’, the output voltage will be fast discharged to 0V via an internal 300Ω resistor. This discharging path doesn’t use protections such as OCP/OTP.
Input Capacitor CIN Consideration
It is recommended that the input capacitor be at least 1μF and be ceramic type for better temperature coefficient and lower ESR (Equivalent Series Resistance).
Output Capacitor COUT Considerations
The output capacitance plays an important role in keeping the output voltage stable. For the ceramic type capacitor, the capacitance should be at least 1μF. For the E-cap type capacitor, the capacitance should be at least 2.2μF. Rev. 1.00 15 May 29, 2020 Document Outline Features Applications General Description Selection Table Block Diagram Pin Assignment Pin Descriptions Absolute Maximum Ratings Recommended Operating Range Electrical Characteristics Typical Performance Characteristic Application Information Power-on Considerations OCP and OTP Protections Fast Output Discharging Function Input Capacitor CIN Consideration Output Capacitor COUT Considerations Thermal Considerations Power Dissipation Calculation Application Circuits Basic Circuits High Output Current Positive Voltage Regulator Short-Circuit Protection by Tr1 Increasing Output Voltage Circuits Constant Current Regulator Dual Supply Package Information 3-pin SOT89-3 Outline Dimensions 5-pin SOT23-5 Outline Dimensions 8-pin SOP-EP (150mil) Outline Dimensions