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Basic Information
Question 1
What is the difference between the HT71XX and the HT75XX series voltage regulators?
Answer
With the exception of maximum current output the functional features of the two series are identical. The maximum output current of the HT71XX series is 30mA while the maximum output current of the HT75XX series is 100mA.
Question 2
What are the differences between the new HT71XX-1 series of voltage regulators and the old HT71XX series that they replace?
Answer
The old HT71XX series of voltage regulators have an output voltage tolerance of 5% whose smallest SMD package is the SOT89 type. The new HT71XX-1 series have an output voltage tolerance of 3% whose smallest SMD package is the SOT25 type. The functional features of the two series of devices are identical so the new devices can be used as direct replacements for the older devices.
Question 3
What are the values of output current for the voltage regulators on offer? Answer
The maximum output current, Iout, for the HT71XX-1 (HT71XX) series of devices is 30mA. For the HT75XX-1(HT75XX) series of devices the maximum output current is 100mA. The new HT73XX devices will offer a maximum output current of 300mA when released.
Question 4
What are the ranges of output voltages offered by the HT71 series of voltage regulators?
Answer
The HT71XX-1 (HT71XX) series of voltage regulators is offered in voltage ranges of 3.0V, 3.3V, 3.6V, 4.4V and 5.0V.
Question 5
What is the maximum input voltage that the HT71 series of voltage regulators can withstand?
Answer
The maximum input voltage of the HT71XX-1 (HT 71XX) series is 24V.
Question 6
What kinds of packages are the HT71 series of voltage regulators offered in?
Answer
The old version of the HT 71XX has both TO92 and SOT89 packages. The new version, the HT 71XX-1 series is offered in TO92 and SOT89 packages as well as an additional SOT25 package type.
Question 7
What is the Vout tolerance of the HT71 voltage regulator?
Answer
The HT71XX provides a +/-5% voltage tolerance while the HT71XX-1 offers an enhanced +/-3% voltage tolerance.
Question 8
What are the main differences between the HT75XX-1 and the 78L05 device?
Answer
The two main differences between these devices is in the area of dropout voltage and current consumption:
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Voltage drop：HT75XX-1 belongs to the LDO (Low Dropout) category of regulators as its maintains a dropout voltage of only 100mV. The 78L05 cannot be classified as a Low Dropout Regulator as its dropout voltage is around 1.5V. In other words, for the HT75XX-1 if the input voltage is larger than the output voltage by 100mA, the voltage stabilization function will continue to operate providing enhanced battery operation.
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Current Consumption: The current consumption of the HT75XX-1 is below 20uA placing the regulator firmly in the low power consumption regulator category. The 78L05 is requires a current usually higher than 200~300uA. The HT75XX-1 therefore has excellent power saving advantages making the device extremely suitable for hand-held products.
Question 9
What's the differences between the new regulator HT75XX-1 series and the old HT75XX series?
Answer
The older HT75XX devices have an output voltage tolerance of 5% and whose smallest package is the SMD type SOT89. The replacement devices, the HT75XX-1 series, have an enhanced output voltage tolerance of 3%. Their smallest SMD package is the SOT25 type. The other functional features of the two devices are identical so the new devices can be used as direct replacements for the old ones.
Question 10
What kinds of output voltage does the HT75 series voltage regulators offer ?
Answer
HT75XX-1(HT75XX) offers 3.0V, 3.3V, 3.6V, 4.4V, and 5.0V voltage levels.
Question 11
What is the maximum input voltage that the HT75 series voltage regulators can withstand?
Answer
The maximum input voltage of the HT75XX-1 (HT 75XX) is 24V.
Question 12
What kinds of package does the HT75 voltage regulator offer?
Answer
The old version of the HT75XX has both TO92 and SOT89 packages. The new version of the HT75XX-1 offers TO92, SOT89 and an additional SOT25 package type.
Question 13
What output voltage ranges are offered by the HT73 voltage regulator series?
Answer
The HT73XX series of voltage regulators offer voltages in the following categories:
1.8V, 2.5V, 2.7V, 3.0V, 3.3V, 3.5V and 5.0V voltage levels.
Question 14
What is the maximum input voltage that the HT73 series voltage regulators can withstand?
Answer
The maximum input voltage of the HT73XX series is 12V.
Question 15
What packages are the HT73 voltage regulator series supplied in?
Answer
The HT73XX series of voltage regulators is supplied in both TO92 and SOT89 packages.
Question 16
What is the working temperature range of the HT71XX-1, HT75XX-1 and HT73XX devices?
Answer
The operating temperature range for the HT71XX-1、HT75XX-1、HT73XX device range is from -40℃ to 85℃
Functional Description
Question 1
In the specification of the Holtek Power Regulators, what is
meant by the Power Consumption parameter in the Absolute Maximum
Ratings section?
Answer
This parameter indicates the maximum power that the regulator can handle, which is dependent upon the difference between the input and output voltages placed across the device.
Application Description
Question 1
Can the new HT71XX-1 series of voltage regulator devices replace the older HT71XX series?
Answer
The HT71XX-1 series are fully compatible with the HT71XX series and so can be directly replaced.
Question 2
Why are the pin-outs on the HT7150-1 TO92 package not the same as that specified in the datasheet?
Answer
The HT7150-1 TO92 package should have the mark 71XXA-1. If it has the mark 71XX-1 then it has different pin-outs, however this pin-out package has already ceased production. For the correct pin-outs and markings consult the following table:
Question 3
For the HT71XX-1 devices, when the input voltage is 30V, why does the output voltage exceed the stated tolerance?
Answer
The HT71XX-1 device largest input voltage is 24V, within this voltage range the HT71XX-1 devices will operate normally. The output voltage tolerance range is from -3% to +3%. However if 24V is exceeded, it is not possible to guarantee that the output voltage level will be normal or that they can withstand these high voltages. For these reasons the device will exhibit abnormal behavior.
Question 4
Can HT75XX-1 be replaced by the HT75XX?
Answer
The present HT75XX series can be totally replaced by the new HT75XX-1 series.
Question 5
What is the Vout tolerance of the HT75 voltage regulators?
Answer
HT75XX offers a +/-5% tolerance while the HT75XX-1 provides an enhanced +/-3%
tolerance.
Question
6
What is the Vout tolerance of the HT73 series of voltage
regulators?
Answer
The HT73XX series of voltage regulators are supplied with an output voltage tolerance of
+/-3%.
Question 7
For the HT7550-1, when the input voltage is 24V, and the output current is 50ma, the device gets quite hot. What is the reason for this and is there a way to resolve this problem?
Answer
According to calculations, the HT7550-1, with an input voltage of 24V and an output current of 50ma, will consume a power level of 950mW, calculated from the formula: ((24V-5V) x 50mA = 950mW). As this value far exceeds the maximum permitted power consumption value of 250mW for the TO92 package, the device naturally will naturally overheat. If it is required to supply higher output currents, and at the same time prevent the package from overheating, then the input/ouput voltage differential must be reduced to keep the power consumption within specification values.
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