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Basic Information
Question 1
What frequencies does the HT4XR01T3 support?
Answer
It can support from 300MHz to 450MHz. The frequency is the 32times of crystal frequency. For example, using 13.56MHz crystal can support 433.92MHz frequency.
Question 2
What power is required for whole Tx module?
Answer
As HT4XR01T3 provides 9dB output power in 3V, Tx module only needs 3V power supply other than 12V.
Question 3
What is the power consumption in standby mode?
Answer
Less than 2uA (LIRC off, LXT off)
Functional Description
Question 1
What is the benefit using HT4xR01T3 other than saw resonator + MCU solution?
Answer
Except for highly integrating transistor and filter circuit into MCU, crystal based HT4xR01T3 provides more flexible frequency selection and wider operation temperature than traditional saw resonator.
Question 2
What is the benefit using HT4xR01T3 other than L/C circuit + MCU solution?
Answer
To pass FCC or ETSI regulation, L/C circuit needs more R/L/C components to build up a filter chain to remove harmonic noise. However, HT4xR01T3 only need 3 R/C components to filter out harmonic noise.
Question 3
What accuracy can MCU IRC clock be calibrated after referencing CREF clock?
Answer
About 30us deviation for actual clock frequency.
Application Description
Question 1
Why is the HT6XF03T3 suitable for rolling code applications?
Answer
Rolling code applications usually need to use an EEPROM to store the manufacturer’s code first, so the HT6XF03T3 with an internal 64x8 EEPROM is very suitable for this field of applications.
Question 2
What is the advantage of the HT6XF03T3 compared with the traditional SAW resonator with a transistor?
Answer
In addition to the integration of a transistor and filter circuits into a single chip, the HT6XF03T3 provides more frequency selections (300MHz ~ 450MHz) and a wider operating temperature range than traditional SAW resonators.
Question 3
How long can a CR2032 (3V, 170mAh) battery be used for if the device is used to transmit 10 times a day?
Answer
It takes 12.5mA for the HT6XF03T3 to transmit a “1”, 3mA for a “0”and 2uA in the power-down mode. Therefore the average consumption for transmission is about (12.5+3)/2 = 7.75mA. About 77.5mA sec is needed taking 1second as the base every time for ten times a day. Also add 172.8mA sec for the 86400 sec power down time. Then the device will consume about 250.3mA.sec = 0.07mAh per day. Therefore, one CR2032 may be used for 170/0.07= 2428.6 days, about 6.7 years.
Points to Note
Question 1
When using the HIRC, if the I/O pin which is shared with OSC1 is to be used as an AC zero crossing detector, will there be any influence on the HIRC oscillation frequency? If yes, which MCUs will be affected and how can this problem be resolved?? Answer
If the HIRC is used and if the I/O pin which is shared with OSC1 is used as an AC zero crossing detector pin, the HIRC oscillation frequency will be influenced.
The affected MCUs are:
All MCUs whose I/O pin is pin-shared with OSC1 (including the enhanced OTP type MCU and Flash type MCU etc.)
How to resolve this issue:
1. Avoid using the I/O pin that is shared with OSC1 as AC zero crossing detector pin.
2. If the problem can still not be resolved, add external circuitry to ensure that the voltage applied on the OSC1 pin remains withing the range of VDD and VSS.
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