HT9831

315/433MHz ASK Transmitter

Block Diagram

Rev. 1.20

1

November 5, 2014

Features

General Description

The HT9831 is a highly integrated ASK transmitter IC for

remote wireless applications in the 300 to 450MHz fre-

quency band. This transmitter IC is a true

²data-in, an-

tenna-out

² monolithic device making it very easy for

users to implement a wireless system. It is only neces-

sary to supply a crystal generated reference frequency,

which is the RF carrier frequency divided by 32, and a

few additional external parts to create a complete and

versatile transmitter. The HT9831 is capable of deliver-

ing +9.5dBm into a 50

W load. This power level is possi-

ble due to a small form factor transmitter (lossy antenna)

which can operate near the maximum transmission reg-

ulation limit. The HT9831 utilises ASK/OOK - Amplitude

Shift Keying/On-Off Keying- UHF receiver types from

wide-band super-regenerative radios to narrow-band,

high performance super-heterodyne receivers. The

HT9831 minimum ASK data rate is 10kbps which sup-

ports a more complicated control protocol.

To minimise power consumption, the HT9831 provides

a data tracking function. In the Idle Mode, the internal

PLL will be switched off, but when high to low data is re-

ceived the PLL will be switched on and data will be

transmitted without delay. The PLL will be turned off au-

tomatically and the HT9831 will return to the Idle Mode

after no data input transients have been received for

more than 300ms. As there is a reference clock output

for the MCU, the MCU can use its internal RC clock

rather than using an additional crystal for precise timing.

With these combined features the HT9831 can provide

a power-saving and cost effective solution for a huge

range of remote wireless applications.

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Applications