Operating Principles - Holtek BA45F56 Series Function Description


ISINK0/1 provide a constant infrared emission current, A0PI and A0NI process the infrared
received signal

ISINK0/1 constant current output is adjustable

Two sets of ISINK for use by different types of smoke – white/black smoke

RF circuit includes the antenna and input/output matching circuit

Time-division duplex (TDD) method must be used for RF signal transmission and reception -
only transmission or reception can be performed at a time

RF transmission
Digital packet regulator → Gaussian filter → ΣΔ Modulator → Frequency synthesis → High
power amplifier → Antenna

RF reception
Antenna → Low noise amplifier → Intermediate frequency(IF) → Intermediate frequency
composite band-pass filter → Signal strength detector → Digital packet demodulator

Operating Principles

Communication Pin Description
AN0571EN V1.00
BA45F56xx Wireless Transceiver Application
46 45 44 43 42 41 40 39
1
NC
2
CLDO
3
GIO4
NC 4 BA45F5640
5 BA45V5640
NC
46 QFN-A
V_LNA
6
7
RFIN
RFOUT 8
VSSRF
9
10 11 12 13 1415 161718 19 20 21 22
Figure 2. BA45F5640 Pin Assignment
2 / 14
38 37 36 35 34 33
32
VSS
31
VSS
30
VDD
NC
29
28
NC
27 A0NI
26 A0PI
25 PB0/INT0/SCS/STP/A0PB
24 PA5/STCK/A1O
23
November 5, 2020