AN2451
Electrical characteristics
Doc ID 12791 Rev 3
7/55
1 Electrical
characteristics
Table 1.
Electrical characteristics of the ST7540 reference design
Parameter
Test conditions
Value
Unit
Min
Typ
Max
Operating conditions
Ambient operating temperature
If ST7540 junction temperature
exceeds 180 °C device shuts
down
85 °C
Transceiver section transmitting specifications (Tx mode)
Selected channel frequency
FSK carrier
72
kHz
Transmitting output voltage level at mains output
R7 = 47k
Ω
, R8 = 15k
Ω
– See
Table 2
2
2.25
V rms
Transmitting output current limit
R6=1.1k
Ω
– See Figure 2
500 mA
rms
2
nd
harmonic distortion
at mains output
Loaded with CISPR 16-1
network
-55
dB
C
3
rd
harmonic distortion
at mains output
Loaded with CISPR 16-1
network
-61
50Hz attenuation
100 dB
Receiving specifications (Rx mode)
Minimum detectable Rx signal
BER<10
-3
, negligible noise
48
dBµV rms
Auxiliary supply
5 V regulated voltage
ST7540 internally generated
-5%
5.05
+5%
V
5 V current capability
50 mA
3.3 V regulated voltage
ST7540 internally generated
-5%
3.3
+5%
V
3.3 V current capability
50 mA
Power supply section
AC mains voltage range
85
265
V
Mains frequency
50-60 Hz
Output voltage
Green led ON
-10%
12.3
+10%
V
Output voltage ripple
Iout = 500 mA, Vin=85 Vac
1
%
Peak output current
500 mA
Output power
5.6 W
Efficiency at Pout=3.5W
70
%
Nominal transformer isolation*
Primary to secondary/
secondary to auxiliary
4 kV
