ST7540TR STMicroelectronics, ST7540TR Datasheet - Page 28

• Manufacturer Part Number: ST7540TR
• Description: IC TXRX FSK POWER LINE 28-TSSOP
• Manufacturer: STMicroelectronics
• Type: Transceiverr

Specifications of ST7540TR

• Number Of Drivers/receivers: 1/1
• Voltage - Supply: 5 V ~ 9 V
• Mounting Type: Surface Mount
• Package / Case: 28-TSSOP Exposed Pad, 28-eTSSOP, 28-HTSSOP
• For Use With: 497-5485 - BOARD EVAL ST7540 PWR LINE TXRX
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Protocol: -
• Lead Free Status / Rohs Status: Compliant
• Other names: 497-5528-2

Functional description
28/44
Figure 17. Voltage and current feedback external interconnection example
Voltage Control Loop Formula
The Current control loop acts to limit the maximum Peak Output current inside
PA_OUT.
The current control loop acts through the voltage control loop decreasing the Output
Peak-to-Peak Amplitude to reduce the Current inside the Power Line Interface.
The current sensing is done by mirroring the current in the High side MOS of the Power
Amplifier (not dissipating current Sensing). The Output Current Limit (up to 500mrms),
is set by means of an external resistor (R
resistor converts the current sensed into a voltage signal. The Peak current sensing
block works as the Output Voltage sensing Block:
–
–
–
Figure 17
If V(CL) < CL
If CL
If V(CL) > CL
TH
shows the typical connection of Current anVoltage control loops.
- CL
ALC
HYST
TH
TH
V
OUTPK
CURRENT
VOLTAGE
- CL
+ CL
LOOP
LOOP
< V(CL) < CL
80pF typ.
HYST
HYST
≅
D03IN1421
R
------------------- -
1
Voltage Control Loop Acting
R
The next gain level is decreased by 1 step
+
2
R
PA_OUT/TX_OUT
2
Vsense
CL
AVss
TH
⋅
(
+ CL
Vsense
10nF
CL
RCL
HYST
) connected between CL and V
TH
R1
R2
Vout
No Gain Change
±
Vsense
HYST
)
Vsense
Vsense
SS
TH
. The
HYST
1.865V (Typ)
V
V
CL HYST
CL TH
ST7540