ST7538P STMicroelectronics, ST7538P Datasheet - Page 16

• Manufacturer Part Number: ST7538P
• Description: Telecom Line Management ICs 1/2 Duplex FSK Modem
• Manufacturer: STMicroelectronics
• Type: Single Chipr

Specifications of ST7538P

• Product: Modem Chip
• Supply Voltage (max): 5.25 V, 12.5 V
• Supply Voltage (min): 4.75 V, 7.5 V
• Supply Current: 5 mA, 370 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Package / Case: TQFP-44
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ST7538
3.7 Transmission Mode
The transmit mode is set when
ulator and the Power Line Interface are turned ON. The transmit Data (TXD) enter synchronously or asyn-
chronously to the FSK modulator.
– Host Controller Synchronous Communication Mode: on CLR/T rising edge, TXD Line Value is read and
– Host Controller Asynchronous Communication Mode: TXD data enter directly to the FSK Modulator.The
In both conditions no Protocol Bits are added by ST7538.
The FSK frequencies are synthesized in the FSK modulator from a 16 MHz crystal oscillator by direct dig-
ital synthesis technique. The frequencies Table in different Configuration is reported in Table 8. The fre-
quencies precision is same as external crystal one’s.
In the analog domain, the signal is filtered in order to reduce the output signal spectrum and to reduce the
harmonic distortion. The transition between a symbol and the following is done at the end of the on-going
half FSK sinewave cycle.
Figure 14. Transmitting Path Block Diagram
16/30
sent to the FSK Modulator. ST7538 Manage the Transmission timing according to the BaudRate Se-
lected
Host Controller Manages the Transmission timing
ZCOUT
CLR/T
TOUT
TxD
7
5
8
15
D-TYPE
FLOP
FLIP
Bit 14
CLR/T GENERATOR
MODULATOR
RxTx
Bit 7 & 8
Bit 0-5
FSK
Pin =”0” and REG_DATA Pin =”0”. In transmitting mode the FSK Mod-
DAC
THERMAL
SENSOR
TIMER
ZERO CROSSING
TRANSMISSION
Band Pass
ZCIN
FILTER
Bit 0-2
16
ALC
CURRENT
VOLTAGE
LOOP
LOOP
PLI
PLI
PLI
D03IN1420
29
23
19
21
24
Vsense
CL
ATOP1
ATOP2
ATO