MMBTA92LT1 データシートの表示（PDF） - Silicon Laboratories

部品番号

コンポーネント説明

一致するリスト

MMBTA92LT1

Global ISOmodem-EVB

Silicon Laboratories 

Si2493/57/34/15/04

Global ISOmodem-EVB

2.2. Modem Daughter Card Operation

The Si2493/57/34/15/04URT-EVB daughter card is a

complete modem solution perfectly suited for use in an

embedded system. The daughtercard contains both the

modem system-side chip and the isolated line interface

(DAA).

The daughter card requires a 3.3 V supply capable of

providing at least 35 mA and communicates with the

system via LVCMOS/TTL-compatible digital signals on

JP1. The RJ-11 jack (TIP and RING) is connected via

JP2. Be sure to provide the proper power-on reset pulse

to the daughter card if it is used in the stand-alone

mode.

2.2.1. Reset Requirements

The Si2493/57/34/15/04 ISOmodem® daughter card

must be properly reset at powerup. The reset pin (pin 8)

of the Si2493/57/34/15/04 (JP103, J101 pin 13) must be

held low for at least 5.0 ms after power is applied and

stabilized to ensure the device is properly reset.

2.2.2. Crystal Requirements

Clock accuracy and stability are important in modem

applications. To ensure reliable communication between

modems, the clock must remain within ±100 ppm of the

design value over the life of the modem. The crystal

selected for use in a modem application must have a

frequency tolerance of less than ±100 ppm for the

combination of initial frequency tolerance, drift over the

normal operating temperature range, and five year

aging. Other considerations, such as production

variations in PC board capacitance and the tolerance of

loading capacitors, must also be taken into account.

2.2.3. Protection

The Si2493/57/34/15/04-EVB meets or exceeds all FCC

and international PTT requirements and

recommendations for high-voltage surge and isolation

testing without any modification. The protection/isolation

circuitry includes C1, C2, C8, C9, FB1, FB2, and RV1.

The PCB layout is also a key “component” in the

protection circuitry. The Si2493/57/34/15/04-EVB

provides isolation to 3 kV. Contact Silicon Laboratories

for information about designing to higher levels of

isolation.

Rev. 0.7

11

Share Link: