參數(shù)資料
型號(hào): TCM38C17IDLDL
廠商: Texas Instruments, Inc.
英文描述: QComboE FOUR-CHANNEL QUAD PCM COMBO
中文描述: QComboE四通道的Quad的PCM組合
文件頁(yè)數(shù): 13/22頁(yè)
文件大?。?/td> 314K
代理商: TCM38C17IDLDL
TCM38C17IDL
QCombo
FOUR-CHANNEL (QUAD) PCMCOMBO
SLWS040C – JUNE 1996 – REVISED OCTOBER 1999
13
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PRINCIPLES OF OPERATION
system reliability and design considerations
The TCM38C17IDL system reliability and design considerations are described in the following paragraphs.
latch-up
Latch-up is possible in all CMOS devices. It is caused by the firing of a parasitic SCR that is present due to the
inherent nature of CMOS. When a latch-up occurs, the device draws excessive amounts of current and will
continue to draw heavy current until power is removed. Latch-up can result in permanent damage to the device
if supply current to the device is not limited.
Even though the QCombo is heavily protected against latch-up, it is still possible to cause latch-up under certain
conditions in which excess current is forced into or out of one or more terminals. Latch-up can occur when the
supply voltage drops momentarily below ground or possibly if a signal is applied to a terminal after power has
been applied but before the ground is connected. This can happen if the device is hot inserted into a card with
the power applied, or if the device is mounted on a card that has an edge connector and the card is hot inserted
into a system with the power on.
To help ensure that latch-up does not occur, it is considered good design practice to connect a reverse-biased
Schottky diode with a forward voltage drop of less than or equal to 0.4 V (1N5711 or equivalent) between the
power supply and GND (see Figure 5). It is possible that a QCombo-equipped card with an edge connector can
not be hot inserted into a powered-up system. In this case, it is also important to ensure that the ground edge
connector traces are longer than the power and signal traces so that the card ground is always the first to make
contact.
VDD
GND
Figure 5. Latch-Up Protection Diode Connection
device power-up sequence
Latch-up also can occur if a signal source is connected without the device being properly grounded. A signal
applied to one terminal could then find a ground through another signal terminal on the device. To ensure proper
operation of the device and as a safeguard against this sort of latch-up, it is recommended that the following
power-up sequence always be used:
1.
Ensure that no signals are applied to the device before the power-up sequence is complete.
2.
Connect GND.
3.
Apply power.
4.
Force a power down-condition in the device.
5.
Connect the master clock.
6.
Release the power-down condition.
7.
Apply FS synchronization pulses.
8.
Apply the analog signal inputs.
When powering down the device, this procedure should be followed in the reverse order.
相關(guān)PDF資料
PDF描述
TCM38C17 ()
TCM809JELB713 3-Pin Microcontroller Reset Monitors
TCM809JENB713 3-Pin Microcontroller Reset Monitors
TCM809JVLB713 3-Pin Microcontroller Reset Monitors
TCM809JVNB713 3-Pin Microcontroller Reset Monitors
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TCM38C17IDLR 制造商:Texas Instruments 功能描述:Audio Codec 1ADC / 1DAC 48-Pin SSOP T/R
TCM4110 制造商:TI 制造商全稱:Texas Instruments 功能描述:PCM U-LOW COMPANDING CODES
TCM4205J4 制造商:Texas Instruments 功能描述:
TCM4-23-2+ 制造商:MINI C 功能描述:
TCM4-25 制造商:Mini-Circuits 功能描述:500 MHz - 2500 MHz RF TRANSFORMER