Electronic Components Datasheet Search |
|
TC534 Datasheet(PDF) 10 Page - TelCom Semiconductor, Inc |
|
TC534 Datasheet(HTML) 10 Page - TelCom Semiconductor, Inc |
10 / 15 page 3-56 TELCOM SEMICONDUCTOR, INC. 5V PRECISION DATA ACQUISITION SUBSYSTEMS TC530 TC534 20 VINMAX RINT (MΩ) = where: VINMAX = Maximum Input Voltage (full count voltage) RINT = Integrating Resistor (in M Ω) For loop stability, RINT should be ≥ 50kΩ. (2) Select Reference (CREF) and Auto Zero (CAZ) Capacitors CREF and CAZ must be low leakage capacitors (such as polypropylene). The slower the conversion rate, the larger the value CREF must be. Recommended capacitors for CREF and CAZ are shown in Table 1. Larger values for CAZ and CREF may also be used to limit roll-over errors. Table 1. CREF and CAZ Selection Conversions Typical Value of Suggested * Per Second CREF, CAZ ( µF) Part Number >7 0.1 WIMA MK12 .1/63/20 2 to 7 0.22 WIMA MK12 .22/63/20 2 or less 0.47 WIMA MK12 .47/63/20 *WIMA Corp. listing on the last page of this data sheet. 3. Calculate Integrating Capacitor (CINT) The integrating capacitor must be selected to maxi- mize integrator output voltage swing. The integrator output voltage swing is defined as the absolute value of VDD (or VSS) less 0.9V (i.e. |VDD – 0.9V| or |VSS + 0.9V|). Using the 20 µA buffer maximum output current, the value of the integrating capacitor is calculated using the following equation: (VS – 0.9) (tINT)(20) CINT (µF) = where: tINT = Integration Period VS = Applied Supply Voltage CINT = Integrator Capacitor Value (in µF) It is critical that the integrating capacitor have a very low dielectric absorption. PPS capacitors are an example of one such chemistry. Table 2 summa- rizes various capacitors suitable for CINT. Value Suggested Part Number* 0.1 WIMA MK12 .1/63/20 0.22 WIMA MK12 .22/63/20 0.33 WIMA MK12 .33/63/20 0.47 WIMA MK12 .47/63/20 *WIMA Corp. listing on the last page of this data sheet. 4. Calculate VREF The reference deintegration voltage is calculated using: VREF (in Volts) = (VS – 0.9)(CINT)(RINT) 2(tINT) Serial Port Communication with the TC530/534 is accomplished over a 3 wire serial port. Data is clocked into DIN on the rising edge of DCLK and clocked out of DOUT on the falling edge of DCLK. R/W must be HIGH to read converted data from the serial port and LOW to write the LOAD VALUE to the TC530/ 534. Load Value Write Cycle (Figure 4) Following the power-up reset pulse, the LOAD VALUE (which sets the duration of AZ and INT) must next be transmitted to the serial port. To accomplish this, the proces- sor monitors the state of EOC (which is available as a hardware output or at DOUT). R/W is taken low to initiate the write cycle only when EOC is low (during the AZ phase). (Failure to observe EOC low may cause an offset voltage to be developed across CINT resulting in erroneous readings). The 8 bit LOAD VALUE data on DIN is clocked in by DCLK. The processor then terminates the write cycle by taking R/W high. (Data is transferred from the serial input shift register to the time base counter on the rising edge of R/W, and data conversion is initiated). Data Read Cycle (Figure 5) Data is shifted out of the serial port in the following order: End of Conversion (EOC), Overrange (OVR), Sign (SGN), conversion data (MSB first). When R/W is high, the state of the EOC bit can be polled by simply reading the state of DOUT. This allows the processor to determine if new data is available without connecting an additional wire to the EOC output pin (this is especially useful in a polled environment). Input Multiplexer (TC534 Only) A 4 input, differential multiplexer is included in the TC534. The states of channel address lines A0 and A1 determine which differential VIN pair is routed to the con- Table 2. Recommend Capacitor for CINT |
Similar Part No. - TC534 |
|
Similar Description - TC534 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |