June 2003
User’s Guide
SBAU087
Страница 1: ...June 2003 User s Guide SBAU087...
Страница 2: ...t that any license either express or implied is granted under any TI patent right copyright mask work right or other TI intellectual property right relating to any combination machine or process in wh...
Страница 3: ...handling or use of the goods Please be aware that the products received may not be regulatory compliant or agency certified FCC UL CE etc Due to the open construction of the product it is the user s r...
Страница 4: ...here is uncertainty as to the load specification please contact a TI field representative During normal operation some circuit components may have case temperatures greater than 60 C The EVM is design...
Страница 5: ...refers to them in the singular when necessary as ADS1244 45EVM When a statement applies to both the ADS1244 and ADS1245 devices they may be referred to in the singular when necessary as ADS1244 45 In...
Страница 6: ...use in a laboratory test environment only It generates uses and can radiate radio frequency energy and has not been tested for compliance with the limits of computing devices pursuant to sub part J of...
Страница 7: ...points 2 6 2 2 Jumpers 2 7 2 2 1 J2 Analog Digital Ground Shorting Jumper 2 7 2 2 2 J3 ADS1244 45 Analog Supply Current Measurement Jumper 2 7 2 3 Switches 2 8 2 3 1 S1 System Clock Select 2 8 2 3 2 S...
Страница 8: ...Diagram 4 2 4 2 Top Side Layout 4 3 4 3 Bottom Side Layout 4 3 2 1 Analog Connector Pin Descriptions 2 3 2 2 Serial Connector Pin Descriptions 2 4 2 3 Power Connector Pin Descriptions 2 5 2 4 Testpoi...
Страница 9: ...bit delta sigma analog to digital converters Designed for prototyping and evaluation they include a reference circuit and an oscillator circuit with two selectable frequencies Topic Page 1 1 Introduct...
Страница 10: ...44 45 See TI s web site for more information and software 1 2 Built in Accessories The ADS1244 45EVM includes a system clock generator and a low noise voltage reference Both features are optional you...
Страница 11: ...4576MHz clock source or an exter nally provided clock When the external clock is selected the onboard oscilla tor is disabled to save power and prevent interference Switch S2 selects the input signal...
Страница 12: ...o the proper pins on the power connector If you are not measuring the ADS1244 45 s supply current remember to place shorting blocks on jumpers J3 and J4 Without these blocks the ADS1244 45 will not be...
Страница 13: ...1 5 Introduction...
Страница 14: ...Circuit Description This chapter describes the ADS1244 45EVM connectors controls and circuit design in detail Topic Page 2 1 I O Connectors and Testpoints 2 2 2 2 Jumpers 2 7 2 3 Switches 2 8 Chapter...
Страница 15: ...airs in a pass through configuration Each pair has a male sur face mount header on the top component side of the board and a corre sponding female surface mount socket on the bottom solder side of the...
Страница 16: ...The negative input pins are so named because the voltage on such a pin is subtracted from a positive pin during a reading Table 2 1 Analog Connector Pin Descriptions Pin No Pin Name Standard Name Dire...
Страница 17: ...a ready 16 SCL SCL I O I2C clock line 17 SYSCLK TOUT Input External system clock input 19 OBCLKEN GPIO5 Output Clock mode indicator 20 SDA SDA I O I2C data line 6 12 18 GND DGND Power Signal ground Th...
Страница 18: ...ionally connected to DGND through J2 6 DGND Digital ground Ground 7 1 8VD Positive digital supply 1 8V Possible digital supply selected using S5 8 VD1 Positive digital supply Not used 9 3 3VD Positive...
Страница 19: ...ignal CLK TP4 System clock AVDD TP3 Analog supply DVDD TP1 Digital supply GND TP2 Ground The CLK testpoint is attached to the CLK pin on the ADS1244 45 It reflects the actual CLK signal controlling th...
Страница 20: ...together If you are using a single power supply you should usually place a shorting block across this jumper If you are using two different supplies each with its own ground you should usually leave t...
Страница 21: ...B 2 Middle Onboard 2 4576MHz High EXT Bottom External J5 pin 17 Low This switch also controls the state of OBCLKEN This signal enables the oscillator U2 and is also brought to pin 19 of J5 External sy...
Страница 22: ...REF EXT Left External J1 pins 18 and 20 J1 pin 20 J1 pin 18 OBH Middle On board high common mode AVDD 2 5V OBL Right Zero shorted to reference 2 5V AGND In the EXT position J1 pins 18 and 20 are conn...
Страница 23: ...44 45 device The posi tions of the switch are described in Table 2 8 Table 2 8 Digital Power Supply Level Select Switch Board Marking Switch Position Digital Power Supply Source 1V8 Top 1 8V typ J6 pi...
Страница 24: ...This chapter provides guidelines on using the ADS1244 45EVM and connecting other systems to it Topic Page 3 1 The Input Filtering Capacitors 3 2 3 2 The Serial Interface 3 3 3 3 The Serial EEPROM 3 3...
Страница 25: ...re not populated since they would be redundant with REF connected to ground as is usually the case The performance of the ADS1244 is often improved by these capacitors On the input the capacitors atte...
Страница 26: ...terrupt the processor if your processor supports this If the microcontroller has an SPI peripheral you can also use this together with an interrupt input to read from the ADS1244 45 This is done by co...
Страница 27: ...e 4 2 on page 4 3 The bottom solder side layout is shown in Figure 4 3 on page 4 3 The bill of materi als is shown in Section 4 3 on page 4 4 Both the schematic and the bill of materials apply for the...
Страница 28: ...Schematic 4 2 4 1 Schematic Figure 4 1 Schematic Diagram...
Страница 29: ...Board Layout 4 3 Schematic and Layout 4 2 Board Layout Figure 4 2 Top Side Layout Figure 4 3 Bottom Side Layout...
Страница 30: ...C256 I SN U1 Voltage reference Texas Instruments REF1004I 2 5 U4 Positive edge triggered D type flip flop Texas Instruments SN74LVC1G80DBVR D3 D4 Schottky diode Panasonic MA2Q705 N A ADS1244 EVM PWB T...