전자부품 데이터시트 검색엔진 |
|
AD7864AS-2 데이터시트(PDF) 9 Page - Analog Devices |
|
AD7864AS-2 데이터시트(HTML) 9 Page - Analog Devices |
9 / 19 page AD7864 –9– REV. A AD7864-1 Figure 2 shows the analog input section of the AD7864-1. Each input can be configured for ±5 V or ±10 V operation on the AD7864-1. For ±5 V (AD7864-1) operation, the V INXA and VINXB inputs are tied together and the input voltage is applied to both. For ±10 V (AD7864-1) operation, the V INXB input is tied to AGND and the input voltage is applied to the VINXA input. The VINXA and VINXB inputs are symmetrical and fully inter- changeable. Thus for ease of PCB layout on the ±10 V range, the input voltage may be applied to the VINXB input while the VINXA input is tied to AGND. 2.5V REFERENCE T/H TO ADC REFERENCE CIRCUITRY 6k R2 R3 TO INTERNAL COMPARATOR AD7864-1 R1 R4 AGND VIN1B VIN1A VREF Figure 2. AD7864-1 Analog Input Structure For the AD7864-1, R1 = 6 k Ω, R2 = 24 kΩ, R3 = 24 kΩ and R4 = 12 k Ω. The resistor input stage is followed by the high input impedance stage of the track/hold amplifier. The designed code transitions take place midway between suc- cessive integer LSB values (i.e., 1/2 LSB, 3/2 LSBs, 5/2 LSBs etc.) LSB size is given by the formula, 1 LSB = FSR/4096. For the ±5 V range, 1 LSB = 10 V/4096 = 2.44 mV. For the ±10 V range, 1 LSB = 20 V/4096 = 4.88 mV. Output coding is twos complement binary with 1 LSB = FSR/4096. The ideal input/ output transfer function for the AD7864-1 is shown in Table I. Table I. Ideal Input/Output Code Table for the AD7864-1 Analog Input l Digital Output Code Transition +FSR/2 – 3/2 LSB2 011 . . . 110 to 011 . . . 111 +FSR/2 – 5/2 LSB 011 . . . 101 to 011 . . . 110 +FSR/2 – 7/2 LSB 011 . . . 100 to 011 . . . 101 AGND + 3/2 LSB 000 . . . 001 to 000 . . . 010 AGND + 1/2 LSB 000 . . . 000 to 000 . . . 001 AGND – 1/2 LSB 111 . . . 111 to 000 . . . 000 AGND – 3/2 LSB 111 . . . 110 to 111 . . . 111 –FSR/2 + 5/2 LSB 100 . . . 010 to 100 . . . 011 –FSR/2 + 3/2 LSB 100 . . . 001 to 100 . . . 010 –FSR/2 + 1/2 LSB 100 . . . 000 to 100 . . . 001 NOTES 1FSR is full-scale range and is 20 V for the ± 10 V range and 10 V for the ±5 V range, with VREF = +2.5 V. 21 LSB = FSR/4096 = 4.883 mV ( ±10 V—AD7864-1) and 2.441 mV (± 5 V— AD7864-1) with VREF = +2.5 V. AD7864-2 Figure 3 shows the analog input section of the AD7864-2. Each input can be configured for 0 V to +5 V operation or 0 V to +2.5 V operation. For 0 V to +5 V operation, the VINXB input is tied to AGND and the input voltage is applied to the VINXA input. For 0 V to 2.5 V operation, the VINXA and VINXB inputs are tied together and the input voltage is applied to both. The VINXA and VINXB inputs are symmetrical and fully interchange- able. Thus for ease of PCB layout on the 0 V to +5 V range, the input voltage may be applied to the VINXB input while the VINXA input is tied to AGND. For the AD7864-2, R1 = 6 k Ω and R2 = 6 kΩ. Once again, the designed code transitions occur on successive integer LSB values. Output coding is straight (natural) binary with 1 LSB = FSR/4096 = 2.5 V/4096 = 0.61 mV, and 5 V/4096 = 1.22 mV, for the 0 V to 2.5 V and the 0 V to 5 V options respectively. Table II shows the ideal input and output transfer function for the AD7864-2. 2.5V REFERENCE T/H TO ADC REFERENCE CIRCUITRY 6k R2 TO INTERNAL COMPARATOR AD7864-2 R1 VIN1B VIN1A VREF Figure 3. AD7864-2 Analog Input Structure Table II. Ideal Input/Output Code Table for the AD7864-2 Analog Input1 Digital Output Code Transition +FSR – 3/2 LSB 2 111 . . . 110 to 111 . . . 111 +FSR – 5/2 LSB 111 . . . 101 to 111 . . . 110 +FSR – 7/2 LSB 111 . . . 100 to 111 . . . 101 AGND + 5/2 LSB 000 . . . 010 to 000 . . . 011 AGND + 3/2 LSB 000 . . . 001 to 000 . . . 010 AGND + 1/2 LSB 000 . . . 000 to 000 . . . 001 NOTES 1FSR is full-scale range and is 0 V to 2.5 V and 0 V to 5 V for AD7864-2 with VREF = +2.5 V. 21 LSB = FSR/4096 and is 0.61 mV (0 V to 2.5 V) and 1.22 mV (0 V to 5 V) for AD7864-2 with VREF = +2.5 V. |
유사한 부품 번호 - AD7864AS-2 |
|
유사한 설명 - AD7864AS-2 |
|
|
링크 URL |
개인정보취급방침 |
ALLDATASHEET.CO.KR |
ALLDATASHEET 가 귀하에 도움이 되셨나요? [ DONATE ] |
Alldatasheet는? | 광고문의 | 운영자에게 연락하기 | 개인정보취급방침 | 링크교환 | 제조사별 검색 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 |