전자부품 데이터시트 검색엔진 |
|
AD5233 데이터시트(PDF) 11 Page - Analog Devices |
|
AD5233 데이터시트(HTML) 11 Page - Analog Devices |
11 / 16 page REV. 0 AD5207 –11– Table IV. DRWB (DEC) ( ) Output State 255 10006 Full-Scale (RAB – 1 LSB + RW) 128 5045 Midscale 184 1 LSB 0 45 Zero-Scale (Wiper Contact Resistance) Note that in the zero-scale condition a finite wiper resistance of 45 Ω is present. Care should be taken to limit the current flow between W and B in this state to a maximum current of no more than 5 mA. Otherwise, degradation or possibly destruction of the internal switch contacts can occur. Similar to the mechanical potentiometer, the resistance of the RDAC between the wiper W and Terminal A also produces a digitally controlled resistance RWA. When these terminals are used, the B Terminal should be let open or tied to the wiper terminal. Setting the resistance value for RWA starts at a maximum value of resistance and decreases as the data loaded in the latch is increased in value. The general equation for this operation is: RD D RR WA AB W () =× + 256 256 – (2) For example, when RAB = 10 k Ω, B terminal is either open or tied to W, the following output resistance, RWA, will be set for the following RDAC latch codes. Table V. DRWA (DEC) ( ) Output State 255 84 Full-Scale (RAB/256 + RW) 128 5045 Midscale 1 10006 1 LSB 0 10045 Zero-Scale The typical distribution of RAB from channel to channel matches within ±1%. Device-to-device matching is process-lot depen- dent and is possible to have ±30% variation. The change in RAB with temperature has a 500 ppm/ °C temperature coefficient. PROGRAMMING THE POTENTIOMETER DIVIDER Voltage Output Operation The digital potentiometer easily generates an output voltage proportional to the input voltage. Let’s ignore the effect of the wiper resistance for the moment. For example, when con- necting A Terminal to 5 V and B Terminal to ground, it produces a programmable output voltage at the wiper starting at zero volts up to 1 LSB less than 5 V. Each LSB of voltage is equal to the voltage applied across terminal AB divided by the 256 position of the potentiometer divider. Since AD5207 is capable for dual supplies, the general equation defining the output volt- age with respect to ground for any given input voltage applied to terminals AB is: VD D V D V WA B () =+ − 256 256 256 (3) Operation of the digital potentiometer in the divider mode results in more accurate operation over temperature. Unlike the rheostat mode, the output voltage is dependent on the ratio of RWA and RWB and not the absolute values; therefore, the drift reduces to 15 ppm/ °C. There is no voltage polarity constraint between Terminals A, B, and W as long as the terminal voltage stays within VSS < VTERM < VDD. RDAC CIRCUIT SIMULATION MODEL The internal parasitic capacitances and the external capacitive loads dominate the ac characteristics of the RDACs. Config- ured as a potentiometer divider the –3 dB bandwidth of the AD5207BRU10 (10 k Ω resistor) measures 600 kHz at half scale. TPC 16 provides the large signal BODE plot characteris- tics of the three available resistor versions 10 k Ω and 50 kΩ. The gain flatness versus frequency graph, TPC 16, predicts filter applications performance. A parasitic simulation model has been developed and is shown in Figure 9. Listing I provides a macro model net list for the 10 k Ω RDAC: CW 70pF CB CA B A RDAC 10k W CB = 45pF CA = 45pF Figure 9. RDAC Circuit Simulation Model for RDAC = 10 k Ω Listing I. Macro Model Net List for RDAC .PARAM D=255, RDAC=10E3 * .SUBCKT DPOT (A,W) * CA A 0 45E-12 RAW A W {(1-D/256) *RDAC+50} CW W 0 70E-12 RBW W B {D/256 *RDAC+50} CB B 0 45E-12 * .ENDS DPOT |
유사한 부품 번호 - AD5233 |
|
유사한 설명 - AD5233 |
|
|
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 |