| Motore di ricerca datesheet componenti elettronici |
|
LTC1093CSW Scheda tecnica(PDF) 21 Page - Linear Technology |
|
|
|||||||||||||||||||||||||||||
LTC1093CSW Scheda tecnica(HTML) 21 Page - Linear Technology |
|
21 / 32 page ![]() 21 LTC1091/LTC1092 LTC1093/LTC1094 S APPLICATI I FOR ATIO 3. Analog Inputs Because of the capacitive redistribution A/D conversion techniques used, the analog inputs of the LTC1091/ LTC1092/LTC1093/LTC1094 have capacitive switching input current spikes. These current spikes settle quickly and do not cause a problem. However, if large source resistances are used or if slow settling op amps drive the inputs, care must be taken to ensure that the transients caused by the current spikes settle completely before the conversion begins. Source Resistance The analog inputs of the LTC1091/LTC1092/LTC1093/ LTC1094 look like a 60pF capacitor (CIN) in series with a 500 Ω resistor (RON) as shown in Figure 7. CIN gets switched between the selected “+” and “–” inputs once during each conversion cycle. Large external source resis- tors and capacitances will slow the settling of the inputs. It is important that the overall RC time constants be short enough to allow the analog inputs to completely settle within the allowed time. “+” Input Settling This input capacitor is switched onto the “+” input during the sample phase (tSMPL, see Figure 8). The sample phase is the 1 1/2 CLK cycles before the conversion starts. The voltage on the “+” input must settle completely within this sample time. Minimizing RSOURCE+ and C1 will improve the input settling time. If large “+” input source resistance must be used, the sample time can be increased by using a slower CLK frequency. With the minimum possible sample time of 3 µs, RSOURCE+ < 2k and C1 < 20pF will provide adequate settling. Figure 5. Poor VCC Bypassing. Noise and Ripple Can Cause A/D Errors 10 µs/DIV 1091-4 F05 0.5mV/DIV Figure 6. Good VCC Bypassing Keeps Noise and Ripple on VCC Below 1mV 0.5mV/DIV 10 µs/DIV 1091-4 F06 3RD CLK ↑ RON = 500Ω 4TH CLK ↓ CIN = 60pF LTC1091 “+” INPUT RSOURCE+ VIN+ C1 “–” INPUT RSOURCE– VIN– C2 LTC091-4 F07 Figure 7. Analog Input Equivalent Circuit |
|
Link URL |
| Lei ha avuto il aiuto da alldatasheet? [ DONATE ] |
Di alldatasheet | Richest di pubblicita | contatti | Privacy Policy | Collegamento alla scheda tecnica | scambio Link | Ricerca produttore 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 |