Motore di ricerca datesheet componenti elettronici |
|
ADMC401 Scheda tecnica(PDF) 11 Page - Analog Devices |
|
ADMC401 Scheda tecnica(HTML) 11 Page - Analog Devices |
11 / 60 page ADMC401 –11– REV. B POWER DISSIPATION To determine total power dissipation in a specific application, the following equation should be applied for each output: C × V DD 2 × f C = load capacitance, f = output switching frequency. Example: In an application where external data memory is used and no other outputs are active, power dissipation is calculated as follows: Assumptions: • External data memory is accessed every cycle with 50% of the address pins switching. • External data memory writes occur every other cycle with 50% of the data pins switching. • Each address and data pin has a 10 pF total load at the pin. • The application operates at VDD = 5.0 V and tCK = 38.5 ns. Total Power Dissipation = PINT + (C × V DD 2 × f) PINT = VDD × (I DD Digital + IDD Analog) (C × V DD 2 × f) is calculated for each output: # of Pins C VDD 2 f Address, DMS 8 × 10 pF × 52 V × 26 MHz = 52.00 mW Data Output, WR 9 × 10 pF × 52 V × 13 MHz = 29.25 mW RD 1 × 10 pF × 52 V × 13 MHz = 3.25 mW CLKOUT 1 × 10 pF × 52 V × 26 MHz = 6.50 mW 91.00 mW Total power dissipation for this example is PINT + 91 mW. TEST CONDITIONS Output Disable Time Output pins are considered to be disabled when they have stopped driving and started a transition from the measured output high or low voltage to a high impedance state. The out- put disable time (tDIS) is the difference of tMEASURED and tDECAY, as shown in the Output Enable/Disable diagram. The time is the interval from when a reference signal reaches a high or low voltage level to when the output voltages have changed by 0.5 V from the measured output high or low voltage. The decay time, tDECAY, is dependent on the capacitative load, CL, and the cur- rent load, iL, on the output pin. It can be approximated by the following equation: t CV I DECAY L L = × 05 . from which tt t DIS MEASURED DECAY =− is calculated. If multiple pins (such as the data bus) are dis- abled, the measurement value is that of the last pin to stop driving. 3.0V 1.5V 0.0V 2.0V 1.5V 0.3V INPUT OUTPUT Figure 7. Voltage Reference Levels for AC Measure- ments (Except Output Enable/Disable) Output Enable Time Output pins are considered to be enabled when that have made a transition from a high-impedance state to when they start driving. The output enable time (tENA) is the interval from when a reference signal reaches a high or low voltage level to when the output has reached a specified high or low trip point, as shown in the Output Enable/Disable diagram. If multiple pins (such as the data bus) are enabled, the measurement value is that of the first pin to start driving. 2.0V 1.0V tENA REFERENCE SIGNAL OUTPUT tDECAY VOH (MEASURED) OUTPUT STOPS DRIVING OUTPUT STARTS DRIVING tDIS tMEASURED VOL (MEASURED) VOH (MEASURED) – 0.5V VOL (MEASURED) +0.5V HIGH-IMPEDANCE STATE. TEST CONDITIONS CAUSE THIS VOLTAGE LEVEL TO BE APPROXIMATELY 1.5V. VOH (MEASURED) VOL (MEASURED) Figure 8. Output Enable/Disable TO OUTPUT PIN 50pF +1.5V IOH IOL Figure 9. Equivalent Device Loading for AC Measure- ments (Including All Fixtures) |
Codice articolo simile - ADMC401 |
|
Descrizione simile - ADMC401 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEETIT.COM |
Lei ha avuto il aiuto da alldatasheet? [ DONATE ] |
Di alldatasheet | Richest di pubblicita | contatti | Privacy Policy | 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 |