T89C51RD2-3CWC-M datasheet(75/86 Pages) ATMEL

75 / 86 page

Rev. F - 15 February, 2001

T89C51RD2

Figure 27. Clock Signal Waveform for ICC Tests in Active and Idle Modes

9.5. AC Parameters

9.5.1. Explanation of the AC Symbols

Each timing symbol has 5 characters. The first character is always a “T” (stands for time). The other characters,

depending on their positions, stand for the name of a signal or the logical status of that signal. The following is

a list of all the characters and what they stand for.

Example:TAVLL = Time for Address Valid to ALE Low.

TLLPL = Time for ALE Low to PSEN Low.

TA =0to+70

°C; V

SS =0V;VCC =5V ± 10%; M range.

TA = -40

°Cto+85°C; V

SS =0V;

VCC =5V ± 10%; M range.

TA =0to+70

°C; V

SS =0V;2.7V<VCC < 3.3 V; L range.

TA = -40

°Cto+85°C; V

SS =0V;2.7V<VCC < 3.3 V; L range.

AC characteristics of -M parts at 3 volts are similar to -L parts

(Load Capacitance for port 0, ALE and PSEN = 100 pF; Load Capacitance for all other outputs = 80 pF.)

Table 38, Table 41 and Table 44 give the description of each AC symbols.

Table 39, Table 42 and Table 45 give for each range the AC parameter.

Table 40, Table 43 and Table 46 give the frequency derating formula of the AC parameter for each speed range

description. To calculate each AC symbols. take the x value in the correponding column (-M or -L) and use this

value in the formula.

Example: TLLIU for -M and 20 MHz, Standard clock.

x=35ns

T=50ns

TCCIV =4T-x=165 ns

VCC-0.5V

0.45V

0.7VCC

0.2VCC-0.1

TCLCH

TCHCL

TCLCH = TCHCL = 5ns.

T89C51RD2-3CWC-M Datasheet(PDF) 75 Page - ATMEL Corporation