10

601 Hardware Specifications, Rev 3

Preliminary/Subject to Change without Notice

1.3.2.2 Output AC Specifications

The output specifications of the 601 and 601v for both driving high and driving low depend on the capacitive

loading on each output and the drive capability enabled for that output. Additionally, the timing

specifications for outputs driving low depend on the voltage swing required to drive to 0.8 V

(either 5.5–0.8 V or 3.6–0.8 V).

Table 7 provides the output AC timing specifications (shown in Figure 3) as absolute values for a theoretical

0 pF load. In order to derive the actual timing specifications guaranteed for a given set of conditions

(capacitive loading, drive capability, and voltage swing), the loading factors provided in Table 6 must be

used. The actual specifications are defined as follows:

tpd (actual) = ttable + (loading factor *Cload)

where:

tpd (actual) = the specification guaranteed

ttable = the value from Table 7

Cload = the capacitive loading on that signal in the system (minimum of 20 pF must be used)

For example, if an output buffer for a 50-MHz device is driving a load of 100 pF, the output propagation

delay, due to the capacitive load, driving high would be calculated as follows:

tpd (actual) = 10.5 ns + (100 pF * 0.047 ns/pF) = 15.2 ns.

Table 6. Loading Factors for Output Signals

Loading Factor

for Selected

Buffer Size

50 MHz

66 MHz

80 MHz

100 MHz

(601v)

Normal1

Double2

Normal1

Double2

Normal1

Double2

Normal1

Double2

Driving low

(5.5 V to 0.8 V)

0.088

0.053

0.080

0.048

0.072

0.043

0.072

0.039

Driving low

(3.6 V to 0.8V)

0.060

0.036

0.055

0.033

0.051

0.030

0.049

0.029

Driving high

(0.0 V to 2.0 V)

0.047

0.028

0.042

0.025

0.037

0.022

0.035

0.018

Notes: 1. Normal mode means that SC_DRIVE is negated.

2. Double drive is only available for the following signals: ABB, DBB, SHD, ARTRY, TS, and XATS.

Double drive is enabled by strapping the SC_DRIVE pin to Vdd. (Double drive mode increases the

capacitive drive capability of the signal by enabling a second driver.)

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com