 2004 Microchip Technology Inc.

Preliminary

DS21894B-page 19

MCP2122

4.3

Timing Diagrams and Specifications

FIGURE 4-3:

EXTERNAL CLOCK TIMING

TABLE 4-3:

EXTERNAL CLOCK TIMING REQUIREMENTS

AC Characteristics

Standard Operating Conditions (unless otherwise specified)

Operating Temperature: –40

Section 4.1 “DC Characteristics”

Param.

No.

Sym

Characteristic

Min

Max

Units

Conditions

External 16XCLK Period

(2, 3)

542.5

—

—

ns

1A

External 16XCLK

DC

—

1.8432

MHz

1C

—

—

±2

%

Note 5

Clock in (16XCLK)

Low or High Time

50

—

—

ns

Clock in (16XCLK)

—

—

7.5

ns

Note 5

Note 1: Data in the Typical (“Typ”) column is at 5V, +25

°C, unless otherwise stated. These parameters are for

design guidance only and are not tested.

2: All specified values are based on characterization data for that particular oscillator type under standard

operating conditions with the device executing code. Exceeding these specified limits may result in an

unstable oscillator operation and/or higher than expected current consumption.

When an external clock input is used, the “max” cycle time limit is “DC” (no clock) for all devices.

3: A duty cycle of no more than 60/40 (High-Time/Low-Time or Low-Time/High-Time) is recommended for

external clock inputs.

4: This is the clock error from the desired clock frequency. The total system clock error includes the error from

the transmitter and the error of receiver (from the desired clock frequency). If the transmitter is 2% fast from

the target frequency, and the receiver is 2% slow from the target frequency, the total error is 4%.

5: These parameters (shaded) are characterized but are not tested. These values should be used for design

guidance only.

16XCLK

Q4

Q1

Q2

Q3

Q4

Q1

13

3

44