Datasheet

© 2007 Microchip Technology Inc. Preliminary DS21894C-page 25
MCP2122
FIGURE 4-7: 16XCLK AND THE TX AND TXIR WAVEFORMS
TABLE 4-7: TX AND TXIR REQUIREMENTS
AC Characteristics
Standard Operating Conditions (unless otherwise specified)
Operating Temperature: –40°C ≤ T
A ≤ +125°C (Extended)
Operating Voltage VDD range is described in
Section 4.1 “DC Characteristics”.
Param.
No.
Symbol Characteristic Min Typ
(1)
Max Units Conditions
IR113 TTXRF TX pin rise time and fall time — — 25 ns Note 2
IR114 T
TXJ TX to 16XCLK jitter — — 1 TXCLK Note 2
IR120 TTXL2TXIRH TX falling edge (↓) to
TXIR rising edge (↑)
(1)
7— 8TXCLK
TTXIRPW TXIR pulse width Smaller of Smaller of
IR121A 3 — 3 T
XCLK At 115200 baud
IR121B
1.41 3.5 5 µs At 9600 baud (Note 3)
IR122 TTXIRP TXIR bit period — 16 — TXCLK
20C TTXIRR TXIR pin rise time — 10 25 ns VDD ≥ 2.7V (Note 2)
20D
— 10 60 ns VDD = 1.8V (Note 2)
21C TTXIRF TXIR pin fall time — 10 25 ns Note 2
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: These parameters (shaded) are characterized but are not tested. These values should be used for design
guidance only.
3: This specification is not tested. This value is from the design target
16XCLK
01
Data bit x Data bit x+1
16 CLK 16 CLK
Bit Value
to TX
IR121A
6 CLK
TXIRI (3 * 16XCLK pulses)
IR113
IR122
IR113
IR114
IR115
TXIR Time Out
IR121C
TXIR pin
IR124
IR123
IR121B