Datasheet

MCP2122
DS21894C-page 24 Preliminary © 2007 Microchip Technology Inc.
FIGURE 4-6: TX AND TXIR WAVEFORMS
TABLE 4-6: TX AND TXIR REQUIREMENTS
AC Characteristics
Standard Operating Conditions (unless otherwise specified)
Operating Temperature: –40°C ≤ T
A ≤ +125°C (Extended)
Operating Voltage V
DD range is described in
Section 4.1 “DC Characteristics”.
Param.
No.
Sym Characteristic Min Typ
(1)
Max Units Conditions
IR100A T
TXBIT Transmit Baud Rate — 16 — TXCLK
IR100B TTXIRBIT Transmit Baud Rate 16 — 16 TXCLK
IR102A ETXBIT Host UART TX Error — — ± 2 % Note 2, 3
IR102B E
TXIRBIT TXIR Error from 16XCLK — 0 — % Note 2, 4
IR113 TTXRF TX pin rise time and fall
time
— — 25 ns Note 2
IR114 T
TXPDIRJ 16XCLK to TX jitter — — 1 TXCLK Note 2
IR120 T
TXL2TXIRH TX falling edge (↓) to
TXIR rising edge (↑)
(1)
7—8TXCLK
IR121A TTXIRPW TXIR pulse width 3 — 3 TXCLK At 115200 baud
IR121B
1.41 3.5 5 µs At 9600 baud (Note 5)
IR122 TTXIRP TXIR bit period
(1)
—16—TXCLK
IR123 TTXIRRF TXIR pin rise time and fall
time
— — 10 ns 50 pF load (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: The TX pin operation may be asynchronous to the 16XCLK pin. This is the error from the desired baud rate
for the system.
4: The TXIR pin operation is synchronous to the 16XCLK pin. Any error present on the 16XCLK pin
(Parameter 1C) will be refelected on the TXIR pin.
5: This specification is not tested. This value is from the design target.
16XCLK
TX
TXIR
0100 01
IR100
IR121
Bit Bit Bit Bit Bit ...
IR122 IR122 IR122 IR122 IR122 IR122
IR114
IR113
IR113
IR115
IR120