MAX17823B datasheet(44/121 Pages) MAXIM

44 / 121 page

________________________________________________________________________________________________________________________________________________________________

MAX17823B

12-Channel High-Voltage Data Acquisition System

www.maximintegrated.com

Maxim Integrated | 44

UART Receiver

The UART receiver has a wide common-mode input range to tolerate harsh EMC conditions. It can be operated in

differential mode or single-ended mode per Table 19. By default, the UART receivers are configured for differential

mode. In single-ended mode, the RXP input is grounded and the RXN input receives inverse data as described in

the Applications section (Figure 64). In single-ended mode, the receiver input threshold is negative so that a zero

differential voltage (VRXP, VRXN = 0V) is considered to be a logic one and a negative differential voltage (VRXN high) is

a logic zero.

Zero Crossing Comparator

High Comparator

Low Comparator

1.18MΩ

41.6kΩ

RXP

RXN

VCM =

VDDL/3

1.18MΩ

Digital Core

VDDL/60

4pF

30kΩ

GNDL

Figure 26. UART Receiver

UART RX Modes

During the first preamble received after a reset, the receiver automatically detects if the received signal is single-

ended and if so, places the receiver in single-ended mode. Therefore the device must be reset for any change in the

RX-mode hardware configuration to be detected.

The receiver mode is indicated by the ALRTCOMMSEL bit (for lower port) and ALRTCOMMSEU bit (for upper port)

of the FMEA1 register as shown in Table 19. If the RXP input is open-circuit, the RX-mode detection will place the

UART in single-ended mode so that the port can still operate albeit with reduced noise immunity. The host can

diagnose this condition by checking ALRTCOMMSEL and ALRTCOMMSEU after any POR event. Any other faults

result in communication errors.

Table 19. UART RX Modes

RXP

RXN

ALRTCOMMSEn

RX Mode

connected to data

connected to inverse data

Differential Mode (normal)

grounded

connected to inverse data

Single-Ended Mode (normal)

open-circuit (fault)

connected to inverse data

Single-Ended Mode (low noise immunity)

connected to data

open-circuit (fault)

Differential Mode (communication errors)

MAX17823B Datasheet(PDF) 44 Page - Maxim Integrated Products

MAX17823B Datasheet(HTML) 44 Page - Maxim Integrated Products

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL