MUX

HART

PA/FF

Transmit

Modulator

Receive

Modulator

DAC

Buffer

Carrier

Detect

Bandpass

Filter

Clock

Generator

Precision

Oscillator

Voltage

Reference

CLK_CFG1 CLKO

CLK_CFG0

XEN

X2

X1

REF

REF_EN

MOD_OUT

MOD_INF

MOD_IN

IOVDD

AVDD

DGND

GND

BPFEN

UART_RTS / SCLK

UART_OUT / SDO

DUPLEX / SDI

UART_IN / CS

CD / IRQ

RST

REG_CAP

IF_SEL

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An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. ADVANCE INFORMATION for pre-production products; subject to

change without notice.

DAC8740H, DAC8741H, DAC8742H

SBAS862 – JUNE 2017

DAC874xH, HART and FOUNDATION Fieldbus / PROFIBUS PA Modems

1

1 Features

1

•

HART-Compliant Physical Layer Modem

–

1200/2200 Hz HART FSK Sinusoids

–

Register Programmable Amplitude of TX

Signals

(DAC8741H / DAC8742H only)

–

Integrated RX Demodulator and Band-Pass

Filter with Minimal External Components

•

Foundation Fieldbus Compliant H1 Controller and

Medium Attachment Unit (MAU)

–

31.25 kbit/s Communication Based on

Manchester Coded Bus Powered (MBP)

–

Integrated Manchester Encoder and Decoder

–

Compliant with PROFIBUS PA

•

Low Quiescent Current: 200 uA Max

•

Integrated 1.5 V Reference

•

Flexible Clocking Options

–

External Crystal Oscillator

–

External CMOS Clock

•

Digital Interface

–

DAC8740H: UART

–

DAC8741H: SPI

–

DAC8742H: UART and SPI

•

Reliability: CRC Bit Error Checking, Watchdog

Timer (DAC8741H and DAC8742H only)

•

Wide Operating Temperature: –55°C to 125°C

•

4 mm x 4 mm QFN and 5 mm x 5 mm TQFP

Packages

2 Applications

•

Industrial Process Control and Automation

•

PLC or DCS I/O Modules

•

Field and Sensor Transmitters

3 Description

The DAC8740H, DAC8741H, and DAC8742H are

PA compliant low power modems designed for

industrial process control and industrial automation

applications.

In HART mode, the DAC874xH integrates all of the

required circuitry to operate as half-duplex HART

physical layer modems, in either slave or master

configurations with minimal external components for

filtering.

In

FOUNDATION

Fieldbus

mode,

the

DAC874xH integrates all of the required circuitry to

operate

as

half-duplex

FOUNDATION

Fieldbus

compliant H1 Controllers and MAUs.

The HART, FOUNDATION Fieldbus, or PROFIBUS

PA, data stream can be transferred from the

microcontroller through either a UART interface or an

integrated FIFO accessed by a SPI interface. The

SPI interface includes an SDO pin for daisy-chain

support,

various

interrupts,

and

other

extended

features.

The devices operate from a supply of 2.7V to 5.5V

while consuming only 200 uA, making them an

excellent

choice

for

loop-powered

or

2-wire

applications. They operate from –55°C to 125°C and

are available in 24-lead VQFN and 32-lead TQFP

packages.

Device Information(1)

PART NUMBER

PACKAGE

BODY SIZE (NOM)

DAC8740H

VQFN (24)

4 mm × 4 mm

DAC8741H

VQFN (24)

4 mm × 4 mm

DAC8742H

TQFP (32)

5 mm × 5 mm

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

Simplified Schematic