Detailed Description

The MAX5865 integrates dual 8-bit receive ADCs and

dual 10-bit transmit DACs while providing ultra-low

power and highest dynamic performance at a conver-

sion rate of 40Msps. The ADCs’ analog input amplifiers

The DACs’ analog outputs are fully differential with

±400mV full-scale output range at 1.4V common mode.

The MAX5865 includes a 3-wire serial interface to con-

trol operating modes and power management. The ser-

ial interface is SPI™ and MICROWIRE™ compatible.

The MAX5865 serial interface selects shutdown, idle,

standby, transmit, receive, and transceiver modes.

The MAX5865 can operate in FDD or TDD applications

by configuring the device for transmit, receive, or trans-

ceiver modes through a 3-wire serial interface. In TDD

mode, the digital bus for receive ADC and transmit

DAC can be shared to reduce the digital I/O to a single

10-bit parallel multiplexed bus. In FDD mode, the

MAX5865 digital I/O can be configured for an 18-bit,

parallel multiplexed bus to match the dual 8-bit ADC

and dual 10-bit DAC.

The MAX5865 features an internal precision 1.024V

bandgap reference that is stable over the entire power-

supply and temperature ranges.

Ultra-Low-Power, High-Dynamic-

Performance, 40Msps Analog Front End

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13

SPI is a trademark of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp.

Figure 1. MAX5865 ADC Internal T/H Circuits

S3b

S3a

COM

S5b

S5a

QA+

QA-

S1

OUT

OUT

C2a

C2b

S4c

S4a

S4b

C1b

C1a

INTERNAL

BIAS

INTERNAL

BIAS

COM

HOLD

HOLD

CLK

INTERNAL

NONOVERLAPPING

CLOCK SIGNALS

TRACK

TRACK

S2a

S2b

S3b

S3a

COM

S5b

S5a

IA+

IA-

S1

OUT

OUT

C2a

C2b

S4c

S4a

S4b

C1b

C1a

INTERNAL

BIAS

INTERNAL

BIAS

COM

S2a

S2b

MAX5865