+1.2V, and must be differentially terminated at the far

end of each transmission line pair (true and comple-

mentary) with 100

Ω.

Out-Of-Range Operation

A single output pair (DOR+, DOR-) is provided to flag

an out-of-range condition, if either the I or Q channel is

out-of-range, where out-of-range is above +FS or below

-FS. It features the same latency as the ADCs output

data and is demultiplexed in a similar fashion. With a

400MHz system clock, DOR+ and DOR- are clocked at

up to 200MHz.

Applications Information

Single-Ended Analog Inputs

The MAX107 is designed to work at full-speed for both

single-ended and differential analog inputs without sig-

nificant degradation in its dynamic performance. Both

input channels I (INI+, INI-) and Q (INQ+, INQ-) have

2k

Ω impedance and allow for AC- and DC-coupled

input signals. In a typical DC-coupled single-ended

configuration (Table 1), the analog input signals enter

the analog input amplifier stages at the in-phase-input

pins INI+/INQ+, while the inverted phase input INI-

/INQ- pins are AC-coupled to AGNDI/AGNDQ. Single-

ended operation allows for an input amplitude of

Differential Analog Inputs

To obtain +FS digital outputs with differential input drive

(Table 2), 400mV must be applied between INI+ (INQ+)

and INI- (INQ-). Midscale digital output codes occur

when there is no voltage difference between INI+

(INQ+) and INI- (INQ-). For a -FS digital output code

both in-phase (INI+, INQ+) and inverted input (INI-,

INQ-) must see -400mV.

Single-Ended to Differential

Conversion Using a Balun

An RF balun (Figure 3) provides an excellent solution to

convert a single-ended signal to a fully differential sig-

nal, required by the MAX107 for optimum performance.

At higher frequencies, the MAX107 provides better

SFDR and THD with fully differential input signals over

single-ended input signals. In differential input mode,

even-order harmonics are suppressed and each input

requires only half the signal-swing compared to single-

ended mode.

Clock Input

The MAX107 features clock inputs designed for either

single-ended or differential operation with very flexible

input drive requirements. The clock inputs (AC- or DC-

coupled) provide a 5k

and are internally buffered with a preamplifier to ensure

proper operation of the converter even with small-

amplitude sine-wave sources. The MAX107 was

Dual, 6-Bit, 400Msps ADC with On-Chip,

Wideband Input Amplifier

______________________________________________________________________________________

13

IN-PHASE INPUTS

(INI+, INQ+)

INVERTED INPUTS

(INI-, INQ-)

OUT-OF-RANGE BIT

(DOR+, DOR-)

OUTPUT CODE

AC-coupled to AGND_

1

011111

AC-coupled to AGND_

0

011111

AC-coupled to AGND_

0

000000/111111

AC-coupled to AGND_

0

100000

AC-coupled to AGND_

1

100000

Table 1. Digital Output Codes Corresponding to a DC-Coupled Single-Ended Analog

IN-PHASE INPUTS

(INI+, INQ+)

INVERTED INPUTS

(INI-, INQ-)

OUT-OF-RANGE BIT

(DOR+, DOR-)

OUTPUT CODE

1

011111

0

011111

0

000000/111111

0

100000

1

100000

Table 2. Digital Output Codes Corresponding to a DC-Coupled Differential Analog Input