amplifier inputs is internally biased to a 2.35V reference

through a 20k

Ω resistor, eliminating external DC bias

circuits. A series 0.1µF capacitor is required at the

amplifier input for AC-coupled signals.

When operating with AC-coupled inputs, the input

amplifier’s DC offset voltage is nulled to within ±1/2LSB

by an on-chip, offset-correction amplifier. An external

compensation capacitor is required to set the dominant

pole of the offset-correction amplifier’s frequency

response (Figures 2 and 3). The compensation capaci-

tor will determine the low-frequency corner of the ana-

log input response according to the following formula:

where C is the value of the compensation capacitor in

Low-Power, 90Msps, 6-Bit ADC

6

_______________________________________________________________________________________

6 BITS

DATA

BUFFER

DIGITAL

DEMODULATOR

OR

DSP

6

DCLK

TANK

MAX1011

LO

RF

Figure 1. IF Sampling Receiver

Figure 2. Single-Ended AC-Coupled Input

Figure 3. Differential AC-Coupled Input

MAX1011

INPUT

AMP

20k

2.35V INTERNAL REFERENCE

20k

IN+

OCC+

OCC-

IN-

0.1

µF

0.22

µF

0.1

µF

OFFSET

CORREC-

TION

MAX1011

INPUT

AMP

20k

2.35V INTERNAL REFERENCE

20k

IN+

OCC+

OCC-

IN-

0.1

µF

0.1

µF

OFFSET

CORREC-

TION

0.22

µF