1.8V, Low-Power, 12-Bit, 170Msps

ADC for Broadband Applications

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11

Analog Inputs (INP, INN)

INP and INN are the fully differential inputs of the

MAX1213N. Differential inputs usually feature good

rejection of even-order harmonics, which allows for

enhanced AC performance as the signals are progress-

ing through the analog stages. The MAX1213N analog

inputs are self-biased at a 0.74V common-mode voltage

(Figure 2). Both inputs are self-biased through 900

Ω

resistors, resulting in a typical differential input resis-

tance of 1.8k

Ω. Drive the analog inputs of the

MAX1213N in AC-coupled configuration to achieve the

best dynamic performance. See the Transformer-

Coupled, Differential Analog Input Drive section.

MAX1213N

12-BIT PIPELINE

ADC

FROM CLOCK-

MANAGEMENT BLOCK

T/H

TO COMMON MODE

INP

INP

INP - INN

GND

GND

INN

INN

900

Ω

900

Ω

Figure 2. Simplified Analog Input Architecture and Allowable Input Voltage Range