_______________Detailed Description
Converter Operation
The MAX1003 contains two 6-bit analog-to-digital con-
verters (ADCs), a buffered voltage reference, and oscil-
lator circuitry. The ADCs use a flash conversion
technique to convert an analog input signal into a 6-bit
parallel digital output code. The MAX1003’s unique
design includes 63 fully differential comparators and a
proprietary encoding scheme that ensures no more
than 1LSB dynamic encoding error. The control logic
interfaces easily to most digital signal processors
(DSPs) and microprocessors (µPs) with +3.3V CMOS-
compatible logic interfaces. Figure 1 shows the
MAX1003 in a typical application.
Programmable Input Amplifiers
The MAX1003 has two (I and Q) programmable-gain
input amplifiers with a -0.5dB bandwidth of 55MHz and
true differential inputs. To maximize performance in
high-speed systems, each amplifier has less than 5pF
of input capacitance. The input amplifier gain is pro-
grammed, via the GAIN pin, to provide three possible
input full-scale ranges (FSRs) as shown in Table 1.
MAX1003
Low-Power, 90Msps, Dual 6-Bit ADC
_______________________________________________________________________________________ 5
______________________________________________________________Pin Description
PIN
Gain-Select Input. Sets input full-scale range: 125/250/500mVp-p (Table 1).GAIN1
FUNCTIONNAME
Positive I-Channel Offset-Correction Compensation. Connect a 0.22µF capacitor for AC-coupled
inputs. Ground for DC-coupled inputs.
IOCC+2
I-Channel Noninverting Analog InputIIN+4
Negative I-Channel Offset-Correction Compensation. Connect a 0.22µF capacitor for AC-coupled
inputs. Ground for DC-coupled inputs.
IOCC-3
+5V ±5% Supply. Bypass with a 0.01µF capacitor to GND (pin 7).V
CC
6
+5V ±5% Supply. Bypass with a 0.01µF capacitor to GND (pin 11).V
CC
8
Analog GroundGND
7, 11, 12,
18, 19
I-Channel Inverting Analog InputIIN-5
Negative Oscillator/Clock InputTNK-10
Q-Channel Inverting Analog InputQIN-14
+5V ±5% Supply. Bypass with a 0.01µF capacitor to GND (pin 12).V
CC
13
Negative Q-Channel Offset-Correction Compensation. Connect a 0.22µF capacitor for AC-coupled
inputs. Ground for DC-coupled inputs.
QOCC-16
Q-Channel Digital Outputs 0–5. DQ5 is the most significant bit (MSB).DQ5–DQ020–25
Positive Q-Channel Offset-Correction Compensation. Connect a 0.22µF capacitor for AC-coupled
inputs. Ground for DC-coupled inputs.
QOCC+17
Q-Channel Noninverting Analog InputQIN+15
Positive Oscillator/Clock InputTNK+9
Digital Output GroundOGND27
I-Channel Digital Outputs 0–5. DI5 is the most significant bit (MSB).DI0–DI530–35
Digital Clock Output. Frames the output data.DCLK29
Digital Output Supply, +3.3V ±300mV. Bypass each with a 47pF capacitor to OGND (pin 27).V
CCO
26, 28
+5V ±5% Supply. Bypass with a 0.01µF capacitor to GND (pin 19).V
CC
36
250Open
125V
CC
GAIN
500GND
INPUT FULL-SCALE RANGE
(mVp-p)
Table 1. Input Amplifier Programming