Rainbow Electronics MAX1011 - Manual (Page 5)

_______________Detailed Description
Converter Operation
The MAX1011 integrates a 6-bit analog-to-digital con-
verter (ADC), a buffered voltage reference, and oscilla-
tor circuitry. The ADC uses a flash conversion technique
to convert an analog input signal into a 6-bit parallel
digital output code. The MAX1011’s unique design
includes 63 fully differential comparators and a propri-
etary encoding scheme that ensures no more than
1LSB dynamic encoding error. The control logic inter-
faces easily to most digital signal processors (DSPs)
and microprocessors (µPs) with +3.3V CMOS-compati-
ble logic interfaces. Figure 1 shows the MAX1011 in a
typical application.
Programmable Input Amplifier
The MAX1011 has a programmable-gain input amplifier
with a -0.5dB bandwidth of 55MHz and a true differen-
tial input. To maximize performance in high-speed
systems, the amplifier has less than 3pF of input
capacitance. The input amplifier gain is programmed
via the GAIN pin to provide three possible input full-
scale ranges (FSRs) as shown in Table 1.
Single-ended and differential AC-coupled input circuit
examples are shown in Figures 2 and 3. Each of the
MAX1011
Low-Power, 90Msps, 6-Bit ADC
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Pin Description
PIN
Gain-Select Input. Sets input full-scale range: 125/250/500mVp-p (Table 1). GAIN 1
FUNCTION NAME
Positive Offset-Correction Compensation. Connect a 0.22µF capacitor for AC-coupled inputs. Ground
pin 2 for DC-coupled inputs.
OCC+ 2
Noninverting Analog Input IN+ 4
Negative Offset-Correction Compensation. Connect a 0.22µF capacitor for AC-coupled inputs. Ground
pin 3 for DC-coupled inputs.
OCC- 3
+5V ±5% Supply. Bypass with a 0.01µF capacitor to GND (pin 9). V CC 6
Analog Ground GND
9, 10,
12, 13
Inverting Analog Input IN- 5
+5V ±5% Supply. Bypass with a 0.01µF capacitor to GND (pin 10). V CC 11
Digital Clock Output. Frames the output data. DCLK 18
Digital Output Supply, +3.3V ±300mV. Bypass with a 47pF capacitor to OGND (pin 16). V CCO 17
Digital Outputs 0–5. D5 is the most significant bit (MSB). D0–D5 19–24
250 Open
125 V CC
GAIN
500 GND
INPUT FULL-SCALE RANGE
(mVp-p)
Table 1. Input Amplifier Programming
Positive Oscillator/Clock Input TNK+ 7
Negative Oscillator/Clock Input TNK- 8
No Connection N.C. 15
Digital Output Ground OGND 16
+5V ±5% Supply. Bypass with a 0.01µF capacitor to GND (pin 13). V CC 14