Rainbow Electronics MAX107 - Manual (Page 11)

Detailed Description
The MAX107 is a dual, +5V, 6-bit, 400Msps flash ana-
log-to-digital converter (ADC), designed for high-speed,
high bandwidth I&Q digitizing. Each ADC (Figure 1)
employs a fully differential, wide bandwidth input stage,
6-bit quantizers and a unique encoding scheme to limit
metastable states to typically one error per 10
16 clock
cycles, with no error exceeding a maximum of 1LSB. An
integrated 6:12 output demultiplexer simplifies interfac-
ing to the part by reducing the output data rate to one-
half the sampling clock rate. The MAX107 outputs data
in LVDS two’s complement format.
When clocked at 400Msps, the MAX107 provides a typ-
ical signal-to-noise plus distortion (SINAD) of 36.7dB
with a 125MHz input tone. The analog input of the
MAX107 is designed for differential or single-ended use
with a ±400mV full-scale input range. In addition, the
MAX107 features an on-board +2.5V precision
bandgap reference, which is scaled to meet the analog
input full-scale range.
Principle of Operation
The MAX107 employs a flash or parallel architecture.
The key to this high-speed flash architecture is the use
of an innovative, high-performance comparator design.
Each quantizer and downstream logic translates the
comparator outputs into 6-bit, parallel codes in two’s
complement format and passes them on to the internal
6:12 demultiplexer. The demultiplexer enables the
ADCs to provide their output data at half the sampling
speed on primary and auxiliary ports. LVDS data is
available at speeds of up to 200MHz per output port.
Input Amplifier Circuits
As with all ADCs, if the input waveform is changing
rapidly during conversion, effective number of bits
(ENOB), signal-to-noise plus distortion (SINAD), and
signal-to-noise ratio (SNR) specifications will degrade.
The MAX107’s on-board, wide-bandwidth input ampli-
MAX107
Dual, 6-Bit, 400Msps ADC with On-Chip,
Wideband Input Amplifier
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PIN NAME FUNCTION
62 P2I+ Primary Output Data Bit 2, I-Channel
63 A2I- Complementary Auxiliary Output Data Bit 2, I-Channel
64 A2I+ Auxiliary Output Data Bit 2, I-Channel
65, 72 OV CC I
I-Channel Outputs, Digital Supply. Supplies I-channel output drivers and DREADY circuit. Bypass to
OGND with 0.01
µF in parallel with 47pF for proper operation.
66, 71 OGNDI
I-Channel Outputs, Digital Ground. Connect to designated digital ground (OGND) on PC board
for proper operation.
67 P3I- Complementary Primary Output Data Bit 3, I-Channel
68 P3I+ Primary Output Data Bit 3, I-Channel
69 A3I- Complementary Auxiliary Output Data Bit 3, I-Channel
70 A3I+ Auxiliary Output Data Bit 3, I-Channel
73 P4I- Complementary Primary Output Data Bit 4, I-Channel
74 P4I+ Primary Output Data Bit 4, I-Channel
75 A4I- Complementary Auxiliary Output Data Bit 4, I-Channel
76 A4I+ Auxiliary Output Data Bit 4, I-Channel
77 P5I- Complementary Primary Output Data Bit 5, I-Channel
78 P5I+ Primary Output Data Bit 5, I-Channel
79 A5I- Complementary Auxiliary Output Data Bit 5, I-Channel
80 A5I+ Auxiliary Output Data Bit 5, I-Channel
Pin Description (continued)