SPT7938
12-BIT, 40 MSPS, 170 mW A/D CONVERTER
FEATURES
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Monolithic 40 MSPS Analog-to-Digital Converter
170 mW Power Dissipation
On-Chip Track-and-Hold
Single +5 V Power Supply
TTL/CMOS Outputs
20 pF Input Capacitance
Selectable +3 V or +5 V Logic I/O
APPLICATIONS
• All High-Speed Applications Where
Low Power Dissipation Is Required
• Video Imaging
• Medical Imaging
• Radar Receivers
• IR Imaging
• Digital Communications
GENERAL DESCRIPTION
The SPT7938 is a 12-bit monolithic, low-cost, low-power
analog-to-digital converter capable of minimum word rates
of 40 MSPS. The on-chip track-and-hold function assures
very good dynamic performance without the need for exter-
nal components. The input drive requirements are mini-
mized due to the SPT7938’s low input capacitance of only
20 pF.
Power dissipation is extremely low at only 170 mW typical at
40 MSPS with a power supply of +5.0 V. The digital outputs
are +3 V or +5 V, and are user selectable. The SPT7938 has
incorporated proprietary circuit design and CMOS process-
ing technologies to achieve its advanced performance. In-
puts and outputs are TTL/CMOS compatible to interface
with TTL/CMOS logic systems. Output data format is
straight binary.
The SPT7938 is available in a 28-lead SSOP package over
the industrial temperature range.
BLOCK DIAGRAM
ADC Section 1
A
IN
1:18
Mux
T/H
Auto-
Zero
CMP
13-Bit
SAR
13
13
D12 Out of Range
D11 (MSB)
D10
P1
P2
CLK In
Timing
P17
and
Control
P18
DAC
D9
ADC Section 2
13
D8
13-Bit
18:1
Mux/
Error
Correction
D7
D6
D5
D4
D3
D2
D1
Reference Ladder
EN
DØ (LSB)
.
.
.
.
.
.
.
.
.
.
.
.
ADC Section 17
ADC Section 18
T/H
Auto-
Zero
CMP
13
13-Bit
SAR
13
DAC
13
VRHF
VRHS
VRLS
VRLF
CADEKA [ CADEKA MICROCIRCUITS LLC. ]
