SPT7937
12-BIT, 28 MSPS, 170 mW A/D CONVERTER
TECHNICAL DATA
MARCH 5, 2002
FEATURES
• Monolithic 28 MSPS analog-to-digital converter
• 170 mW power dissipation
• On-chip track-and-hold
• Single +5 V power supply
• TTL/CMOS outputs
• 5 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
• IR imaging
• Digital communications
DESCRIPTION
The SPT7937 is a 12-bit monolithic, low-cost, low-power
analog-to-digital converter capable of minimum sample
rates of 28 MSPS. The SPT7937 has incorporated propri-
etary parallel SAR circuit design and CMOS processing
technologies to achieve its advanced performance.
The on-chip track-and-hold function assures very good
dynamic performance without the need for external
components.
Power dissipation is extremely low at only 170 mW typical
at 28 MSPS with a power supply of +5.0 V. The digital out-
puts are +3 V or +5 V, and are user selectable. Inputs and
outputs are TTL/CMOS compatible to interface with TTL/
CMOS logic systems. Output data format is straight binary.
The SPT7937 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
D9
P1
P2
CLK In
Timing
P17
and
Control
P18
DAC
.
.
.
ADC Section 2
ADC Section 17
ADC Section 18
T/H
Auto-
Zero
CMP
.
.
.
.
.
.
.
.
.
13
13
13-Bit
18:1
Mux/
Error
Correction
D8
D7
D6
D5
D4
D3
D2
D1
13-Bit
SAR
13
DAC
13
Reference Ladder
DØ (LSB)
V
RHF
V
RHS
V
RLS
V
RLF
CADEKA [ CADEKA MICROCIRCUITS LLC. ]
