SPT7725 Datasheet, PDF (1/12 Pages) Fairchild Semiconductor – 8-BIT, 300 MSPS, FLASH A/D CONVERTER

SPT7725
8-BIT, 300 MSPS, FLASH A/D CONVERTER
FEATURES
• Metastable errors reduced to 1 LSB
• Low input capacitance: 10 pF
• Wide input bandwidth: 210 MHz
• 300 MSPS conversion rate
• Typical power dissipation: 2.2 watts
TECHNICAL DATA
AUGUST 17, 2001
APPLICATIONS
• Digital oscilloscopes
• Transient capture
• Radar, EW, ECM
• Direct RF down-conversion
• Medical electronics: ultrasound, CAT instrumentation
GENERAL DESCRIPTION
The SPT7725 is a monolithic flash A/D converter capable
of digitizing a two volt analog input signal into 8-bit digital
words at a 300 MSPS (typ) update rate.
For most applications, no external sample-and-hold is re-
quired for accurate conversion due to the device’s narrow
aperture time, wide bandwidth, and low input capacitance.
A single standard –5.2 volt power supply is required for
operation of the SPT7725, with nominal power dissipation
of 2.2 W. A proprietary decoding scheme reduces meta-
stable errors to the 1 LSB level.
The SPT7725 is available in 42-lead ceramic sidebrazed
DIP, surface-mount 44-lead cerquad, and 46-lead PGA
packages (all are pin-compatible with the SPT7710); the
cerquad and PGA packages allow access to additional
reference ladder taps, an overrange bit, and a data ready
output. The SPT7725 is available in the industrial tem-
perature range.
BLOCK DIAGRAM
V_RTS
V_RTF
Analog Input
(Force or Sense)
AGND
DGND
V_EE
Preamp
Comparator
256
Clock
Buffer
255
V_R3
152
LINV MINV
MSB D7
DRINV
DREAD
Overrange
151
D7 MSB
128
V_R2
127
64
V_R1
63
2
V_RBF
V_RBS
Convert ^CLK
CLK
1
2
Analog Input
(Sense or Force)
256 to
8-Bit
Encoder
D6
D5
D4
D3
D2
D1
LSB D0
ECL
Latches
and
Buffers
D6
D5
These functions are
D4
available in the PGA and
cerquad packages only.
D3
D2
D1
D0 LSB
VEE
AGND