SPT SPT7921SCJ, SPT7921SCQ Datasheet

SPT7921
12-BIT, 20 MSPS, TTL, A/D CONVERTER
FEATURES
Monolithic
• 12-Bit 20 MSPS Converter
• 66 dB SNR @1 MHz Input
• On-Chip Track/Hold
• Bipolar ±2.0 V Analog Input
• Low Power (1.1 W Typical)
• TTL Outputs
GENERAL DESCRIPTION
The SPT7921 A/D converter is the industry's first 12-bit monolithic analog-to-digital converter capable of sample rates greater than 20 MSPS. On board input buffer and track/hold function assures excellent dynamic perfor­mance without the need for external components. Drive requirement problems are minimized with an input ca­pacitance of only 5 pF.
Logic inputs and outputs are TTL. An overrange output signal is provided to indicate overflow conditions. Output data
APPLICATIONS
• Radar Receivers
• Professional Video
• Instrumentation
• Medical Imaging
• Electronic Warfare
• Digital Communications
• Digital Spectrum Analyzers
• Electro-Optics
format is straight binary. Power dissipation is very low at only
1.1 watts with power supply voltages of +5.0 and -5.2 volts. The SPT7921 also provides a wide input voltage range of ±2.0 volts.
The SPT7921 is available in 32-lead ceramic sidebrazed DIP and 44-lead cerquad packages over the commercial tem­perature range. Consult the factory for availability of die, military temperature and /883 versions.
BLOCK DIAGRAM
V
Input
IN
Buffer
Analog Gain
Compression
Processor
Signal Processing Technologies, Inc.
4-Bit Flash
Converter
Track-and-Hold
Amplifiers
Asynchronous
SAR
4
Error
Correction,
Decoding
and
Output TTL
Drivers
8
4755 Forge Road, Colorado Springs, Colorado 80907, USA
Phone: (719) 528-2300 FAX: (719) 528-2370
12
Digital
Output
ABSOLUTE MAXIMUM RATINGS (Beyond which damage may occur)1 25 °C
Supply Voltages
VCC...........................................................................+6 V
Output
Digital Outputs .............................................. 0 to -30 mA
VEE............................................................................ -6 V
Temperature
Input Voltages
Analog Input................................................ VFB≤VIN≤V
VFT, VFB. ....................................................+3.0 V, -3.0 V
Reference Ladder Current .....................................12 mA
CLK IN .......................................................................V
FT
CC
Operating Temperature ................................. 0 to +70 °C
Junction Temperature .........................................+175 °C
Lead Temperature, (soldering 10 seconds)........+300 °C
Storage Temperature................................ -65 to +150 °C
Note: 1. Operation at any Absolute Maximum Rating is not implied. See Electrical Specifications for proper nominal
applied conditions in typical applications.
ELECTRICAL SPECIFICATIONS
TA=T unless otherwise specified.
PARAMETERS CONDITIONS LEVEL MIN TYP MAX UNITS
Resolution 12 Bits DC Accuracy +25 °C
Analog Input f
Reference Input f
Timing Characteristics
Dynamic Performance
to T
MIN
Integral Nonlinearity ± Full Scale V ±2.0 LSB Differential Nonlinearity 100 kHz Sample Rate V ±0.8 LSB No Missing Codes VI Guaranteed
Input Voltage Range VI ±2.0 V Input Bias Current TA=+25 °C I 30 60 µA Input Resistance T Input Capacitance V 5 pF Input Bandwidth 3 dB Small Signal V 120 MHz +FS Error V ±5.0 LSB
-FS Error V ±5.0 LSB
Reference Ladder Resistance VI 500 800 Reference Ladder Tempco V 0.8 /°C
Maximum Conversion Rate VI 20 MHz Overvoltage Recovery Time V 20 ns Pipeline Delay (Latency) IV 1 Clock Cycle Output Delay TA=+25 °C V 14 18 ns Aperture Delay Time T Aperture Jitter Time TA=+25 °C V 5 ps-RMS
Effective Number of Bits
=500 kHz 10.2 Bits
f
IN
f
=1.0 MHz 10.0 Bits
IN
=3.58 MHz 9.5 Bits
f
IN
, VCC=+5.0 V, VEE=-5.2 V, DVCC=+5.0 V, VIN=±2.0 V, VSB=-2.0 V, VST=+2.0 V, f
MAX
TEST TEST SPT7921
=1 MHz
CLK
=+25 °C, VIN=0 V I 100 300 k
A
=1 MHz
CLK
=+25 °CV 1 ns
A
=20 MHz, 50% clock duty cycle,
CLK
Signal-To-Noise Ratio (without Harmonics) f
=500 kHz TA=+25 °C I 64 67 dB
IN
f
=1 MHz TA=+25 °C I 64 66 dB
IN
f
=3.58 MHz TA=+25 °C I 62 64 dB
IN
SPT
T
A=TMIN
T
A=TMIN
TA=T
MIN
to T
to T to T
MAX
MAX
MAX
IV 58 61 dB
IV 58 60 dB IV 58 60 dB
SPT7921
2 3/10/97
ELECTRICAL SPECIFICATIONS
TA=T
MIN
to T
, VCC=+5.0 V, VEE=-5.2 V, DVCC=+5.0 V, VIN=±2.0 V, VSB=-2.0 V, VST=+2.0 V, f
MAX
=20 MHz, 50% clock duty cycle,
CLK
unless otherwise specified.
TEST TEST SPT7921
PARAMETERS CONDITIONS LEVEL MIN TYP MAX UNITS
Dynamic Performance
Harmonic Distortion
=500 kHz TA=+25 °C I 63 66 dB
f
IN
=1.0 MHz TA=+25 °C I 63 65 dB
f
IN
f
=3.58 MHz TA=+25 °C I 59 61 dB
IN
T
A=TMIN
T
A=TMIN
T
A=TMIN
to T to T to T
MAX
MAX
MAX
IV 59 62 dB IV 59 61 dB IV 57 59 dB
Signal-to-Noise and Distortion
=500 kHz TA=+25 °C I 60 63 dB
f
IN
f
=1.0 MHz TA=+25 °C I 60 62 dB
IN
f
=3.58 MHz TA=+25 °C I 57 59 dB
IN
Spurious Free Dynamic Range Differential Phase Differential Gain
2
2
Digital Inputs f
Logic 1 Voltage T Logic 0 Voltage T Maximum Input Current Low T Maximum Input Current High T
T T T
1
TA=+25 °C V 74 dB
A=TMIN
A=TMIN
A=TMIN
to T to T to T
MAX
MAX
MAX
IV 55 58 dB IV 55 57 dB IV 54 56 dB
TA=+25 °C V 0.2 Degree TA=+25 °C V 0.7 %
=1 MHz
CLK
=+25 °C I 2.4 4.5 V
A
=+25 °C I 0.8 V
A
=+25 °C I 0 +5 +20 µA
A
=+25 °C I 0 +5 +20 µA
A
Pulse Width Low (CLK) IV 20 ns Pulse Width High (CLK) IV 20 300 ns
Digital Outputs f
Logic 1 Voltage T
=1 MHz
CLK
=+25 °C I 2.4 V
A
Logic 0 Voltage TA=+25 °C I 0.6 V
Power Supply Requirements
Voltages V
Currents I
DV
-V
CC
DI
-I
CC
EE
EE
CC
CC
TA=+25 °C I 135 150 mA TA=+25 °C I 40 55 mA TA=+25 °C I 45 70 mA
IV 4.75 5.0 5.25 V IV 4.75 5.0 5.25 V IV -4.95 -5.2 -5.45 V
Power Dissipation VI 1.1 1.3 W Power Supply Rejection 5 V ±0.25 V, -5.2 ±0.25 V V 1.0 LSB
Typical thermal impedances (unsoldered, in free air):
32L sidebrazed DIP:
θ
= +50 °C/W
ja
44L cerquad:
θ
= +78 °C/W
ja
at 1 M/s airflow = +58 °C/W
θ
ja
θ
= +3.3 °C/W
jc
1
fIN = 1 MHz.
2
fIN = 3.58 and 4.35 MHz.
SPT
SPT7921
3 3/10/97
TEST LEVEL CODES
TEST LEVEL
TEST PROCEDURE
All electrical characteristics are subject to the following conditions:
All parameters having min/max specifications are guaranteed. The Test Level column indi­cates the specific device testing actually per­formed during production and Quality Assur­ance inspection. Any blank section in the data column indicates that the specification is not tested at the specified condition.
Figure 1A: Timing Diagram
N
tt
pwH pwL
II
III IV
V
VI
I
100% production tested at the specified temperature. 100% production tested at TA = +25 °C, and sample
tested at the specified temperatures. QA sample tested only at the specified temperatures. Parameter is guaranteed (but not tested) by design
and characterization data. Parameter is a typical value for information purposes
only. 100% production tested at TA = +25 °C. Parameter is
guaranteed over specified temperature range.
N+1
N+2
CLK
t
d
OUTPUT DATA
N-2 N-1
DATA VALID
N
DATA VALID
N+1
Figure 1B: Single Event Clock
CLK
t
d
OUTPUT DATA
DATA VALID
Table I - Timing Parameters
PARAMETERS DESCRIPTION MIN TYP MAX UNITS
t
d
t
pwH
CLK to Data Valid Prop Delay - 14 18 ns CLK High Pulse Width 20 - 300 ns
t
pwL
SPT
CLK Low Pulse Width 20 - - ns
SPT7921
4 3/10/97
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