SPT SPT7912SCU, SPT7912SCJ Datasheet

SPT7912

12-BIT, 30 MSPS, ECL, A/D CONVERTER

The SPT7912 A/D converter is industry's first 12-bit mono­lithic analog-to-digital converter capable of sample rates
greater than 30 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.

Inputs and outputs are ECL to provide a higher level of noise
immunity in high speed system applications. An overrange
output signal is provided to indicate overflow conditions.

Output data format is straight binary. Power dissipation is
very low at only 1.4 watts with power supply voltages of +5.0
and -5.2 volts. The SPT7912 also provides a wide input
voltage range of ±2.0 volts.

The SPT7912 is available in a 32-lead ceramic sidebrazed
DIP package and in die form. A commercial temperature
range of 0 to +70 °C is currently offered.

GENERAL DESCRIPTION

V

IN

12

DIGITAL

OUTPUT

4

4-BIT FLASH

CONVERTER

INPUT

BUFFER

ANALOG GAIN

COMPRESSION

PROCESSOR

TRACK AND HOLD

AMPLIFIERS

ASYNCHRONOUS

SAR

ERROR

CORRECTION,

DECODING

AND

OUTPUT ECL

DRIVERS

8

Signal Processing Technologies, Inc.

4755 Forge Road, Colorado Springs, Colorado 80907, USA

Phone: [phone] FAX: [phone]

FEATURES

• Monolithic

• 12-Bit 30 MSPS Converter

• 65 dB SNR @ 1 MHz Input

• On-Chip Track/Hold

• Bipolar ±2.0 V Analog Input

• Low Power (1.4 W Typical)

• 5 pF Input Capacitance

• ECL Outputs

APPLICATIONS

• Radar Receivers

• Professional Video

• Instrumentation

• Medical Imaging

• Electronic Warfare

• Digital Communications

• Digital Spectrum Analyzers

• Electro-Optics

BLOCK DIAGRAM

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SPT7912

ABSOLUTE MAXIMUM RATINGS (Beyond which damage may occur)1 25 °C

Note: 1. Operation at any Absolute Maximum Rating is not implied. See Electrical Specifications for proper nominal

applied conditions in typical applications.

Supply Voltages

VCC............................................................... -0.3 to +6 V

VEE............................................................... +0.3 to -6 V

Input Voltages

Analog Input............................................... VFB≤VIN≤V

FT

VFT, VFB. ................................................... +3.0 V, -3.0 V

Reference Ladder Current .....................................12 mA

Output

Digital Outputs .............................................. 0 to -30 mA

Temperature

Operating Temperature ................................. 0 to +70 °C

Junction Temperature .........................................+175 °C

Lead Temperature, (soldering 10 seconds)........ +300 °C

Storage Temperature................................-65 to +150 °C

ELECTRICAL SPECIFICATIONS

TA=T

MIN

to T

MAX

, 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

clock=

30 MHz, 50% clock duty

cycle, unless otherwise specified.

TEST TEST SPT7912

PARAMETERS CONDITIONS LEVEL MIN TYP MAX UNITS

Resolution 12 Bits
DC Accuracy (+25 °C)

Integral Nonlinearity ± Full Scale V ±2.0 LSB
Differential Nonlinearity 250 kHz Sample Rate V ±0.8 LSB
No Missing Codes VI Guaranteed

Analog Input

Input Voltage Range VI ±2.0 V
Input Bias Current VI 30 60 µA
Input Resistance VIN=0 V VI 100 300 kΩ
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 Input

Reference Ladder Resistance VI 500 800 Ω
Reference Ladder Tempco V 0.8 Ω/°C

Timing Characteristics

Maximum Conversion Rate VI 30 40 MHz
Overvoltage Recovery Time V 20 ns
Pipeline Delay (Latency) IV 1 Clock Cycle
Output Delay V 5 ns
Aperture Delay Time V 1 ns
Aperture Jitter Time V 5 ps-RMS

Dynamic Performance

Effective Number of Bits
fIN=500 kHz 10.0 Bits
fIN=1.0 MHz 9.8 Bits
fIN=3.58 MHz 9.5 Bits

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SPT7912

ELECTRICAL SPECIFICATIONS

TA=T

MIN

to T

MAX

, 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

clock=

30 MHz, 50% clock duty

cycle, unless otherwise specified.

TEST TEST SPT7912

PARAMETERS CONDITIONS LEVEL MIN TYP MAX UNITS

Dynamic Performance

Signal-To-Noise Ratio
(without Harmonics)
f

IN

=500 kHz +25 °C I 63 66 dB

T

MIN

to T

MAX

IV 58 61 dB

f

IN

=1 MHz +25 °C I 63 65 dB

T

MIN

to T

MAX

IV 58 60 dB

f

IN

=3.58 MHz +25 °C I 62 64 dB

T

MIN

to T

MAX

IV 58 60 dB

Harmonic Distortion

1

fIN=500 kHz +25 °C I 63 65 dB

T

MIN

to T

MAX

IV 59 61 dB

f

IN

=1.0 MHz +25 °C I 62 64 dB

T

MIN

to T

MAX

IV 58 60 dB

f

IN

=3.58 MHz +25 °C I 59 61 dB

T

MIN

to T

MAX

IV 57 59 dB

Signal-to-Noise and Distortion

f

IN

=500 kHz +25 °C I 60 62 dB

T

MIN

to T

MAX

IV 55 58 dB

f

IN

=1.0 MHz +25 °C I 59 61 dB

T

MIN

to T

MAX

IV 55 57 dB

f

IN

=3.58 MHz +25 °C I 57 59 dB

T

MIN

to T

MAX

IV 54 56 dB

Spurious Free Dynamic Range

2

+25 °C V 74 dB

Differential Phase

3

+25 °C V 0.2 Degree

Differential Gain

3

+25 °C V 0.7 %

Digital Inputs

Logic 1 Voltage VI -1.1 V
Logic 0 Voltage VI -1.5 V
Maximum Input Current Low VI -500 ±200 +750 µA
Maximum Input Current High VI -500 ±300 +750 µA
Pulse Width Low (CLK) IV 15 ns
Pulse Width High (CLK) IV 15 300 ns

Digital Outputs

Logic 1 Voltage 50 Ω to -2 V VI -1.1 -0.8 V
Logic 0 Voltage 50 Ω to -2 V VI -1.8 -1.5 V

Power Supply Requirements

Voltages V

CC

IV +4.75 +5.25 V

-V

EE

IV -4.95 -5.45 V

Currents I

CC

VI 150 190 mA

-I

EE

VI 125 160 mA
Power Dissipation Outputs Open VI 1.4 1.8 W
Power Supply Rejection Ratio (5 V±0.25 V, -5.2 V ±0.25 V) V 1.0 LSB

Typical thermal impedances (unsoldered, in free air): 32L sidebrazed DIP. θja = 50 °C/W.

1

64 distortion BINS from 4096 pt FFT.

2

fIN = 1 MHz.

3

fIN = 3.58 and 4.35 MHz.

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SPT7912

Figure 1A: Timing Diagram

DESCRIPTION PARAMETERS MIN TYP MAX UNITS

CLK to Data Valid Prop Delay t

d

-5 ns

CLK High Pulse Width t

pwH

15 - 300 ns

CLK Low Pulse Width t

pwL

15 - - ns

Table I - Timing Parameters

CLK

OUTPUT
DATA

t

d

tt

pwH pwL

DATA VALID

N+1

A

A

A

A

N

N+1

N+2

DATA VALID

N

N-2 N-1

CLK

Figure 1B: Single Event Clock

DATA VALID

CLK

OUTPUT
DATA

t

d

CLK

TEST LEVEL CODES

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.

TEST PROCEDURE

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.

TEST LEVEL

I

II

III
IV

V

VI