SPT SPT7722BCU, SPT7722BIG, SPT7722BIJ, SPT7722BIQ, SPT7722AIG Datasheet

Signal Processing Technologies, Inc.

4755 Forge Road, Colorado Springs, Colorado 80907, USA

Phone: [phone] Fax: [phone] Web Site: http://www .spt.com e-mail: [e-mail]

SPT7725

8-BIT, 300 MSPS, FLASH A/D CONVERTER

TECHNICAL DATA

AUGUST 17, 2001

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

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 re­quired 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 meta­stable 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 tem­perature range.

256

255

152

151

128

127

64

63

2

1

256 to

8-Bit

Encoder

ECL

Latches

and

Buffers

AGNDAnalog Input

(Sense or Force)

V

EE

CLK

CLK

V

RBF

Convert

V

RBS

V

R1

V

R3

V

RTS

V

RTF

V

R2

2

Analog Input

(Force or Sense)

AGND DGND V

EE

LINV MINV

DRINV

DREAD

Overrange

D7 MSB

D6

D5

D4

D3

D2

D1

D0 LSB

MSB D7

D6

D5

D4

D3

D2

D1

LSB D0

These functions are
available in the PGA and
cerquad packages only.

Clock

Buffer

Preamp Comparator

BLOCK DIAGRAM

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SPT7725

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

Negative Supply Voltage (VEE TO GND) –7.0 to +0.5 V

Ground Voltage Differential ....................–0.5 to +0.5 V

Input Voltage

Analog Input Voltage ...............................V

EE

to +0.5 V

Reference Input Voltage..........................VEE to +0.5 V

Digital Input Voltage ................................VEE to +0.5 V

Reference Current V

RTF

to V

RBF

........................25 mA

Output

Digital Output Current ...............................0 to –30 mA

Temperature

Operating Temperature,ambient............. –25 to +85 °C

junction ...................... +150 °C

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

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

ELECTRICAL SPECIFICATIONS

TA= T

MIN

to T

MAX

, VEE=–5.2 V , R

Source

=50 Ω, V

RBF

=–2.00 V , VR2=–1.00 V , V

RTF

=0.00 V , ƒ

CLK

=250 MHz, Duty Cycle=50%, unless otherwise specified.

TEST TEST SPT7725A SPT7725B

PARAMETERS CONDITIONS LEVEL MIN TYP MAX MIN TYP MAX UNITS
DC Accuracy

Integral Linearity Error ƒ

CLK

= 100 kHz VI –0.75 ±0.60 +0.75 –0.95 ±0.80 +0.95 LSB

Differential Linearity Error ƒ

CLK

= 100 kHz VI –0.75 +0.75 –0.95 +0.95 LSB

No missing codes Guaranteed Guaranteed

Analog Input

Offset Error V

RT

VI –30 +30 –30 +30 mV

Offset Error V

RB

VI –30 +30 –30 +30 mV
Input Voltage Range VI –2.0 0.0 –2.0 0.0 Volts
Input Capacitance Over full

input range V 10 10 pF
Input Resistance V 15 15 kΩ
Input Current VI 250 500 250 500 µA
Input Slew Rate V 1,000 1,000 V/µs
Large Signal Bandwidth V

IN

=F.S. V 210 210 MHz

Small Signal Bandwidth V

IN

=500 mV

P-P

V 335 335 MHz

Clock Synchronous

Input Currents V 40 40 µA

Reference Input

Ladder Resistance VI 100 200 300 100 200 300 Ω
Reference Bandwidth V 10 10 MHz

Timing Characteristics

Maximum Sample Rate IV 250 300 250 300 MSPS
Clock to Data Delay V 2.4 2.4 ns
Output Delay Tempco V 2 2 ps/°C
CLK-to-Data Ready Delay (t

D

) V 2.0 2.0 ns
Aperture Jitter V 5 5 ps
Acquisition Time V 1.5 1.5 ns

Dynamic Performance

Signal-to-Noise Ratio ƒ

IN

= 3.58 MHz VI 45 47 44 46 dB

ƒ

IN

= 50 MHz VI 39 42 38 41 dB

Total Harmonic Distortion ƒIN = 3.58 MHz VI –52 –48 –50 –46 dB

ƒ

IN

= 50 MHz VI –43 –40 –42 –39 dB

Signal-to-Noise and Distortion ƒ

IN

= 3.58 MHz VI 44 46 42 44 dB

(SINAD) ƒIN = 50 MHz VI 37 39 35 37 dB

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SPT7725

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 b lank section in the data
column indicates that the specification is not
tested at the specified condition.

Unless otherwise noted, all test are pulsed
tests; therefore, T

J

= TC = TA.

LEVEL TEST PROCEDURE

I 100% production tested at the specified temperature.

II 100% production tested at TA = +25 °C, and sample tested at the

specified temperatures.
III QA sample tested only at the specified temperatures.
IV Parameter is guaranteed (but not tested) by design and characteri-

zation data.

V Parameter is a typical value for information purposes only.

VI 100% production tested at TA = +25 °C. Parameter is guaranteed

over specified temperature range.

ELECTRICAL SPECIFICATIONS

TA= T

MIN

to T

MAX

, VEE=–5.2 V , R

Source

=50 Ω, V

RBF

=–2.00 V , VR2=–1.00 V , V

RTF

=0.00 V , ƒ

CLK

=250 MHz, Duty Cycle=50%, unless otherwise specified.

TEST TEST SPT7725A SPT7725B

PARAMETERS CONDITIONS LEVEL MIN TYP MAX MIN TYP MAX UNITS
Digital Inputs

Digital Input High Voltage
(MINV, LINV) VI –1.1 –0.7 –1.1 –0.7 Volts
Digital Input Low Voltage
(MINV, LINV) VI –2.0 –1.5 –2.0 –1.5 Volts
Clock Low Width, t

PWL

VI 2.2 2.0 2 1.8 ns

Clock High Width, t

PWH

VI 2.2 2.0 2 1.8 ns

Digital Outputs

Digital Output High Voltage 50 Ω to –2 V V I –1.1 –1.1 Volts
Digital Output Low Voltage 50 Ω to –2 V VI –1.5 –1.5 Volts

Power Supply Requirements

Supply Current +25 °C VI 425 550 425 550 mA
Power Dissipation +25 °C VI 2.2 2.9 2.2 2.9 W

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SPT7725

TYPICAL PERFORMANCE CHARACTERISTICS

SNR vs Input Frequency

THD vs Input Frequency

SINAD vs Input Frequency SNR, THD, SINAD vs Temperature

1 10 100

34

36

38

40

42

44

46

48

50

52

Input Frequency (MHz)

S = 250 MSPS

Signal-to-Noise Ratio (dB)

1 10 100

30

35

40

45

50

55

60

65

70

75

Input Frequency (MHz)

S = 250 MSPS

Total Harmonic Distortion (dB)

1 10 100

34

36

38

40

42

44

46

48

50

52

Input Frequency (MHz)

S = 250 MSPS

Signal-to-Noise and Distortion (dB)

Temperature (°C)

40 20 0 20 40 60 80

30

35

40

45

50

SNR

THD

SINAD

S = 250 MSPS
IN = 100 MHz

SNR, THD, SINAD (dB)