Analog Devices AD7899 a Datasheet

5 V Single Supply

FEATURES Fast (2.2 ␮s) 14-Bit ADC 400 kSPS Throughput Rate

0.3 ␮s Track/Hold Acquisition Time Single Supply Operation Selection of Input Ranges: ⴞ10 V, ⴞ5 V and ⴞ2.5 V

0 V to 2.5 V and 0 V to 5 V

High-Speed Parallel Interface which Also Allows

Interfacing to 3 V Processors Low Power, 80 mW Typ Power-Saving Mode, 20 ␮W Typ Overvoltage Protection on Analog Inputs Power-Down Mode via STBY Pin

GENERAL DESCRIPTION

The AD7899 is a fast, low-power, 14-bit A/D converter that operates from a single 5 V supply. The part contains a 2.2 µs successive-approximation ADC, a track/hold amplifier, 2.5 V reference, on-chip clock oscillator, signal conditioning circuitry, and a high-speed parallel interface. The part accepts analog input ranges of ±10 V, ± 5 V, ± 2.5 V, 0 V to 2.5 V, and 0 V to 5 V. Overvoltage protection on the analog input for the part allows the input voltage to be exceeded without damaging the parts.

Speed of conversion can be controlled either by an internally trimmed clock oscillator or by an external clock.

A conversion start signal (CONVST) places the track/hold into hold mode and initiates conversion. The BUSY/EOC signal indicates the end of the conversion.

Data is read from the part via a 14-bit parallel data bus using the standard CS and RD signals. Maximum throughput for the AD7899 is 400 kSPS.

The AD7899 is available in a 28-lead SOIC and SSOP packages.

14-Bit 400 kSPS ADC

AD7899

FUNCTIONAL BLOCK DIAGRAM

REF

6k⍀

REFERENCE

–

14-BIT

ADC

CONVERSION

CONTROL

LOGIC

CONVST OPGNDGND

INT/EXT

CLOCK

SELECT

CLKIN

STBY

INA

INB

BUSY/EOC

AVDD

AD7899

TRACK/HOLD

SIGNAL

SCALING

PRODUCT HIGHLIGHTS

1. The AD7899 features a fast (2.2 µs) ADC allowing throughput rates of up to 400 kSPS.

2. The AD7899 operates from a single 5 V supply and consumes only 80 mW typ making it ideal for low power and portable applications.

3. The part offers a high-speed parallel interface. The interface can operate in 3 V and 5 V mode allowing for easy connection to 3 V or 5 V microprocessors, microcontrollers, and digital signal processors.

4. The part is offered in three versions with different analog input ranges. The AD7899-1 offers the standard industrial ranges of ±10 V and ± 5 V; the AD7899-2 offers a unipolar range of 0 V to 2.5 or 0 V to 5 V, and the AD7899-3 has an input range of ±2.5 V.

2.5V

DRIVE

OUTPUT

LATCH

CLOCK

DB13

DB0

INT

REV. A

Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 www.analog.com Fax: 781/326-8703 © Analog Devices, Inc., 2001

AD7899–SPECIFICATIONS

(VDD = 5 V ⴞ 5%, AGND = DGND = 0 V, V T

to T

MIN

and valid for V

MAX

= 3 V ⴞ 5% and 5 V ⴞ 5% unless otherwise noted.)

DRIVE

= Internal. Clock = Internal, all specifications

REF

ABS

Parameter Version

Version

Unit Test Conditions/Comments

SAMPLE AND HOLD

–0.1 dB Full Power Bandwidth 500 500 500 kHz typ –3 dB Full Power Bandwidth 4.5 4.5 4.5 MHz typ

Aperture Delay 20 20 20 ns max Aperture Jitter 25 25 25 ps typ

DYNAMIC PERFORMANCE

fIN = 100 kHz, fS = 400 kSPS

AD7899-1

Signal to (Noise + Distortion)

@ 25C 78 78 78 dB min

Ratio

to T

MIN

Total Harmonic Distortion

MAX

Peak Harmonic or Spurious Noise

78 78 77 dB min –84 –84 –82 dB max

–86 –86 –85 dB max

AD7899-2

Signal to (Noise + Distortion)

@ 25C 78 dB min

Ratio

to T

MIN

Total Harmonic Distortion

MAX

Peak Harmonic or Spurious Noise

77 dB min –82 dB max

–82 dB max

AD7899-3

Signal to (Noise + Distortion)

@ 25C 78 78 dB min

Ratio

to T

MIN

Total Harmonic Distortion Peak Harmonic or Spurious Noise

Intermodulation Distortion

MAX

77 77 dB min –84 –84 dB max

–86 –86 dB max

fa = 49 kHz, fb = 50 kHz 2nd Order Terms –89 –89 –89 dB typ 3rd Order Terms –89 –89 –89 dB typ

DC ACCURACY

Resolution 14 14 14 Bits Relative Accuracy (INL) Differential Nonlinearity (DNL)

± 2 ± 1.5 ±2 LSB max

± 1 ± 1 ± 1 LSB max No Missing Codes Guaranteed

AD7899-1

Input Voltage Range ± 5, ± 10 ± 5, ± 10 Volts Input Current 0.8, 0.8 0.8, 0.8 mA max V Positive Gain Error Negative Gain Error

± 10 ± 8 ± 12 LSB max ± 10 ± 8 ± 12 LSB max

= –5 V and –10 V Respectively

Bipolar Zero Error ± 12 ± 8 ± 12 LSB max

AD7899-2

Input Voltage Range 0 to 2.5 Volts

0 to 5 Input Current 0.4, 800 µA max V Positive Gain Error Offset Error

± 14 LSB max

± 10 LSB max

= 2.5 V, VIN = 5 V

AD7899-3

Input Voltage Range ± 2.5 ± 2.5 Volts Input Current 0.8 0.8 mA max V Positive Gain Error Negative Gain Error

± 14 ± 12 LSB max

= –2.5 V

Bipolar Zero Error ± 14 ± 12 LSB max

REFERENCE INPUT/OUTPUT

IN Input Voltage Range 2.375/2.625 2.375/2.625 2.375/2.625 V

REF

IN Input Capacitance

REF

OUT Output Voltage 2.5 2.5 2.5 V nom

REF

OUT Error @ 25C ± 10 ± 10 ± 10 mV max

REF

OUT Error T

REF

OUT Temperature Coefficient 25 25 25 ppm/C typ

REF

OUT Output Impedance 6 6 6 kΩ typ See Reference Section

REF

MIN

to T

MAX

10 10 10 pF max

± 20 ± 20 ± 25 mV max

MIN/VMAX

2.5 V ± 5%

–2–

REV. A

AD7899

ABS

Parameter Version

OGIC INPUTS

Input High Voltage, V Input Low Voltage, V Input Current, I

Input Capacitance, C

INH

INL

V V ± 10 ± 10 ± 10 µA max 10 10 10 pF max

DRIVE

/2 + 0.4 V /2 – 0.4 V

Version

/2 + 0.4 V

DRIVE

/2 – 0.4 V

DRIVE

Version

/2 + 0.4 V min VDD = 5 V ± 5%

DRIVE

/2 – 0.4 V max VDD = 5 V ± 5%

DRIVE

Unit Test Conditions/Comments

LOGIC OUTPUTS

Output High Voltage, V Output Low Voltage, V

– 0.4 V

DRIVE

0.4 0.4 0.4 V max I

DRIVE

– 0.4 V

– 0.4 V min I

DRIVE

SOURCE

= 1.6 mA

SINK

= 400 µA

DB13–DB0

High Impedance

Leakage Current ± 10 ± 10 ± 10 µA max Capacitance

10 10 10 pF max

Output Coding

AD7899-1, AD7899-3 Two’s Complement AD7899-2 Straight (Natural) Binary

CONVERSION RATE

Conversion Time 2.2 2.2 2.2 µs max Track/Hold Acquisition Time

2, 3

0.3 0.3 0.3 µs max

Throughput Time 400 400 400 kSPS max

POWER REQUIREMENTS

5 5 5 V nom

Normal Mode 25 25 25 mA max Typically 16 mA Standby Mode 20 20 20 µA max (5 µA typ) Logic Inputs = 0 V or

Power Dissipation

Normal Mode 125 125 125 mW max Typically 80 mW, V

Standby Mode 100 100 125 µW max

NOTES

Temperature Ranges are as follows : A, B Versions: –40C to +85C. S Version: –55°C to +125°C.

Performance measured through full channel (SHA and ADC).

See Terminology.

Sample tested @ 25°C to ensure compliance.

Specifications subject to change without notice.

= 5 V

REV. A

–3–

AD7899

1, 2

TIMING CHARACTERISTICS

to T

and valid for V

MAX

= 3 V ⴞ 5% and 5 V ⴞ 5% unless otherwise noted.)

DRIVE

(VDD = 5 V ⴞ 5%, AGND = DGND = 0 V, V

A, B and S

Parameter Versions Unit Test Conditions/Comments

CONV

2.2 µs max Conversion Time, Internal Clock

2.46 µs max CLKIN = 6.5 MHz

ACQ

EOC

WAKE-UP

– External V

REF

0.3 µs max Acquisition Time 120 ns min EOC Pulsewidth 180 ns max 2 µs max STBY Rising Edge to CONVST Rising Edge

(See Standby Mode Operation)

35 ns min CONVST Pulsewidth 70 ns min CONVST Rising Edge to BUSY Rising Edge

Read Operation

0 ns min CS to RD Setup Time 0 ns min CS to RD Hold Time 35 ns min Read Pulsewidth 35 ns max Data Access Time after Falling Edge of RD, V 40 ns max Data Access Time after Falling Edge of RD, V 5 ns min Bus Relinquish Time after Rising Edge of RD 30 ns max

0 ns min BUSY Falling Edge to RD Delay

External Clock

NOTES

Sample tested at 25°C to ensure compliance. All input signals are measured with tr = tf = 1 ns (10% to 90% of V

See Figures 5, 6, 7, and 8.

Measured with the load circuit of Figure 1 and defined as the time required for an output to cross 0.8 V or 2.0 V.

These times are derived from the measured time taken by the data outputs to change 0.5 V when loaded with the circuit of Figure 1. The measured number is then extrapolated back to remove the effects of charging or discharging the 50 pF capacitor. This means that the times quoted in the timing characteristics are the true bus relinquish times of the part and as such are independent of external bus loading capacitances.

Refer to the Standby Mode Operation section.

Specifications subject to change without notice.

0 ns min CLKIN to CONVST Rising Edge Setup Time 20 ns min CLKIN to CONVST Rising Edge Hold Time 100 ns min CONVST Rising Edge to CLK Falling Edge

= Internal, Clock = Internal; All specifications T

REF

DRIVE

) and timed from a voltage level of V

DRIVE

= 5 V = 3 V

/2.

DRIVE

MIN

1.6mA

OUTPUT

50pF

400␮A

1.6V

Figure 1. Load Circuit for Access Time and Bus Relinquish Time

–4–

REV. A

AD7899

WARNING!

ESD SENSITIVE DEVICE

ABSOLUTE MAXIMUM RATINGS*

(TA = 25°C unless otherwise noted)

VDD to AGND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V

to DGND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V

to DGND . . . . . . . . . . . . . . . . . . . . . . . . . V

DRIVE

+ 0.3 V

Analog Input Voltage to AGND

AD7899-1 (±10 V Range) . . . . . . . . . . . . . . . . . . . . ± 18 V

AD7899-1 (±5 V Range) . . . . . . . . . . . . . . . –9 V to +18 V

AD7899-2 . . . . . . . . . . . . . . . . . . . . . . . . . . –1 V to +18 V

AD7899-3 . . . . . . . . . . . . . . . . . . . . . . . . . . –4 V to +18 V

Reference Input Voltage to AGND . . . –0.3 V to V

Digital Input Voltage to DGND . . . . . –0.3 V to V

Digital Output Voltage to DGND . . . . –0.3 V to V

+ 0.3 V

Operating Temperature Range

Commercial (A, B Version) . . . . . . . . . . . –40°C to +85°C

SOIC Package, Power Dissipation . . . . . . . . . . . . . . . 450 mW

Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . . 95°C/W

Lead Temperature, Soldering

Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . 215°C

Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . 220°C

SSOP Package, Power Dissipation . . . . . . . . . . . . . . . 450 mW

Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . . 95°C/W

Lead Temperature, Soldering

Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . 215°C

Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . 220°C

Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

Military (S Version) . . . . . . . . . . . . . . . . . –55°C to +125°C

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

Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . 150°C

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD7899 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

ORDERING GUIDE

Relative Temperature Package Package

Model Input Ranges Accuracy Range Description Option

AD7899AR-1 AD7899BR-1 AD7899SR-1

5V, ±10 V

5V, ±10 V AD7899AR-2 0 V to 5 V, 0 V to 2.5 V AD7899AR-3 AD7899BR-3 AD7899ARS-1

2.5 V

5V, ±10 V AD7899ARS-2 0 V to 5 V, 0 V to 2.5 V AD7899ARS-3

2.5 V

2 LSB –40C to +85C Small Outline R-28

1.5 LSB –40C to +85C Small Outline R-28

2 LSB –55C to +125C Small Outline R-28

2 LSB –40C to +85C Small Outline R-28

1.5 LSB –40C to +85C Small Outline R-28

2 LSB –40C to +85C Shrink Small Outline RS-28

REV. A

–5–

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