Texas Instruments ADS7822UC, ADS7822 Datasheet

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ADS7822

SAR

Control

Serial

Interface

OUT

Comparator

S/HAmp

CS/SHDN

DCLOCK

+In

REF

-In

CDAC

12-Bit, 200kHz, microPower Sampling

ANALOG-TO-DIGITAL CONVERTER

FEATURES DESCRIPTION

• 200kHz Sampling Rate

• microPower:

1.6mW at 200kHz

0.54mW at 75kHz

0.06mW at 7.5kHz

• Power Down: 3 µ A max

• Mini-DIP-8, SO-8, and MSOP-8 Packages

• Pseudo-Differential Input

• Serial Interface

APPLICATIONS

• Battery-Operated Systems

• Remote Data Acquisition

• Isolated Data Acquisition

• Simultaneous Sampling, Multichannel

Systems

ADS7822

SBAS062B – JANUARY 1996 – REVISED MAY 2006

The ADS7822 is a 12-bit sampling analog-to-digital (A/D) converter with ensured specifications over a

2.7V to 5.25V supply range. It requires very little power even when operating at the full 200kHz rate. At lower conversion rates, the high speed of the device enables it to spend most of its time in the power-down mode—the power dissipation is less than 60 µ W at 7.5kHz.

The ADS7822 also features operation from 2.0V to 5V, a synchronous serial interface, and a pseudo-differential input. The reference voltage can be set to any level within the range of 50mV to V

Ultra low power and small size make the ADS7822 ideal for battery-operated systems. It is also a perfect fit for remote data-acquisition modules, simultaneous multichannel systems, and isolated data acquisition. The ADS7822 is available in a plastic mini-DIP-8, an SO-8, or an MSOP-8 package.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.

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ADS7822

SBAS062B – JANUARY 1996 – REVISED MAY 2006

This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

ORDERING INFORMATION

MAXIMUM MAXIMUM INTEGRAL DIFFERENTIAL LINEARITY LINEARITY SPECIFIED TRANSPORT

PRODUCT (LSB) (LSB) LEAD DESIGNATOR RANGE MARKING

ADS7822E ± 2 ± 2 MSOP-8 DGK –40 ° C to +85 ° C A22

ADS7822EB ± 1 ± 1 MSOP-8 DGK –40 ° C to +85 ° C A22

ADS7822EC ± 0.75 ± 0.75 MSOP-8 DGK –40 ° C to +85 ° C A22

ADS7822P ± 2 ± 2 P –40 ° C to +85 ° C ADS7822P ADS7822P Rails, 50

ADS7822PB ± 1 ± 1 P –40 ° C to +85 ° C ADS7822PB ADS7822PB Rails, 50

ADS7822PC ± 0.75 ± 0.75 P –40 ° C to +85 ° C ADS7822PC ADS7822PC Rails, 50

ADS7822U ± 2 ± 2 SO-8 D –40 ° C to +85 ° C ADS7822U

ADS7822UB ± 1 ± 1 SO-8 D –40 ° C to +85 ° C ADS7822UB

ADS7822UC ± 0.75 ± 0.75 SO-8 D –40 ° C to +85 ° C ADS7822UC

ERROR ERROR PACKAGE- PACKAGE TEMPERATURE PACKAGE ORDERING MEDIA,

Plastic

DIP-8

Plastic

DIP-8

Plastic

DIP-8

(1)

(2)

NUMBER QUANTITY

ADS7822E/250

ADS7822E/2K5

ADS7822EB/250

ADS7822EB/2K5

ADS7822EC/250

ADS7822EC/2K5

ADS7822U Rails, 100

ADS7822U/2K5

ADS7822UB Rails, 100

ADS7822UB/2K5

ADS7822UC Rails, 100

ADS7822UC/2K5

Tape and Reel,

250

Tape and Reel,

2500

Tape and Reel,

250

Tape and Reel,

2500

Tape and Reel,

250

Tape and Reel,

2500

Tape and Reel,

2500

Tape and Reel,

2500

Tape and Reel,

2500

(1) For the most current package and ordering information, see the Package Option Addendum located at the end of this data sheet, or see

the TI website at www.ti.com.

(2) Performance grade information is marked on the reel.

ABSOLUTE MAXIMUM RATINGS

(1)

over operating free-air temperature range (unless otherwise noted)

ADS7822 UNIT

Analog input –0.3 to V Logic input –0.3 to 6 V Case temperature +100 ° C Junction temperature +150 ° C Storage temperature +125 ° C External reference voltage +5.5 V

(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings

only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum rated conditions for extended periods may affect device reliability.

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+6 V

+ 0.3 V

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ADS7822

SBAS062B – JANUARY 1996 – REVISED MAY 2006

ELECTRICAL CHARACTERISTICS: +V

At –40 ° C to +85 ° C, +V

PARAMETER TEST CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNIT

ANALOG INPUT

Full-scale input span +In – (–In) 0 V

Absolute input range

Capacitance 25 25 25 pF Leakage current ± 1 ± 1 ± 1 µ A

SYSTEM PERFORMANCE

Resolution 12 12 12 Bits No missing codes 11 12 11 Bits Integral linearity error –2 ± 0.5 +2 –1 ± 0.5 +1 –0.75 ± 0.25 +0.75 LSB Differential linearity error –2 ± 0.5 +2 –1 ± 0.5 +1 –0.75 ± 0.25 +0.75 LSB Offset error –3 +3 –3 +3 –1 +1 LSB Gain error –3 +3 –3 +3 –1 +1 LSB Noise 33 33 33 µ Vrms Power-supply rejection 82 82 82 dB

SAMPLING DYNAMICS

Conversion time 12 12 12 Clk Cycles Acquisition time 1.5 1.5 1.5 Clk Cycles Throughput rate 75 75 75 kHz

DYNAMIC CHARACTERISTICS

Total harmonic distortion VIN= 2.5V SINAD VIN= 2.5V Spurious-free dynamic range VIN= 2.5V

REFERENCE OUTPUT

Voltage range 0.05 V

Resistance

Current drain f

DIGITAL INPUT/OUTPUT

Logic family CMOS CMOS CMOS

Logic levels

Data format Straight Binary Straight Binary Straight Binary

POWER-SUPPLY REQUIREMENTS

Quienscent current

Power down CS = V

TEMPERATURE RANGE

Specified performance –40 +85 –40 +85 –40 +85 ° C

(1) LSB means least significant bit. With V (2) The maximum clock rate of the ADS7822 is less than 1.2MHz in this power-supply range.

= +2.7V, V

+In –0.2 VCC+ 0.2 –0.2 VCC+ 0.2 –0.2 VCC+ 0.2 V –In –0.2 +1.0 –0.2 +1.0 –0.2 +1.0 V

at 1kHz –82 –82 –82 dB

at 1kHz 71 71 71 dB

at 1kHz 86 86 86 dB

CS = GND, f CS = V At code 710h 8 40 8 40 8 40 µ A

SAMPLE

CS = V

IIH= +5 µ A 2.0 5.5 2.0 5.5 2.0 5.5 V IIL= +5 µ A –0.3 0.8 –0.3 0.8 –0.3 0.8 V IOH= –250 µ A 2.1 2.1 2.1 V IOL= 250 µ A 0.4 0.4 0.4 V

Specified performance 2.7 3.6 2.7 3.6 2.7 3.6 V See Notes See Note f

SAMPLE

= 7.5kHz 0.8 0.8 0.8 µ A

(2)

and

(3)

= 7.5kHz

(5)

= 75kHz

= +2.5V, f

REF

= 0Hz 5 5 5 G Ω

(3)

(4) (5)

equal to +2.5V, one LSB is 0.61mV.

REF

= +2.7V

= 75kHz, and f

SAMPLE

ADS7822 ADS7822B ADS7822C

REF

5 5 5 G Ω

0.001 3 0.001 3 0.001 3 µ A

2.0 2.7 2.0 2.7 2.0 2.7 V

3.6 5.25 3.6 5.25 3.6 5.25 V 20 20 20 µ A

200 325 200 325 200 325 µ A

3 3 3 µ A

= 16 × f

CLK

0 V

0.05 V

SAMPLE

, unless otherwise noted.

REF

0 V

0.05 V

REF

(3) See the Typical Characteristics for more information. (4) f (5) See the Power Dissipation section for more information regarding lower sample rates.

= 1.2MHz, CS = V

CLK

for 145 clock cycles out of every 160.

(1)

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ADS7822

SBAS062B – JANUARY 1996 – REVISED MAY 2006

ELECTRICAL CHARACTERISTICS: +V

At –40 ° C to +85 ° C, +V

PARAMETER TEST CONDITIONS MIN TYP MAX MIN TYP MAX UNIT

ANALOG INPUT

Full-scale input span +In – (–In) 0 V

Absolute input range

Capacitance 25 25 pF Leakage current ± 1 ± 1 µ A

SYSTEM PERFORMANCE

Resolution 12 12 Bits No missing codes 11 12 Bits Integral linearity error –2 +2 –1 +1 LSB Differential linearity error ± 0.8 –1 ± 0.5 +1 LSB Offset error –3 +3 –3 +3 LSB Gain error –4 +4 –3 +3 LSB Noise 33 33 µ Vrms Power-supply rejection 70 70 dB

SAMPLING DYNAMICS

Conversion time 12 12 Clk Cycles Acquisition time 1.5 1.5 Clk Cycles Throughput rate 200 200 kHz

DYNAMIC CHARACTERISTICS

Total harmonic distortion VIN= 5V SINAD VIN= 5V Spurious-free dynamic range VIN= 5V

REFERENCE OUTPUT

Voltage range 0.05 V

Resistance

Current drain f

DIGITAL INPUT/OUTPUT

Logic family CMOS CMOS

Logic levels

Data format Straight Binary Straight Binary

POWER-SUPPLY REQUIREMENTS

Quienscent current f Power down CS = V

TEMPERATURE RANGE

Specified performance –40 +85 –40 +85 ° C

= +5V, V

+In –0.2 VCC+ 0.2 –0.2 VCC+ 0.2 V –In –0.2 +1.0 –0.2 +1.0 V

CS = GND, f CS = V

At code 710h 40 100 40 100 µ A

= 12.5kHz 2.5 2.5 µ A

SAMPLE

CS = V

IIH= +5 µ A 3.0 5.5 3.0 5.5 V IIL= +5 µ A –0.3 0.8 –0.3 0.8 V IOH= –250 µ A 3.5 3.5 V IOL= 250 µ A 0.4 0.4 V

Specified performance 4.75 5.25 4.75 5.25 V

= 200kHz 320 550 320 550 µ A

SAMPLE

= +5V, f

REF

at 10kHz –78 –78 dB

at 10kHz 71 71 dB

at 10kHz 79 79 dB

= 0Hz 5 5 G Ω

SAMPLE

= +5V

= 200kHz, and f

ADS7822 ADS7822B

= 16 × f

CLK

5 5 G Ω

0.001 3 0.001 3 µ A

, unless otherwise noted.

SAMPLE

REF

3 3 µ A

0 V

0.05 V

REF

(1)

(1) LSB means least significant bit. With V

equal to +5V, one LSB is 1.22mV.

REF

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PIN CONFIGURATION

DCLOCK

OUT

CS/SHDN

REF

+In

-In

GND

ADS7822

D, DGK, OR P PACKAGE

SO, MSOP, or DIP

(TOP VIEW)

PIN ASSIGNMENTS

NAME NO. DESCRIPTION

REF

+In 2 Noninverting input –In 3 Inverting input. Connect to ground or to remote ground sense point. GND 4 Ground CS/SHDN 5 Chip select when low; Shutdown mode when high.

OUT

DCLOCK 7 Data clock synchronizes the serial data transfer and determines conversion speed. +V

1 Reference input

The serial output data word is comprised of 12 bits of data. In operation, the data are valid on the falling edge of DCLOCK. The

second clock pulse after the falling edge of CS enables the serial output. After one null bit, the data are valid for the next edges.

8 Power supply

ADS7822

SBAS062B – JANUARY 1996 – REVISED MAY 2006

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1.00

0.75

0.50

0.25

0.00

-0.25

-0.50

-0.75

-1.00

IntegralLinearityError(LSB)

0 2048 4095

Code

1.00

0.75

0.50

0.25

0.00

-0.25

-0.50

-0.75

-1.00

DifferentialLinearityError(LSB)

0 2048 4095

Code

350

300

250

200

150

100

SupplyCurrent( A)

-50 -25 0 25 50 75 100

Temperature( C)°

120

100

SupplyCurrent(nA)

-50 -25 0 25 50 75 100

Temperature( C)°

400

350

300

250

200

150

100

QuiescentCurrent(

A)m

1 2 3 4 5

V (V)

1000

100

SampleRate(kHz)

1 2 3 4 5

V (V)

ADS7822

SBAS062B – JANUARY 1996 – REVISED MAY 2006

At TA= +25 ° C, V

= +2.7V, V

REF

TYPICAL CHARACTERISTICS

= +2.5V, f

SAMPLE

= 75kHz, f

CLK

= 16 × f

SAMPLE

, unless otherwise specified.

INTEGRAL LINEARITY ERROR DIFFERENTIAL LINEARITY ERROR

vs CODE vs CODE

Figure 1. Figure 2.

SUPPLY CURRENT POWER-DOWN SUPPLY CURRENT

vs TEMPERATURE vs TEMPERATURE

QUIESCENT CURRENT MAXIMUM SAMPLE RATE

Figure 3. Figure 4.

vs V

Figure 5. Figure 6.

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1.2

1.0

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

ChangeinOffset(LSB)

1 2 3 4 5

ReferenceVoltage(V)

V =5V

0.6

0.4

0.2

-0.2

-0.4

-0.6

Deltafrom25

°C(LSB)

-50

-25

0 25 50 75 100

Temperature(°C)

2.5

2.0

1.5

1.0

0.5

0.0

-0.5

-1.0

-1.5

ChangeinGain(LSB)

1 2 3 4 5

ReferenceVoltage(V)

V =5V

0.15

0.10

0.05

-0.05

-0.10

-0.15

Deltafrom25

C(LSB)°

-50 -25 0 25 50 75 100

Temperature( C)°

12.00

11.75

11.50

11.25

11.00

10.75

10.50

10.25

10.00

EffectiveNumberofBits(rms)

0.1 1 10

ReferenceVoltage(V)

V =5V

Peak-to-PeakNoise(LSB)

0.1 1 10

ReferenceVoltage(V)

V =5V

At TA= +25 ° C, V

TYPICAL CHARACTERISTICS (continued)

= +2.7V, V

CHANGE IN OFFSET CHANGE IN OFFSET

vs REFERENCE VOLTAGE vs TEMPERATURE

REF

= +2.5V, f

SAMPLE

= 75kHz, f

CLK

= 16 × f

SAMPLE

Figure 7. Figure 8.

ADS7822

SBAS062B – JANUARY 1996 – REVISED MAY 2006

, unless otherwise specified.

CHANGE IN GAIN CHANGE IN GAIN

vs REFERENCE VOLTAGE vs TEMPERATURE

Figure 9. Figure 10.

EFFECTIVE NUMBER OF BITS PEAK-TO-PEAK NOISE

vs REFERENCE VOLTAGE vs REFERENCE VOLTAGE

Figure 11. Figure 12.

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