Burr Brown Corporation ADS1286UB-2K5, ADS1286UB, ADS1286UA-2K5, ADS1286UA, ADS1286U-2K5 Datasheet

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ADS1286

ADS1286

ADS1286

12-Bit Micro Power Sampling

ANALOG-TO-DIGITAL CONVERTER

FEATURES

●SERIAL INTERFACE

●GUARANTEED NO MISSING CODES

●20kHz SAMPLING RATE

●LOW SUPPLY CURRENT: 250μA

APPLICATIONS

●REMOTE DATA ACQUISITION

●ISOLATED DATA ACQUISITION

●TRANSDUCER INTERFACE

●BATTERY OPERATED SYSTEMS

DESCRIPTION

The ADS1286 is a 12-bit, 20kHz analog-to-digital

converter with a differential input and sample and hold amplifier and consumes only 250μA of supply cur-

rent. The ADS1286 offers an SPI and SSI compatible serial interface for communications over a two or three wire interface. The combination of a serial two wire interface and micropower consumption makes the ADS1286 ideal for remote applications and for those requiring isolation.

The ADS1286 is available in a 8-pin plastic mini DIP and a 8-lead SOIC.

SAR	Control
VREF
+In		DOUT
CDAC	Serial
–In	Interface	DCLOCK
S/H Amp	Comparator	CS/SHDN

International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: [phone]

Twx: 910-952-1111 • Internet: http://www.burr-brown.com/ • Cable: BBRCORP • Telex: 066-6491 • FAX: [phone] •mmediateI		Product Info: [phone]
© 1996 Burr-Brown Corporation	PDS-1335B	Printed in U.S.A. October, 1998

SPECIFICATIONS

At TA = TMIN to TMAX, +VCC = +5V, VREF = +5V, fSAMPLE = 12.5kHz, , fCLK = 16 • fSAMPLE, unless otherwise specified.

ADS1286, ADS1286A

ADS1286K, ADS1286B

ADS1286C, ADS1286L

PARAMETER

CONDITIONS

MIN

TYP

MAX

MIN

TYP

MAX

MIN

TYP

MAX

UNITS

ANALOG INPUT

Full-Scale Input Range

+In – (–In)

0

VREF

V

Absolute Input Voltage

+In

–0.2

VCC +0.2

V

–In

–0.2

+0.2

V

Capacitance

25

pF

Leakage Current

±1

mA

SYSTEM PERFORMANCE

Resolution

12

Bits

No Missing Codes

12

Bits

Integral Linearity

±1

±2

±0.5

±1

LSB

Differential Linearity

±0.5

±1.0

±0.75

±0.25

±0.75

LSB

Offset Error

0.75

±3

LSB

Gain Error

±2

±8

LSB

Noise

50

mVrms

Power Supply Rejection

82

dB

SAMPLING DYNAMICS

Conversion Time

12

Clk Cycles

Acquisition Time

1.5

Clk Cycles

Small Signal Bandwidth

500

kHz

DYNAMIC CHARACTERISTICS

Total Harmonic Distortion

VIN = 5.0Vp-p at 1kHz

–85

dB

VIN = 5.0Vp-p at 5kHz

–83

dB

SINAD

VIN = 5.0Vp-p at 1kHz

72

dB

Spurious Free Dynamic Range

VIN = 5.0Vp-p at 1kHz

90

dB

REFERENCE INPUT

REF Input Range

1.25

2.5

VCC+0.05V

V

Input Resistance

CS = VCC

5000

MW

CS = GND, fCLK = 0Hz

5000

MW

Current Drain

CS

= VCC

0.01

2.5

mA

tCYC ³ 640ms, fCLK £ 25kHz

2.4

20

mA

tCYC = 80ms, fCLK = 200kHz

2.4

20

mA

DIGITAL INPUT/OUTPUT

Logic Family

CMOS

Logic Levels:

VIH

IIH = +5mA

3

+VCC

V

VIL

IIL = +5mA

0.0

0.8

V

VOH

IOH = 250mA

3

+VCC

V

VOL

IOL = 250mA

0.0

0.4

V

Data Format

Straight Binary

POWER SUPPLY REQUIREMENTS

Power Supply Voltage

VCC

+4.50

5

5.25

V

Quiescent Current, VANA

tCYC ³ 640mS, fCLK £ 25kHz

200

400

mA

tCYC = 90mS, fCLK = 200kHz

250

500

mA

Power Down

CS

= VCC

3

mA

TEMPERATURE RANGE

Specified Performance

ADS1286, K, L

0

+70

°C

ADS1286A, B, C

–40

+85

°C

Specifications same as grade to the left.

TIMING CHARACTERISTICS

fCLK = 200kHz, TA = TMIN to TMAX.

SYMBOL	PARAMETER						CONDITIONS	MIN	TYP	MAX	UNITS
tSMPL	Analog Input Sample Time						See Operating Sequence	1.5		2.0	Clk Cycles
tSMPL (MAX)	Maximum Sampling Frequency						ADS1286			20	kHz
tCONV	Conversion Time						See Operating Sequence		12		Clk Cycles
tdDO	Delay TIme, DCLOCK¯ to DOUT Data Valid						See Test Circuits		85	150	ns
tdis	Delay TIme,		CS		- to DOUT Hi-Z		See Test Circuits		25	50	ns
ten	Delay TIme, DCLOCK¯ to DOUT Enable						See Test Circuits		50	100	ns
thDO	Output Data Remains Valid After DCLOCK¯						CLOAD = 100pF	15	30		ns
tf	DOUT Fall Time						See Test Circuits		70	100	ns
tr	DOUT Rise Time						See Test Circuits		60	100	ns
tCSD	Delay Time,	CS		¯		to DCLOCK¯	See Operating Sequence			0	ns
tSUCS	Delay Time,			¯		to DCLOCK-	See Operating Sequence	30			ns
		CS

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	ADS1286	2

ABSOLUTE MAXIMUM RATINGS(1)

+VCC .....................................................................................................	+6V
Analog Input .......................................................	–0.3V to (+VCC + 300mV)
Logic Input .........................................................	–0.3V to (+VCC + 300mV)
Case Temperature .........................................................................	+100°C
Junction Temperature ....................................................................	+150°C
Storage Temperature .....................................................................	+125°C
External Reference Voltage ..............................................................	+5.5V

NOTE: (1) Stresses above these ratings may permanently damage the device.

PIN CONFIGURATION

VREF				+VCC
	1		8
				DCLOCK
+In	2	ADS1286	7
				DOUT
–In	3		6
GND	4		5		CS/SHDN

8-Pin Mini PDIP

8-Lead SOIC

ELECTROSTATIC DISCHARGE SENSITIVITY

Electrostatic discharge can cause damage ranging from performance degradation to complete device failure. BurrBrown Corporation recommends that all integrated circuits be handled and stored using appropriate ESD protection methods.

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 published specifications.

PIN ASSIGNMENTS

PIN		NAME		DESCRIPTION
1		VREF		Reference Input.
2			+In	Non Inverting Input.
3			–In	Inverting Input. Connect to ground or remote ground sense point.
4		GND		Ground.
5				Chip Select when low, Shutdown Mode when high.
		CS/SHDN
6		DOUT		The serial output data word is comprised of 12 bits of data. In operation the data is 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 is valid for the next 12 edges.
7		DCLOCK		Data Clock synchronizes the serial data transfer and determines conversion speed.
8		+VCC		Power Supply.

PACKAGE/ORDERING INFORMATION

				PACKAGE
	INTEGRAL	TEMPERATURE		DRAWING
PRODUCT	LINEARITY	RANGE	PACKAGE	NUMBER(1)
ADS1286P	±2	0°C to +70°C	Plastic DIP	006
ADS1286PK	±2	0°C to +70°C	Plastic DIP	006
ADS1286PL	±1	0°C to +70°C	Plastic DIP	006
ADS1286U	±2	0°C to +70°C	SOIC	182
ADS1286UK	±2	0°C to +70°C	SOIC	182
ADS1286UL	±1	0°C to +70°C	SOIC	182
ADS1286PA	±2	–40°C to +85°C	Plastic DIP	006
ADS1286PB	±2	–40°C to +85°C	Plastic DIP	006
ADS1286PC	±1	–40°C to +85°C	Plastic DIP	006
ADS1286UA	±2	–40°C to +85°C	SOIC	182
ADS1286UB	±2	–40°C to +85°C	SOIC	182
ADS1286UC	±1	–40°C to +85°C	SOIC	182

NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix

C of Burr-Brown IC Data Book.

The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems.

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3	ADS1286

TYPICAL PERFORMANCE CURVES

At TA = +25, VCC = +5V, VREF = +5V, fSAMPLE = 12.5kHz, fCLK = 16 • fSAMPLE, unless otherwise specified.

	2.5		REFERENCE CURRENT vs SAMPLE RATE										4.0		REFERENCE CURRENT vs TEMPERATURE
(μA)	2.0											(μA)	3.5
													3.0
Current	1.5											Current
													2.5
Reference	1.0											Reference	2.0
	0.5
													1.5
	0												1.0
	0		2	4	6	8		10		12			–55		–40		–25		0		25		70		85
					Sample Rate (kHz)													Temperature (°C)

Change in Offset (LSB)

CHANGE IN OFFSET vs REFERENCE VOLTAGE

5

4.5

4

3.5

3

2.5

2

1.5

1

0.5

0

1	2	3	4	5
		Reference Voltage (V)

Delta from 25°C (LSB)

CHANGE IN OFFSET vs TEMPERATURE

0.6

0.4

0.2

0

–0.2

–0.4

–0.6

–55	–40	–25	0	25	70	85
		Temperature (°C)

	CHANGE IN INTEGRAL LINEARITY AND DIFFERENTIAL
		LINEARITY vs REFERENCE VOLTAGE
	0.10
Reference(LSB)	0.05				Gain(LSB)
	–0.05	Change in Differential
	0.00		Linearity (LSB)
fromDelta+5V
	–0.10				Changein
				Change in Integral
	–0.15			Linearity (LSB)
	–0.20
	1	2	3	4	5
			Reference Voltage (V)

CHANGE IN GAIN vs REFERENCE VOLTAGE

4

3.5

3

2.5

2

1.5

1

0.5

0

1	2	3	4	5
		Reference Voltage (V)

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	ADS1286	4