TEXAS INSTRUMENTS ADS1202 Technical data

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1-Bit, 10MHz, 2nd-Order, Delta-Sigma Modulator

ADS1202

SBAS275 – DECEMBER 2002

Motor Control Current Shunt

FEATURES

● 16-BIT RESOLUTION

● 13-BIT LINEARITY

● RESOLUTION/SPEED TRADE-OFF:

10-Bit Effective Resolution with 20µs Signal
Delay (12-bit with 77µs)

●±250mV INPUT RANGE WITH SINGLE 5V SUPPLY

● 2% INTERNAL REFERENCE VOLTAGE

● 2% GAIN ERROR

● FLEXIBLE SERIAL INTERFACE WITH FOUR

DIFFERENT MODES

● IMPLEMENTED TWINNED BINARY CODING AS

SPLIT PHASE OR MANCHESTER CODING FOR
ONE LINE INTERFACING

● OPERATING TEMPERATURE RANGE:

–40°C to +85°C

APPLICATIONS

● MOTOR CONTROL

● CURRENT MEASUREMENT

● INDUSTRIAL PROCESS CONTROL

● INSTRUMENTATION

● SMART TRANSMITTERS

● PORTABLE INSTRUMENTS

● WEIGHT SCALES

● PRESSURE TRANSDUCERS

V
V

V

GND

DESCRIPTION

The ADS1202 is a precision, 80dB dynamic range, delta­sigma (∆∑) modulator operating from a single +5V supply.
The differential inputs are ideal for direct connections to
transducers or low-level signals. With the appropriate digital
filter and modulator rate, the device can be used to achieve
16-bit Analog-to-Digital (A/D) conversion with no missing
codes. Effective resolution of 12 bits can be maintained with
a digital filter bandwidth of 10kHz at a modulator rate of
10MHz. The ADS1202 is designed for use in medium reso­lution measurement applications including current measure­ments, smart transmitters, industrial process control, weigh
scales, chromatography, and portable instrumentation. It is
available in a TSSOP-8 package.

IN+

IN–

DD

2nd-Order

∆∑ Modulator

Buffer

RC Oscillator

20MHz

Reference

Voltage

2.5V

Interface

Circuit

MDAT
MCLK

M0
M1

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.

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

Copyright © 2002, Texas Instruments Incorporated

www.ti.com

ABSOLUTE MAXIMUM RATINGS

Over operating free-air temperature (unless otherwise noted)

(1)

ELECTROSTATIC
DISCHARGE SENSITIVITY

Supply Voltage, GND to VDD................................................. –0.3V to 6V

Analog Input Voltage Range ......................... GND – 0.4V to VDD + 0.3V

Digital Input Voltage Range .......................... GND – 0.3V to V

Power Dissipation ............................................................................ 0.25W

Operating Virtual Junction Temperature Range, T
Operating Free-Air Temperature Range, T
Storage Temperature Range, T

Lead Temperature 1.6mm (1/16") from Case for 10s .................. +260°C

NOTE: (1) Stresses beyond those listed under the 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 the Recommended Operating Conditions is not implied.
Exposure to absolute-maximum-rated conditions for extended periods may
affect device reliability.

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

STG

........ –40°C to +150°C

J

....................–40°C to +85°C

A

+ 0.3V

DD

PACKAGE/ORDERING INFORMATION

MAXIMUM
INTEGRAL SPECIFIED

PRODUCT ERROR (LSB) GAIN ERROR (%) PACKAGE-LEAD DESIGNATOR

ADS1202 12 ±2 TSSOP-8 PW –40°C to +85°C ADS1202I ADS1202IPWT Tape and Reel, 250
ADS1202

NOTE: (1) For the most current specifications and package information, refer to our web site at www.ti.com.

LINEARITY MAXIMUM PACKAGE TEMPERATURE PACKAGE ORDERING TRANSPORT

"" """"

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.

(1)

RANGE MARKING NUMBER MEDIA, QUANTITY

ADS1202IPWR Tape and Reel, 2000

PIN CONFIGURATION

Top View TSSOP

1

M0

2

V

IN+

V

IN–

M1

ADS1202

3

4

8

V

DD

7

MCLK

6

MDAT

5

GND

PIN DESCRIPTIONS

PIN

NUMBER NAME DESCRIPTION

1 MO Mode Input
2V
3V
4 M1 Mode Input
5 GND Power Supply Ground
6 MDAT Modulator Data Output
7 MCLK Modulator Clock Input or Output
8VDDPower Supply, +5V Nominal

+ Analog Input: Noninverting Input

IN

– Analog Input: Inverting Input

IN

RECOMMENDED OPERATING CONDITIONS

PARAMETER MIN NOM MAX UNIT

Supply Voltage, V
Analog Input Voltage, V
Operating Common-Mode Signal, V
External Clock
Operating Junction Temperature Range –40 105 °C

NOTE: (1) With reduced accuracy, minimum clock can go up to 500kHz.

DD

IN

(1)

CM

DISSIPATION RATING

T

< 25°C FACTOR TA = 70°CTA = 85°C

A

PACKAGE RATING T

TSSOP-8 483.6mW 3.868mW/°C 309.5mW 251.4mW

NOTE: (1) This is the inverse of the traditional junction-to-ambient thermal
resistance (R
informational purposes only.

POWER ABOVE POWER POWER

). Thermal resistances are not production tested and are for

θ

JA

DERATING

= 25°C

A

(1)

RATING RATING

4.75 5.0 5.25 V
–250 +250 mV

05V
81012MHz

EQUIVALENT INPUT CIRCUIT

AV

DD

RON = 350Ω

A

IN

AGND

Diode Turn on Voltage: 0.35V

Equivalent Analog Input Circuit

C

(SAMPLE)

= 5pF

BV

DD

D

IN

BGND

Equivalent Digital Input Circuit

2

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ADS1202

SBAS275

ELECTRICAL CHARACTERISTICS

Over recommended operating free-air temperature range at –40°C to +85°C, VDD = 5V, +In = –250mV to 250mV, –In = 0V, and MCLK = 10MHz, unless otherwise noted.

ADS1202IPW

PARAMETER CONDITIONS MIN TYP

(1)

RESOLUTION 16 Bits
DC ACCURACY

Integral Nonlinearity INL ±3 ±12 LSB

Differential Linearity
Input Offset V
Input Offset Drift TCV
Gain Error G
Gain Error Drift TCG
Power-Supply Rejection Ratio PSRR 4.75V < V

(1)

DNL ±1 LSB

OS

OS
ERR
ERR

< 5.25V 80 dB

DD

0.005 0.018 %

±300 ±1000 µV

28µV/°C

±0.25 ±2%

20 ppm/°C

ANALOG INPUT

Full-Scale Range FSR +In – (–In) ±320 mV
Operating Common-Mode Signal

(2)

–0.1 5 V
Input Capacitance Common-Mode 3 pF
Input Leakage Current ±1nA
Differential Input Resistance Equivalent 28 kΩ
Differential Input Capacitance 5pF
Common-Mode Rejection Ratio

(2)

CMRR At DC 90 dB

V

= ±1.25Vp-p at 50kHz 85 dB

IN

INTERNAL VOLTAGE REFERENCE

Reference Voltage V
Initial Accuracy Scale to 320mV ±2+-+ %
Reference Temperature Drift dV
PSRR 80 dB

OUT

/dT ±20 ppm/°C

OUT

Scale to 320mV 2.450 2.5 2.550 V

Startup Time 0.1 ms

INTERNAL CLOCK FOR MODES, 0, 1, AND 2

Clock Frequency 8 10 12 MHz

EXTERNAL CLOCK FOR MODE 3

Clock Frequency 16 20 24 MHz

AC ACCURACY

Signal-to-Noise Ratio + Distortion SINAD V
Signal-to-Noise Ratio SNR V
Total Harmonic Distortion THD V
Spurious Free Dynamic Range SFDR V

= ±250mVp-p at 5kHz 70 dB

IN

= ±250mVp-p at 5kHz 67 70.5 dB

IN

= ±250mVp-p at 5kHz –84 dB

IN

= ±250mVp-p at 5kHz 84 dB

IN

DIGITAL INPUT

Logic Family TTL with Schmitt Trigger
High-Level Input Voltage V
Low-Level Input Voltage V
High-Level Input Current I
Low-Level Input Current I
Input Capacitance C

IH

IL

IH

IL

J

VI = V

DD

VI = GND –2.5 0.005 µA

2.6 VDD + 0.3 V

–0.3 0.8 V

0.005 2.5 µA

5pF

DIGITAL OUTPUT

High-Level Digital Output V

Low-Level Digital Output V

Output Capacitance C
Load Capacitance C

OH

OL

O

L

VDD = 4.5V, IO = –5mA 4.6 V

V

= 4.5V, IO = –15mA 3.9 V

DD

VDD = 4.5V, IO = 5mA 0.4 V

V

= 4.5V, IO = 15mA 1.1 V

DD

5pF

POWER SUPPLY

Supply Voltage V
Operating Supply Current I

DD
CC

Power Dissipation V

Mode 0 6 7.5 mA
Mode 3 8 9.5 mA

= 5V, Mode 0 30 37.5 mW

DD

V

= 5V, Mode 3 40 47.5 mW

DD

4.5 5 5.5 V

OPERATING TEMPERATURE –40 +85 °C

NOTES: (1) All typical values are at T
line through the transfer curve for V
typical information parameter not tested.

= +25°C. (2) Ensured by design. (3) Integral nonlinearity is defined as one-half the peak-to-peak deviation of the best fit

A

+ = –250mV to +250mV, expressed either as the number of LSBs or as a percent of measured input range (500mV). (4) Only

IN

MAX UNITS

30 pF

ADS1202

SBAS275

www.ti.com

3

TIMING DIAGRAMS

MCLK

MDAT

DIAGRAM 1: Mode 0 Operation.

MCLK

t

C1

t

W1

t

C2

t

D1

MDAT

DIAGRAM 2: Mode 1 Operation.

MCLK

MDAT

t

W2

t

C1

t

w1

t

C3

t

w3

t

D2

t

D3

10 1100

DIAGRAM 3: Mode 2 Operation.

4

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ADS1202

SBAS275

TIMING DIAGRAMS (Cont.)

t

C4

MCLK

t

w4

t

D4

MDAT

DIAGRAM 4: Mode 3 Operation.

TIMING CHARACTERISTICS

over recommended operating free-air temperature range –40°C to +85°C, VDD = 5V, and MCLK = 10MHz, unless otherwise noted.

SPEC DESCRIPTION MODE MIN MAX UNITS

t

C1

t

W1

t

D1

t

C2

t

W2

t

D2

t

D3

t

C3

t

W3

t

C4

t

W4

t

D4

t

R1

t

F1

NOTE: All input signals are specified with t

Clock Period 0 90 110 ns
Clock HIGH Time 0 tC1/2 – 5t

/2 + 5 ns

C1

Data delay after rising edge of clock 0 tC1/4 – 10 tC1/4 + 10 ns
Clock Period 1 180 220 ns
Clock HIGH Time 1 tC2/2 – 5t

/2 + 5 ns

C2

Data delay after rising edge of clock 1 tC2/4 – 10 tC2/4 + 10 ns
Data delay after falling edge of clock 1 tC2/4 – 10 tC2/4 + 10 ns
Clock Period 2 90 110 ns
Clock HIGH Time 2 tC3/2 – 5t

/2 + 5 ns

C3

Clock Period 3 45 55 ns
Clock HIGH Time 3 10 tC4 – 10 ns
Data delay after falling edge of clock 3 0 10 ns
Rise Time of Clock 3 0 10 ns
Fall Time of Clock 3 0 10 ns

= tF = 5ns (10% to 90% of VDD) and timed from a voltage level of (VIL + VIH)/2. See timing diagrams 1 thru 4.

R

ADS1202

SBAS275

www.ti.com

5

TYPICAL CHARACTERISTICS

VDD = 5V, +In = –250mV to 250mV, –In = 0V, and MCLK = 10MHz, unless otherwise noted.

INTEGRAL NONLINEARITY vs INPUT SIGNAL (Mode 0)

2
1
0

–1
–2
–3

INL (LSB)

–4
–5
–6
–7

INTEGRAL NONLINEARITY vs TEMPERATURE

7

6

5

4

3

INL (LSB)

2

1

0

–40 –20 200408060 100

25°C

–40°C

+85°C

0–320 –240 –80–160 80 240160 320

Differential Input Voltage (mV)

Mode 0

Mode 3

Temperature (°C)

INTEGRAL NONLINEARITY vs INPUT SIGNAL (Mode 3)

2

1

0

–1

–2

INL (LSB)

–3

–4

–5

0.010

0.009

0.008

0.007

0.006

0.005

INL (%)

0.004

0.003

0.002

0.001

INTEGRAL NONLINEARITY vs TEMPERATURE

0

–40 –20 200408060 100

25°C

–40°C

0–320 –240 –80–160 80 240160 320

Differential Input Voltage (mV)

Mode 0

Mode 3

Temperature (°C)

+85°C

300
200
100

0

–100
–200
–300

Offset (µV)

–400
–500
–600
–700

–40 –20 200408060 100

6

OFFSET vs TEMPERATURE

Mode 3

Mode 0

Temperature (°C)

www.ti.com

0.14

0.12

0.10

0.08

0.06

Gain (%)

0.04

0.02

0

–40 –20 200408060 100

GAIN vs TEMPERATURE

Mode 3

Mode 0

Temperature (°C)

ADS1202

SBAS275

TYPICAL CHARACTERISTICS (Cont.)

SIGNAL-TO-NOISE RATIO vs TEMPERATURE

–40 –20 200408060 100

Temperature (°C)

SNR (dB)

71.0

70.8

70.6

70.4

70.2

70.0

69.8

69.6

69.4

69.2

69.0

Mode 0

Mode 3

EFFECTIVE NUMBER OF BITS

vs DECIMATION RATIO

0 400 800 1200 1600 2000

Decimation Ratio (OSR)

ENOB

16

14

12

10

8

6

4

Sinc

3

Filter

Sinc

2

Filter

VDD = 5V, +In = –250mV to 250mV, –In = 0V, and MCLK = 10MHz, unless otherwise noted.

80
70
60
50
40
30

RMS Noise (µV)

20
10

0

–320 –240 –80–160 0 24016080 320

71.0

70.6

70.2

RMS NOISE vs INPUT VOLTAGE LEVEL

Differential Input Voltage (mV)

SIGNAL-TO-NOISE + DISTORTION

vs TEMPERATURE

Mode 3

69.8

SINAD (dB)

69.4

69.0
–40 –20 200408060 100

Temperature (°C)

SPURIOUS-FREE DYNAMIC RANGE

AND TOTAL HARMOINIC DISTORTION

95
93
91
89
87
85
83

SFDR (dB)

81
79
77
75

–40 –20 200408060 100

ADS1202

SBAS275

vs TEMPERATURE (Mode 0)

SFDR

THD

Temperature (°C)

Mode 0

0.5Vp-p
5kHz

–95
–93
–91
–89
–87
–85

THD (dB)

–83
–81
–79
–77
–75

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SPURIOUS-FREE DYNAMIC RANGE

AND TOTAL HARMOINIC DISTORTION

95
93
91
89
87
85
83

SFDR (dB)

81
79
77
75

–40 –20 200408060 100

vs TEMPERATURE (Mode 3)

SFDR

THD

Temperature (°C)

–95
–93
–91
–89
–87
–85
–83
–81
–79
–77
–75

THD (dB)

7