ZSSC3138BE2_技术文档

ZSSC3138

Sensor Signal Conditioner for

Ceramic Sensor Applications

Datasheet

Brief Description

Benefits

The ZSSC3138 is a member of the ZSSC313x

product family of CMOS integrated circuits designed

for automotive/ industrial sensor applications. All

family members are well suited for highly accurate

amplification and sensor-specific correction of

resistive bridge sensor signals. An internal 16-bit

RISC microcontroller running a correction algorithm

compensates sensor offset, sensitivity, temperature

drift, and non-linearity of the connected sensor

element. The required calibration coefficients are

stored by the one-pass calibration procedure on chip

(EEPROM).

•

Family approach offers the best fitting IC selec-

tion to build cost-optimized applications

•

No external trimming components required

Low number of external components needed

PC-controlled configuration and one-pass/

end-of-line calibration via I²C™* or ZACwire™

interface: simple, cost efficient, quick, and precise

•

High accuracy (0.25% FSO** @ -25 to +85°C;

0.5% FSO @ -40 to +125°C)

Optimized for automotive/industrial environments

due to robust protection circuitries, excellent

electromagnetic compatibility and AEC-Q100

qualification

The ZSSC3138 offers a maximum analog gain of

420 and two offset compensation features. These fit

perfectly with the requirements of ceramic thick-film-

based sensor elements as well as strain gauges.

The high amplification in combination with the offset

compensation offers the capability to set up ceramic

thick-film-based sensor applications without laser

trimming, which leads to better long-term stability.

Available Support

•

Evaluation Kits

Application Notes

Mass Calibration System

Physical Characteristics

Features

•

Supply voltage 4.5 to 5.5 V

•

Adjustable to nearly all resistive bridge sensor

types, analog gain of 420, maximum overall gain

of 1680

Operation temperature: -40°C to +125°C

(-40°C to +150°C extended temperature range

depending on product version)

•

Enhanced sample rate: 7.8 kHz maximum

High ADC resolution 15/16 bit

•

Available in RoHS-compliant JEDEC-SSOP14

package or delivery as die

Safety functionality sensor connection

Internal temperature compensation

Digital compensation of sensor offset, sensitivity,

temperature drift, and non-linearity

ZSSC3138 Minimum Application Requirements

•

Output options: ratiometric analog voltage output

(5 - 95% maximum, 12.4 bit resolution) or

ZACwire^TM(digital One-Wire Interface (OWI))

VCC

Sensor

Module

•

Sensor biasing by voltage

High voltage protection up to 33 V

Supply current: 5.5mA maximum

Reverse polarity and short circuit protection

OUT

ZSSC3138

Wide operation temperature range between

-40 to +150°C

•

Traceability by user-defined EEPROM entries

GND

*

Note: I²C™ is a trademark of NXP.

** FSO = Full Scale Output.

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January 25, 2016

ZSSC3138

Sensor Signal Conditioner for

Ceramic Sensor Applications

Datasheet

ZSSC3138 Application Example

Out / OWI

GND

C2

100nF

8

7

6

5

4

3

2

1

VSSE

AOUT

VBN

VDDE

VDD

n.c.

V_SUPP

+4.5V to +5.5V

C3

47nF

9

Sensor Bridge

10

11

12

13

14

VBR_B

VBP

SCL

SDA

Serial Interface

SDA

VBR_T

N.C.

VSSA

VDDA

C4

C5

C1

100nF

Ordering Information (See data sheet section 8 for complete delivery options.)

Product Sales Code

Description

Package

ZSSC3138BE1

ZSSC3138 die – tested; temperature range -40 to +150°C

Unsawn wafer: add “B” to sales code

Die on frame: add “C” to sales code

ZSSC3138BA1

ZSSC3138BE2

ZSSC3138BA2

ZSSC313xKITV1.1

ZSSC3138 die – tested; temperature range -40 to +125°C

ZSSC3138 SSOP14 – temperature range -40 to +150°C

ZSSC3138 SSOP14 – temperature range -40 to +125°C

Unsawn wafer: add “B” to sales code

Die on frame: add “C” to sales code

Tube: add “T” to sales code

Tape & Reel: add “R”

Tube: add “T” to sales code

Tape & Reel: add “R”

ZSSC313x Evaluation Kit, version 1.1, including Evaluation

Board, ZSSC3138 IC samples, USB cable

Kit

ZSSC313x Mass

Calibration System V1.1

Modular Mass Calibration System (MSC) for ZSSC313x

including MCS boards, cable, connectors

Kit

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January 25, 2016

ZSSC3138 Datasheet

Contents

1

Electrical Characteristics...............................................................................................................................5

1.1. Absolute Maximum Ratings....................................................................................................................5

1.2. Operating Conditions..............................................................................................................................5

1.3. Electrical Parameters .............................................................................................................................6

1.3.1. Supply Current and System Operation Conditions..........................................................................6

1.3.2. Analog Front-End (AFE) Characteristics .........................................................................................6

1.3.3. Temperature Measurement .............................................................................................................6

1.3.4. A/D Conversion................................................................................................................................6

1.3.5. Sensor Check...................................................................................................................................7

1.3.6. DAC and Analog Output ..................................................................................................................7

1.3.7. System Response............................................................................................................................8

1.4. Interface Characteristics and EEPROM.................................................................................................9

1.4.1. I²C^TMInterface..................................................................................................................................9

1.4.2. ZACwire™ One-Wire Interface (OWI) .............................................................................................9

1.4.3. EEPROM..........................................................................................................................................9

Circuit Description .......................................................................................................................................10

2.1. Signal Flow ...........................................................................................................................................10

2.2. Application Modes ................................................................................................................................11

2.3. Analog Front-End (AFE).......................................................................................................................11

2.3.1. Programmable Gain Amplifier (PGA).............................................................................................12

2.3.2. Offset Compensation .....................................................................................................................12

2.3.3. Measurement Cycle .......................................................................................................................13

2.3.4. Analog-to-Digital Converter............................................................................................................14

2.4. Temperature Measurement..................................................................................................................16

2.5. System Control and Conditioning Calculation......................................................................................16

2.5.1. General Working Modes ................................................................................................................16

2.5.2. Startup Phase ...............................................................................................................................17

2.5.3. Conditioning Calculation ................................................................................................................17

2.6. Analog or Digital Output .......................................................................................................................18

2.7. Serial Digital Interface ..........................................................................................................................18

2.8. Failsafe Features..................................................................................................................................18

2.9. High Voltage, Reverse Polarity, and Short Circuit Protection ..............................................................19

Application Circuit Examples.......................................................................................................................20

Pin Configuration and Package...................................................................................................................21

ESD Protection............................................................................................................................................22

Quality and Reliability..................................................................................................................................22

Customization..............................................................................................................................................22

Ordering Information ...................................................................................................................................22

2

3

4

5

6

7

8

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January 25, 2016

ZSSC3138 Datasheet

9

Related Documents.....................................................................................................................................23

10 Glossary ......................................................................................................................................................24

11 Document Revision History.........................................................................................................................25

List of Figures

Figure 2.1 Block Diagram of the ZSSC3138...................................................................................................10

Figure 2.2 Measurement Cycle with 1 Bridge Sensor Signal Measurement per Special Measurement........14

Figure 3.1 Application with On-Chip Diode Temperature Sensor...................................................................20

Figure 4.1 ZSSC3138 SSOP14 Pin Diagram .................................................................................................21

List of Tables

Table 1.1

Table 1.2

Table 1.3

Table 1.4

Table 2.1

Table 2.2

Table 2.3

Table 3.1

Table 4.1

Absolute Maximum Ratings.............................................................................................................5

Operating Conditions .......................................................................................................................5

Electrical Parameters.......................................................................................................................6

Interface Characteristics and EEPROM ..........................................................................................9

Adjustable Gains, Resulting Sensor Signal Spans and Common Mode Ranges .........................12

Extended Analog Zero Compensation Ranges (XZC) ..................................................................13

ADC Resolution versus Output Resolution and Sample Rate.......................................................16

External Components for Application Circuit Examples ................................................................20

Pin Configuration and Definition ....................................................................................................21

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January 25, 2016

ZSSC3138 Datasheet

1

Electrical Characteristics

1.1. Absolute Maximum Ratings

Parameters apply in operation temperature range and without time limitations.

Table 1.1

No.

Absolute Maximum Ratings

Parameter

Symbol

Conditions

Min

Max

Unit

1.1.1

Supply voltage ¹⁾

VDDE_AMR

To VSSE, refer to

section 3 for application

circuits

-33

33

VDC

1.1.2

1.1.3

Potential at AOUT pin ¹⁾

Analog supply voltage ¹⁾

V_OUT

Referenced to VSSE

-33

33

VDC

VDDA_AMR

Referenced to VSSA,

VDDE - VDDA < 0.35V

-0.3

6.5

1.1.4

Voltage at all analog and

digital IO pins

V_{A_IO}

V_{D_IO}

Referenced to VSSA

-0.3

-55

VDDA + 0.3

150

VDC

1.1.5

Storage temperature

T_STG

°C

1)

Refer to the ZSSC313x High Voltage Protection Description for specification and detailed conditions.

1.2. Operating Conditions

All voltages are referenced to VSSA.

Table 1.2

No.

Operating Conditions

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

1.2.1

Ambient temperature ^{1) 2)}

T_{AMB_TQE}

Extended Temperature

Range (TQE)

-40

150

°C

T_{AMB_TQA}

Advanced-Performance

Temperature Range

(TQA)

-40

125

85

°C

T_{AMB_TQI}

Best-Performance

Temperature Range (TQI)

-25

1.2.2

1.2.3

Supply voltage

Bridge resistance ^{3) 4)}

VDDE

R_BR

4.5

2

5.0

5.5

25

VDC

kΩ

1)

2)

3)

4)

Maximum operation temperature range depends on product version (refer to section 8).

See the temperature profile description in the ZSSC313x Dice Package Document.

No measurement in mass production, parameter is guaranteed by design and/or quality observation.

Symmetric behavior and identical electrical properties (especially the low pass characteristic) of both sensor inputs of the ZSSC3138 are required.

Unsymmetrical conditions of the sensor and/or external components connected to the sensor input pins of the ZSSC3138 can generate a failure in

signal operation.

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January 25, 2016

ZSSC3138 Datasheet

1.3. Electrical Parameters

All parameter values are valid under the operating conditions specified in section 1.2 (special definitions

excluded). All voltages referenced to VSSA.

Note: See important notes at the end of Table 1.3.

Table 1.3

Electrical Parameters

No.

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

1.3.1. Supply Current and System Operation Conditions

1.3.1.1 Supply current

I_S

Without bridge and load

current, f_OSC≤ 3 MHz

5.5

4

mA

1.3.1.2 Oscillator frequency ¹⁾

f_OSC

Adjustment guaranteed for

whole temperature range

(T_{AMB_TQE)}

2

3

MHz

1.3.2. Analog Front-End (AFE) Characteristics

1.3.2.1 Input span

V_{IN_SP}

Analog gain: 105 to 2.8

Analog gain: 420 to 2.8

8

1

275

10

mV/V

nA

1.3.2.2 Parasitic differential input

I_{IN_OFF}

Temperature range

T_{AMB_TQE}

-10

1)

offset current

Temperature range

T_{AMB_TQI}

-2

2

nA

1.3.2.3 Common mode

input range

V_{IN_CM}

Depends on gain adjust;

XZC off (refer to section

2.3.1)

0.29

0.65

VDDA

1.3.2.4 Analog offset

compensation range

Depends on gain

adjustment; refer to

section 2.3.2

-300

300

% V_{IN_SP}

1.3.3. Temperature Measurement

(Refer to section 2.4.)

1.3.3.1 Internal temperature diode

sensitivity

ST_TSI

Raw values,

without conditioning

700

13

2700

ppm FS

/ K

1.3.4. A/D Conversion

1.3.4.1 A/D resolution ¹⁾

1.3.4.2 DNL ¹⁾

r_ADC

16

Bit

DNL_ADC

r_ADC=13bit, f_OSC=3MHz,

best fit, complete AFE,

range according to 1.3.4.5

0.95

LSB

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January 25, 2016

ZSSC3138 Datasheet

No.

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

1.3.4.3 INL TQA

INL_ADC

r_ADC=13bit, f_OSC=3MHz,

best fit, complete AFE,

range according to 1.3.4.5

4

LSB

1.3.4.4 INL TQE

INL_{ADC_TQE}r_ADC=13bit, f_OSC=3MHz,

best fit, complete AFE,

5

LSB

range according to 1.3.4.5,

temperature range T_{AMB_TQE}

1.3.4.5 ADC input range

1.3.5. Sensor Check

V_{ADC_IN}

0.1

0.9

VDDA

1.3.5.1 Sensor connection loss

1.3.5.2 Sensor input short

R_{SCC_min}

Detection threshold

100

0

kΩ

R_{SSC_short}

Short detection

guaranteed

50

Ω

1.3.5.3 Sensor input no short

R_{SSC_pass}

Corresponds with

minimum sensor output

resistance

1000

Ω

1.3.6. DAC and Analog Output

1.3.6.1 D/A resolution

r_DAC

Analog output, 10-90%

12

Bit

mA

1.3.6.2 Output current sink and

source for VDDE=5V

I_{OUT_SRC/SINK}V_OUT: 5-95%, R_LOAD≥ 2kΩ

V_OUT: 10-90%, R_LOAD≥1kΩ

2.5

5

mA

1.3.6.3 Short circuit current

1.3.6.4 Output signal range

I_{OUT_max}

To VDDE/VSSE ²⁾

With R_LOAD≥ 2kΩ

With R_LOAD≥ 1kΩ

C_LOAD< 50nF

-25

0.05

0.1

25

mA

V_{OUT_RANGE}

0.95

0.90

VDDE

V/µs

Ω

1.3.6.5 Output slew rate ¹⁾

SR_OUT

0.1

1.3.6.6 Output resistance in

diagnostic mode

R_{OUT_DM}

Diagnostic range:

<4 to 96>%, R_LOAD≥ 2kΩ

<8 to 92>%, R_LOAD≥ 1kΩ

82

1.3.6.7 Load capacitance ¹⁾

C_LOAD

C3 + C_LOAD

150

nF

(refer to section 3)

1.3.6.8 DNL

DNL_OUT

INL_OUT

-1.5

-5

1.5

5

LSB

1.3.6.9 INL TQA

1.3.6.10 INL TQE

Best fit, r_DAC=12bit

INL_{OUT_TQE}Best fit, r_DAC=12bit,

temperature range T_{AMB_TQE}

-8

8

1.3.6.11 Output leakage current

at 150°C

I_{OUT_LEAK}

In case of power or

ground loss

-25

25

µA

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January 25, 2016

ZSSC3138 Datasheet

No.

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

1.3.7. System Response

1) 3)

1.3.7.1 Startup time

t_STARTUP

1-step ADC, f_OSC=3MHz

r_ADC=14bit)

35

ms

(To 1^stoutput, ROM check

disabled)

2-step ADC, f_OSC=3MHz,

r_ADC=14bit)

5

ms

1.3.7.2 Response time ¹⁾

t_RESPONSE

1-step ADC, f_OSC=4MHz,

r_ADC=13bit

8.7

13.1

384

17.4

(100% input step; refer to

Table 2.3)

2-step ADC, f_OSC=4MHz,

r_ADC=13bit

256

512

µs

1.3.7.3 Bandwidth ¹⁾

BW

1-step ADC

2-step ADC

200

7.8

Hz

(In comparison to an

equivalent analog SSC.

Refer to Table 2.3)

kHz

1.3.7.4 Analog output noise

V_{NOISE_PP}

Shorted inputs

10

3

mV

1)

peak-to-peak

bandwidth ≤ 10kHz

1.3.7.5 Analog output noise

RMS ¹⁾

V_{NOISE_RMS}Shorted inputs

bandwidth ≤ 10kHz

1.3.7.6 Ratiometricity error

RE

Maximum error for

1000

ppm

VDDE=5V to 4.5/5.5V

1.3.7.7 Overall failure ⁴⁾

F_{OVERALL_TQI}f_OSC≤3MHz, r_ADC=13bit,

0.25

(0.1)

% FS

temperature range T_{AMB_TQI}

Deviation from ideal line

including INL, gain, offset

and temperature errors.

F_{OVERALL_TQA}f_OSC≤3MHz, r_ADC=13bit,

0.5

% FS

temperature range T_{AMB_TQA}

(0.25)

No sensor-caused effects.

F_{OVERALL_TQE}f_OSC≤3MHz, r_ADC=13bit,

1.0

Failure for digital readout

shown in parenthesis.

temperature range T_{AMB_TQE}

(0.5)

1)

2)

3)

4)

No measurement in mass production, parameter is guaranteed by design and/or quality observation.

Minimum output voltage to VDDE or maximum output voltage to VSSE.

Depends on resolution and configuration. Start routine begins approximately 0.8ms after power on.

If XZC is active, additional overall failure of 25ppm/K for XZC=31 maximum. Failure decreases linearly for XZC<31.

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January 25, 2016

ZSSC3138 Datasheet

1.4. Interface Characteristics and EEPROM

Table 1.4

Interface Characteristics and EEPROM

No.

Parameter Symbol

Conditions

Min

Typ

Max

Unit

1.4.1. I²C^TMInterface

(Refer to the ZSSC313x Functional Description for timing details)

1.4.1.1 I²C voltage level HIGH

V_I²C,HIGH

0.8

VDDA

pF

1.4.1.2 I²C voltage level LOW ¹⁾

1.4.1.3 Slave output level LOW ¹⁾

1.4.1.4 SDA load capacitance ¹⁾

1.4.1.5 SCL clock frequency ¹⁾

1.4.1.6 Internal pull-up resistor ¹⁾

V_I²C,LOW

0.2

0.15

400

100

V_{I²C,LOW_OUT}Open drain, I_OL<2mA

C_SDA

f_I²C

f_OSC≥2MHz

kHz

R_I²C,PULLUPI

25

kΩ

1.4.2. ZACwire™ One-Wire Interface (OWI)

(Refer to the ZSSC313x Functional Description for timing details)

1.4.2.1 OWI voltage level HIGH ¹⁾

1.4.2.2 OWI voltage level LOW ¹⁾

1.4.2.3 Slave output level LOW ¹⁾

1.4.2.4 Start window ¹⁾

V_OWI,HIGH

0.75

VDDA

ms

V_OWI,LOW

0.2

0.15

455

V_{OWI,LOW_OUT}Open drain, I_OL<2mA

t_OWI,STARTWINAt f_OSC=3MHz

96

175

1.4.3. EEPROM

1.4.3.1 Ambient temperature for

EEPROM programming ¹⁾

T_{AMB_EEP}

-40

150

°C

1.4.3.2 Write cycles ¹⁾

n_{EEP_WRI}

Write <= 85°C

Write up to 150°C

≤175°C

100 000

100

8 * 10⁸

1.4.3.3 Read cycles ^{1) 2)}

1.4.3.4 Data retention ^{1) 3)}

n_{EEP_READ}

t_{EEP_RETENTION}1300h at 175°C

( = 3000h at 150°C

15

a

+ 27000h at 125°C

+ 100000h at 55°C)

1.4.3.5 Programming time ¹⁾

t_{EEP_WRI}

Per written word

12

ms

1)

2)

3)

No measurement in mass production, parameter is guaranteed by design and/or quality observation.

Valid for the dice. Note that the package and the temperature version causes additional restrictions.

Over lifetime and valid for the dice. Use the calculation sheet IDT Temperature Profile Calculation Sheet for temperature stress calculation. Note that

the package and the temperature version causes additional restrictions.

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January 25, 2016

ZSSC3138 Datasheet

2

Circuit Description

2.1. Signal Flow

The ZSSC3138’s signal path is partly analog and partly digital. The analog section is differential – this means the

differential bridge sensor signal is internally handled via two signal lines that are rejected symmetrically around an

internal common mode potential (analog ground = VDDA/2).

As a result of the differential design, it is possible to amplify positive and negative input signals that are within the

common mode range of the signal input.

Figure 2.1

Block Diagram of the ZSSC3138

ZACwire

™

Digital

Data I/O

EEPROM

RAM

I²C™

*

Analog

Output

PGA

TS

ADC

CMC

DAC

BAMP

ROM

Analog Domain

Digital Domain

ZSSC3138

* Note: I²C™ is a trademark of NXP.

PGA

Programmable Gain Amplifier

TS

On-chip Temperature Sensor (pn-junction)

Multiplexer

MUX

ADC

Analog-to-Digital Converter

Calibration Microcontroller

CMC

ROM

RAM

EEPROM

DAC

Read-Only Memory for Correction Formula and Algorithm

Volatile Memory for Calibration Parameters and Configuration

Non-volatile Memory for Calibration Parameters and Configuration

Digital-to-Analog Converter

BAMP

Output Buffer Amplifier

The differential signal from the bridge sensor is pre-amplified by the programmable gain amplifier (PGA). The

multiplexer (MUX) transmits the signals from either the bridge sensor or the internal temperature sensor to the

analog-to-digital converter (ADC) in a specific sequence. The ADC converts these signals into digital values.

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January 25, 2016

ZSSC3138 Datasheet

The digital signal conditioning is processed by the calibration microcontroller (CMC). It is based on a correction

formula that uses sensor-specific coefficients determined during calibration. The formula is located in ROM, and

the sensor-specific coefficients are stored in EEPROM. Depending on the programmed output configuration, the

conditioned sensor signal is output as an analog signal, or alternatively can be readout via a digital serial interface

(I²C™ or ZACwire™). The configuration data and the correction parameters must also be programmed into the

EEPROM via the digital interfaces.

2.2. Application Modes

For each application, a configuration set must be established by programming the on-chip EEPROM for the

following modes:

•

Sensor channel

. Input range: The gain adjustment of the analog front-end (AFE) with respect to the maximum sensor

signal span and the zero point of the A/D conversion must be selected.

. Extended analog offset compensation (XZC): If required, this compensates large sensor offsets; e.g., if

the sensor offset voltage is near to or larger than the sensor span.

. Resolution/response time: The A/D converter must be configured for resolution. The ADC order (first or

second order) must also be configured. These settings influence the sampling rate and the signal

integration time, and thus, the noise immunity.

•

Temperature

. Temperature measurement

2.3. Analog Front-End (AFE)

The analog front-end (AFE) consists of the three-stage programmable gain amplifier (PGA), the multiplexer

(MUX), and the analog-to-digital converter (ADC).

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January 25, 2016

ZSSC3138 Datasheet

2.3.1.

Programmable Gain Amplifier (PGA)

Table 2.1 shows the adjustable gains, the sensor signal spans, and the valid common mode range.

Table 2.1

Adjustable Gains, Resulting Sensor Signal Spans and Common Mode Ranges

Input Common Mode Range

V_{IN_CM}[% VDDA] ²⁾

XZC = Off

PGA Gain

a_IN

Maximum Span

V_{IN_SP}[mV/V] ¹⁾

XZC = On

45 to 55

Not applicable

420

280

210

140

105

70

1.8

2.7

29 to 65

32 to 57

3.6

5.4

7.1

10.7

14.3

21.4

28.5

53.75

80

52.5

35

26.3

14

9.3

7

107

267

2.8

1)

2)

Recommended maximum internal signal range is 75% of supply voltage.

Span is calculated by the following formula: Span = 0.75 (VBR_T – VBR_B) / Gain.

Refer to section 2.3.2 for an explanation of the extended analog zero compensation (XZC).

2.3.2.

Offset Compensation

The ZSSC3138 processes a sensor-offset correction during the digital signal conditioning by the calibration

microcontroller (CMC).

The ZSSC3138 also supports an extended analog zero compensation (XZC) for large offsets up to a maximum of

approximately 300% of signal span, depending on the gain adjustment (Table 2.2). This prevents overdriving the

analog signal path in the case of a large sensor offset by adding a compensation voltage to the second

amplification stage.

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January 25, 2016

ZSSC3138 Datasheet

Table 2.2

PGA Gain

Extended Analog Zero Compensation Ranges (XZC)

Maximum Span

V_{IN_SP}[mV/V]

Offset Shift / XZC Step

Maximum Offset Shift

[mV/V]

Maximum Shift (XZC =

±31)

a_IN

[% V_{IN_SP}]

[% V_{IN_SP}

388%

237%

388%

237%

388%

237%

388%

237%

161%

388%

237%

161%

26%

]

420

280

210

140

105

70

1.8

2.7

12.5 %

7.6 %

7.8

7.1

15.5

14.2

31

3.6

12.5 %

7.6 %

5.4

7.1

12.5 %

7.6 %

10.7

14.3

21.4

28.5

53.75

80

28

52.5

35

12.5 %

7.6 %

32

57

26.3

14

5.2 %

52

12.5 %

7.6 %

194

189

161

72

9.3

7

107

267

5.2 %

2.8

0.83 %

2.3.3.

Measurement Cycle

The measurement cycle is controlled by the CMC. Depending on EEPROM settings, the multiplexer (MUX)

selects the following input signals in a defined sequence:

•

Pre-amplified bridge sensor signal

Temperature sensor signal

Internal offset of the input channel (V_OFF

)

The cycle diagram in Figure 2.2 shows the basic structure of the measurement cycle. After power-on, the startup

routine is processed, which performs all required measurements to expedite acquiring an initial valid conditioned

sensor output. After the startup routine, the normal measurement cycle runs.

13

January 25, 2016

ZSSC3138 Datasheet

Figure 2.2

Measurement Cycle with 1 Bridge Sensor Signal Measurement per Special Measurement

Measurement Cycle with Bridge Signal Output

CTAZ CT BRAZ

CFGAPP:BRCNT = 0

Startup

(1 bridge sensor signal measurement per special measurement)

12

BR CTAZ BR

CT

BR

CMV

BR SSCP BR SSCN BR BRAZ

Measurements

per Cycle

Measurement Cycle

Measurement Cycle Phases

Main Signals Measurement

Safety Functions Measurement *

Analog Output Updated

Bridge Sensor

BR

Calibration Temperature

Measurement

Sensor Short Check

Positive-Biased Measurement

Sensor Common Mode Voltage

Measurement

Bridge Sensor Signal

CT

SSCP

SSCN

CMV

Measurement

Bridge Sensor

BRAZ

Calibration Temperature

Auto-Zero Measurement

Sensor Short Check

Negative-Biased Measurement

CTAZ

* Not available for all ZSSC313x products. See Table 1.1

in the ZSSC313x Functional Description.

Auto-Zero Measurement

2.3.4.

Analog-to-Digital Converter

The A/D converter is implemented using full-differential switched-capacitor technique.

•

Programmable ADC resolutions are r_ADC=<13, 14>bit. The ZSSC3138 supports <15, 16>bit resolution with

range zooming.

The A/D conversion is integrating, inherently monotone, and insensitive to short and long term instability of the

clock frequency. The conversion time t_ADCdepends on the desired resolution and can be roughly calculated by

equation (1):

2^r^ADC

t_ADC

=

f

(1)









OSC

2





Where

r_ADC

f_OSC

Resolution of A/D conversion

Frequency of internal oscillator (refer to 1.3.1)

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January 25, 2016

ZSSC3138 Datasheet

The ZSSC3138 supports a high sample rate ADC mode (2-step conversion) with the advantage of a much shorter

conversion time but with the drawback of a lower noise immunity caused by the shorter signal integration time.

The conversion time t_ADC,2stepin this mode is roughly calculated by equation (2):

2⁽^r

_ADC+3 2

)

t_ADC,2-step

=

f

(2)





OSC







2



Refer to the ZSSC313x Bandwidth Calculation Sheet for a detailed calculation of sampling time and bandwidth.

The result of the A/D conversion is a relative counter result Z corresponding to the following equation:

V_{ADC_DIFF}

r

ADC

Z = 2

⋅(

− RS)

(3)

V_{ADC_REF}

Where

r_ADC

Resolution of A/D conversion

V_{ADC_DIFF}

V_{ADC_REF}

RS

Differential ADC input voltage

ADC reference voltage (V_{VBR_T}-V_{VBR_B}or V_VDDA-V_VSSA, if BRREF=1)

Digital ADC Range Shift (RS = 1/16, 1/8, 1/4, 1/2; controlled by the EEPROM contents)

With the RS value, a sensor input signal can be shifted in the optimal input range of the ADC.

The condition required for ensuring the specified accuracy, stability, and non-linearity parameters of the analog

front-end is that the differential ADC input voltage V_{ADC_DIFF}does not exceed the range of 10% to 90% of the ADC

reference voltage V_{ADC_REF}. This requirement must be met for the whole temperature range and for all sensor

tolerances.

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January 25, 2016

ZSSC3138 Datasheet

Table 2.3

ADC Resolution versus Output Resolution and Sample Rate

Output Resolution ¹⁾Sample Rate ²⁾

ADC Adjustment

Averaged Bandwidth ²⁾

ADC

Sample

Rate Mode

r_ADC

[bit]

Digital

[bit]

Analog

[bit]

f_OSC=3MHz

[Hz]

f_OSC=4MHz

[Hz]

f_OSC=3MHz

[Hz]

f_OSC=4MHz

[Hz]

13

14

15

16

13

14

15

16

13

14

13

14

12

345

178

460

237

130

67

172

89

Normal

High

90

120

34

45

61

17

23

5859

3906

2930

1953

7813

5208

3906

2604

2203

1469

1101

734

2937

1958

1468

979

1)

2)

Output resolution does not exceed ADC resolution. PGA gain should be such that the differential ADC input signal uses at least 50% of ADC input

range to ensure maximum achievable output resolution.

Refer to the ZSSC313x Bandwidth Calculation Sheet for a detailed calculation of sampling time and bandwidth.

2.4. Temperature Measurement

The ZSSC3138 supports acquiring temperature data needed for conditioning of the sensor signal using an

internal pn-junction temperature sensor.

Refer to the ZSSC313x Functional Description for a detailed explanation of temperature sensor adaptation and

adjustment.

2.5. System Control and Conditioning Calculation

The system control supports the following tasks/features:

•

Managing the startup sequence

Controlling the measurement cycle regarding to the EEPROM-stored configuration data

Sensor signal conditioning (calculation of the 16-bit correction for each measurement signal using the

EEPROM-stored conditioning coefficients and the ROM-based formulas)

Processing communication requests received via the digital interfaces

Performing failsafe tasks and message detected errors by setting diagnostic states

•

2.5.1.

General Working Modes

ZSSC3138 supports three different working modes:

•

Normal Operation Mode (NOM) – for continuous processing of signal conditioning

Command Mode (CM) – for calibration and access to all internal registers

Diagnostic Mode (DM) – for failure messages

16

January 25, 2016

ZSSC3138 Datasheet

1

2.5.2.

Startup Phase

After power-on, the startup phase is processed, which includes

•

Internal supply voltage settling including reset of the circuitry by the power-on reset block (POR).

Refer to the ZSSC313x High Voltage Protection Description for power-on/off thresholds.

Duration (beginning with V_VDDA-V_VSSA=0V): 500µs to 2ms; AOUT: high impedance.

•

System start and configuration, EEPROM readout, and signature check.

Duration: ~200µs; AOUT: lower diagnostic range (LDR).

Processing the measurement cycle start routine.

Duration: 5x A/D conversion time; AOUT behavior depends on configured one-wire communication mode

(refer to section 2.6):

OWIANA or OWIDIS  AOUT: lower diagnostic range (LDR)

OWIWIN or OWIENA  AOUT: tri-state

If an error is detected during the startup phase, the Diagnostic Mode (DM) is activated and the analog output at

the AOUT pin remains in the lower diagnostic range.

After the startup phase, the continuous running measurement and sensor signal conditioning cycle is started, and

analog or digital output of the conditioned sensor signal is activated. If the one-wire communication mode

OWIWIN is selected, the OWI startup window expires before analog output is available.

2.5.3.

Conditioning Calculation

The digitalized value for the bridge signal is processed with a conditioning formula to remove offset and

temperature dependency and to compensate nonlinearity up to 3^rdorder. The result is a non-negative 15-bit value

for the measured bridge sensor signal in the range [0; 1). This value is available for readout via I²C or OWI

communication. For the analog output, the value is clipped to the programmed output limits.

Note: The extent of signal deviation that can be compensated by the conditioning calculation depends on the

specific sensor signal characteristics. For a rough estimation, assume the following: offset compensation

and gain correction are not limited. Notice that resolution of the digitally gained signal is determined by

the ADC resolution in respect to the dynamic input range used. The temperature correction includes first

and second order terms and should be adequate for all practically relevant cases. The non-linearity

correction of the sensor signal is possible for second-order up to about 30% FS regarding ideal fit and for

third-order up to about 20% FS. Overall, the conditioning formula applied is able to reduce the non-

linearity of the sensor signal by a factor of 10.

1

All timing values are roughly estimated for an oscillator frequency f_OSC=3MHz and are proportional to that frequency.

17

January 25, 2016

ZSSC3138 Datasheet

2.6. Analog or Digital Output

The AOUT pin is used for analog output and for one-wire communication (OWI). The latter can be used for digital

readout of the conditioned sensor signal and for end-of-line sensor module calibration. The ZSSC3138 supports

different modes for the analog output in interaction with OWI communication:

•

OWIENA:

OWIWIN:

Analog output is deactivated; OWI readout of the signal data is enabled.

Analog output starts after the startup phase and after the OWI startup window if OWI

communication is not initiated; OWI communication for configuration or for end-of-line

calibration can be started during the OWI startup window (maximum ~500ms) by sending the

START_CM command.

•

OWIANA:

OWIDIS:

Analog output starts after the startup phase; OWI communication for configuration or for end-

of-line calibration can be started during the OWI startup window (maximum ~500ms) by

sending the START_CM command; for command transmission, the driven analog output at

the AOUT pin must be overwritten by the external communication master (AOUT drive

capability is current-limited).

Analog output starts after the startup phase; OWI readout of the signal data is disabled.

The analog output signal is driven by an offset compensated, rail-to-rail output buffer that is current-limited to

prevent damage to the ZSSC3138 from a short circuit between the analog output and power supply or ground.

Output resolution of at least 12-bit in the range of 10% to 90% FS is ensured by a 12.4-bit resistor string DAC.

2.7. Serial Digital Interface

The ZSSC3138 includes a serial digital I²C^TMinterface and a ZACwire^TMinterface for one-wire communication

(OWI). The digital interfaces allow configuration and calibration of the sensor module. OWI communication can be

used to perform an end-of-line calibration via the analog output pin AOUT of a completely assembled sensor

module. The interfaces also provide the readout of the conditioned sensor signal data during normal operation.

Refer to the ZSSC313x Functional Description for a detailed description of the serial interfaces and the

communication protocols.

2.8. Failsafe Features

The ZSSC3138 detects various failures. When a failure is detected, Diagnostic Mode (DM) is activated. DM is

indicated by setting the output pin AOUT to the Lower Diagnostic Range (LDR). When using digital serial

communication protocols (I²C™ or OWI) to read conditioning results data, the error status is indicated by a

specific error code.

A watchdog timer controls the proper operation of the microcontroller. The operation of the internal oscillator is

monitored by an oscillator-failure detection circuit. EEPROM and RAM content are checked when accessed.

Control registers are parity protected.

The sensor connection is checked with regard to broken wires or short circuits (sensor connection check, sensor

short check).

Refer to the ZSSC313x Functional Description for a detailed description of failsafe features and methods of error

indication.

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January 25, 2016

ZSSC3138 Datasheet

2.9. High Voltage, Reverse Polarity, and Short Circuit Protection

The ZSSC3138 is designed for 5V power supply operation.

The ZSSC3138 and the connected sensor are protected from overvoltage and reverse polarity damage by an

internal supply voltage limiter. The analog output AOUT can be connected (short circuit, overvoltage, and reverse

polarity) with all potentials in the protection range under all potential conditions at the pins VDDE and VSSE.

To guarantee this operation, all external components (see application circuit in section 3) are required. The

protection is not time-limited.

Refer to the ZSSC313x High Voltage Protection Description for a detailed description of protection cases and

conditions.

19

January 25, 2016

ZSSC3138 Datasheet

3

Application Circuit Examples

The application circuits contain external components that are needed for overvoltage, reverse polarity, and short

circuit protection.

Note:

Table 3.1

Symbol

C1

Also check the ZSSC313x application notes for application examples and board layout.

External Components for Application Circuit Examples

Component

Capacitor

Min

100

4

Typ ²⁾

Max

Unit Remarks

470

nF

C2

C3 ¹⁾

47

160

10

nF

Value includes the load capacitor C3 and the

capacitance of the connection cable.

C4, C5 ¹⁾

Capacitor

0

nF

Recommended to increase EMI immunity.

Value includes the filter capacitor C4 and C5

and the sensor connection line capacitance.

1)

2)

Increasing capacitors C3, C4, and C5 increases EMI immunity.

Dimensioning is only for example and must be adapted to the requirements of the application.

Figure 3.1

Application with On-Chip Diode Temperature Sensor

Out / OWI

GND

C2

100nF

8

7

6

5

4

3

2

1

VSSE

AOUT

VBN

VDDE

VDD

n.c.

V_SUPP

+4.5V to +5.5V

C3

47nF

9

Sensor Bridge

10

11

12

13

14

VBR_B

VBP

SCL

SDA

Serial Interface

SDA

VBR_T

n.c.

VSSA

VDDA

C4

C5

C1

100nF

20

January 25, 2016

ZSSC3138 Datasheet

4

Pin Configuration and Package

Table 4.1

Pin Configuration and Definition

Pin No Pin Name Description

Remarks

1

2

3

4

5

6

7

8

9

VDDA

VSSA

SDA

Positive Analog Supply Voltage

Negative Analog Supply Voltage

I²C™ Serial Data

Internal analog supply

Internal analog ground

Digital I/O; internal pull-up to VDDA

Digital input; internal pull-up to VDDA

SCL

I²C™ Clock

N.C.

Not connected

VDD

Positive Digital Supply Voltage

Positive External Supply Voltage

Negative External Supply Voltage

Internal digital supply

High voltage analog supply

Ground

VDDE

VSSE

AOUT

Analog Output

High voltage analog I/O

and ZACwire^TMSerial Data

10

11

VBN

Negative Input from Sensor Bridge

Analog input

Analog I/O

VBR_B

Negative Sensor Bridge Supply Voltage

Depending on application circuit, short to VSSA

12

13

VBP

Positive Input from Sensor Bridge

Analog input

VBR_T

Positive Sensor Bridge Supply Voltage

Analog I/O

Depending on application circuit, short to VDDA

14

N.C.

Not connected

The standard package of the ZSSC3138 is an RoHS-compliant SSOP14 “green” package (5.3mm body width)

with a lead pitch of 0.65 mm.

Figure 4.1

ZSSC3138 SSOP14 Pin Diagram

VSSE

AOUT

VBN

VDDE

VDD

N.C.

VBR_B

VBP

SCL

SDA

B

Revision

VBR_T

N.C.

VSSA

VDDA

PPPP

Product and Package Code

LLLLLLLL Lot Number

YYWW Date Code (Year, Work Week)

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January 25, 2016

ZSSC3138 Datasheet

5

ESD Protection

All pins have an ESD protection of >2000V according to the Human Body Model (HBM). The pins VDDE, VSSE

and AOUT have an additional ESD protection of >4000V (HBM).

ESD protection is tested with devices in SSOP14 packages during product qualification. The ESD test follows the

Human Body Model with 1.5kOhm/100pF based on MIL 883, Method 3015.7.

6

Quality and Reliability

The ZSSC3138 is qualified according to the AEC-Q100 standard, operating temperature grade 0.

A fit rate <5fit (T=55°C, S=60%) is guaranteed. A typical fit rate of the semiconductor technology used is 2.5fit.

7

Customization

For high-volume applications that require an upgraded or downgraded functionality compared to the ZSSC3138,

IDT can customize the circuit design by adding or removing certain functional blocks.

Please contact IDT for further information.

8

Ordering Information

Product Sales Code

ZSSC3138BA2T

Description

Package

Tube

ZSSC3138 SSOP14 – temperature range -40 to +125°C

ZSSC3138 die – temperature range -40 to +125°C

ZSSC3138BA2R

ZSSC3138BA1B

Reel

Tested dice on unsawn

wafer

ZSSC3138BA1C

ZSSC3138BE2T

ZSSC3138BE2R

ZSSC3138BE1B

ZSSC3138BE1C

ZSSC313xKITV1.1

ZSSC3138 die – temperature range -40 to +125°C

ZSSC3138 SSOP14 – temperature range -40 to +150°C

ZSSC3138 die – temperature range -40 to +150°C

Tested dice on frame

Tube

Reel

Tested dice on unsawn wafer

Tested dice on frame

ZSSC313x Evaluation Kit, revision 1.1, including Evaluation Board, Kit

ZSSC3138 IC samples, USB cable

ZSSC313x Mass

Modular Mass Calibration System (MSC) for ZSSC313x including

Kit

Calibration System V1.1 MCS boards, cable, connectors

22

January 25, 2016

ZSSC3138 Datasheet

9


型号：	ZSSC3138BE2
厂家：	RENESAS TECHNOLOGY CORP
描述：	Sensor Signal Conditioner for Ceramic Sensor Applications
文件：	总26页 (文件大小：424K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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