Features AMIS HART Modem used designs presently using SYM20C
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A5191HRT
Features
AMIS HART Modem
used designs presently using SYM20C15 Single-chip, half-duplex 1200 bits second modem Bell shift frequencies 1200 2200 3.3V 5.0V power supply Transmit-signal wave shaping Receive band-pass filter
power: optimal intrinsically safe applications CMOS compatible Internal oscillator requires 460.8 crystal ceramic resonator Meets HART physical layer requirements Industrial temperature range Available 28-pin PLCC 32-pin LQFP packages
Description
A5191HRT single-chip, CMOS modem Highway Addressable Remote Transducer (HART) field instruments masters. modem external passive components provide functions needed satisfy HART physical layer requirements including modulation, demodulation, receive filtering, carrier detect transmit-signal shaping. A5191HRT pincompatible with SYM20C15. Description Functional Description sections details compatibility with SYM20C15. A5191HRT uses Phase Continuous Frequency Shift Keying (FSK) 1200 bits second. conserve power receive circuits disabled during transmit operations vice versa. This provides half-duplex operation used HART communications.
Figure 28-Pin PLCC Pinout Diagram
Figure 32-Pin LQFP Pinout Diagram
TEST12
TEST5 INRESET TEST7 TEST8 TEST9 OTXA IAREF
TEST11 ITXD INRTS IXTL OXTL
XXXXYZZ A5191HRTP
TEST5 TEST6 TEST7 TEST8 TEST9 OTXA IAREF
TEST4 TEST3 TEST2 TEST1 TEST12 ORXD
TEST4
TEST3
TEST2
TEST1
ORXD
XXXXYZZ A5191HRTL
TEST11 ITXD INRTS VSSA IXTL OXTL
ICDREF
ORXAF
VDDA
OCBIAS
TEST10
IRXAC
IRXA
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ICDREF OCBIAS TEST10 VSSA VDDA IRXA ORXAF IRXAC
A5191HRT
AMIS HART Modem
Table Pinout Summary 28-Pin PLCC, A5191HRTP (12197-504) Signal Name TEST1 TEST2 TEST3 TEST4 TEST5 INRESET TEST7 TEST8 TEST9 OTXA Type Input Input Input Input Input Input Output Connect connect connect connect Connect Reset digital logic when Connect Connect Connect Output transmit analog. modulated HART transmit signal 4-20 loop interface circuit. Analog reference voltage Carrier detect reference voltage Comparator bias current Connect Analog supply voltage modulated HART receive signal from 4-20 loop interface circuit Analog receive filter output Analog receive comparator input Crystal oscillator output Crystal oscillator input Ground Digital supply voltage Request send Input transmit date. Transmitted HART data stream from UART. connect Received demodulated HART data UART Carrier detect output connect Description
IAREF ICDREF OCBIAS TEST10 VDDA IRXA ORXAF IRXAC OXTL IXTL INRTS ITXD TEST11 ORXD TEST12
Input Input Output Input Power Input Output Input Output Input Ground Power Input Input Output Output
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A5191HRT
AMIS HART Modem
Table Pinout Summary 32-Pin LQFP, A5191HRTL (12197-503) Signal Name TEST5 INRESET TEST7 TEST8 TEST9 OTXA Type Input Input Input Input Input Ground Output Connect Reset digital logic when low. Connect normal operation Connect Connect Connect Digital ground Output transmit analog. modulated HART transmit signal 4-20 loopinterface circuit. Analog reference voltage Carrier detect reference voltage Comparator bias current Connect Analog ground Analog supply voltage modulated HART receive signal from 4-20 loop interface circuit Analog receive filter output Analog receive comparator input Crystal oscillator output Crystal oscillator input Analog ground Digital ground Digital supply voltage Request send Input transmit data. Transmitted HART data stream from UART. connect Received demodulated HART data UART Carrier detect output connect Connect connect Digital supply voltage connect connect Description
IAREF ICDREF OCBIAS TEST10 VSSA VDDA IRXA ORXAF IRXAC OXTL IXTL VSSA INRTS ITXD TEST11 ORXD TEST12 TEST1 TEST2 TEST3 TEST4
Input Input Output Input Ground Power Input Output Input Output Input Ground Ground Power Input Input Output Output Input Power
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A5191HRT
AMIS HART Modem
Descriptions
IAREF: Analog Reference Voltage
This analog input sets operating point operational amplifiers comparators usually selected split potential between VSS. IAREF Characteristics page 2200 When ITXD high, modulator output frequency 1200
IXTL: Oscillator Input
This input internal oscillator must connected parallel mode 460.8 ceramic resonator when using internal oscillator grounded when using external 460.8 clock signal.
ICDREF: Carrier Detect Reference Voltage
This analog input controls which level carrier detect (OCD) becomes active. This determined voltage difference between ICDREF IAREF. Selecting ICDREF IAREF equal 0.08 will carrier detect nominal mVp-p.
OCBIAS: Comparator Bias Current
current through this output controls operating parameters internal operational amplifiers comparators. normal operation, OCBIAS current
INRESET: Reset Digital Logic
When logic (VSS) this input holds digital logic Reset. During normal operation INRESET should VDD. INRESET should held minimum after shown Figure below.
Figure Reset Timing
OCD: Carrier Detect Output
This output goes high when valid input recognized IRXA. received signal greater than threshold specified ICDREF four cycles IRXA signal, valid input recognized.
ORXAF*: Analog Receive Filter Output
INRESET
This signal square wave output receiver highpass filter.
ORXD: Digital Receive Output (CMOS)
This signal outputs digital receive data. When received signal (IRXA) 1200 ORXD outputs logic high. When received signal (IRXA) 2200 ORXD outputs logic low. ORXD qualified internally with OCD.
OTXA: Analog Transmit Output
This output provides trapezoidal signal controlled ITXD. When ITXD low, output frequency 2200 When ITXD high, output frequency 1200 This output active when INRTS when INRTS high.
Note: This signal also present 20C15. labeled Test6. 20C15 datasheet mentions reset function this does emphasize reset chip. Reliable operation modem requires hardware reset shown Figure This true AMIS 12197-503 12197-504 well 20C15.
OXTL: Oscillator Output
This output from internal oscillator must connected external 460.8 clock signal parallel mode 460.8 ceramic resonator when using internal oscillator.
INRTS: Request Send
This active-low input selects operation modulator. OTXA enabled when this signal low. This signal must held high during power-up.
TEST(12:1): Factory Test
These factory test pins. normal operation, these signals Table Table
IRXA*: Analog Receive Input
This input accepts 1200/2200 signals from external filter.
VDD: Digital Power
This power digital modem circuitry.
IRXAC: Analog Receive Comparator Input
This positive input carrier detect comparator receiver filter comparator.
VDDA: Analog Supply Voltage
This power analog modem circuitry.
ITXD: Digital Transmit Input (CMOS)
This input modulator accepts digital data form. When ITXD low, modulator output frequency
VSS: Ground
This analog digital ground.
VSSA: Analog Ground
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A5191HRT
AMIS HART Modem
Functional Description
A5191HRT functional equivalent SYM20C15 HART Modem. contains transmit data modulator signal shaper, carrier detect circuitry, analog receiver demodulator circuitry oscillator, shown Figure
Figure A5191HRT Block Diagram
output demodulator qualified with carrier detect signal (OCD), therefore, only IRXA signals large enough detected (100 mVp-p typically) carrier detect circuit produce received serial data ORXD. Maximum demodulator jitter percent given input frequencies within HART specifications, clock frequency 460.8 (±1.0 percent) zero input (IRXA) asymmetry. TRANSMIT-SIGNAL SHAPER transmit-signal shaper generates HART compliant modulated signal OTXA. Figure Figure show transmit-signal forms A5191HRT. IAREF 1.235 VDC, OTXA will have voltage swing from approximately 0.25 0.75 VDC.
Figure OTXA Waveform (1200
ITXD INRTS ORXD
Control Logic
Modulator Transmit Wave Shaping
OTXA
IXTL OXTL
Carrier Detect Oscillator
Receive Filter Demodulator
IRXA IRXAC ORXAF IAREF ICDREF OCBIAS
internal HART modem modulates transmit-signal demodulates receive signal. transmit-signal shaper enables A5191HRT transmit HART compliant signal. carrier detected comparing receiver filter output with difference between external voltage references. analog receive circuitry band-pass filters received signal input modem carrier detect circuitry. oscillator provides modem with stable time base using either simple external resonator external clock source. A5191HRTLOGIC modem consists modulator demodulator. modem uses shift frequencies nominally 1200 (for 2200 (for rate 1200 bits/second.
Modulator
modulator accepts digital data form ITXD input generates modulated signal OTXA output. INRTS must logic modulator active.
200mV
200µs
Figure OTXA Waveform (2200
Demodulator
demodulator accepts signal IRXA input reproduces original modulating signal ORXD output. nominal rate 1200 bits second. Figure illustrates demodulation process.
Figure Demodulator Signal Timing
IRXA ORXD
200mV 200µs
1/1200
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A5191HRT
AMIS HART Modem
Bias Current Resistor
A5191HRT requires bias current resistor connected between OCBIAS VSS. bias current controls operating parameters internal operational amplifiers comparators. value bias current resistor determined reference voltage IAREF following formula:
CARRIER DETECT CIRCUITRY Carrier Detect Comparator shown Figure below generates logic output IRXAC voltage below ICDREF. comparator output into carrier detect block (see Figure page carrier detect block drives carrier detect output high INRTS high four consecutive pulses comparator have arrived. stays high long INRTS high next comparator pulse received less than Once goes inactive, takes four consecutive pulses comparator assert again. Four consecutive pulses amount 3.33 when received signal 1200 1.82 when received signal 2200 ANALOG RECEIVER CIRCUITRY
recommended bias current resistor when IAREF equal 1.235 VDC. Figure external capacitor values have tolerance percent resistors have tolerance percent, except which tolerance percent. External A5191HRT, filter exhibits three-pole, high-pass filter one-pole, low-pass filter 2500 Internally, A5191HRT high-pass pole low-pass pole kHz. low-pass pole vary much percent. input impedance entire filter greater than frequencies below kHz.
Voltage References
A5191HRT requires voltage references, IAREF ICDREF. IAREF sets operating point internal operational amplifiers comparators. 1.235 reference (Analog Devices AD589) suitable IAREF. level which (carrier detect) becomes active determined voltage difference (ICDREF IAREF). Selecting voltage difference 0.08 will carrier detect nominal mVp-p.
Figure Receive Filter Schematic
422k (15) ORXAF (14) IRXA Recieve Filter
Amplifier
216k
220pf (16)IRXAC
Hart_In
470pf
215k
499k
300pf
215k 787k
Receive Comparator
214k 40pf
Receive Demodulator
14.7k 1.235V R10* 200k (8)IAREF
Carrier Detect Comparator
Carrier Detect
Modem3
(9)ICDREF
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A5191HRT
AMIS HART Modem
capacitors depend recommendations manufacturer resonator. Typically, capacitors range used.
OSCILLATOR A5191HRT requires 460.8 clock signal OXTL. This provided external clock external components connected A5191HRT internal oscillator.
External Clock Option
desirable external 460.8 clock shown Figure rather than internal oscillator because high cost availability ceramic resonators. addition, A5191HRT consumes less current when external clock used. Minimum current consumption occurs with clock connected OXTL IXTL connected VSS.
Internal Oscillator Option
oscillator cell will function with either 460.8 crystal ceramic resonator. parallel resonant ceramic resonator connected between OXTL IXTL. Figure illustrates crystal option clock generation using 460.8 percent tolerance) parallel resonant crystal tuning capacitors. actual values
Figure Crystal Oscillator
Figure Oscillator with External Clock
OXTL OSCILLATOR CELL Frequency 460.8 IXTL
460.8
OXTL OSCILLATOR CELL IXTL Frequency
Ordering Information
A5191HRT available 28-pin plastic leaded chip carrier (PLCC) 32-pin low-profile quad flat pack (LQFP). following part number when ordering. Contact your local sales representative more information: www.amis.com/sales.
Package Type
Part Name
Part Number
32-pin LQFP 28-pin PLCC
A5191HRTL A5191HRTP
12197-503 12197-504
Electrical Specifications
ABSOLUTE MAXIMUMS
Symbol Parameter Min. Max. Units
VOUT
Cautions:
Ambient Storage Temperature Supply Voltage Input, Output Lead Temperature (Soldering
-0.3 -0.3
VDD+0.3
CMOS devices damaged high-energy electrostatic discharge. Devices must stored conductive foam with pins shunted. Precautions should taken avoid application voltages higher than maximum rating. Stresses above absolute maximum ratings result damage device. Remove power before insertion removal this device.
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A5191HRT
AMIS HART Modem
CHARACTERISTICS
(VDD -40°C +85°C)
Symbol
Parameter
Min.
Typical
Max.
Units
Input Voltage, Input Voltage Output Voltage, (IOL 0.67mA)
3.0-5.5 3.0-5.5 0.7*VDD 3.0-5.5
0.3*VDD
Output Voltage, High (IOH= -0.67mA) 3.0-5.5 Input Capacitance Analog Input IRXA Digital Input Input Leakage Current Output Leakage Current Power Supply Current
(RBIAS 500k, IAREF =1.235
IIL/IH IOLL IAREF
±500 1.235 1.15
Analog Reference
ICDREF1 Carrier Detect Reference
(IAREF 0.08
OCBIAS Comparator Bias Current
(RBIAS 500k, IAREF =1.235
HART specification requires Carrier Detect (OCD) active between mVp-p. Setting ICDREF IAREF 0.08 will carrier detect nominal mVp-p.
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A5191HRT
AMIS HART Modem
CHARACTERISTICS
(VDD -40°C +85°C)
Name
Description
Min.
Typical
Max.
Units
IRXA
ORXAF
IRXAC OTXA
ORXD
Receive Analog Input Leakage Current Frequency Mark (Logic Frequency Space (Logic Output High-pass Filter Slew Rate Gain Bandwith (GBW) Voltage Range Carrier Detect Receive Filter Input Leakage Current Modulator Output Frequency' Mark (Logic Frequency Space (Logic Amplitude (IAREF 1.235 Slope Loading (IAREF 1.235 Receive Digital Output Rise/Fall Time Carrier Detect Output Rise/Fall Time
1190 2180
1200 2200 0.025
±150 1210 2220
V/µs V/µs mVp-p mV/µs
0.15
0.15 ±500 1196.9 2194.3 2.79
modular output frequencies proportional input clock frequency (460.8 kHz).
MODEM CHARACTERISTICS
(VDD -40°C +85°C)
Parameter
Min.
Typical
Max.
Units
Demodulator Jitter Conditions Input frequencies 1200 2200 Clock frequency 460.8 Input (HLXA) asymmetry,
CERAMIC RESONATOR EXTERNAL CLOCK SPECIFICATIONS
(VDD -40°C +85°C)
Parameter
Min.
Typical
Max.
Units
Resonator Tolerance Frequency External Clock Frequency Duty Cycle Amplitude
460.8 456.2 460.8 465.4
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A5191HRT
AMIS HART Modem
Mechanical Specifications
Symbol Min. Nom. Max.
Figure Lead PLCC
.165 .099 .485 .450 .390 .485 .450 .390
.172 .101 .490 .452 .420 .300 .490 .452 .420 .300 .050
.180 .110 .495 .455 .430 .495 .455 .430
.048 .042 PLCS
IDENTIFIER ZONE
View
Bottom View
.032 .026 SEATING PLANE
Side View
0.076 .021 .013 .020 .045 .025
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A5191HRT
AMIS HART Modem
Symbol
Min.
Nom.
Max.
Figure Lead LQFP
0.05 1.35
0.45 0.30 0.09
0.10 1.40 9.00 4.50 7.00 9.00 4.50 7.00 0.60 0.80 0.37
1.60 0.15 1.45
0.75 0.45 0.20 0.10 0.20
0.20
INDEX
0.08
0.08 0.20
1.00 (REF) DETAIL
DETAIL
2001 Semiconductor, Inc.
Semiconductor makes warranty products, other than those expressly contained company's standard warranty contained Semiconductor's Terms Conditions. company assumes responsibility errors which appear this document, reserves right change devices specifications detailed herein time without notice, does make commitment update information contained herein. licenses patents other intellectual property Semiconductor granted company connection with sale Semiconductor products, expressly implication. HART registered trademark HART Communication Foundation.
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