Datasheet Linear Technology LTC1050CS8#TRPBF — Ficha de datos

Hojas de datos

Precios

Embalaje

Paramétricos

Plan ecológico

Notas de aplicación

• Descargar
  Application Considerations for an Instrumentation Lowpass Filter &mdash AN20
  PDF, 2.8 Mb, Archivo publicado: sept 1, 1986
  Discusses the principles of operation of the LTC1062 and helpful hints for its application. Various application circuits are explained in detail with focus on how to cascade two LTC1062s and how to obtain notches. Noise and distortion performance are fully illustrated.
  Extracto del documento

  Application Note 20
  September 1986
  Application Considerations for an
  Instrumentation Lowpass Filter
  Nello Sevastopoulos
  Description of this, the value of the (R C) product is critically related
  to the filter passband flatness and to the filter stability.
  The internal circuitry of the LTC1062 is driven by a clock
  which also determines the п¬Ѓlter cutoff frequency. For a
  maximally flat amplitude response, the clock should be
  100 times the desired cutoff frequency and the (R, C)
  should be chosen such as: The LTCВ®1062 is a versatile, DC accurate, instrumentation
  lowpass п¬Ѓlter with gain and phase that closely approximate
  a 5th order Butterworth п¬Ѓlter. The LTC1062 is quite different from presently available lowpass switched-capacitor
  п¬Ѓlters because it uses an external (R, C) to isolate the
  IC from the input signal DC path, thus providing DC accuracy. Figure 1 illustrates the architecture of the circuit.
  The output voltage is sensed through an internal buffer,
  then applied to an internal switched-capacitor network
  which drives the bottom plate of an external capacitor to
  form an input-to-output 5th order lowpass п¬Ѓlter. The input
  and output appear across an external resistor and the IC
  part of the overall п¬Ѓlter handles only the AC path of the
  signal. A buffered output is also provided (Figure 1) and …

• Descargar
  Thermocouple Measurement &mdash AN28
  PDF, 988 Kb, Archivo publicado: feb 1, 1988
  Considerations for thermocouple-based temperature measurement are discussed. A tutorial on temperature sensors summarizes performance of various types, establishing a perspective on thermocouples. Thermocouples are then focused on. Included are sections covering cold-junction compensation, amplifier selection, differential/isolation techniques, protection, and linearization. Complete schematics are given for all circuits. Processor- based linearization is also presented with the necessary software detailed.
  Extracto del documento

  Application Note 28
  February 1988
  Thermocouple Measurement
  Jim Williams
  Introduction Thermocouples in Perspective In 1822, Thomas Seebeck, an Estonian physician, accidentally joined semicircular pieces of bismuth and copper
  (Figure 1) while studying thermal effects on galvanic arrangements. A nearby compass indicated a magnetic disturbance. Seebeck experimented repeatedly with different
  metal combinations at various temperatures, noting relative
  magnetic п¬Ѓeld strengths. Curiously, he did not believe that
  electric current was flowing, and preferred to describe the
  effect as “thermo-magnetism.” He published his results in
  a paper, “Magnetische Polarisation der Metalle und Erze
  durch Temperatur-Differenz” (see references). Temperature is easily the most commonly measured
  physical parameter. A number of transducers serve temperature measuring needs and each has advantages and
  considerations. Before discussing thermocouple-based
  measurement it is worthwhile putting these sensors in
  perspective. Figure 2’s chart shows some common contact
  temperature sensors and lists characteristics. Study reveals
  thermocouple strengths and weaknesses compared to
  other sensors. In general, thermocouples are inexpensive,
  wide range sensors. Their small size makes them fast and
  their low output impedance is a benefit. The inherent voltage output eliminates the need for excitation. Subsequent investigation has shown the “Seebeck Effect”
  to be fundamentally electrical in nature, repeatable, and
  quite useful. Thermocouples, by far the most common …

• Descargar
  Using the LTC Op Amp Macromodels &mdash AN48
  PDF, 297 Kb, Archivo publicado: nov 8, 1991
  LTC's op amp macromodels are described in detail, along with the theory behind each model and complete schematics of each topology. Extended modeling topics are discussed, such as phase/frequency response modifications and asymmetric slew rate for JFET op amp models. LTC's macromodels are optimized for accuracy and fast simulation times. Simulation times can be further reduced by using streamlining techniques found throughout AN48.
  Extracto del documento

  Application Note 48
  November 1991
  Using the LTC Op Amp Macromodels
  Getting the Most from SPICE and the LTC Library
  Walt Jung INTRODUCTION This application note is an overview discussion of the
  Linear Technology SPICE macromodel library. It assumes
  little if any prior knowledge of this software library or its
  history. However, it does assume familiarity with both the
  analog simulation program SPICE (or one of its many
  derivatives), and modern day op amps, including bipolar,
  JFET, and MOSFET amplifier technologies.
  Some Preliminary SPICE Facts of Life
  In the past few years, SPICE simulations have really begun
  to capture a high level of attention on the part of analog
  circuit designers. Perhaps this is due to more affordable
  high performance computers, or perhaps the time for
  simulation is now upon us. In any event, the bottom line is
  that IC vendors are now making macromodels for op amps
  available to their customers.
  For the analog circuit designer, there can be no better fate
  for simulations, viewing this situation in terms of which
  model to use. Designers no longer need worry about
  whether the third party supplier’s model can really cut it. …

• Descargar
  Linear Technology Magazine Circuit Collection, Volume III &mdash AN67
  PDF, 1.2 Mb, Archivo publicado: sept 1, 1996
  Application Note 67 is a collection of circuits for data conversion, interface and signal processing from the first five years of Linear Technology. This application note includes circuits such as fast video multiplexers for high speed video, an ultraselective bandpass filter circuit with adjustable gain, and a fully differential, 8-channel, 12-bit A/D system. The categories included in this app note are data conversion, interface, filters, instrumentation, video/op amps and miscellaneous circuits.
  Extracto del documento

  Application Note 67
  September 1996
  Linear Technology Magazine Circuit Collection, Volume III
  Data Conversion, Interface and Signal Processing
  Richard Markell, Editor
  INTRODUCTION
  Application Note 67 is a collection of circuits from the first
  five years of Linear Technology, targeting data conversion,
  interface and signal processing applications. This
  Application Note includes circuits such as fast video
  multiplexers for high speed video, an ultraselective
  bandpass filter circuit with adjustable gain and a fully differential, 8-channel, 12-bit A/D system. The categories
  included herein are data conversion, interface, filters,
  instrumentation, video/op amps and miscellaneous
  circuits. Application Note 66, which covers power products
  and circuits from Linear Technology ’s first five years, is
  also available from LTC. ARTICLE INDEX
  Data Conversion . 3
  Fully Differential, 8-Channel, 12-Bit A/D System Using the LTCВ®1390 and LTC1410 . 3
  12-Bit DAC Applications . 5
  LTC1329 Micropower, 8-Bit, Current Output DAC Used for Power Supply Adjustment,
  Trimmer Pot Replacement . 7
  12-Bit Cold Junction Compensated, Temperature Control System with Shutdown . 8 …

• Descargar
  A Collection of Differential to Single-Ended Signal Conditioning Circuits for Use with the LTC2400, a 24-Bit No Latency Delta Sigma ADC in an SO-8 &mdash AN78
  PDF, 177 Kb, Archivo publicado: agosto 7, 1999
  This application note describes six low power differential-tosingle- ended signal conditioning circuits for the LTC2400 No Latency ΔΣTM 24-bit ADC. These circuits offer the customer a number of choices for conditioning differential input signals as low as 5mV to as high as ±2.5V, as well as operation on a single 5V or ±5V supplies. Each circuit description also covers circuit design and implementation techniques that can help preserve the LTC2400's inherently high effective resolution. AN78 concludes with two circuits for digitizing temperature when using an RTD or Type S thermocouple.
  Extracto del documento

  Application Note 78
  August 1999
  A Collection of Differential to Single-Ended Signal Conditioning
  Circuits for Use with the LTC2400, a 24-Bit No Latency ∆Σ ADC
  in an SO-8
  By Kevin R. Hoskins and Derek V. Redmayne
  INTRODUCTION
  The LTC®2400 is the industry’s first No Latency ∆ΣTM ADC
  that combines automatic offset and full-scale calibration,
  an internal oscillator, a sinc4 digital filter, and serial I/O to
  yield a 24-bit ADC with 1.5ВµVRMS input noise and singleshot conversion time architecture. It is the ideal
  A/D converter for temperature measurement and high
  effective resolution instrumentation applications, such as
  digital multimeters.
  This application note contains six circuits that
  extend the LTC2400’s capabilities using a number of low power differential-to-single-ended signal conditioning circuits. These circuits offer the customer a number of
  choices for conditioning differential input signals as low as
  5mV to as high as В±2.5V, as well as operation on a single
  5V or В±5V supplies. In each case, careful circuit design and
  implementation techniques were used to maintain or preserve the LTC2400’s inherently high effective resolution.
  In some cases, circuit accuracies (uncalibrated) exceed
  17 bits.
  , LTC and LT are registered trademarks of Linear Technology Corporation. …

Notas de Diseño

• Descargar
  LTC2400 High Accuracy Differential to Single-Ended Differential to Single-Ended Converter Has Very High Uncalibrated Accuracy and Low Offset and Drift &mdash Design Solutions 1
  PDF, 39 Kb, Archivo publicado: abr 1, 1999
  Extracto del documento

  Design Solutions 1
  April 1999
  LTC2400 High Accuracy Differential to Single-Ended
  Converter for В± 5V Supplies
  Differential to Single-Ended Converter Has Very High Uncalibrated Accuracy and
  Low Offset and Drift
  by Kevin R. Hoskins and Derek V. Redmayne
  SPECIFICATIONS
  В® VCC = VREF = LT 1236-5; VFS = 40mV;
  RSOURCE = 175Ω (Balanced)
  PARAMETER
  Input Voltage Range CIRCUIT
  TOTAL
  (MEASURED) LTC2400 (UNITS)
  – 3 to 40 Zero Error 12.7 mV
  1.5 ВµV Input Current See Text Nonlinearity В±1 4 ppm Input-Referred Noise
  (without averaging) 0.3* 1.5 ВµVRMS Input-Referred Noise
  (averaged 64 readings) 0.05* ВµVRMS Resolution (with averaged readings) 19.6 Bits Overall Accuracy (uncalibrated**) 18.1 Bits В±5 5 V Supply Current 1.6 0.2 mA CMRR 120 dB Common Mode Range В±5 V Supply Voltage *Input-referred noise with a gain of 101.
  **Does not include gain setting resistors. OPERATION
  The circuit in Figure 1 is ideal for low level differential
  signals in applications that have a В±5V supply and need
  high accuracy without calibration. The circuit combines an
  LTC В®1043 and LTC1050 as a differential to single-ended …

• Descargar
  High Accuracy, Differential to Single-Ended Conversion for Wide Range Bipolar Input Signals Bipolar Differential to Single-Ended Converter Drives the LTC2400's Input Rail-to-Rail &mdash Design Solutions 4
  PDF, 37 Kb, Archivo publicado: abr 1, 1999
  Extracto del documento

  Design Solutions 4
  April 1999
  High Accuracy, Differential to Single-Ended Conversion for
  Wide Range Bipolar Input Signals
  Bipolar Differential to Single-Ended Converter Drives the LTC2400’s Input Rail-to-Rail
  by Kevin R. Hoskins and Derek V. Redmayne
  SPECIFICATIONS
  VCC = VREF = LT 1236-5; VFS = В±2.45V;
  RSOURCE = 175Ω (Balanced)
  В® PARAMETER
  Input Voltage Range
  Zero Error CIRCUIT
  TOTAL
  (MEASURED) LTC2400 (UNITS)
  В±2.45
  22 V
  1.5 ВµV Input Current See Text Nonlinearity В±2.5 4 ppm Input-Referred Noise
  (without averaging) 6.5 1.5 ВµVRMS 1 ВµVRMS Resolution (with averaged readings) 22.2 Bits Overall Accuracy (uncalibrated) 17.1 Bits Input-Referred Noise
  (averaged 64 readings) Supply Voltage 5 5 V Supply Current 2.1 0.2 mA CMRR 118 dB 0 to 5 V Common Mode Range OPERATION
  The circuit in Figure 1 is ideal for wide dynamic range
  differential signals in applications that have a 5V supply.
  The circuit uses one-half of an LTCВ®1043 to perform a
  differential to single-ended conversion over an input common mode range that includes the power supplies. This …

• Descargar
  LTC2400 Differential to Single-Ended Converter for Single 5V Supply This Converter Has High Accuracy, Very Low Offset and Offset Drift, Rail-to-Rail Input Common Mode Range and is Live at Zero &mdash Design Solutions 6
  PDF, 62 Kb, Archivo publicado: mayo 1, 1999
  Extracto del documento

  Design Solutions 6
  May 1999
  LTC2400 Differential to Single-Ended Converter for
  Single 5V Supply
  This Converter Has High Accuracy, Very Low Offset and Offset Drift, Rail-to-Rail Input
  Common Mode Range and is “Live at Zero”
  by Kevin R. Hoskins and Derek V. Redmayne
  SPECIFICATIONS
  ® VCC = VREF = LT 1019-2.5; RSOURCE = 175Ω (Balanced)
  PARAMETER
  Input Voltage Range
  Zero Error CIRCUIT
  TOTAL
  (MEASURED) LTC2400 (UNITS)
  – 0.5 to 5
  2 mV
  1.5 ВµV Input Current See Text Nonlinearity В±5 4 ppm Noise (without averaging) 0.21* 1.5 ВµVRMS Noise (averaged 64 readings) 0.026* ВµVRMS Resolution (with averaged readings) 17.6 Bits Overall Accuracy (uncalibrated**) 17.6 Bits Supply Voltage 5 5 V Supply Current 2.6 0.2 mA CMRR 120 dB 0 to 5 V Common Mode Range *Input referred noise with a gain of 101
  **Does not include gain setting resistors, offset and gain error removed OPERATION
  The circuit in Figure 1 is ideal for low level differential
  signals, typically 2mV/ V, in single supply applications and
  features a “live at zero” operation. The circuit combines an
  LTCВ®1043 and LTC1050 as a differential to single-ended
  amplifier that has an input common mode range that …

• Descargar
  LTC2400 High Accuracy Differential to Single-Ended Converter for В±5V Supplies &mdash DN207
  PDF, 76 Kb, Archivo publicado: jul 1, 1999
  Extracto del documento

  LTC2400 High Accuracy Differential to Single-Ended
  Converter for ±5V Supplies – Design Note 207
  Differential to Single-Ended Converter Has Very High
  Uncalibrated Accuracy and Low Offset and Drift
  Kevin R. Hoskins and Derek V Redmayne
  Introduction
  The circuit in Figure 1 is ideal for low level differential
  signals in applications that have a В±5V supply and need
  high accuracy without calibration. The circuit achieves
  19.6-bit resolution and 18.1-bit accuracy. These and
  other specifications are summarized in Table 1.
  Operation
  The circuit in Figure 1 combines an LTC В®1043 and
  LTC1050 as a differential to single-ended amplifier
  that has an input common mode range that includes
  the power supplies. It uses the LTC1043 to sample a
  differential input voltage, holds it on CS and transfers
  it to a ground-referred capacitor, CH. The voltage on
  CH is applied to the LTC1050’s noninverting input and 5V 0.1μF amplified by the gain set by resistors R1 and R2 (101
  for the values shown). The amplifier’s output is then
  converted to a digital value by the LTC2400.
  The LTC1043 achieves its best differential to singleended conversion when its internal switching frequency
  operates at a nominal 300Hz, as set by the 0.01ОјF …

• Descargar
  24-Bit ADC Measures from DC to Daylight &mdash DN219
  PDF, 76 Kb, Archivo publicado: dic 1, 1999
  Extracto del documento

  24-Bit ADC Measures from DC to Daylight – Design Note 219
  Derek Redmayne
  The need to measure a wide variety of physical phenomena is increasingly important in intelligent sensors. The
  following circuit gives eight examples of the flexibility of
  the LTC В®2408 for sensing real world phenomena. The
  eight inputs of the LTC2408 are used here in a variety
  of ways that would not be practical without the dynamic
  range of the LTC2408.
  GUARD RING 5V ELECTROMETER
  INPUT
  (pH, PIEZO) 3 7 + 2 R5
  5k, 1% 6 LT1793 All of the examples shown use single-ended sensing
  and an absolute minimum of external circuitry. Inputs
  to the circuit shown range from high voltage DC to
  ultraviolet light. Output data represents amplitude or
  power levels for signals in all the AC inputs.
  L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks
  of Linear Technology Corporation. All other trademarks are the property of their
  respective owners.
  DC
  VOLTMETER
  INPUT
  1mV TO 1000V R1 …

• Descargar
  Ultra Low Noise Op Amp Combines Chopper and Bipolar Op Amps &mdash DN36
  PDF, 99 Kb, Archivo publicado: jul 1, 1990
  Extracto del documento

  Ultra Low Noise Op Amp Combines Chopper and
  Bipolar Op Amps – Design Note 36
  Nello Sevastopoulos
  low noise voltage of the LTВ®1007 precision bipolar op
  amp appears in Figure 1. This composite op amp can,
  for instance, be used as a strain gauge amplifier. One
  half of the LTC1051 dual chopper op amp, LTC1051,
  integrates the small LT1007 input offset voltage and
  applies a DC correction voltage at its pin-8 via divider
  (R2, R3). The other half of the LTC1051, buffers the VOS
  nulling circuitry eliminating loading at input A. Resistors R1, R2, R3 allow the integrator full output swing
  assuring VOS correction of the LT1007. The ratio of R3
  to R2 is made as high as possible to limit noise injection
  of the chopper into pin-8 of the bipolar op amp. The
  total measured input VOS was 2ОјV, with a 10nV/В°C drift. Chopper op amp technology has continuously improved.
  Contemporary single, dual and quad low noise chopper
  op amps (LTCВ®1050/51/53), with internal sample and
  hold capacitors, are compatible with industry standard
  op amp sockets.
  Chopper op amps are mainly used to amplify small DC
  signals and these applications require excellent VOS, VOS
  drift, low bias current and low noise. The outstanding
  VOS performance of chopper op amps is well known. …

• Descargar
  Chopper vs Bipolar Op Amps—An Unbiased Comparison &mdash DN42
  PDF, 70 Kb, Archivo publicado: dic 1, 1990
  Extracto del documento

  Chopper vs Bipolar Op Amps—An Unbiased Comparison
  Design Note 42
  George Erdi Table 1 lists the parameters of importance. In all input
  parameters (except noise) the advantage unquestionably goes to the choppers. 5ОјV maximum offset voltage, 0.5ОјV/В°C maximum drift are commonly found
  Table 1. Chopper Stabilized vs Precision Bipolar Op Amps
  ADVANTAGE
  PARAMETER
  Offset Voltage
  Offset Drift
  All Other DC Specs CHOPPER BIPOLAR COMMENTS
  вњ“
  вњ“
  вњ“ No Contest Wideband, 20Hz to
  1MHz вњ“ See Details in Text Noise вњ“ See Details in Text вњ“ Rail to Rail Swing
  2mA Limit on
  Choppers Output: Light Load
  Heavy Load
  Single Supply
  Application вњ“ вњ“ Inherent to
  Choppers Needs
  Special Design
  Bipolars В±15V Supply Voltage вњ“ Except LTC1150 Prejudice/Tradition вњ“ Still a Chopper
  Problem Cost 08/90/86_conv вњ“ Unless DC …

• Descargar
  Temperature Measurement Using Data Acquisition Systems &mdash DN5
  PDF, 77 Kb, Archivo publicado: marzo 1, 1989
  Extracto del documento

  Temperature Measurement Using Data Acquisition Systems
  Design Note 5
  William Rempfer and Guy Hoover
  Introduction
  Accurate temperature measurement is a difficult and
  very common problem. Whether recording a temperature, regulating a temperature or modifying a process
  to accommodate a temperature, the LTCВ®1090 family
  of data acquisition systems can provide an important
  link in the chain between the blast furnace temperature
  and the microcontroller. Features of the LTC1090 family
  can make temperature measurement easier, cheaper
  and more accurate.
  High DC input resistance and reduced span operation
  allow direct connection to many standard temperature
  sensors. Multiplexer options allow one chip to measure
  up to 8 channels of temperature information. Single
  supply operation, modest power requirements (~5mW)
  and serial interfaces make remote location possible.
  Switching power on and off lowers power consumption (560ОјW) even more for battery applications.
  Finally, because few sensors have accuracies as good as 0.1%, the 10-bit resolution and 0.05% accuracy of
  the LTC1090 family are just right for most temperature
  sensing applications.
  Thermocouple Systems …

• Descargar
  Chopper Amplifiers Complement a DC Accurate Low-Pass Filter &mdash DN9
  PDF, 369 Kb, Archivo publicado: marzo 1, 1988
  Extracto del documento

  Chopper Amplifiers Complement a DC
  Accurate Low-Pass Filter – Design Note 9
  Nello Sevastopoulos
  Monolithic switched-capacitor low-pass filters, although
  they offer precise frequency responses, cannot usually be used for DC accurate applications because of
  their prohibitive DC offsets and poor gain linearity. The
  LTC В®1062, however, is quite different from currently
  available low-pass switched capacitor filters because it
  uses an external (R, C) to isolate the IC from the inputsignal DC path and to provide antialiasing for incoming
  signals larger than half its clock frequency. The LTC1062
  is ideal when used in conjunction with high performance
  chopper-stabilized op amps.
  The LTC1050 is an ultra low offset, low noise chopper with
  the sampling capacitors internal. It can remove residual
  clock noise without adding further DC error. Also, the
  internal capacitor minimizes board area.
  Figure 1 shows a low cost, 7th order DC accurate, 10Hz
  low-pass filter where amplitude and phase response
  closely approximate a Bessel filter. The required clock
  frequency is 2kHz, thus yielding clock to cutoff frequency
  ratio of 200:1. VIN R'
  196k R
  16k …

Artículos

• Descargar
  LTC2400 Differential Bridge Digitizers &mdash LT Journal
  PDF, 120 Kb, Archivo publicado: jun 1, 1999
  Extracto del documento

  DESIGN IDEAS LTC2400 Differential Bridge Digitizers
  by Kevin R. Hoskins and Derek Redmayne
  Both circuits combine an LTC1043
  precision switched capacitor block and
  an LTC1050 chopper stabilized op amp,
  creating a differential input, singleended output bridge amplifier that has
  a rail-to-rail common mode input
  range. The LTC1043 samples a differential input voltage, holds it on CS and
  transfers it to a ground-referred capacitor, CH. The voltage on CH is applied
  to the LTC1050’s noninverting input
  and amplified by the gain set by resistors R1 and R2 (101 for the values
  shown). The amplifier’s output is then
  converted to a digital value by the
  LTC2400.
  The LTC1043 achieves its best differential to single-ended conversion
  when its internal switching frequency
  is set by a 0.01ВµF capacitor, C1, and
  when 1ВµF capacitors are used for CS
  and CH. Using any other value will
  compromise the accuracy. For
  example, a C1 value of 0.1µF will typically increase the circuit’s overall
  nonlinearity tenfold. CS and CH should
  be a film type such as mylar or polypropylene. Conversion accuracy is …

• Descargar
  Consider New Precision Amplifiers for Updated Industrial Equipment Designs &mdash LT Journal
  PDF, 154 Kb, Archivo publicado: sept 1, 2009
  Extracto del documento

  L DESIGN FEATURES Consider New Precision Amplifiers for
  Updated Industrial Equipment Designs
  by Brian Black Introduction
  Industrial equipment is designed for
  long life cycles, so the electronic components used in industrial applications
  are often chosen with significant emphasis on proven performance, quality
  and reliability. Precision amplifiers are
  no exception. Even if new and innovative amplifiers become available over a
  product’s lifetime, a redesigned board
  is often built using the same proven
  op amps in the old board. Even for
  entirely new applications, designers
  will choose amplifiers that have proven
  their mettle in other circuits, making a
  choice based more on familiarity than
  performance.
  Although an amplifier may have
  been tried and proven in a design, it
  is not necessarily the best solution for
  every new design. Many can benefit
  from using more recently released
  amplifiers, which can improve overall
  system performance, reduce power …

Linea modelo

Clasificación del fabricante

• Signal Conditioning > Amplifiers > Operational Amplifiers (Op Amps) > Rail-to-Rail Amplifiers | Precision Amplifiers (Vos | Zero-Drift Amplifiers | Low Power Amplifiers (Is < 1mA/amp) | Low Bias Current Amplifiers (Ib < 100pA) | High Voltage Amplifiers (>12V)
• Space & Harsh Environment > Extended Temperature Plastic (H & MP) > Extended Temperature (H & MP) Amplifiers

Otros nombres:

LTC1050CS8TRPBF, LTC1050CS8 TRPBF