MCP3201-BI/SN - 12-Bit 100ksps SAR ADC with SPI | Microchip Technology
Артикул: MCP3201-BI/SN ✓ АктивенMCP3201-BI/SN Обзор
An ADC is a mixed-signal integrated circuit that converts a continuous analog voltage into a digital code that a microcontroller can process. The MCP3201 belongs to the SAR ADC family, the alternative to flash and pipeline converters: a sample-and-hold front end captures the input, an internal DAC generates a comparison voltage, and a successive approximation register walks through 12 clock cycles to settle on a final code. This architecture gives good accuracy at low cost, low power, and no pipeline latency, at the cost of lower throughput than flash converters.
Key features include 12-bit resolution with differential nonlinearity specified at plus or minus 1 LSB and integral nonlinearity of plus or minus 1 LSB in the MCP3201-B grade, a 100 ksample/s maximum conversion rate, a pseudo-differential input referenced to a single external voltage reference, and an SPI-compatible serial interface that shares the same clock and data-in lines with SPI flash. Typical conversion time is short enough for continuous sampling in control loops, and typical effective number of bits is 11.8.
The MCP3201-BI/SN is specified for industrial temperature operation from -40 degrees C to +85 degrees C, in a narrow-body 8-pin SOIC. The -B suffix denotes the plus or minus 1 LSB INL version, -I denotes industrial temperature grade, and SN denotes the SOIC-8 package. Because the device uses a pseudo-differential input, the negative input pin serves as the reference return, and the converter features a low-noise architecture that suits precision measurement.
Typical applications include potentiometer and resistive sensor readout, temperature and pressure transducer front ends, industrial instrumentation, battery-operated portable instruments, and hobbyist or educational SPI ADC breakout boards. The device is frequently paired with 3.3 V microcontrollers such as the MSP430 or STM32 families when a system needs a higher resolution analog measurement than the built-in ADC can deliver.
When designing around the MCP3201-BI/SN, keep the analog trace short, place the reference bypass capacitor directly at the VREF+ pin, and route the SPI clock away from the VIN+ trace to avoid injected noise in the least significant bits. A solid ground plane under the analog section and a single-point connection back to the digital ground reduces offset error. Verify the sampling capacitor settling time before the conversion start when driving the input from a high-impedance source.
This page combines manufacturer specification data, package and pin details, drop-in ordering alternatives, and practical design guidance so that engineers can evaluate the MCP3201-BI/SN without reconstructing the same information from multiple documents.
Аналоги без доработки для MCP3201-BI/SN — тот же корпус, pin-to-pin совместимость. Компоненты в других корпусах, требующие переработки PCB, исключены.
Варианты в этой серии
Модели той же серии, совместимые без доработки с MCP3201-BI/SN (тот же форм-фактор и посадочное место) — отличается по Package, Mounting Type, Operating Temperature, Architecture, Converter Type.
MCP3201-CI/SN
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MCP3201T-BI/SN
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MCP3201-BI/SN Максимальные параметры и электрические характеристики
| Разрешение | 12 bit |
| Conversion Rate | 100 ksample/s |
| Input Channels | 1 (single pseudo-differential input) |
| Architecture | Successive approximation register (SAR) |
| Differential Nonlinearity (DNL) | +/-1 LSB |
| Integral Nonlinearity (INL), -B grade | +/-1 LSB |
| Integral Nonlinearity (INL), -C grade | +/-2 LSB |
| Typical INL | 0.75 LSB |
| Effective Number of Bits (ENOB) | 11.8 bit |
| SFDR (typical) | 86 dB |
| Напряжение питания | 2.7 V minimum supply operation |
| Analog Input Voltage Range | -0.1 V to 4.9 V |
| Интерфейс | SPI-compatible serial interface (CS, DIN, SCLK) |
| Sample and Hold | On-board sample-and-hold circuitry |
| Рабочая температура | -40 C to +85 C |
| Screening Level | Industrial |
| Корпус | 8-pin SOIC (SN) |
| Тип монтажа | Surface mount |
| Статус RoHS | Compliant |
| REACH Status | Compliant |
Конфигурация выводов MCP3201-BI/SN
| Контакт 1 | CS — Chip select active low, initiates conversion and serial transfer |
| Контакт 2 | DIN — Serial data in (MOSI), also returns converted data on MISO |
| Контакт 3 | SCLK — Serial clock input |
| Контакт 4 | VSS — Analog and digital ground reference |
| Контакт 5 | VREF+ — Positive voltage reference input |
| Контакт 6 | VIN- — Negative analog input / pseudo-differential reference return |
| Контакт 7 | VIN+ — Positive analog input |
| Контакт 8 | VDD — Positive supply voltage |
Типичное применение
MCP3201-BI/SN подходит для 6 применениеs: Precision Analog Sensor Front End, Potentiometer and Control Panel Readout, Battery-Powered Portable Instruments, Industrial Process Monitoring, Educational and Prototyping SPI ADC Modules, Audio and Vibration Level Sampling.
Precision Analog Sensor Front End
The MCP3201-BI/SN suits single-transducer measurement chains that need better resolution than a typical microcontroller ADC delivers. With 12 bits of resolution, plus or minus 1 LSB differential nonlinearity and a typical effective number of bits of 11.8, a 0 to 3.3 V sensor signal is resolved into roughly 0.8 mV steps, which directly improves the usable resolution of resistive dividers, strain bridges and thermistors. The pseudo-differential input lets the negative pin act as a quiet analog return for the transducer, rejecting common-mode noise that would otherwise eat significant counts. Because the SAR architecture completes a conversion in a fixed number of clock cycles, a host microcontroller can trigger a conversion on a timer and read the result with a simple CS-low/DIN-low/clock-out/read-data sequence over SPI, keeping the firmware deterministic. For steady-state monitoring loops the 100 ksample/s ceiling is far above the control bandwidth needed, so the design can be optimised for noise averaging rather than speed. Keep the divider or bridge output impedance low enough that the internal sample-and-hold capacitor settles within the acquisition window, and place the reference bypass capacitor at the VREF+ pin to keep the code reference quiet.
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Potentiometer and Control Panel Readout
User-adjustable potentiometers, encoders and rotary controls are common in instrumentation panels where position must be reported digitally to a controller. The MCP3201-BI/SN converts the wiper voltage against the pseudo-differential reference return, and the 12-bit code gives 4096 distinct positions over the reference span, which is ample resolution for menu navigation, set-point entry and position feedback. Because the conversion is fully deterministic and driven by the SPI clock, the host can service several controls by toggling the chip-select line between them. The device's low 2.7 V minimum supply also lets the converter sit alongside a 3.3 V logic rail without a level-shifting stage, keeping the analog section compact. In multi-potentiometer designs, give each control its own chip-select line where board space allows, because multiplexing several high-impedance dividers through one analog switch adds charge-sharing errors to the sample-and-hold node. Keep the divider track connected directly to the VIN+ pin and the bottom of the divider bonded to the VIN- pin so that the reference rejection characteristic of the pseudo-differential input actually applies to the control track rather than to a shared board ground.
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Battery-Powered Portable Instruments
Handheld meters, environmental monitors and field loggers must measure accurately while drawing very little power, and the MCP3201-BI/SN is well matched to that constraint. It runs from a 2.7 V minimum supply, requires only a few external passive components, and presents an SPI interface that the host can leave idle between samples, so the converter does not force continuous clocking. The 12-bit result is typically delivered in microseconds, meaning the sampling burst itself consumes little of the duty cycle in a duty-cycled acquisition scheme. The -40 to +85 C industrial temperature grade also suits instruments that operate in unheated enclosures, vehicles or outdoor cabinets. For low-power designs, power the VREF+ pin from the same switched rail as the converter so that the analog node never floats while the host is asleep, and make sure the supply rail collapses cleanly rather than drifting slowly, since a slowly falling rail can hold the sample-and-hold node in an undefined state. Use a short, shielded route from VIN+ to the source to keep hand-held instrument noise out of the least significant bits.
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Industrial Process Monitoring
In factory monitoring equipment the MCP3201-BI/SN gives a controller an accurate single-channel measurement of a slowly varying process variable such as tank level, pressure or flow-derived voltage. The 12-bit resolution and plus or minus 1 LSB differential nonlinearity keep the reported value stable enough for threshold decisions without averaging tricks, while the pseudo-differential input ties the measurement return to a local analog reference point that reduces the effect of ground potential differences between a remote sensor and the controller board. The SPI framing is straightforward to service from any industrial microcontroller, so the same firmware pattern used for the rest of the telemetry can also service the analog channel. Where long field wiring is involved, keep the sensor loop short and terminate it at the board edge, and place the reference bypass capacitor at the converter rather than at the power entry point, because the reference node is what actually sets the accuracy of the code. The -40 to +85 C rating covers unheated control cabinets and industrial equipment rooms that exceed typical office ambient.
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Educational and Prototyping SPI ADC Modules
The MCP3201-BI/SN is a staple on classroom and maker boards that add a higher-resolution analog channel to a microcontroller board, and the SOIC-8 footprint keeps the module small enough for a half-breadboard or a small perf board. The SPI interface is the same three-wire-plus-chip-select arrangement used by SPI flash, so students and hobbyists can reuse existing driver code and libraries, and many microcontroller platforms expose a dedicated ADC chip-select line already routed. With 4096 codes, a classroom potentiometer, LDR divider or NTC thermistor produces a visibly responsive reading rather than a coarse jump, which makes it a good teaching vehicle for sampling theory, scaling and filtering. The 100 ksample/s capability also lets learners plot waveforms such as audio envelope or a slow ripple instead of only static values. Because the part is available in tube and tape-and-reel ordering codes, both breadboard prototyping and small production runs are supported. Keep a decoupling capacitor at VDD on the module and avoid routing the SCLK trace directly under the analog input trace.
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Audio and Vibration Level Sampling
Envelope and vibration-level monitoring also benefits from a dedicated external converter, because the 12-bit code of the MCP3201-BI/SN captures slow amplitude trends with far more resolution than a typical mixed-signal microcontroller ADC pin. Sampling at up to 100 ksample/s, the part can follow ripple and shock envelopes for condition monitoring, motor analysis and audio level metering, and the typical SFDR of 86 dB keeps harmonic distortion low enough that the detected envelope is not dominated by converter artefacts. Use the internal sample-and-hold with a short acquisition interval after asserting chip-select, and make sure the input source impedance stays low, otherwise the settling time of the sampling network will cut short the sample window and reduce the effective resolution. Route the analog trace away from switching nodes and motor drive stages, and reference the pseudo-differential return to the sensor ground so that the digital switching reference does not leak into the measurement. For a small microcontroller based logger, the same SPI bus can carry the conversion result alongside data storage without slowing the sample loop.
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Справочные инженерные данные для MCP3201-BI/SN — сравнение, рекомендации по проектированию и информация о соответствии.
Руководство по выбору
Сравнение с аналогами
| Параметр | Этот товар | MCP3201-CI/SN | MCP3201T-CI/SN | MCP3201T-BI/SN |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-pin SOIC (SN) | 8-pin SOIC (SN) - same | 8-pin SOIC (SN) - same | 8-pin SOIC (SN) - same |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit |
| Sample Rate | 100 ksample/s | 100 ksample/s | 100 ksample/s | 100 ksample/s |
| Integral Nonlinearity | +/-1 LSB (-B grade) | +/-2 LSB (-C grade) | +/-2 LSB (-C grade) | +/-1 LSB (-B grade) |
| Differential Nonlinearity | +/-1 LSB | +/-1 LSB | +/-1 LSB | +/-1 LSB |
| Effective Number of Bits | 11.8 bit | 11.8 bit | 11.8 bit | 11.8 bit |
| Input Channels | 1 pseudo-differential input | 1 pseudo-differential input | 1 pseudo-differential input | 1 pseudo-differential input |
| Interface | SPI (CS, DIN, SCLK) | SPI (CS, DIN, SCLK) | SPI (CS, DIN, SCLK) | SPI (CS, DIN, SCLK) |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
Ключевые отличия
- Tighter integral nonlinearity in the -B accuracy grade (против MCP3201-CI/SN)
- Same die and footprint across packing and grade options (против MCP3201T-BI/SN)
- Higher accuracy than the -C alternative in the same package (против MCP3201T-CI/SN)
- Single pseudo-differential channel keeps board area and BOM small (против MCP3201-CI/SN)
Заметки по проектированию
Keep the analog section physically separate from the digital section. Route VIN+ as a short, direct trace from the source, and do not run SCLK, CS or DIN beneath or parallel to it. Where the digital bus must cross the analog area, cross it at right angles. The MCP3201 uses a pseudo-differential input, so bond the VIN- return to the analog ground of the source rather than to a shared digital ground plane, and place the reference bypass capacitor at the VREF+ pin with a short ground lead to keep switching currents out of the reference node.
The most common integration mistake is underestimating the acquisition settling requirement when the source impedance is high. The internal sample-and-hold capacitor must charge to the input voltage before the conversion starts, and a divider with a high upper resistance can leave residual error that shows up as code-to-code jitter. Either lower the source impedance by adding a buffer such as a low-noise RRIO op-amp, or extend the acquisition interval in the firmware. A second common error is assuming the DIN pin is write-only; on this device the same pin returns the converted data, so the host SPI configuration must use full-duplex mode with the correct pin mapping.
Estimated: for a 3.3 V supply with the VREF+ tied to the same rail, the converter input and reference rails sit at 3.3 V, so the permitted analog input span is bounded by the reference. If your sensor output can exceed the supply rail, use a divider and clamp network rather than relying on the input clamp diodes, because injected clamp current distorts the conversion and can stress the pins. Provide a local 0.1 uF ceramic bypass capacitor at VDD with a short ground return, and decouple the reference node separately so that supply ripple does not modulate the conversion reference.
The SPI clock edge defines the sampling instant, so a noisy clock injects error directly into the result. Drive SCLK from the host controller through a contiguous trace that does not switch layers unnecessarily, and keep the clock return path on a solid plane. If the host SPI bus is long or crosses a switching node, add a small series resistor of roughly 22 to 47 ohms at the converter to damp ringing, and verify the settling of the data line after the final clock edge before sampling it. Averaging several consecutive conversions in firmware is a low-cost way to reduce uncorrelated noise without altering the hardware.
Информация о соответствии
RoHS and REACH compliance are indicated in the published compliance comparisons for this part. The -I industrial temperature grade is not an AEC-Q100 automotive qualification; confirm the exact ordering code if automotive qualification is required.
