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Microchip Technology QT300-D
- Part No.:
- QT300-D
- Manufacturer:
- Microchip Technology
- Category:
- Multifunction
- Package:
- Datasheet:
-
QT300-D.pdf
- Description:
- SENSOR MULT CAPACITIVE
- Quantity:
- Payment:
- Shipping:
Inventory:3,908
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Product details
Overview
QT300-D from Quantum Research Group is a self-contained 16-bit capacitance-to-digital converter (CDC) IC designed for raw femtofarad-level capacitance measurement in instrumentation and touch-sensing systems. It delivers unprocessed 16-bit binary output via SPI (master/slave) or single-wire UART, supports 1nF–500nF external sampling capacitors, and operates across 0°C to +70°C with 2V–5V supply.
For engineers reviewing the QT300-D datasheet, QT300-D pinout, QT300-D application, or QT300-D equivalent, this page provides verified technical context, validated pin functions per interface mode, real-world timing constraints (Tbd, Tacq, Tbs), confirmed resolution vs. Cs/Cx dependencies, and selection guidance among functionally comparable CDCs for fluid level, proximity, and material sensing designs.
Technical Context
The QT300-D implements charge-transfer burst-mode acquisition without internal signal processing-outputting only raw 16-bit digital values dependent on Cs (sample capacitor) and Cx (sensed capacitance). Its logarithmic response enables wide dynamic range (0–100pF Cx) and resolution down to 7fF/bit at optimal Cs/Cx combinations.
It supports three serial configurations: SPI slave (4-wire, host-clocked up to 40kHz), SPI master (device-clocked, SCD-programmable rate), and 1W UART (bidirectional single-pin, baud set by trigger pulse width). All modes require explicit host-initiated /REQ or 1W pulse ≥30µs to start acquisition, with low-power idle between requests.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 16-bit raw output; resolution per bit as low as 7fF (measured at Vdd=3.0V, Cs=10nF, Cx=5pF) |
| Capacitance Range | Cx: 0–100pF; Cs: 1nF–500nF - gain and sensitivity directly scaled by Cs value |
| Interface Options | SPI slave/master (4-wire) or 1W UART - selectable via cloning; no internal processing or filtering |
| Timing Control | Burst duration (Tbd) and acquire time (Tacq) vary with Cs/Cx; burst spacing (Tbs) fully host-controlled |
| Supply & Temp | Vdd = 2V–5V; operating range 0°C to +70°C (QT300-D suffix); 100nF bypass cap required at Vdd/Vss |
| Output Format | Two-byte MSB-first transmission; no checksum, parity, or framing - host handles data interpretation |
| Power Management | On-demand operation only; enters low-power idle when /REQ and 1W are high; no standby current spec given |
Pinout & Package
QT300-D is packaged in an 8-pin DIP (dual-in-line) with 0.3-inch width, lead pitch 0.1 inch (2.54 mm), and standard through-hole mounting. Pin functions differ between SPI and 1W UART modes - configuration is fixed at clone time and not runtime-switchable.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 /DRDY | Data Ready (active-low open-drain) | Signals completion of acquisition and readiness to transmit; requires external pullup; floats when idle |
| 2 SCK | SPI Clock | Input in slave mode; output in master mode; idle state (high/low) set via SM parameter during cloning |
| 3 SNS1 | Sense Electrode 1 | Primary capacitive input node; connects directly to sensor electrode; no internal bias or drive |
| 4 Vss | Negative Supply (Ground) | Reference return for analog and digital circuitry; must be low-impedance and decoupled near device |
| 5 SNS2 | Sense Electrode 2 | Secondary capacitive input; used for differential or dual-electrode configurations; same electrical role as SNS1 |
| 6 /REQ | Request Acquisition Input | Active-low trigger; ≥30µs pulse initiates burst; must return high before burst end to avoid Setup mode entry |
| 7 SDO | Serial Data Output | Transmits MSB-first 16-bit data; floats when idle; connects to host SDI in SPI slave mode |
| 8 Vdd | Positive Supply | 2V–5V analog/digital supply; also serves as internal reference - ripple & stability directly affect measurement accuracy |
Key Features
| Feature | Design Value |
|---|---|
| Raw 16-bit CDC output | Delivers unprocessed digital counts - host MCU performs calibration, filtering, and application logic |
| Logarithmic Cs/Cx response | Enables >100:1 dynamic range; doubling Cs doubles signal level; doubling Cx halves signal level |
| Multi-device SPI bus support | Multiple QT300-D units share SCK/SDO/DRDY lines with individual /REQ lines - no address or CS needed |
| Single-pin 1W UART interface | Reduces host GPIO count to one bidirectional line with 10kΩ pullup; baud rate set dynamically per acquisition |
| Clonable setup parameters | SCD (clock speed), MLS (byte spacing), SM (interface mode) stored in EEPROM; 100,000 write cycles rated |
Applications
| Fluid Level Sensing | Proximity Detection |
|---|---|
Use Scenario: Measuring liquid height in non-metallic tanks using parallel-plate or coaxial electrodes immersed in fluid. IC Role / Device Role / Timing Role: QT300-D acts as a direct Cx-to-digital transducer; Cx changes linearly with fill level; burst timing synchronized to eliminate mains noise. Use Value: Enables sub-millimeter resolution without analog front-end components; Cs selection (e.g., 100nF) sets sensitivity for 0–50cm range. |
Use Scenario: Detecting presence/absence of human hand or object within 5–50mm of PCB-mounted electrode. IC Role / Device Role / Timing Role: QT300-D measures parasitic capacitance shift on SNS1/SNS2; acquisition triggered at 10–100Hz to balance response and power. Use Value: Eliminates need for dedicated touch controller; raw data allows custom gesture algorithms on host MCU. |
| Moisture Detection | Material Composition Analysis |
Use Scenario: Monitoring moisture content in soil, grain, or building materials via inter-digitated electrode array. IC Role / Device Role / Timing Role: QT300-D converts dielectric constant shift (via Cx change) into digital counts; Cs tuned (e.g., 47nF) for optimal SNR in humid environments. Use Value: Achieves ±2% RH-equivalent repeatability using low-cost electrodes; immune to temperature drift when Cs is stable film type. |
Use Scenario: Discriminating between plastic, wood, metal, or composite materials placed atop a shielded sense plate. IC Role / Device Role / Timing Role: QT300-D captures absolute Cx and ΔCx under controlled burst conditions; multi-electrode arrays use SNS1/SNS2 differentially. Use Value: Delivers 12+ distinct material signatures using only raw 16-bit counts - no factory calibration required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar capacitance-to-digital converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADI AD7745 | 24-bit ΣΔ ADC with integrated excitation; I²C interface; internal temperature sensor; 12pF max Cx range | Higher resolution but narrower Cx range; includes on-chip calibration; requires external electrode drive | Choose AD7745 for precision lab-grade measurements where Cx < 12pF and temperature compensation is critical. |
| Microchip MTCH101 | 16-bit CDC with built-in auto-calibration, baseline tracking, and gesture engine; I²C/SPI; 2.7–5.5V supply | Processed output (delta, proximity, gesture flags); no raw data mode; optimized for consumer touch UI | Choose MTCH101 when host MCU lacks resources for raw-data processing and standardized touch behavior is required. |
Compared with AD7745 and MTCH101, the QT300-D uniquely provides unprocessed 16-bit counts with femtofarad sensitivity, full Cs/Cx dependency transparency, and multi-device SPI sharing - making it optimal for industrial instrumentation where host-based signal conditioning and custom algorithms are mandatory.
Availability
QT300-D is available at Aetrix Electronics and suitable for fluid level sensors, proximity detection systems, moisture monitoring devices, and material analysis instruments requiring stable component supply across industrial OEM production cycles.
Supply support for QT300-D includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Quantum Research Group (QRG) is a UK-based semiconductor company specializing in capacitive sensing technology since 1999, with core IP in charge-transfer architectures and low-noise CDC design.
The QT300-D belongs to QRG's "QT" family of raw-output capacitance converters, engineered specifically for applications demanding full control over signal processing - including industrial instrumentation, scientific measurement, and custom human-machine interfaces.
FAQ
What interface modes does the QT300-D support, and how are they selected?
The QT300-D supports SPI slave, SPI master, and 1W UART modes - selected permanently during manufacturing via cloning with the QTM300CA adapter and QT3View software. The SM parameter (0–4) determines mode; no runtime switching is possible. Each mode uses distinct pin assignments (e.g., SCK is input in slave, output in master), and configuration is stored in on-chip EEPROM.
How does the sampling capacitor (Cs) affect QT300-D performance?
The external Cs capacitor (1nF–500nF) directly controls QT300-D gain and sensitivity: doubling Cs doubles output signal level and differential sensitivity. Cs also impacts burst duration (Tbd) - larger Cs increases acquisition time and reduces maximum update rate. Stable NP0/C0G or PPS film types are recommended to minimize drift; X7R ceramics may introduce nonlinearity.
Can multiple QT300-D devices share the same SPI bus, and what pins must be isolated?
Yes - multiple QT300-D units can share SCK, SDO, and /DRDY lines on one SPI bus because all outputs float when inactive. Only the /REQ line must be individually wired per device to enable independent triggering. No chip-select (CS) signal is used; acquisition is initiated solely by pulsing the dedicated /REQ pin low for ≥30µs.
What is the minimum and maximum Cx range measurable by the QT300-D?
The QT300-D is specified for Cx from 0pF to 100pF under recommended conditions (Vdd = 3.0V, Cs = 10nF–200nF). Resolution degrades at extremes: below 1pF, noise dominates; above 100pF, signal compression occurs due to log response saturation. For reliable operation, Cx should remain within 0.5–80pF when using Cs = 100nF.
Does the QT300-D include internal temperature compensation, and how does temperature affect its output?
No - the QT300-D provides no internal temperature compensation. Output drift is inherent: typical signal deviation is ±5% over 0°C–85°C (QT300-IS), with QT300-D exhibiting similar behavior. Drift correlates strongly with Cs capacitor stability; PPS film caps show <0.5% drift over range, while ceramic types may exceed 3%. Host firmware must implement calibration if thermal stability is required.
QT300-D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- Quantum, QProx™
- Packaging:
- -
- Product Status:
- Obsolete
- Sensor Type:
- Capacitive
- Output Type:
- PWM
- Operating Temperature:
- -
QT300-D FAQ
1.How can I place an order for QT300-D through Aetrix?
Please submit a Request for Quotation (RFQ) for QT300-D on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for QT300-D reliable?
The price and inventory of QT300-D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for QT300-D is usually 5 days.
3.What payment methods are accepted for QT300-D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for QT300-D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for QT300-D?
QT300-D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your QT300-D order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for QT300-D?
For technical support, including QT300-D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your QT300-D requirements.
6.How does Aetrix verify that QT300-D is sourced from the original manufacturer or authorized distributors?
All QT300-D products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that QT300-D meets industry standards.
7.What is the process for return or replacement of QT300-D?
All QT300-D units undergo pre-shipment inspection (PSI). If there is an issue with QT300-D, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The QT300-D part is unused and in its original packaging.
Return procedure for QT300-D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
QT300-D Tags
-
ISM303DACTR
STMicroelectronics
-
MS860702BA01-50
TE Connectivity Measurement Specialties
-
SCC2230-D08-05
Murata Electronics
-
SCC2230-E02-05
Murata Electronics
-
SCC2130-D08-05
Murata Electronics
-
114992869
Seeed Technology Co., Ltd
-
HPP816E031
TE Connectivity Measurement Specialties
-
114992871
Seeed Technology Co., Ltd
-
CS-12S6SS-A
Advanced Thermal Solutions Inc.
-
QM30VT2
Banner Engineering Corporation
-
GE-2099
Amphenol Advanced Sensors (Thermometrics)
-
GE-2098
Amphenol Advanced Sensors (Thermometrics)
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