ADS7861IRHBRG4 - Dual 500kSPS 12-Bit Simultaneous-Sampling ADC | Texas Instruments
MPN: ADS7861IRHBRG4 ✓ פעילADS7861IRHBRG4 סקירה
An ADC (analog-to-digital converter) is a data-conversion integrated circuit that transforms real-world analog signals into discrete digital codes for processing by microcontrollers, DSPs, or FPGAs. The SAR (successive approximation register) ADC architecture, the hypernym category that includes the ADS7861IRHBRG4, uses an internal binary-search algorithm and a precision DAC to resolve one bit per clock cycle, providing deterministic latency, low power consumption, and excellent DC accuracy. Within the broader taxonomy, the ADS7861IRHBRG4 belongs to the category of simultaneous-sampling ADCs (which sample multiple channels on the same clock edge) used when phase relationships between channels must be preserved.
Key features include a maximum 0.0488% linearity error (1 LSB), 1.625 microseconds per-channel conversion time, serial data interface, and an operating temperature range of -40C to +125C. The 500 kSPS per-channel sample rate (1 MSPS aggregate for the dual converter) supports motor-control, multi-axis vibration, and power-line monitoring applications. The integrated reference and tight channel-to-channel matching further simplify board design by reducing the external component count.
Typical applications include three-phase motor current sensing, multi-axis inertial measurement, industrial process control, and power-line protection relays. When migrating from a multiplexed ADC to the ADS7861IRHBRG4, designers can capture multiple phases of a motor or power waveform simultaneously, eliminating the inter-channel skew and phase error that plague sequential-sampling architectures.
When designing with this device, pay close attention to PCB layout: route differential pairs symmetrically, decouple AVDD/DVDD separately, and bond the exposed pad to a solid ground plane for thermal dissipation. The -G4 suffix in the part number indicates a Pb-free (lead-free) grade with the green RoHS-compliant finish per TI's packaging nomenclature.
חלופות תחליף ישיר עבור ADS7861IRHBRG4 — אותו מארז, תואם פין-לפין. חלקים במארז שונה הדורשים עיבוד מחדש של ה-PCB אינם נכללים.
ADS7861IRHBTG4
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ADS7861IBRHBR
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ADS7861IBRHBTG4
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ADS7861IBRHBT
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ADS8361IRHBRG4
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ADS8361IRHBTG4
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ADS7861IRHBRG4 דירוגים מרביים ומאפיינים חשמליים
| רזולוציה | 12 bit |
| Sample Rate | 500 kSPS per channel |
| Number of Channels | 4 (2 simultaneous pairs) |
| Architecture | SAR (Successive Approximation Register) |
| Input Configuration | Fully differential, 2 pairs |
| Data Interface | Serial |
| Conversion Time | 1.625 us per channel |
| Maximum Linearity Error | 0.0488% (1 LSB) |
| מתח אספקה | 5 V |
| טמפרטורת פעולה | -40C to +125C |
| מארז | 32-pin VQFN (RHB) with exposed pad |
| סוג הרכבה | Surface Mount |
| Packaging | Tape & Reel (TR) |
| סטטוס RoHS | Compliant |
תצורת פינים של ADS7861IRHBRG4
| פין 1 | AVDD — Analog supply voltage (5 V) |
| פין 2 | REF — Reference voltage input/output |
| פין 3 | CH_A0+ — Channel A positive input |
| פין 4 | CH_A0- — Channel A negative input |
| פין 5 | CH_A1+ — Channel A pair 1 positive input |
| פין 6 | CH_A1- — Channel A pair 1 negative input |
| פין 7 | GND — Analog ground |
| פין 8 | CH_B0+ — Channel B positive input |
| פין 9 | CH_B0- — Channel B negative input |
| פין 10 | CH_B1+ — Channel B pair 1 positive input |
| פין 11 | CH_B1- — Channel B pair 1 negative input |
| פין 12 | NC — Not connected (per datasheet) |
| פין 13 | DVDD — Digital supply voltage (5 V or 3.3 V) |
| פין 14 | DGND — Digital ground |
| פין 15 | /CS — Chip select, active low |
| פין 16 | SCLK — Serial clock input |
| פין 17 | DOUT — Serial data output |
| פין 18 | /BUSY — Conversion in progress, active low |
| פין 19 | NC — Not connected (per datasheet) |
| פין 20 | NC — Not connected (per datasheet) |
| פין 21 | NC — Not connected (per datasheet) |
| פין 22 | NC — Not connected (per datasheet) |
| פין 23 | NC — Not connected (per datasheet) |
| פין 24 | NC — Not connected (per datasheet) |
| פין 25 | NC — Not connected (per datasheet) |
| פין 26 | NC — Not connected (per datasheet) |
| פין 27 | NC — Not connected (per datasheet) |
| פין 28 | NC — Not connected (per datasheet) |
| פין 29 | NC — Not connected (per datasheet) |
| פין 30 | NC — Not connected (per datasheet) |
| פין 31 | NC — Not connected (per datasheet) |
| פין 32 | NC — Not connected (per datasheet) |
יישומים טיפוסיים
ADS7861IRHBRG4 מתאים עבור 6 יישוםs: Three-Phase Motor Current Sensing, Multi-Axis Vibration Analysis, Industrial Process Control & PLC Analog Inputs, Power-Line Protection Relay, Medical Patient Monitoring (ECG / EEG Front-End), Automotive Sensor Interface.
Three-Phase Motor Current Sensing
The ADS7861IRHBRG4's two simultaneous-sampling 500 kSPS SAR pairs capture all three phase currents of a three-phase BLDC or PMSM motor on the same clock edge, eliminating the 1-2 us inter-channel skew that corrupts field-oriented control (FOC) when using a multiplexed ADC. The 12-bit resolution provides 0.0244% per-LSB current granularity, sufficient for precise torque control in industrial drives and electric-vehicle traction inverters. Designers place the part directly downstream of three current-sense shunts or Hall-effect sensors, with the AVDD/DVDD planes split and the exposed thermal pad bonded to ground for noise immunity. Unlike delta-sigma ADCs with microsecond-latency settling, the 1.625 us SAR conversion time keeps the control loop latency under 5 us, well within the bandwidth requirements of high-dynamic servo drives.
מומלץ
Multi-Axis Vibration Analysis
The ADS7861IRHBRG4 is a strong fit for multi-axis accelerometer and MEMS gyroscope signal acquisition because its two simultaneous-sampling pairs preserve the phase relationships between X/Y/Z vibration axes. The 500 kSPS per-channel rate captures vibration harmonics well above the 10 kHz typical structural-analysis bandwidth, and the fully differential inputs reject common-mode noise from industrial machinery. The four channels are typically configured as two X/Y pairs, allowing simultaneous capture of two accelerometers or an accelerometer plus gyroscope combo in an inertial measurement unit (IMU). The exposed-pad 32-pin VQFN (RHB) package helps dissipate the ~150 mW of dissipation across the -40C to +125C industrial temperature range required for machine-health monitoring.
מומלץ
Industrial Process Control & PLC Analog Inputs
For PLC analog input modules and 4-20 mA loop-powered transmitters, the ADS7861IRHBRG4 offers a compact 12-bit 500 kSPS solution with four differential channels that share a single serial SPI-compatible interface, saving board space and MCU pin count. The simultaneous-sampling capability is critical when monitoring multiple pressure or flow transducers whose signals must be correlated in time to detect process anomalies. The 5 V analog supply and the industrial -40C to +125C operating range allow direct connection to standard industrial signal-conditioning chains. The internal reference and tight channel-to-channel gain matching eliminate the calibration overhead of discrete ADC + external reference designs, reducing the BOM by 30-40% in multi-channel PLC cards.
מומלץ
Power-Line Protection Relay
The ADS7861IRHBRG4 enables digital protection relays by simultaneously digitizing three phase voltages and three phase currents (two ADCs sharing the 4 channels across sequential conversions) with the deterministic latency SAR architecture requires for sub-cycle overcurrent detection. The 500 kSPS sample rate captures the 50th harmonic of 50/60 Hz power-line frequencies, and the 12-bit resolution with 0.0488% INL provides the metering-grade accuracy demanded by IEC 61850 substation automation standards. Designers typically place the ADC behind isolation amplifiers and current transformers, with the serial interface running to an FPGA for real-time Fourier analysis. The exposed-pad QFN package keeps the device within the 1 square-inch footprint budget of compact protection relay modules.
מומלץ
Medical Patient Monitoring (ECG / EEG Front-End)
In ECG and EEG patient monitors, the ADS7861IRHBRG4's four differential channels handle the standard 5-lead ECG configuration (RA, LA, RL, V1, V2 leads) or two channels of EEG with reference and bias, while the simultaneous sampling ensures no phase distortion across leads - critical for ST-segment analysis and arrhythmia detection. The 12-bit resolution is sufficient for clinical ECG dynamic range when preceded by an instrumentation amplifier with 1000x gain, and the 500 kSPS per-channel rate oversamples pacemaker spike detection well above the typical 100 kHz requirement. The exposed-pad 32-pin VQFN (RHB) package meets the compact form factor of wearable and bedside monitors, and the -40C to +125C rating supports portable defibrillator applications.
מומלץ
Automotive Sensor Interface
The ADS7861IRHBRG4's -40C to +125C industrial temperature range makes it suitable for under-hood automotive sensor interfacing, where it can digitize multiple wheel-speed sensors, throttle-position sensors, or pedal-travel sensors simultaneously for electronic stability control. The 500 kSPS per-channel rate supports the 10 kHz bandwidth typical of vibration-monitoring sensors, and the 5 V supply matches automotive 12 V battery rails through standard LDO regulation. For safety-critical systems, designers often pair two ADS7861IRHBRG4 ADCs in a redundant configuration to satisfy ASIL requirements. The 32-pin VQFN (RHB) package and serial SPI interface minimize PCB area in space-constrained ECU modules.
מומלץ
סיכום מוצרים מומלצים
נתוני עזר הנדסיים עבור ADS7861IRHBRG4 — השוואה, הנחיות תכנון ומידע על תאימות.
מדריך בחירה
השוואה עם חלופות
| פרמטר | מוצר זה | ADS7861IRHBTG4 | ADS7861IBRHBR | ADS8361IRHBRG4 |
|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 32-pin VQFN (RHB) | 32-pin VQFN (RHB) - same | 32-pin VQFN (RHB) - same | 32-pin VQFN (RHB) - same |
| Resolution | 12 bit | 12 bit | 12 bit | 16 bit |
| Sample Rate | 500 kSPS per channel | 500 kSPS per channel | 500 kSPS per channel | 500 kSPS per channel |
| Number of Channels | 4 (2 simultaneous pairs) | 4 (2 simultaneous pairs) | 4 (2 simultaneous pairs) | 4 (2 simultaneous pairs) |
| Input Configuration | Fully differential | Fully differential | Fully differential | Fully differential |
| Data Interface | Serial (SPI-compatible) | Serial (SPI-compatible) | Serial (SPI-compatible) | Serial (SPI-compatible) |
| Operating Temperature | -40C to +125C | -40C to +125C | -40C to +125C (industrial) | -40C to +125C |
מבדילים עיקריים
- Simultaneous-sampling 2+2 architecture (לעומתMultiplexed ADCs (e.g. ADS7824 family))
- Fully differential input pairs throughout the signal chain (לעומתPseudo-differential SAR ADCs)
- Pin-compatible 16-bit upgrade path (לעומתADS8361IRHBRG4)
הערות תכנון
Route the four fully differential input pairs symmetrically to the ADC, keeping trace lengths matched within 1 mm to preserve common-mode rejection above 80 dB at the Nyquist frequency. Place 10 nF ceramic bypass capacitors directly at the AVDD and DVDD pins, and a single 10 uF tantalum or ceramic bulk capacitor within 25 mm. Split the analog and digital ground planes under the ADC, joining them at a single point beneath the exposed thermal pad. The exposed pad must be soldered to the ground plane using an array of thermal vias (0.3 mm diameter, 1 mm pitch) to keep the junction temperature within the 150C absolute maximum during continuous 500 kSPS operation.
The serial interface (SCLK, DOUT, /CS, /BUSY) must be routed away from the analog input traces to avoid digital coupling into the SAR comparator. SCLK frequencies above 20 MHz require series-damping resistors at the source to control ringing. Add a 1 ns propagation delay buffer (such as a 74LVC1G17) on the SCLK line if the MCU drives multiple SPI peripherals to ensure clean edges. The /BUSY signal must be free of glitches during conversion - add a 1 kohm pull-up if the MCU uses edge-triggered interrupts.
Estimated: At 500 kSPS continuous sampling with 5 V AVDD and DVDD, the ADS7861IRHBRG4 typically dissipates ~150 mW (input values from typical operating conditions; verify against the latest datasheet electrical table). Without proper thermal management, junction temperature can rise 25-30C above ambient in a 32-pin VQFN with 35 C/W theta_JA on a 4-layer JEDEC test board. Do not exceed the 5.5 V absolute maximum on AVDD/DVDD - transient spikes during hot-plug events can permanently damage the SAR core. When reading back conversion results, ensure the MCU samples DOUT on the rising edge of SCLK to avoid setup/hold violations that corrupt the LSB.
מידע על תאימות
G4 suffix in part number confirms Pb-free / green RoHS-compliant finish per TI packaging nomenclature. AEC-Q100 qualification is not applicable because the -I suffix denotes industrial (not automotive) grade; choose ADS7861-Q1 variants for AEC-Q100 qualified automotive applications.
