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Texas Instruments ADS7861E/2K5
- Part No.:
- ADS7861E/2K5
- Manufacturer:
- Texas Instruments
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 24-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
ADS7861E/2K5.pdf
- Description:
- IC ADC 12BIT SAR 24SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:5,003
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Product details
Overview
ADS7861E/2K5 from Texas Instruments is a dual, 12-bit, 500kSPS simultaneous-sampling analog-to-digital converter with four fully differential input channels (CH A0±, A1±, B0±, B1±), 2µs per-channel throughput, 80dB common-mode rejection at 50kHz, and operation over –40°C to +125°C - deployed in motor control systems requiring phase-coherent multi-axis acquisition.
For engineers reviewing the ADS7861E/2K5 datasheet, ADS7861E/2K5 pinout, ADS7861E/2K5 application, or ADS7861E/2K5 equivalent, key selection considerations include simultaneous dual-channel sampling integrity, internal 2.5V reference accuracy (±25ppm/°C drift), SSI serial interface timing (16-cycle conversion @ 8MHz clock), and SSOP-24 package thermal pad grounding requirements.
Technical Context
The ADS7861E/2K5 implements two independent SAR ADC cores with matched aperture delay (3.5ns typical, ±100ps matching) and fully differential sample-and-hold amplifiers preserving signal phase between channel pairs. Its dual serial interface supports either parallel output on SERIAL DATA A/B (M1=0) or time-multiplexed output on SERIAL DATA A only (M1=1).
Channel selection is controlled by M0 (two- vs. four-channel mode), A0 (channel pair select), and CONVST edge-triggered hold initiation - enabling deterministic timing for real-time closed-loop control. The internal 2.5V reference is double-buffered and capable of sourcing 2mA, with external reference support from 1.2V to 2.6V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 1.22mV LSB step size with 2.5V reference, sufficient for ±10V bipolar input via level-shift circuitry. |
| Sampling Rate | 500kSPS per channel - requires 8MHz master clock (16 cycles/conversion), enabling 2µs total throughput per channel. |
| Input Structure | Four fully differential inputs (A0±, A1±, B0±, B1±) - provides 80dB CMRR at 50kHz, critical for noisy industrial motor drive environments. |
| Reference | Internal 2.5V ±25ppm/°C - eliminates external reference component count; REFIN/REFOUT pins allow external reference override (1.2–2.6V range). |
| Power Consumption | 40mW at +125°C - enables thermally constrained embedded designs without active cooling. |
| Operating Temperature | –40°C to +125°C - qualified for under-hood automotive and industrial motor control applications. |
| Interface | SSI serial (CMOS-compatible) - supports MSB-first 12-bit data + status flags on falling clock edges; RD/CONVST sync simplifies controller firmware. |
Pinout & Package
ADS7861E/2K5 is packaged in SSOP-24 with exposed thermal pad (internally connected to substrate; recommended to connect to AGND). Pin 1 = DGND, Pin 12 = AGND, Pin 13 = +VA (analog supply), Pin 24 = +VD (digital supply); both supplies must be ≤+5.25V and decoupled with 0.1µF ceramic + 10µF tantalum capacitors.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| DGND (1) | Digital Ground | Must be connected directly to AGND (Pin 12) to minimize ground bounce between digital and analog domains. |
| CH A0+ / CH A0− (7, 8) | Differential Input Channel A0 | Accepts ±2.5V differential signal centered at internal 2.5V reference; matched impedance required to maintain <±0.5 LSB gain error. |
| M0 (15) | Mode Select: Two/Four-Channel | M0=0 → two-channel mode (A0 selects A0/B0 or A1/B1); M0=1 → four-channel sequential mode (A0 ignored). |
| CONVST (17) | Conversion Start Trigger | Rising edge initiates simultaneous hold on both SHAs; must be asserted ≥15ns before or ≥5ns after CLK rising edge to avoid ambiguous timing windows. |
| SERIAL DATA A (22) | Primary Serial Output | Carries 12-bit data + 2 status bits (channel ID) MSB-first; active when CS=LOW; tri-stated when CS=HIGH or M1=HIGH in Mode II/IV. |
Key Features
| Feature | Design Value |
|---|---|
| Simultaneous Sampling | Two independent SAR cores acquire CH A0±/B0± or CH A1±/B1± at identical instants - preserves phase relationship for vector control algorithms. |
| No Missing Codes | Guaranteed 12-bit monotonicity across full temperature range - eliminates code ambiguity in safety-critical position feedback loops. |
| Aperture Matching | ≤100ps channel-to-channel aperture delay mismatch - ensures <0.01° phase error at 10kHz input frequency. |
| Internal Reference Stability | ±25ppm/°C drift and 50µVPP noise - reduces calibration burden in field-deployed inverters operating across wide ambient ranges. |
| High CMRR | 80dB at 50kHz - rejects common-mode noise from IGBT switching transients in 3-phase power converters. |
Applications
| Motor Control | Multi-Axis Positioning Systems |
|---|---|
Use Scenario: Real-time current sensing in three-phase PMSM servo drives using shunt resistors on all phases. IC Role / Device Role / Timing Role: Simultaneously samples high-side and low-side current feedback (CH A0±/B0±) to compute instantaneous torque vector without phase skew. Use Value: Enables field-oriented control (FOC) with <0.01° phase alignment between current axes, improving efficiency by up to 3% versus non-simultaneous ADCs. |
Use Scenario: Coordinated motion control of X-Y-Z gantry stages with synchronized encoder and load-cell feedback. IC Role / Device Role / Timing Role: Acquires position (A0±/A1±) and force (B0±/B1±) signals at identical timestamps to prevent trajectory interpolation errors. Use Value: Eliminates cross-axis jitter in CNC machining paths, reducing contouring error by >40% compared to multiplexed sampling. |
| 3-Phase Power Control | Industrial Inverter Monitoring |
Use Scenario: Voltage and current monitoring on all three legs of an IGBT-based VFD for overcurrent protection and harmonic analysis. IC Role / Device Role / Timing Role: Four-channel mode (M0=1) sequentially samples line-to-line voltages (A0±/A1±) and phase currents (B0±/B1±) with <100ps inter-channel timing skew. Use Value: Supports real-time THD calculation (<–71dB at +125°C) and cycle-by-cycle fault detection within 2µs window. |
Use Scenario: Predictive maintenance telemetry in HVAC compressors using vibration + temperature + current signatures. IC Role / Device Role / Timing Role: Simultaneous acquisition of motor winding current (A0±) and bearing vibration (B0±) enables coherent FFT analysis of mechanical-electrical coupling. Use Value: Detects early-stage bearing wear via phase-aligned spectral correlation, extending mean time between failures by 35%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel simultaneous-sampling ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS8327IPW | Single 16-bit, 500kSPS SAR ADC; no simultaneous dual-channel capability; SPI interface only. | Requires external multiplexer and timing coordination for dual-signal capture; lacks inherent phase coherence. | Select only if higher resolution (16-bit) outweighs need for guaranteed simultaneous sampling and built-in differential input structure. |
| AD7357BRUZ | Dual 14-bit, 4MSPS pipelined ADC; no internal reference; requires external 2.048V ref; 32-lead TQFP. | Higher speed but lower DC accuracy (±3.5 LSB INL vs. ±2 LSB for ADS7861E/2K5); unsuitable for precision motor control at full scale. | Prefer for broadband signal analysis where speed > DC precision; avoid where <±0.5 LSB gain match across temperature is mandatory. |
Compared with ADS8327IPW and AD7357BRUZ, the ADS7861E/2K5 uniquely delivers guaranteed simultaneous sampling across two differential channel pairs within a single IC, internal 2.5V reference with <±0.5 LSB offset drift over –40°C to +125°C, and SSOP-24 footprint optimized for space-constrained motor control PCBs.
Availability
ADS7861E/2K5 is available at Aetrix Electronics and suitable for motor control, multi-axis positioning systems, and 3-phase power control requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for ADS7861E/2K5 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
Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with over 50 years of innovation in precision data converters and industrial-grade ICs.
The ADS7861 product line was designed specifically for high-fidelity, phase-coherent acquisition in real-time motor control and power electronics - emphasizing simultaneous sampling integrity, robustness in EMI-heavy environments, and extended temperature qualification.
FAQ
What is the maximum clock frequency supported by ADS7861E/2K5?
The ADS7861E/2K5 requires a minimum of 16 clock cycles per conversion to achieve its rated 500kSPS throughput, meaning an 8MHz master clock is necessary. The absolute maximum clock frequency is 8MHz - exceeding this violates timing specifications and may cause missing codes or increased aperture jitter. The ADS7861E/2K5 does not support overclocking beyond datasheet limits.
Does ADS7861E/2K5 support external voltage reference?
Yes, the ADS7861E/2K5 supports external reference voltages from 1.2V to 2.6V applied to the REFIN pin, which scales the full-scale input range proportionally (e.g., 1.2V ref → ±1.2V differential input span). When using external reference, the internal 2.5V buffer remains active to isolate the CDAC array, preserving linearity and reducing reference load sensitivity.
How is simultaneous sampling implemented in ADS7861E/2K5?
The ADS7861E/2K5 uses two physically separate SAR ADC cores and two matched differential sample-and-hold amplifiers. A single CONVST rising edge triggers both SHAs to enter hold mode simultaneously, freezing analog inputs at identical instants. Aperture delay matching is specified at ≤100ps, ensuring phase coherence essential for vector control and power quality analysis.
What are the thermal pad grounding requirements for ADS7861E/2K5 in SSOP-24?
The thermal pad on the ADS7861E/2K5 SSOP-24 package is internally connected to the silicon substrate and must be soldered to a dedicated AGND copper pour - electrically isolated from DGND. TI recommends connecting it directly to Pin 12 (AGND) with multiple vias to minimize thermal resistance and reduce analog ground noise coupling into the digital domain.
Can ADS7861E/2K5 operate with unipolar input signals?
Yes, the ADS7861E/2K5 accepts unipolar inputs by biasing the differential inputs around the internal 2.5V reference - for example, applying 0V–5V signals via level-shifting circuitry (as shown in Figure 7 of SBAS110D). The device's bipolar input architecture (–VREF to +VREF) inherently supports this configuration without hardware modification, maintaining full 12-bit resolution and linearity.
ADS7861E/2K5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 500k
- Number of Inputs:
- 4
- Input Type:
- Differential
- Data Interface:
- SPI
- Configuration:
- MUX-S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 2
- Architecture:
- SAR
- Reference Type:
- External, Internal
- Voltage - Supply, Analog:
- 5V
- Voltage - Supply, Digital:
- 5V
- Features:
- Selectable Address, Simultaneous Sampling
- Operating Temperature:
- -40°C ~ 125°C
- Supplier Device Package:
- 24-SSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
ADS7861E/2K5 FAQ
1.How can I place an order for ADS7861E/2K5 through Aetrix?
Please submit a Request for Quotation (RFQ) for ADS7861E/2K5 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 ADS7861E/2K5 reliable?
The price and inventory of ADS7861E/2K5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADS7861E/2K5 is usually 5 days.
3.What payment methods are accepted for ADS7861E/2K5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADS7861E/2K5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADS7861E/2K5?
ADS7861E/2K5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADS7861E/2K5 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 ADS7861E/2K5?
For technical support, including ADS7861E/2K5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADS7861E/2K5 requirements.
6.How does Aetrix verify that ADS7861E/2K5 is sourced from the original manufacturer or authorized distributors?
All ADS7861E/2K5 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 ADS7861E/2K5 meets industry standards.
7.What is the process for return or replacement of ADS7861E/2K5?
All ADS7861E/2K5 units undergo pre-shipment inspection (PSI). If there is an issue with ADS7861E/2K5, 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 ADS7861E/2K5 part is unused and in its original packaging.
Return procedure for ADS7861E/2K5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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