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Texas Instruments ADS7818E/250G4
- Part No.:
- ADS7818E/250G4
- Manufacturer:
- Texas Instruments
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
ADS7818E/250G4.pdf
- Description:
- IC ADC 12BIT SAR 8VSSOP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
ADS7818E/250G4 from Texas Instruments (formerly Burr-Brown) is a 12-bit successive approximation register (SAR) analog-to-digital converter with integrated sample/hold, internal 2.5V bandgap reference, and synchronous serial interface. It delivers 500kHz throughput at 11mW typical power dissipation, supports differential input (±0.2V common-mode on –In), and operates over –40°C to +85°C in MSOP-8 package. It is used in portable spectrum analyzers and battery-powered data loggers requiring low-power, high-speed digitization.
For engineers reviewing the ADS7818E/250G4 datasheet, ADS7818E/250G4 pinout, ADS7818E/250G4 application, or ADS7818E/250G4 equivalent, key selection considerations include guaranteed no-missing-codes performance, unipolar 0–5V input range (with internal reference), 1.625µs conversion time, and support for LSB-first serial output via CONV control - all critical for precision embedded signal acquisition.
Technical Context
The ADS7818E/250G4 employs capacitive redistribution SAR architecture fabricated in 0.6µm CMOS, enabling inherent sample/hold functionality without external components. Its internal 2.5V reference sets a 0–5V full-scale input span, and the VREF pin accepts external references from 2.0V to 2.55V for adjustable input ranges (e.g., 0–4.095V with 2.048V reference).
Digital interface timing is asynchronous between CONV and CLK: conversion start is triggered by CONV falling edge, independent of clock phase, while serial data transfer (MSB-first or LSB-first) is synchronized to CLK rising edges. Power-down mode activates when CONV remains low through the 13th clock cycle, reducing supply current to 0.5mA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit with guaranteed no missing codes - ensures monotonicity and eliminates code gaps in closed-loop control or calibration systems. |
| Throughput Rate | 500kHz maximum - enables real-time sampling of signals up to 350kHz usable bandwidth (SINAD > 68dB). |
| Power Dissipation | 11mW at 500kHz; 2.5mW in power-down - supports extended battery life in portable instrumentation. |
| Analog Input Range | 0V to 5V (unipolar, with internal 2.5V reference); differential input with –In limited to ±0.2V - allows remote ground sensing but not true fully differential operation. |
| Reference Voltage | Internal 2.5V ±0.025V (20ppm/°C drift); externally overdrivable from 2.0V to 2.55V - enables precise full-scale scaling and improved temperature stability with external references. |
| SNR / SINAD | 72dB / 70dB at 100kHz input - meets requirements for medium-resolution spectral analysis and digital signal processing front-ends. |
| Integral Linearity | ±2 LSB max (ADS7818E grade) - sufficient for 10-bit effective resolution in measurement applications where gain/offset calibration is applied. |
Pinout & Package
ADS7818E/250G4 is packaged in an MSOP-8 (Package Drawing 337), 3mm × 3mm body, 0.65mm pitch, thin profile (1.1mm max height), suitable for space-constrained PCB layouts in portable equipment.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VREF | Reference output/buffered reference input | Provides or accepts 2.0–2.55V reference; requires 0.1µF ceramic + 2.2µF tantalum bypassing to suppress SAR switching noise. |
| 2 +In | Non-inverting analog input | Accepts 0–5V unipolar signal relative to –In; input impedance >1GΩ during hold; must settle within 350ns acquisition window. |
| 3 –In | Inverting analog input | Limited to –0.2V to +0.2V; used for remote ground sensing or single-ended bias - not for full differential signal rejection. |
| 4 GND | Analog and digital ground | Single ground pin shared for analog and digital sections; requires low-impedance connection to minimize noise coupling. |
| 5 CONV | Convert control input | Asynchronous command pin: falling edge initiates sample→hold transition; controls power-down entry and LSB-first data mode. |
| 6 DATA | Serial data output | Three-state CMOS output; transmits 12-bit straight-binary result MSB-first (or LSB-first if CONV toggled at clock 13); high-impedance when inactive. |
| 7 CLK | Serial clock input | Accepts 200kHz–8MHz clock; duty cycle insensitive; minimum HIGH/LOW time = 50ns; determines conversion speed and data timing. |
| 8 +VCC | Positive supply | +5V ±5% operation only; requires 0.1µF ceramic + 10µF tantalum decoupling close to pin to stabilize internal reference and logic. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed no missing codes | Ensures monotonic transfer function across full temperature range (–40°C to +85°C), eliminating decision ambiguities in control feedback loops. |
| Configurable serial output order | Supports both MSB-first (default) and LSB-first transmission via CONV timing - simplifies alignment with microcontroller SPI peripherals lacking MSB-first mode. |
| Low-power power-down mode | Reduces quiescent current to 0.5mA (vs 2.2mA active) with zero conversion latency on wake-up - ideal for burst-mode acquisition in energy-harvesting sensors. |
| External reference overdrive capability | Allows substitution of precision external references (e.g., 2.048V) to achieve exact 1mV/LSB scaling or lower temperature drift (<10ppm/°C), improving system-level accuracy. |
| Short-cycle conversion | Enables early termination of conversion after fewer than 12 bits - reduces latency in threshold-detection applications (e.g., overvoltage alarm) without hardware changes. |
Applications
| Portable Spectrum Analyzer Front-End | Battery-Powered Multi-Channel Data Logger |
|---|---|
Use Scenario: Digitizing RF intermediate frequency (IF) signals up to 247kHz with minimal power draw in handheld test equipment. IC Role / Device Role / Timing Role: ADC front-end capturing baseband IF samples; provides 12-bit resolution and 500kHz throughput synchronized to DSP clock. Use Value: Enables real-time FFT-based spectral display with 72dB SNR and <1LSB integral nonlinearity - sufficient for EMI pre-compliance screening. |
Use Scenario: Simultaneous logging of voltage, temperature, and current from multiple sensors in field-deployed environmental monitors. IC Role / Device Role / Timing Role: Low-power sampling ADC interfaced to microcontroller via SPI-compatible serial interface; powers down between readings. Use Value: Extends battery life to >1 year using 2.5mW power-down mode and 350ns acquisition time - supports high-accuracy sensor polling without external sample/hold. |
| DSP-Based Digital Signal Processing System | Wireless Communication Transceiver Monitoring |
Use Scenario: Acquiring analog baseband I/Q signals in software-defined radio (SDR) receivers before digital demodulation. IC Role / Device Role / Timing Role: High-speed SAR ADC feeding TI C6000 DSP; uses synchronous serial interface with continuous CLK and CONV-triggered conversions. Use Value: Delivers 70dB SINAD at 100kHz, supporting 12-bit dynamic range for QPSK/16-QAM symbol recovery without additional dithering. |
Use Scenario: Monitoring PA bias voltage and RF detector outputs in LTE/Wi-Fi modules for adaptive power control and fault detection. IC Role / Device Role / Timing Role: Precision monitoring ADC with internal reference; interfaces to host MCU via isolated serial link to avoid ground loop interference. Use Value: Provides stable 0–5V measurement range and 2.5V reference buffering - ensures accurate PA efficiency tracking across temperature without external reference IC. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7816E/250 | 10-bit resolution, same MSOP-8 package, identical pinout and serial interface; 1.5µs conversion time; 7mW power at 500kHz. | Lower resolution limits usable bandwidth to ~200kHz (SINAD > 60dB); suitable for cost-sensitive sensor monitoring where 10-bit accuracy suffices. | Select ADS7816E/250 when system SNR requirements are ≤62dB and board space/power budget constrain higher-resolution alternatives. |
| ADS8320EB/250 | 16-bit resolution, SPI-compatible interface, 100kSPS max throughput, 2.7–5.5V supply; requires external reference and separate power rails. | Higher resolution but lower speed; lacks integrated reference and power-down mode; needs additional decoupling and layout care for 16-bit performance. | Choose ADS8320EB/250 only when absolute accuracy >12-bit is required and throughput ≤100kSPS is acceptable - not a drop-in replacement. |
Compared with ADS7818E/250G4, ADS7816E/250 trades resolution for lower cost and power, while ADS8320EB/250 offers higher precision at significantly reduced speed and increased system complexity - making ADS7818E/250G4 optimal for 12-bit, 500kHz, self-contained applications.
Availability
ADS7818E/250G4 is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered data acquisition, and wireless transceiver monitoring requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for ADS7818E/250G4 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 acquired Burr-Brown in 2000 and maintains its precision analog portfolio, emphasizing high-performance data converters, amplifiers, and reference ICs for industrial, medical, and test equipment markets.
The ADS7818E/250G4 belongs to TI's legacy high-speed SAR ADC family designed for portable, low-power, precision digitization - targeting applications where integration (internal reference, sample/hold), small footprint (MSOP-8), and guaranteed monotonicity outweigh ultra-high resolution or ultra-low noise.
FAQ
What is the operating temperature range for the ADS7818E/250G4?
The ADS7818E/250G4 is specified for continuous operation from –40°C to +85°C. All key parameters - including integral linearity (±2 LSB), SNR (72dB), and reference drift (20ppm/°C) - are guaranteed across this full industrial temperature range, making it suitable for outdoor and automotive-adjacent instrumentation environments.
Does the ADS7818E/250G4 require an external reference, or can it operate with its internal reference?
The ADS7818E/250G4 can operate fully autonomously using its internal 2.5V bandgap reference, delivering a 0–5V input range. The VREF pin may be overdriven with an external 2.0–2.55V reference to adjust full-scale range or improve temperature stability - no external reference is mandatory for basic operation of the ADS7818E/250G4.
How does the power-down mode work on the ADS7818E/250G4, and what is its recovery time?
The ADS7818E/250G4 enters power-down mode when CONV remains LOW through the 13th clock cycle; supply current drops to 0.5mA. Recovery is immediate - the first conversion after CONV goes HIGH is valid, with no pipeline delay or settling penalty. This makes the ADS7818E/250G4 ideal for burst-sampling applications where latency must remain deterministic.
Can the ADS7818E/250G4 accept differential input signals, and what are the limitations?
The ADS7818E/250G4 accepts differential inputs via +In and –In pins, but –In is restricted to –0.2V to +0.2V. This configuration supports remote ground sensing rather than true differential signal rejection. For full differential operation, external instrumentation amplifiers are required upstream of the ADS7818E/250G4.
What serial interface protocol does the ADS7818E/250G4 use, and is it compatible with standard SPI?
The ADS7818E/250G4 uses a synchronous serial interface with separate CONV (frame sync) and CLK lines, transmitting 12-bit straight-binary data MSB-first by default. While not SPI-standard compliant (no MOSI/MISO), its timing is easily emulated by most microcontrollers' GPIO or SPI peripherals with software-controlled CONV assertion - confirmed in TI application note SBAS078 for ADS7818E/250G4 interfacing.
ADS7818E/250G4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 500k
- Number of Inputs:
- 1
- Input Type:
- Differential
- Data Interface:
- SPI
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- Internal
- Voltage - Supply, Analog:
- 5V
- Voltage - Supply, Digital:
- 5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 8-VSSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
ADS7818E/250G4 FAQ
1.How can I place an order for ADS7818E/250G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for ADS7818E/250G4 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 ADS7818E/250G4 reliable?
The price and inventory of ADS7818E/250G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADS7818E/250G4 is usually 5 days.
3.What payment methods are accepted for ADS7818E/250G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADS7818E/250G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADS7818E/250G4?
ADS7818E/250G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADS7818E/250G4 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 ADS7818E/250G4?
For technical support, including ADS7818E/250G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADS7818E/250G4 requirements.
6.How does Aetrix verify that ADS7818E/250G4 is sourced from the original manufacturer or authorized distributors?
All ADS7818E/250G4 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 ADS7818E/250G4 meets industry standards.
7.What is the process for return or replacement of ADS7818E/250G4?
All ADS7818E/250G4 units undergo pre-shipment inspection (PSI). If there is an issue with ADS7818E/250G4, 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 ADS7818E/250G4 part is unused and in its original packaging.
Return procedure for ADS7818E/250G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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