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Texas Instruments ADS7844NB/1K
- Part No.:
- ADS7844NB/1K
- Manufacturer:
- Texas Instruments
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
ADS7844NB/1K.pdf
- Description:
- IC ADC 12BIT SAR 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:581
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Product details
Overview
ADS7844NB/1K from Texas Instruments is a 12-bit, 8-channel SAR analog-to-digital converter with synchronous serial interface, ±1 LSB INL/DNL, 200 kHz max throughput at +5V, and single-supply operation from 2.7V to 5V. It integrates an on-chip 8-channel multiplexer and supports both single-ended (8 ch) and differential (4 ch) input configurations for portable data acquisition systems.
For engineers reviewing the ADS7844NB/1K datasheet, ADS7844NB/1K pinout, ADS7844NB/1K application, or ADS7844NB/1K equivalent, key selection criteria include its guaranteed no-missing-codes performance, 72 dB SINAD at 10 kHz, shutdown mode (<1 µW), and SSOP-20 package compatibility with MAX147-based designs.
Technical Context
The ADS7844NB/1K implements a capacitive redistribution successive approximation register (SAR) architecture with integrated sample-and-hold. Its analog front-end accepts inputs referenced to COM (single-ended) or across channel pairs (differential), with programmable configuration via 8-bit serial control byte including A2–A0, SGL/DIF, and PD1/PD0 bits.
Digital timing supports three modes: 24-clock (standard), 16-clock (overlapped), and 15-clock (FPGA/ASIC-optimized) conversion cycles. The device uses unbuffered VREF (0.1 V to VCC), where LSB size = VREF/4096, and reference current scales with sample rate and VREF magnitude.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 4096 discrete output codes with monotonic transfer function and no missing codes. |
| Throughput Rate | 200 kHz at +5V - enables real-time sampling of signals up to ~99 kHz Nyquist bandwidth. |
| INL / DNL | ±1 LSB max - ensures high code-edge accuracy critical for closed-loop control and precision measurement. |
| SINAD | 72 dB at 10 kHz - corresponds to ~11.9 effective bits, supporting accurate digitization of low-distortion analog waveforms. |
| Supply Range | 2.7 V to 5 V - allows direct interfacing with 3.3 V or 5 V microcontrollers without level-shifting. |
| Power-Down Current | <1 µW - reduces system standby power in battery-operated PDA and data logger applications. |
| Channel Configuration | 8 single-ended or 4 differential - selectable via SGL/DIF bit, enabling flexible sensor interfacing (e.g., thermocouples, RTDs, voltage rails). |
Pinout & Package
ADS7844NB/1K is housed in a 20-lead SSOP (Shrink Small Outline Package) with 0.65 mm lead pitch, RoHS-compliant, and rated for –40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CH0–CH7 | Analog input channels | Eight configurable inputs; selected via A2–A0 and SGL/DIF bits for single-ended (vs. COM) or differential (pairwise) acquisition. |
| COM | Analog ground reference | Sets zero-code voltage in single-ended mode; must be connected to system ground or stable reference point. |
| SHDN | Hardware shutdown control | Active-low signal forcing sub-µW quiescent current; independent of serial interface state. |
| VREF | Unbuffered reference input | Accepts 0.1 V to VCC; defines full-scale span (LSB = VREF/4096); draws current scaling with sample rate. |
| +VCC, GND (×2) | Power supply terminals | Dual GND pins reduce ground bounce; +VCC powers analog and digital sections from single rail. |
| DOUT, DIN, DCLK, CS, BUSY | Serial interface signals | CMOS-compatible 4-wire SPI-like interface; BUSY indicates conversion or control-bit latching; CS enables tri-state DOUT. |
Key Features
| Feature | Design Value |
|---|---|
| No missing codes over full temperature range | Guarantees monotonicity and predictable code transitions in closed-loop feedback systems. |
| Programmable power-down mode (PD1/PD0) | Enables automatic low-power state between conversions-no wake-up latency; first result valid immediately. |
| Channel-to-channel isolation >100 dB | Minimizes crosstalk in multi-sensor monitoring, preserving signal integrity when scanning across CH0–CH7. |
| Over-voltage tolerant digital inputs | VIH up to 5.5 V regardless of +VCC - simplifies interface with mixed-voltage microcontrollers (e.g., 5 V logic driving 3.3 V ADC). |
| 15-/16-/24-clock conversion flexibility | Supports optimized timing for MCU (24-clock), DSP/FPGA (16-clock), or ASIC (15-clock) host systems. |
Applications
| Data Acquisition Systems | Portable Test Equipment |
|---|---|
Use Scenario: Simultaneous monitoring of multiple voltage rails, temperature sensors, and current shunts in field-deployable environmental loggers. IC Role / Device Role / Timing Role: 12-bit SAR ADC providing time-aligned samples across 8 channels with <1 µs aperture jitter for synchronized waveform capture. Use Value: Enables high-fidelity trending of slow-varying analog parameters (e.g., soil moisture, battery health) with minimal power budget. | Use Scenario: Handheld multimeter or oscilloscope probe interface requiring compact, low-power, multi-channel analog front-end. IC Role / Device Role / Timing Role: Serial-output ADC handling both DC measurements (single-ended) and differential sensor outputs (e.g., strain gauges) with on-the-fly mode switching. Use Value: Eliminates external multiplexer and level-shifting circuitry, reducing BOM count and PCB area in space-constrained instruments. |
| Industrial Process Monitoring | Battery-Powered Medical Devices |
Use Scenario: PLC I/O module digitizing 4–20 mA loop signals, thermocouple outputs, and pressure transducer voltages in factory automation. IC Role / Device Role / Timing Role: Precision ADC with ±1 LSB linearity and 72 dB SINAD ensuring compliance with IEC 61000-4 immunity standards under noisy industrial EMI. Use Value: Delivers metrology-grade accuracy without calibration drift compensation firmware, lowering firmware development cost. | Use Scenario: Wearable vital sign monitor acquiring ECG, skin temperature, and SpO₂ analog signals from low-noise front-end amplifiers. IC Role / Device Role / Timing Role: Low-quiescent-current ADC operating from coin-cell battery; shutdown mode extends runtime between charges. Use Value: Achieves >100-hour continuous operation while maintaining diagnostic-grade signal fidelity for clinical decision support. |
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 |
|---|---|---|---|
| MAX147ACPP+ | Pin-compatible 12-bit 8-ch SAR ADC; identical SSOP-20 footprint; ±1 LSB INL; 133 kSPS max; requires external reference. | Designed for industrial temperature range only (0°C to +70°C); lacks SHDN pin and auto power-down mode. | Select MAX147ACPP+ only if legacy board reuse is required and extended temperature or ultra-low-power shutdown is not needed. |
| ADS7841U | Same TI family; 12-bit, 4-channel, 200 kSPS; QSOP-20; shares identical serial protocol and timing but fewer inputs. | Reduced channel count limits use to simpler systems; lower pin count eases routing but eliminates 8-ch multiplexing capability. | Choose ADS7841U when design requires TI ecosystem consistency and only 4 analog inputs are needed-reducing layout complexity and cost. |
Compared with MAX147ACPP+, ADS7844NB/1K adds SHDN control and –40°C to +85°C operation; versus ADS7841U, it doubles channel count at same speed and package height, making it optimal for space-constrained, multi-sensor edge nodes.
Availability
ADS7844NB/1K is available at Aetrix Electronics and suitable for portable medical devices, industrial process controllers, and battery-powered test equipment requiring stable component supply across long production lifecycles.
Supply support for ADS7844NB/1K 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 decades of expertise in precision data converters and low-power signal chain solutions.
The ADS7844NB/1K belongs to TI's precision SAR ADC product line, engineered for portable, multi-channel measurement applications where resolution, power efficiency, and serial interface simplicity are critical.
FAQ
What is the maximum sample rate of ADS7844NB/1K at 3.3 V supply?
At +VCC = 3.3 V and VREF = 2.5 V, the ADS7844NB/1K achieves up to 125 kHz throughput, as specified in the +2.7 V electrical characteristics table. This is determined by fCLK = 16 × fSAMPLE, with maximum clock frequency limited by supply voltage and process corner.
Does ADS7844NB/1K require an external reference, and what is its acceptable range?
Yes, ADS7844NB/1K requires an external unbuffered reference applied to the VREF pin. The supported range is 0.1 V to +VCC (2.7 V to 5 V), enabling flexible full-scale spans from 100 mV to 5 V. Reference current scales with sample rate and VREF magnitude, reaching up to 40 µA at 125 kHz and 2.5 V.
How does the SHDN pin interact with the PD1/PD0 power-down modes in ADS7844NB/1K?
The SHDN pin forces immediate hardware shutdown (<1 µW) regardless of PD1/PD0 state. When SHDN is HIGH, PD1/PD0 control auto power-down between conversions. If SHDN is LOW while PD1/PD0 = 00b, the device remains in deep shutdown-no conversion possible until SHDN returns HIGH.
Can ADS7844NB/1K perform true differential measurements across non-adjacent channels like CH0 and CH5?
No. ADS7844NB/1K supports only predefined differential pairs: CH0–CH1, CH2–CH3, CH4–CH5, and CH6–CH7, as defined by the SGL/DIF bit and A2–A0 address mapping in Tables I and II. Cross-pair differential acquisition (e.g., CH0 vs CH5) is not supported by the internal multiplexer architecture.
What is the absolute input voltage range allowed on CHx pins of ADS7844NB/1K?
The positive input (e.g., CH0+) accepts –0.2 V to (+VCC + 0.2) V; the negative input (e.g., CH0–) is limited to –0.2 V to +1.25 V at +5 V supply, or –0.2 V to +0.2 V at +2.7 V supply. Exceeding these ranges risks damage or erroneous conversion results.
ADS7844NB/1K Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 200k
- Number of Inputs:
- 4, 8
- Input Type:
- Differential, Single Ended
- Data Interface:
- SPI
- Configuration:
- MUX-S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External
- Voltage - Supply, Analog:
- 2.7V ~ 3.6V, 5V
- Voltage - Supply, Digital:
- 2.7V ~ 3.6V, 5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 20-SSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
ADS7844NB/1K FAQ
1.How can I place an order for ADS7844NB/1K through Aetrix?
Please submit a Request for Quotation (RFQ) for ADS7844NB/1K 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 ADS7844NB/1K reliable?
The price and inventory of ADS7844NB/1K are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADS7844NB/1K is usually 5 days.
3.What payment methods are accepted for ADS7844NB/1K?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADS7844NB/1K transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADS7844NB/1K?
ADS7844NB/1K orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADS7844NB/1K 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 ADS7844NB/1K?
For technical support, including ADS7844NB/1K datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADS7844NB/1K requirements.
6.How does Aetrix verify that ADS7844NB/1K is sourced from the original manufacturer or authorized distributors?
All ADS7844NB/1K 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 ADS7844NB/1K meets industry standards.
7.What is the process for return or replacement of ADS7844NB/1K?
All ADS7844NB/1K units undergo pre-shipment inspection (PSI). If there is an issue with ADS7844NB/1K, 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 ADS7844NB/1K part is unused and in its original packaging.
Return procedure for ADS7844NB/1K:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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