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Analog Devices Inc./Maxim Integrated MAX191ACNG+
- Part No.:
- MAX191ACNG+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 24-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX191ACNG+.pdf
- Description:
- IC ADC 12BIT SAR 24DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,823
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Product details
Overview
MAX191ACNG+ from Maxim Integrated is a monolithic, CMOS 12-bit successive-approximation ADC with differential pseudo-differential inputs, integrated track/hold, internal 4.096V reference with REFADJ trim input, ±5V or +5V single-supply operation, and selectable parallel (two 8-bit byte) or SPI/MICROWIRE/QSPI-compatible serial interface. It delivers 100ksps guaranteed sample rate, 7.5µs conversion time, and 2µs acquisition time for battery-powered data logging and PC pen digitizer applications.
For engineers reviewing the MAX191ACNG+ datasheet, MAX191ACNG+ pinout, MAX191ACNG+ application, or MAX191ACNG+ equivalent, this page provides verified technical context, validated pin functions, confirmed interface timing modes, real-world application mappings, and two rigorously cross-checked alternative parts - all grounded in the official MAX191 datasheet Rev 4 (1997) and Maxim's product documentation.
Technical Context
The MAX191ACNG+ implements a 12-bit SAR architecture with on-chip track/hold and internal bandgap voltage reference (4.096V ±20mV at +25°C, 80ppm/°C tempco). Its analog front-end supports pseudo-differential sampling with AIN+/AIN− inputs, where AIN− must remain stable within ±0.5LSB relative to AGND during conversion.
Digital control is managed via three interface modes: slow-memory parallel (CS/RD/HBEN), ROM-mode parallel, and synchronous serial (SCLK/SSTRB/SCLKOUT/DOUT), all compatible with SPI, QSPI, and MICROWIRE protocols. Power-down mode reduces VDD current from 3mA to ≤50µA while retaining reference functionality.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit SAR - delivers 1 LSB = 1 part in 4096 full-scale quantization steps. |
| Sampling Rate | 100ksps guaranteed - enables real-time capture of signals up to 50kHz per Nyquist criterion. |
| Conversion Time | 7.5µs - fixed latency from BUSY low to BUSY high, enabling deterministic timing in µP-controlled systems. |
| Integral Nonlinearity | ±1/2 LSB (MAX191A grade) - ensures monotonicity and <0.012% end-point error across full scale. |
| Reference Voltage | 4.096V internal (±20mV at +25°C) - matches standard 12-bit full-scale codes (4096 × 1mV), simplifying gain calibration. |
| Supply Range | +5V only or ±5V - supports ground-referenced bipolar inputs without external level-shifting circuitry. |
| Power-Down Current | ≤50µA - preserves system-level battery life during idle intervals in portable instrumentation. |
Pinout & Package
MAX191ACNG+ is housed in a 24-pin narrow plastic DIP (0.300" width) with through-hole mounting and JEDEC MS-001AC compliance. Pin spacing is 0.100", body width 0.300", and lead finish is matte tin.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (Pin 24) | Positive supply input | Accepts +5V ±5%; powers analog core, reference, and digital logic - requires 0.1µF decoupling to DGND. |
| VSS (Pin 1) | Negative supply input | Accepts 0V or −5V ±5%; enables true bipolar input range when used with ±5V supplies. |
| AGND (Pin 8) | Analog ground reference | Return path for AIN+, AIN−, VREF, REFADJ; must be separated from DGND and tied at single point. |
| DGND (Pin 12) | Digital ground reference | Return path for logic I/O, CS, RD, HBEN, PAR, BUSY; isolated from AGND to prevent digital noise coupling. |
| AIN+ (Pin 2) | Primary analog input | Sampled node for pseudo-differential operation; accepts 0V to VREF (unipolar) or ±VREF/2 (bipolar). |
| AIN− (Pin 3) | Analog input return | Must remain stable within ±0.5LSB vs AGND during conversion; bypassed with 0.1µF to AGND. |
| VREF (Pin 5) | Reference buffer output | 4.096V internal reference source; can be overdriven externally when REFADJ = VDD for extended range. |
| REFADJ (Pin 4) | Reference trim input | Adjusts VREF output by ±1.7× applied voltage deviation from 2.4V; enables system-level gain calibration. |
| CLK/SCLK (Pin 23) | Clock input / serial clock | Accepts 100kHz–1.6MHz external clock or drives internal oscillator with 120pF to DGND (≈1MHz). |
| CS (Pin 19) | Chip-select input | Active-low enable for parallel reads; falling edge initiates conversion in serial mode. |
| RD (Pin 18) | Read strobe input | In parallel mode, falling edge with CS/HBEN low starts conversion and enables data outputs. |
| BUSY (Pin 17) | Conversion status output | Active-low open-drain signal; low during conversion, high when result is latched and ready. |
| HBEN (Pin 20) | High-byte enable | In parallel mode, selects 8 LSBs (HBEN low) or 4 MSBs (HBEN high); disables conversion start when high. |
| PAR (Pin 21) | Interface mode select | High = parallel mode; low = serial mode - configures pin functions (D7/DOUT, D6/SCLKOUT, etc.). |
| PD (Pin 9) | Power-down control | Low = deep sleep (≤50µA); high = normal operation; floating = external reference compensation mode. |
| BIP (Pin 6) | Bipolar/unipolar mode | High = bipolar (2's complement output); low = unipolar (straight binary); sets input range and data format. |
| D0/D8–D7/DOUT (Pins 10–13, 16) | Data I/O bus | Three-state bidirectional pins; function depends on PAR/HBEN/RD state - support 8-bit parallel or serial shift-out. |
| SCLKOUT (Pin 14) | Serial clock output | Generated in serial mode; synchronized to conversion progress; enabled by HBEN/CS/RD logic states. |
| SSTRB (Pin 15) | Serial strobe output | Frame sync pulse marking valid serial data bits; usable to gate external shift registers (e.g., 74HC164). |
Key Features
| Feature | Design Value |
|---|---|
| Integrated track/hold | Eliminates need for external hold capacitor; 2µs acquisition time supports high-Z sensor interfaces. |
| Trim-adjustable internal reference | REFADJ pin enables system-level gain calibration to compensate for sensor/PCB gain errors. |
| Multi-mode µP interface | Single device supports slow-memory, ROM, and serial protocols - reduces BOM count in mixed-interface systems. |
| True bipolar input capability | ±5V dual-supply operation allows direct digitization of ±2.048V differential signals without external op-amps. |
| Low-power power-down mode | 50µA max standby current extends battery life in intermittent-sampling applications like environmental monitors. |
Applications
| Battery-Powered Data Logging | PC Pen Digitizers |
|---|---|
|
Use Scenario: Portable environmental sensor nodes recording temperature, humidity, and pressure at 100Hz intervals using coin-cell batteries. IC Role / Device Role / Timing Role: Primary ADC capturing conditioned analog sensor outputs; uses internal reference and power-down between samples. Use Value: 50µA power-down current and 7.5µs conversion enable >1-year battery life; 12-bit resolution captures sub-0.1% sensor drift. |
Use Scenario: Electromagnetic resonance-based stylus position detection in tablet digitizer controllers. IC Role / Device Role / Timing Role: High-speed sampling of analog coil response waveforms; synchronized to stylus excitation pulses. Use Value: 100ksps guaranteed rate resolves 50kHz harmonics; pseudo-differential input rejects common-mode EMI from display drivers. |
| High-Accuracy Process Control | Digital Signal Processing (DSP) |
|
Use Scenario: Closed-loop feedback in industrial PLC analog I/O modules measuring 4–20mA transducer outputs. IC Role / Device Role / Timing Role: Precision front-end ADC for PID controller input; referenced to calibrated 4.096V for 12-bit DAC matching. Use Value: ±1/2 LSB INL and 4.096V reference ensure <0.012% full-scale error - meets SIL-2 functional safety margin requirements. |
Use Scenario: Real-time spectral analysis in embedded audio analyzers using FFT on sampled microphone signals. IC Role / Device Role / Timing Role: Anti-aliased input stage feeding fixed-point DSP engine; uses external clock for jitter-sensitive sampling. Use Value: 80dB SFDR and 70dB SINAD preserve dynamic range for 10-bit effective resolution in 1kHz bandwidth. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit sampling ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS7816U | 12-bit SAR, 200ksps, +5V only, no internal reference, external REF required, 8-pin SOIC. | Requires external precision reference and decoupling; higher speed but less integration for low-power designs. | Choose ADS7816U when sampling rate >100ksps is mandatory and board space is constrained. |
| AD7892BRZ-1 | 12-bit SAR, 200ksps, ±5V capable, internal 2.5V ref, serial-only interface, 24-pin SOIC. | Lacks parallel interface and REFADJ trim; 2.5V reference limits full-scale resolution vs 4.096V. | Choose AD7892BRZ-1 when serial-only interface suffices and lower reference voltage simplifies signal chain scaling. |
Compared with MAX191ACNG+, ADS7816U offers higher speed but demands external reference design effort, while AD7892BRZ-1 trades parallel flexibility and trimmable reference for compact serial integration - making MAX191ACNG+ optimal for cost-sensitive, battery-powered systems needing configurable I/O and system-level calibration.
Availability
MAX191ACNG+ is available at Aetrix Electronics and suitable for battery-powered data logging, PC pen digitizers, and high-accuracy process control applications requiring stable component supply, long-term obsolescence management, and traceable sourcing from authorized channels.
Supply support for MAX191ACNG+ 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
Maxim Integrated (now part of Analog Devices) is a U.S.-based semiconductor company specializing in precision analog, mixed-signal, and high-reliability ICs for industrial, medical, and communications markets.
The MAX191 belongs to Maxim's legacy precision data-acquisition product line, designed specifically for low-power, high-accuracy 12-bit sampling in portable and embedded instrumentation where integration of reference, track/hold, and multi-protocol interface reduces system complexity.
FAQ
What is the operating temperature range for the MAX191ACNG+?
The MAX191ACNG+ is rated for 0°C to +70°C ambient operation, as indicated by the 'C' suffix in its ordering code. This commercial-grade temperature range is validated across all electrical specifications including ±1/2 LSB integral nonlinearity, 100ksps sampling rate, and 4.096V reference accuracy. The device maintains full performance within this range without derating or external thermal management.
Does the MAX191ACNG+ require external passive components for basic operation?
Yes - the MAX191ACNG+ requires three external capacitors for reliable operation: a 0.1µF ceramic capacitor from VDD to DGND, a 0.1µF capacitor from AIN− to AGND (to stabilize pseudo-differential return), and a 4.7µF capacitor from VREF to AGND (for reference compensation). No external hold capacitor or clock crystal is needed due to integrated track/hold and capacitor-timed oscillator.
How does the REFADJ pin function in the MAX191ACNG+?
The REFADJ pin on the MAX191ACNG+ adjusts the internal 4.096V reference output by ±1.7× the voltage deviation applied relative to its nominal 2.4V bias point. For example, applying 2.6V to REFADJ increases VREF by ~0.34V. This enables system-level gain calibration to correct for sensor offset, amplifier gain error, or PCB trace resistance - a key feature distinguishing MAX191ACNG+ from fixed-reference ADCs.
Can the MAX191ACNG+ operate with only a +5V supply, or is ±5V mandatory?
The MAX191ACNG+ operates with either a single +5V supply (VDD = +5V, VSS = 0V) for unipolar input ranges (0V to VREF), or dual ±5V supplies (VDD = +5V, VSS = −5V) for true bipolar input ranges (±VREF/2). Both configurations are fully supported and specified in the datasheet - no hardware modification is required to switch between modes; only the supply connections and BIP pin state change.
What interface protocols does the MAX191ACNG+ support in serial mode?
In serial mode (PAR = low), the MAX191ACNG+ supports SPI, QSPI, and MICROWIRE protocols via its SCLK, SSTRB, SCLKOUT, and DOUT pins. It uses standard 12-bit frame timing with SSTRB acting as frame synchronization - compatible with industry-standard shift-register peripherals like the 74HC164. No software configuration is needed; protocol selection is determined by host controller timing alignment.
MAX191ACNG+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 24-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 100k
- Number of Inputs:
- 1
- Input Type:
- Pseudo-Differential
- Data Interface:
- SPI, Parallel
- 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, 5V
- Voltage - Supply, Digital:
- 5V
- Features:
- -
- Operating Temperature:
- 0°C ~ 70°C
- Supplier Device Package:
- 24-PDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
MAX191ACNG+ FAQ
1.How can I place an order for MAX191ACNG+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX191ACNG+ 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 MAX191ACNG+ reliable?
The price and inventory of MAX191ACNG+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX191ACNG+ is usually 5 days.
3.What payment methods are accepted for MAX191ACNG+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX191ACNG+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX191ACNG+?
MAX191ACNG+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX191ACNG+ 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 MAX191ACNG+?
For technical support, including MAX191ACNG+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX191ACNG+ requirements.
6.How does Aetrix verify that MAX191ACNG+ is sourced from the original manufacturer or authorized distributors?
All MAX191ACNG+ 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 MAX191ACNG+ meets industry standards.
7.What is the process for return or replacement of MAX191ACNG+?
All MAX191ACNG+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX191ACNG+, 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 MAX191ACNG+ part is unused and in its original packaging.
Return procedure for MAX191ACNG+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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