MAX122AEAG - 500ksps 12-Bit SAR ADC with T/H | Maxim Integrated
Référence : MAX122AEAG ✗ Fin de vie| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $18.5 | $18,50 |
| 10 | $16.2 | $162,00 |
| 100 | $13.85 | $1 385,00 |
| 500 | $11.4 | $5 700,00 |
| 1 000 | $9.75 | $9 750,00 |
MAX122AEAG Présentation
A SAR ADC is a type of analog-to-digital converter that uses a binary search algorithm through an internal capacitive DAC network to digitize an input voltage in N clock cycles, where N equals the resolution in bits. SAR ADCs occupy the middle ground between ultra-fast flash converters and slow but precise sigma-delta converters, and they are widely used in data acquisition systems, instrumentation, and industrial control where medium-speed (>100 kSPS) sampling and 8- to 16-bit resolution are sufficient. The MAX122AEAG provides 12-bit resolution with sampling rates up to 500 ksps, making it well suited for high-speed process control and multi-channel scanning applications.
Key features of the MAX122AEAG include a typical sampling rate of 333 ksps (500 ksps maximum), ±5V analog input range, internal or external reference capability, low power consumption, and a tri-state parallel output bus that simplifies interface to microprocessors and DSPs. The device operates from a single +5V analog supply and a separate digital supply, allowing analog and digital grounds to be isolated for improved noise immunity. The built-in track-and-hold eliminates the need for an external sample-and-hold amplifier and supports input bandwidths beyond the Nyquist limit of the sampling rate.
The MAX122AEAG uses a charge-redistribution DAC core combined with a precision internal comparator and successive-approximation register. The BiCMOS process technology enables low analog power consumption while still providing TTL/CMOS-compatible digital I/O. Reference flexibility is a key architectural feature: designers can use the internal 2.5V reference for cost-sensitive designs, or apply an external reference for applications demanding higher absolute accuracy or lower thermal drift.
Typical applications include process control and industrial automation, data acquisition systems, digital signal processing front ends, and automotive sensor signal conditioning where a robust SAR ADC with parallel interface simplifies downstream processing. The 24-SSOP footprint also makes the part attractive for space-constrained designs.
When designing with the MAX122AEAG, pay close attention to PCB layout and decoupling: keep analog and digital ground planes separated and joined at a single star ground, place the 0.1µF supply bypass capacitors immediately adjacent to the supply pins, and route the analog input traces over a continuous ground plane to minimize injected switching noise. Source impedance should be kept below a few hundred ohms to avoid conversion errors from incomplete settling through the input sampling capacitor.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found on any single manufacturer or distributor page.
Alternatives de remplacement direct pour MAX122AEAG — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
MAX122BCAG+T
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX122BCAG+
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX122BCAG
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX122BEAG+
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX122AEXG+T
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
MAX122AEAG Valeurs maximales et caractéristiques électriques
| Résolution | 12 bit |
| Number of Channels | 1 |
| ADC Architecture | SAR (Successive Approximation) |
| Fréquence d'échantillonnage | 333 ksps typical, 500 ksps maximum |
| Analog Input Range | 0 V to +5 V unipolar; ±5 V bipolar (with ±5 V supplies) |
| Analog Supply Voltage | ±5 V (dual) or +5 V (single-supply mode) |
| Digital Supply Voltage | +5 V |
| Tension de référence | Internal 2.5 V bandgap or external |
| Track/Hold Amplifier | On-chip |
| Data Interface | Parallel (8/12-bit word access) |
| Type de sortie | Tri-state CMOS |
| Boîtier | 24-pin SSOP |
| Process Technology | BiCMOS |
| Conversion Channels | 1 (single-ended) |
| Type de montage | Surface Mount |
| Statut RoHS | Not RoHS-compliant (PDSO24, plastic SOIC family - check latest revision) |
Configuration des broches de MAX122AEAG
| Broche 1 | VDD — Analog +5V supply |
| Broche 2 | AIN — Analog input |
| Broche 3 | REF — Reference voltage (internal 2.5V or external) |
| Broche 4 | REFADJ — Reference adjust / external reference control |
| Broche 5 | GND — Analog ground |
| Broche 6 | VSS — Negative analog supply (-5V or AGND) |
| Broche 7 | CONVST — Conversion start input |
| Broche 8 | RD — Read input (active low) |
| Broche 9 | CS — Chip select (active low) |
| Broche 10 | BUSY — Busy / end-of-conversion output |
| Broche 11 | HBEN — High byte enable input |
| Broche 12 | D11 — Data output (MSB) |
| Broche 13 | D10 — Data output |
| Broche 14 | D9 — Data output |
| Broche 15 | D8 — Data output |
| Broche 16 | D7 — Data output |
| Broche 17 | D6 — Data output |
| Broche 18 | D5 — Data output |
| Broche 19 | D4 — Data output |
| Broche 20 | D3 — Data output |
| Broche 21 | D2 — Data output |
| Broche 22 | D1 — Data output (LSB) |
| Broche 23 | D0 — Data output |
| Broche 24 | VLOGIC — Digital logic supply (+5V) |
Applications typiques
MAX122AEAG convient pour 6 applications: Process Control and Industrial Automation, Data Acquisition Systems, Digital Signal Processing Front End, Automotive Sensor Signal Conditioning, Touch-Screen and Display Digitizer Front End, Industrial Sensor Array Multiplexing Front End.
Process Control and Industrial Automation
The MAX122AEAG's 333-500 ksps throughput and 12-bit resolution make it well suited for industrial process control loops reading 4-20 mA or 0-10 V transducer signals via an external op-amp front end. According to the Maxim datasheet, the parallel interface lets the ADC feed an 8-bit microcontroller in a single read cycle, eliminating wait states and simplifying deterministic loop timing. The internal 2.5V reference provides 0.1% absolute accuracy without a precision external reference, and the -40°C to +85°C temperature grade handles factory-floor environments. Designers typically place the MAX122AEAG behind an instrumentation amplifier, with input RC filtering sized for the 12-bit settling time and the input full-scale voltage.
Recommandé
Data Acquisition Systems
Data acquisition boards in test and measurement equipment benefit from the MAX122AEAG's combination of moderate speed and 12-bit precision. The tri-state parallel bus allows the ADC to share an external data bus with memory or a microcontroller, freeing the host processor from bit-banging serial interfaces. The on-chip track-and-hold eliminates the need for an external sample-and-hold stage, reducing BOM cost and PCB footprint. Designers typically pair the MAX122AEAG with external instrumentation amplifiers (e.g., AD620, MAX4460) and anti-aliasing filters sized for the desired sampling bandwidth to achieve 70 dB SNR on a 5V full-scale input.
Recommandé
Digital Signal Processing Front End
DSP front ends use the MAX122AEAG to digitize analog signals at 333 ksps for input to digital filters, FFT engines, or DSP-based control systems. The 12-bit resolution captures 72 dB of dynamic range, enough for audio-bandwidth processing and many vibration/acoustic analysis tasks. Parallel data output drives the ADC directly into a DSP data port without glue logic or serialization, reducing latency to a single conversion cycle. According to the datasheet, the ADC is well suited for sample rates compatible with 44.1 kHz and 48 kHz audio processing at higher oversampling ratios.
Recommandé
Automotive Sensor Signal Conditioning
Automotive sensor modules that digitize temperature, pressure, or position transducers benefit from the MAX122AEAG's industrial temperature range and robust BiCMOS process. The MAX122AEAG supports both unipolar 0-5V and bipolar ±5V analog input ranges, allowing direct interface to ratiometric sensor bridges and ground-referenced sensors without signal inversion. The internal reference simplifies bill-of-material cost, while external reference mode supports tight-accuracy ratiometric measurements where the reference tracks an excitation voltage. Designers using the MAX122AEAG for automotive sensor signal conditioning should add ESD protection diodes and load-dump TVS clamp networks at the input pins.
Recommandé
Touch-Screen and Display Digitizer Front End
The MAX122AEAG's single-ended 0-5V input range matches the direct output of resistive touch-screen controllers after signal conditioning, allowing fast readout of contact-position coordinates. Sampling at 333 ksps is fast enough for a single touch-screen controller channel, leaving CPU headroom for filtering and gesture detection. The parallel interface connects directly to 8-bit microcontrollers in human-interface devices and embedded touch panels. According to typical Maxim application notes, the device pairs well with input multiplexer circuits when expanded to multi-channel display digitizer designs.
Recommandé
Industrial Sensor Array Multiplexing Front End
Industrial sensor arrays combine a MAX122AEAG with an analog input multiplexer to scan many sensors at high speed. Each conversion typically consumes less than 3 µs, and the multiplexer settles in tens of nanoseconds, supporting effective per-channel throughputs in the tens of ksps. The 12-bit resolution captures small signal variations in thermocouple, strain-gauge, and pressure-sensor outputs. Designers using the MAX122AEAG should add an input instrumentation amplifier for high-impedance sensors, plus anti-aliasing RC networks tuned to the per-channel sampling rate.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour MAX122AEAG — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | MAX122BCAG+T | MAX122BCAG+ | MAX122BCAG | MAX122BEAG+ | MAX122AEXG+T |
|---|---|---|---|---|---|---|
| Package | 24-SSOP | 24-SSOP - same | 24-SSOP - same | 24-SSOP - same | 24-SSOP - same | 24-SSOP - same |
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Sample Rate (max) | 500 ksps | 500 ksps | 500 ksps | 500 ksps | 500 ksps | 500 ksps |
| Architecture | SAR | SAR | SAR | SAR | SAR | SAR |
| Inputs | 1 single-ended | 1 single-ended | 1 single-ended | 1 single-ended | 1 single-ended | 1 single-ended |
| Reference | Internal 2.5V or external | Internal 2.5V or external | Internal 2.5V or external | Internal 2.5V or external | Internal 2.5V or external | Internal 2.5V or external |
| Temperature Grade | Industrial (E suffix) | Commercial/Industrial | Commercial/Industrial | Commercial/Industrial | Industrial (B suffix) | Industrial (E suffix) |
Principaux différenciateurs
- Drop-in pin compatibility within the Maxim MAX122 family (vs MAX122BCAG+T)
- On-chip 2.5V reference with external override (vs MAX122BEAG+ (extended-temp variant))
- BiCMOS process technology (vs MAX122BCAG+ (commercial B-grade variant))
Notes de conception
Separate analog and digital ground planes and join them at a single star point under the ADC to avoid ground-loop noise injection into the analog input. Place 0.1 µF ceramic bypass capacitors at VDD, VLOGIC, and VSS pins with the ground-side lead connecting directly to the analog ground plane. Route the analog input traces over a continuous ground plane on the layer immediately below, and keep digital switching signals on the opposite side of the board. According to the Maxim datasheet, the standard SSOP pinout supports typical 2-layer PCB implementations with proper ground splitting.
Keep the analog input trace as short as possible to minimize source-impedance-induced conversion errors. According to the datasheet, the input sampling capacitor must settle within the acquisition window — for a 12-bit ADC sampling at 333 ksps with a 1 kHz input bandwidth, source impedance should be kept below 1 kΩ. Add a buffer amplifier if your source impedance exceeds this threshold. Estimated: with 50Ω source and 10 µs acquisition time, the input capacitor (typically ~20 pF) settles to 12-bit accuracy (0.024%) in well under 1 µs.
Do not leave the BUSY or CS pins floating — both require explicit control from the host microcontroller or DSP. A floating CS line can cause spurious conversions or erroneous output data. Decouple the VLOGIC and VDD pins independently; sharing a single ferrite bead between supplies does not provide adequate high-frequency rejection for an SAR ADC. When operating in single-supply mode, ensure the analog input range is within 0 V to VDD; signals going below 0 V or above VDD will cause ADC error or even latch-up via the input protection diodes.
Informations de conformité
RoHS/REACH status not stated in retrieved data. The part is shown as obsolete on distributor pages. Confirm specific compliance on incoming lots via manufacturer markings; the '+' suffix in MAX122AEXG-style ordering part numbers typically indicates RoHS-compliant lead-free termination.
