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Analog Devices Inc./Maxim Integrated MAX121CWE+
- Part No.:
- MAX121CWE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MAX121CWE+.pdf
- Description:
- IC ADC 14BIT SAR 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,284
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Product details
Overview
MAX121CWE+ from Maxim Integrated is a 14-bit, 308ksps successive-approximation analog-to-digital converter (ADC) with integrated track/hold, buried-zener reference, and DSP-oriented serial interface. It delivers ±5V bipolar input range, 78dB SINAD, 2.9µs conversion time, and operates from +5V/-12V supplies - ideal for high-fidelity digital signal acquisition in telecom and audio front-ends.
For engineers reviewing the MAX121CWE+ datasheet, MAX121CWE+ pinout, MAX121CWE+ application, or MAX121CWE+ equivalent, key selection criteria include its 308ksps throughput with 400ns acquisition time, TTL/CMOS-compatible 1.1–5.5MHz clock interface, two's-complement serial output framing via SFRM/FSTRT, and guaranteed 12-bit no-missing-codes performance over 0°C to +70°C.
Technical Context
The MAX121CWE+ implements a BiCMOS SAR architecture with on-chip track/hold and a low-drift –5V buried-zener reference, enabling stable DC accuracy and low distortion across temperature. Its timing-critical control logic supports three distinct operating modes: CONVST-triggered (precise sampling), CS-triggered (bus multiplexing), and continuous-conversion (DMA/FIFO streaming).
Serial data output uses MSB-first two's-complement format with 14 data bits + 2 trailing zeros, synchronized by either SCLK (inverted or non-inverted relative to CLKIN) or framed by SFRM (polarity configurable via INVFRM) and FSTRT. All digital I/Os are TTL/CMOS-compatible, with VIH ≥ 2.4V and VIL ≤ 0.8V, supporting direct interfacing to TMS320, ADSP2101, µPD77230, and Motorola SPI/QSPI hosts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14-bit - delivers 16,384 discrete output levels with monotonic transfer function and no missing codes over full temperature range. |
| Throughput Rate | 308ksps - enables real-time spectral analysis and voice-band sampling up to 154kHz Nyquist frequency. |
| SINAD | 78dB (typ) at 50kHz - ensures high-fidelity digitization of audio and telecom signals with minimal quantization + harmonic noise. |
| Analog Input Range | ±5V bipolar - accepts differential or single-ended signals referenced to AGND, with overvoltage tolerance to ±15V. |
| Reference Voltage | –5.00V buried-zener - provides <±30ppm/°C drift and eliminates need for external precision reference in most applications. |
| Power Dissipation | 210mW at +5V/–12V - enables compact thermal design without forced cooling in embedded DSP systems. |
| Acquisition Time | 400ns - allows full settling between conversions at maximum throughput, minimizing aperture jitter (30ps typ). |
| Supply Voltages | +5V (VDD), –12V or –15V (VSS) - dual-rail operation supports legacy industrial and telecom power architectures. |
Pinout & Package
MAX121CWE+ is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm pitch, footprint-compatible with industry-standard 20-lead SOIC carriers but offering 30% smaller area. Thermal pad not present; JEDEC MO-153 compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VSS | Negative supply rail (–12V or –15V); requires local 10µF + 0.1µF bypass to AGND for noise suppression. |
| 2 | VDD | Positive supply rail (+5V); bypassed identically to VSS for stable internal bias generation. |
| 3 | AIN | Analog input node with 6kΩ || 10pF equivalent impedance; accepts ±5V bipolar signals with ±15V fault tolerance. |
| 4 | VREF | –5V reference output; must be bypassed with 22µF || 0.1µF (ESR ≤ 100mΩ) for optimal noise and stability. |
| 5 | AGND | Analog ground return; isolated from DGND to minimize digital switching noise coupling into sensitive analog path. |
| 6 | INVCLK | Inverts SCLK polarity relative to CLKIN; tie to DGND for inverted clock output to match host timing requirements. |
| 7 | INVFRM | Inverts SFRM frame polarity; DGND = active-low SFRM, VDD = active-high SFRM for flexible DSP framing compatibility. |
| 8 | DGND | Digital ground return; separate from AGND to prevent ground bounce from corrupting reference or analog inputs. |
| 9 | SFRM | Frame synchronization output; goes low at MSB start and high after 16 clocks - used as RFS or FS input on DSPs. |
| 10 | FSTRT | Frame-start pulse output; 1-clock-wide high pulse preceding MSB - provides precise edge-aligned latching trigger. |
| 11 | SDATA | Serial data output; MSB-first two's-complement 14-bit code + 2 trailing zeros, driven on rising CLKIN edge. |
| 12 | SCLK | Serial clock output; synchronous with CLKIN (or inverted if INVCLK = DGND); drives host processor serial clock input. |
| 13 | CONVST | Active-low conversion start; falling edge initiates sampling and conversion - used for deterministic timing in Mode 1. |
| 14 | CLKIN | TTL/CMOS clock input (0.1–5.5MHz); controls conversion speed, acquisition window, and serial data rate. |
| 15 | CS | Active-low chip select; enables serial outputs and triggers conversion in Mode 2; high = outputs tri-stated. |
| 16 | MODE | Mode configuration; VDD = single/conversion-triggered, DGND = continuous-conversion mode (requires CONVST/CS low). |
| 17–20 | N.C. | No internal connection; pins 17, 18, 19, 20 are unconnected and must remain floating or grounded per layout best practice. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Track/Hold | Eliminates external hold capacitor requirement and guarantees 400ns acquisition time - simplifies front-end design and reduces BOM count. |
| DSP-Optimized Serial Interface | Provides both SFRM and FSTRT framing signals plus INVCLK/INVFRM polarity control - enables glueless connection to ADSP2101, TMS320, and µPD77230 without level shifters or logic gates. |
| Buried-Zener Reference | Delivers –5.00V output with ±30ppm/°C drift and 5mA sink capability - ensures stable full-scale accuracy across 0°C to +70°C without calibration. |
| Three Operating Modes | Supports precise single-shot (Mode 1), bus-shared (Mode 2), and streaming (Mode 3) configurations - adapts to diverse system timing and memory architectures. |
| Overvoltage-Tolerant Input | Withstands ±15V on AIN while operating at ±5V full-scale - protects against transient surges in industrial and telecom line interfaces. |
| Low-Power BiCMOS Process | Consumes only 210mW at full speed - enables dense DSP subsystems with minimal thermal impact and no heatsinking. |
Applications
| Telecom Channel Monitoring | Voice Band Digitization |
|---|---|
|
Use Scenario: Real-time monitoring of analog PSTN line voltage, current, and loop status in central office line cards. IC Role / Device Role / Timing Role: ADC front-end capturing ±5V line signals at 308ksps with 78dB SINAD to detect subtle impairments like echo or crosstalk. Use Value: Enables accurate SLIC diagnostics and compliance testing without external amplification or filtering, reducing component count and board space. |
Use Scenario: High-fidelity speech capture in VoIP gateways and conferencing systems operating within 300Hz–3.4kHz band. IC Role / Device Role / Timing Role: Primary analog input digitizer interfaced directly to ADSP2101 via SFRM/SCLK, delivering 14-bit resolution at Nyquist-sampled rates. Use Value: Preserves voice clarity and intelligibility through low THD (–85dB) and high SFDR (86dB), meeting ITU-T G.711 and G.722 requirements. |
| Spectrum Analyzer Front-End | DSP-Based Servo Control |
|
Use Scenario: Wideband RF signal analysis in portable spectrum analyzers requiring 154kHz effective bandwidth and low phase noise. IC Role / Device Role / Timing Role: High-speed acquisition stage feeding FFT engine; uses continuous-conversion mode (Mode 3) with DMA for zero-gap streaming. Use Value: Achieves 77dB SFDR and <30ps aperture jitter - critical for distinguishing closely spaced tones and minimizing spectral leakage. |
Use Scenario: Closed-loop position/velocity feedback in industrial motor drives using TMS320C54x DSPs for real-time PID computation. IC Role / Device Role / Timing Role: Analog sensor interface converting encoder or current-sense signals with deterministic 2.9µs conversion latency (Mode 1). Use Value: Guarantees sub-microsecond timing consistency between sample capture and control update - essential for stable high-bandwidth servo response. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-speed 14-bit ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS8322IPFB | 16-bit, 250ksps, single-supply +5V only, no internal reference - requires external REF5025 and level-shifting for bipolar input. | Higher resolution but lower speed and no native DSP framing; better suited for precision data loggers than real-time DSP. | Select ADS8322IPFB when absolute DC accuracy >12-bit and single-supply operation outweigh throughput and interface simplicity. |
| AD7865BSZ-1 | 14-bit, quad-channel, 100ksps, ±5V supplies, parallel interface - lacks serial DSP framing and has higher power (350mW). | Designed for multi-sensor acquisition with shared bus; incompatible with SPI/QSPI/DSP serial ports without glue logic. | Choose AD7865BSZ-1 only when simultaneous sampling of four analog channels is required and serial interface is not mandatory. |
Compared with MAX121CWE+, ADS8322IPFB trades 58ksps speed and integrated reference for 2 extra LSBs of resolution, while AD7865BSZ-1 sacrifices serial DSP compatibility and power efficiency for channel density - making MAX121CWE+ uniquely optimized for single-channel, high-throughput, glueless DSP integration.
Availability
MAX121CWE+ is available at Aetrix Electronics and suitable for telecom infrastructure, voice processing, spectrum analysis, and DSP servo control applications requiring stable component supply across extended production lifecycles.
Supply support for MAX121CWE+ 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) designs precision analog, mixed-signal, and high-frequency ICs for demanding industrial, automotive, and communications applications.
The MAX121CWE+ belongs to Maxim's high-speed precision ADC product line, engineered specifically for seamless integration with digital signal processors in real-time acquisition systems where speed, accuracy, and interface simplicity are co-prioritized.
FAQ
What is the operating temperature range for the MAX121CWE+?
The MAX121CWE+ is specified for commercial-grade operation from 0°C to +70°C, as indicated by the "C" suffix in the part number. This range covers standard indoor embedded systems, telecom line cards, and DSP evaluation platforms where ambient thermal conditions remain controlled. The device maintains full performance - including 78dB SINAD, ±2LSB INL, and 308ksps throughput - across this entire interval without derating.
Does the MAX121CWE+ require an external reference voltage?
No, the MAX121CWE+ does not require an external reference voltage. It integrates a precision –5.00V buried-zener reference accessible at the VREF pin, with ±30ppm/°C drift and 5mA sink capability. External bypassing with 22µF || 0.1µF (ESR ≤ 100mΩ) is mandatory for optimal noise and stability, but no external reference IC is needed for standard ±5V full-scale operation.
How does the MAX121CWE+ interface with SPI-compatible microcontrollers?
The MAX121CWE+ supports SPI communication via its SCLK, SDATA, SFRM, and CS pins - though it outputs 16-bit frames (14 data + 2 zeros) instead of standard 8-bit SPI words. To interface, perform two consecutive 8-bit reads: first captures leading zero + 7 MSBs, second captures 7 LSBs + trailing zero. Clock rate is limited to 2MHz for reliable SPI timing, and CPOL=0/CPHA=1 mode must be selected on the host controller.
Can the MAX121CWE+ operate with a –15V negative supply instead of –12V?
Yes, the MAX121CWE+ is fully rated for –12V or –15V negative supply operation (VSS). Electrical characteristics - including power dissipation (213–315mW), THD (–85dB), and reference stability - are guaranteed across VSS = –10.8V to –15.75V. Using –15V improves PSRR margin and may reduce noise in high-dynamic-range applications, provided proper bypassing is maintained.
What is the purpose of the MODE pin on the MAX121CWE+?
The MODE pin configures the MAX121CWE+ into one of two primary operational modes: tied to VDD enables single/conversion-triggered operation (Modes 1 or 2), while tied to DGND activates continuous-conversion mode (Mode 3). In Mode 3, conversions auto-repeat every 16 clock cycles - ideal for FIFO or DMA streaming - and requires CONVST and CS to be held low during normal operation.
MAX121CWE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 14
- Sampling Rate (Per Second):
- 308k
- Number of Inputs:
- 1
- Input Type:
- Single Ended
- Data Interface:
- SPI
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External, Internal
- Voltage - Supply, Analog:
- 5V, -10.8V ~ 15.75V
- Voltage - Supply, Digital:
- 5V, -10.8V ~ 15.75V
- Features:
- -
- Operating Temperature:
- 0°C ~ 70°C
- Supplier Device Package:
- 16-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
MAX121CWE+ FAQ
1.How can I place an order for MAX121CWE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX121CWE+ 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 MAX121CWE+ reliable?
The price and inventory of MAX121CWE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX121CWE+ is usually 5 days.
3.What payment methods are accepted for MAX121CWE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX121CWE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX121CWE+?
MAX121CWE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX121CWE+ 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 MAX121CWE+?
For technical support, including MAX121CWE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX121CWE+ requirements.
6.How does Aetrix verify that MAX121CWE+ is sourced from the original manufacturer or authorized distributors?
All MAX121CWE+ 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 MAX121CWE+ meets industry standards.
7.What is the process for return or replacement of MAX121CWE+?
All MAX121CWE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX121CWE+, 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 MAX121CWE+ part is unused and in its original packaging.
Return procedure for MAX121CWE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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