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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:3,552
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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-compatible 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, this page provides verified technical context, package-specific pin functions, real-world interface timing constraints, and validated alternative options for DSP-coupled data acquisition systems.
Technical Context
The MAX121CWE implements a BiCMOS SAR architecture with on-chip track/hold and a low-drift -5V buried-zener reference, enabling 78dB SINAD and -85dB THD at 308ksps. Its 400ns acquisition time and 10ns aperture delay support precise sampling synchronization with external DSP clocks.
It supports three operational modes: CONVST-triggered (Mode 1), CS-triggered (Mode 2), and continuous-conversion (Mode 3), each requiring specific MODE pin configuration and clock timing alignment. Serial output framing uses SFRM or FSTRT signals, with polarity controlled by INVFRM and clock phase adjusted via INVCLK.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14-bit - delivers 16,384 discrete amplitude levels for high dynamic range signal digitization |
| Throughput Rate | 308ksps - enables real-time capture of audio-band and baseband telecom signals |
| Analog Input Range | ±5V bipolar - accepts differential or single-ended signals centered at ground without level-shifting circuitry |
| SINAD | 78dB (typ) - ensures >12.6 effective bits of resolution under full-scale 50kHz sine input |
| Conversion Time | 2.9µs - fixed 16-clock-cycle latency at 5.5MHz CLKIN, critical for deterministic DSP interrupt handling |
| Reference Voltage | -5.00V buried-zener - provides 30ppm/°C drift and eliminates need for external precision reference |
| Power Dissipation | 210mW - enables dense mixed-signal PCB layouts without forced air cooling |
Pinout & Package
MAX121CWE is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm pitch, optimized for space-constrained DSP interface designs. Thermal pad not present; standard reflow profile applies.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSS | Negative power supply | Accepts -12V or -15V; requires 10µF + 0.1µF bypass to AGND for noise suppression |
| VDD | Positive power supply | +5V supply; bypassing identical to VSS ensures stable internal logic and analog biasing |
| AIN | Analog input | ±5V input with 6kΩ || 10pF impedance; overvoltage tolerant to ±15V for system robustness |
| VREF | Reference output | -5.00V zener reference; must be bypassed with 22µF || 0.1µF to AGND for <30ppm/°C stability |
| AGND / DGND | Analog & digital grounds | Separate ground pins require star-point connection to minimize digital switching noise coupling into ADC core |
| CONVST / CS | Conversion start control | Active-low inputs; falling edge initiates conversion - CONVST for precise timing, CS for bus sharing |
| CLKIN / SCLK | Input clock / serial clock output | TTL/CMOS-compatible 0.1–5.5MHz input; SCLK mirrors CLKIN (or inverted if INVCLK = DGND) |
| SDATA / SFRM / FSTRT | Serial data & framing outputs | MSB-first two's-complement 14-bit + 2-zero stream; SFRM indicates frame boundaries, FSTRT flags MSB availability |
| MODE / INVCLK / INVFRM | Configuration controls | Hardwired pins setting operation mode (single/continuous), clock inversion, and frame polarity |
Key Features
| Feature | Design Value |
|---|---|
| Integrated track/hold | Eliminates external hold capacitor and driver op-amp; 400ns acquisition time enables 5.5MHz max clock in Mode 3 |
| DSP-optimized serial interface | Direct compatibility with TMS320, ADSP2101, µPD77230, and SPI/QSPI protocols - no glue logic required |
| Buried-zener reference | -5.00V output with ±30ppm/°C drift and 5mA sink capability - replaces external reference ICs and reduces BOM count |
| Three configurable operating modes | Mode 1 (CONVST-triggered), Mode 2 (CS-triggered), Mode 3 (continuous) - adapts to real-time control, multiplexed buses, or streaming loggers |
| Overvoltage-tolerant analog input | Withstands ±15V transients on AIN while maintaining ±5V full-scale range - enhances field reliability in noisy environments |
Applications
| Telecom Channel Monitoring | Audio Digitization Front-End |
|---|---|
Use Scenario: Real-time monitoring of analog voice channels in carrier-grade access equipment with automatic gain control feedback loops. IC Role / Device Role / Timing Role: ADC capturing baseband signals up to 3.4kHz with 78dB SINAD to preserve speech intelligibility metrics. Use Value: Bipolar ±5V input accepts line-level signals directly; 308ksps throughput supports oversampling for anti-alias filtering flexibility. |
Use Scenario: High-fidelity analog-to-digital conversion in professional audio interfaces before FPGA-based sample-rate conversion. IC Role / Device Role / Timing Role: Precision sampling engine synchronized to external DSP clock via CONVST for jitter-free capture. Use Value: 14-bit resolution and -85dB THD meet AES17 professional audio standards; SSOP package eases routing near sensitive analog traces. |
| DSP-Based Servo Control | Spectrum Analyzer Signal Chain |
Use Scenario: Closed-loop position sensing in industrial motion controllers using resolver or LVDT analog outputs. IC Role / Device Role / Timing Role: High-speed acquisition of feedback signals with deterministic 2.9µs conversion latency for PID loop timing predictability. Use Value: Continuous-conversion mode (MODE = DGND) streams data to DMA buffers, eliminating CPU polling overhead. |
Use Scenario: Intermediate frequency (IF) sampling stage in portable RF spectrum analyzers covering DC–1.5MHz full-power bandwidth. IC Role / Device Role / Timing Role: Digitizing downconverted IF signals with 77dB SFDR to resolve adjacent channel interference. Use Value: On-chip track/hold and low-aperture jitter (30ps) preserve spectral purity; ±5V range matches typical IF amplifier outputs. |
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 resolution, 500ksps, SPI-only interface, no internal reference - requires external -5V reference and level-shifting for bipolar input | Higher resolution but lacks built-in track/hold and DSP framing signals (SFRM/FSTRT) | Select when >14-bit ENOB is mandatory and system already includes precision reference and interface logic |
| AD7865BSZ-1 | 4-channel 14-bit, 100ksps, parallel/serial interface, ±10V input range, internal +2.5V reference - no negative supply required | Multi-channel capability trades off speed and bipolar input simplicity; incompatible power architecture (-12V/-15V not needed) | Select for multi-sensor acquisition where channel density outweighs per-channel throughput and ±5V bipolar convenience |
Compared with ADS8322IPFB and AD7865BSZ-1, the MAX121CWE uniquely integrates bipolar ±5V input, buried-zener reference, and DSP-native framing - reducing component count and layout complexity in single-channel, high-SNR telecom/audio systems.
Availability
MAX121CWE is available at Aetrix Electronics and suitable for telecom infrastructure, professional audio equipment, industrial servo controllers, and portable spectrum analyzers 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 power-management ICs for demanding industrial, communications, and computing applications.
The MAX121CWE belongs to Maxim's high-performance data acquisition product line, engineered specifically for seamless integration with digital signal processors in real-time signal processing systems.
FAQ
What is the maximum clock frequency supported by MAX121CWE in continuous-conversion mode?
The MAX121CWE supports up to 5MHz CLKIN in continuous-conversion mode (Mode 3) to satisfy the 400ns minimum acquisition time within two clock cycles. At 5.5MHz - its absolute maximum rated clock - only Mode 1 and Mode 2 are guaranteed functional. Exceeding 5MHz in Mode 3 risks incomplete sampling and degraded INL/DNL performance. The MAX121CWE datasheet specifies this limit explicitly in the Timing Characteristics table.
Does MAX121CWE require external components for its internal reference to function correctly?
Yes - the MAX121CWE's -5V buried-zener reference requires mandatory external bypassing: a 22µF electrolytic capacitor (ESR ≤ 100mΩ) in parallel with a 0.1µF ceramic capacitor connected between VREF and AGND. Omitting either capacitor causes increased reference noise, temperature drift beyond ±30ppm/°C, and SINAD degradation. This requirement is documented in the "Internal Reference" section of the MAX121CWE datasheet.
Can MAX121CWE interface directly with an ADSP2101 DSP without level shifters or logic gates?
Yes - the MAX121CWE interfaces natively with the ADSP2101 using direct connections: SCLK drives the DSP's SCLK input, SFRM (with INVFRM = DGND) connects to RFS, SDATA links to DR, and CONVST ties to an output port. All signals are TTL/CMOS-compatible at +5V logic levels, and timing aligns per Figures 16–17 in the MAX121CWE datasheet - no external components are needed.
What is the purpose of the MODE pin on MAX121CWE, and how should it be configured?
The MODE pin selects between single-conversion (MODE = VDD) and continuous-conversion (MODE = DGND) operation. In Mode 1 or 2, it must be hardwired to VDD; in Mode 3, it must be tied to DGND at power-up for reliable initialization. Incorrect MODE voltage causes undefined behavior - e.g., failure to enter continuous mode or spurious conversions. This is specified in the "Operating Modes" section of the MAX121CWE datasheet.
How does the MAX121CWE handle overvoltage conditions on the AIN pin?
The MAX121CWE analog input (AIN) is overvoltage tolerant to ±15V relative to AGND, exceeding its ±5V full-scale range. This protects the internal track/hold and comparator during transient events like ESD or signal crosstalk. However, sustained voltages beyond ±5V will saturate the output code and may increase power dissipation - the MAX121CWE specification guarantees functionality only within ±5V for accurate digitization.
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:
- Obsolete
- 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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