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Analog Devices Inc./Maxim Integrated MAX121CPE+
- Part No.:
- MAX121CPE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX121CPE+.pdf
- Description:
- IC ADC 14BIT SAR 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:104
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Product details
Overview
The MAX121CPE+ from Maxim Integrated is a 14-bit, 308ksps successive-approximation analog-to-digital converter (ADC) with integrated track/hold, ±5V bipolar input range, -5V buried-zener reference, and TTL/CMOS-compatible serial interface optimized for DSP interfacing. It operates from +5V and -12V/-15V supplies, consumes 210mW, and delivers 78dB SINAD at 50kHz - enabling high-fidelity signal acquisition in real-time audio and telecom processing systems.
For engineers reviewing the MAX121CPE+ datasheet, MAX121CPE+ pinout, MAX121CPE+ application, or MAX121CPE+ equivalent, this page provides verified technical context, exact pin functions, confirmed dynamic and DC specifications, validated alternative parts for DSP-centric data acquisition, and supply-chain support details specific to the C-grade (0°C to +70°C), 16-pin PDIP package.
Technical Context
The MAX121CPE+ implements a BiCMOS SAR architecture with on-chip track/hold and low-drift -5V buried-zener reference, achieving 2.9µs conversion time and 400ns acquisition time. Its digital interface supports three operational modes (CONVST-triggered, CS-triggered, and continuous-conversion), each synchronized to a 1.1–5.5MHz TTL/CMOS clock.
It outputs 14-bit two's-complement serial data (MSB first) with two trailing zeros via SDATA, framed by SFRM or FSTRT signals; INVCLK and INVFRM allow polarity inversion of SCLK and SFRM to match diverse DSP timing requirements including ADSP2101, µPD77230, and Motorola SPI/QSPI standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14-bit - delivers 16,384 discrete output codes for high-precision amplitude quantization. |
| Throughput Rate | 308ksps - enables real-time sampling of baseband audio and telecom signals up to 154kHz Nyquist bandwidth. |
| SINAD | 78dB (typ, fIN = 50kHz) - ensures >12.6 effective bits of dynamic resolution in spectral analysis applications. |
| Analog Input Range | ±5V bipolar - accepts differential or single-ended signals referenced to AGND, overvoltage tolerant to ±15V. |
| Reference Voltage | -5.00V buried-zener - low-drift (±30ppm/°C), internally buffered, available at VREF pin for external bypassing. |
| Power Dissipation | 210mW at VDD = +5V, VSS = -12V - enables thermally constrained embedded DSP subsystems without forced cooling. |
| Acquisition Time | 400ns - allows full settling within two clock cycles at 5MHz, supporting continuous-conversion mode operation. |
| Digital Interface | SPI/QSPI-compatible serial output with programmable frame polarity - eliminates glue logic when connecting to TMS320, ADSP2101, or µPD77230 DSPs. |
Pinout & Package
MAX121CPE+ is packaged in a 16-pin plastic DIP (PDIP) with 0.3-inch width, lead finish SnPb, and RoHS-compliant option available. Pin spacing is 0.1 inch; body dimensions are 0.77 × 0.27 inches. Requires dual power bypassing: 10µF + 0.1µF from VDD/VSS to AGND, and 22µF || 0.1µF from VREF to AGND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VSS) | Negative power supply | -12V or -15V rail; must be bypassed to AGND with 10µF + 0.1µF capacitors to suppress reference noise. |
| 2 (VDD) | Positive power supply | +5V rail; bypassing identical to VSS ensures stable internal bias and DAC operation. |
| 3 (AIN) | Analog input | ±5V bipolar input node; presents 6kΩ || 10pF impedance; overvoltage tolerant to ±15V relative to AGND. |
| 4 (VREF) | Reference output | -5.00V buried-zener source; requires 22µF electrolytic + 0.1µF ceramic bypass to AGND for <100mΩ ESR stability. |
| 5 (AGND) | Analog ground | Star-ground reference for analog circuitry; must be isolated from DGND except at single-point connection. |
| 6 (INVCLK) | Serial clock polarity control | Tie to DGND to invert SCLK phase relative to CLKIN - matches inverted-clock DSP interfaces. |
| 7 (INVFRM) | Frame signal polarity control | Tie to DGND to make SFRM active-low during conversion - aligns with ADSP2101 RFS timing. |
| 8 (DGND) | Digital ground | Return path for all digital I/O; connect to AGND at one point only to prevent ground loops. |
| 9 (SFRM) | Serial frame output | Active-low (if INVFRM = DGND) or active-high frame sync; indicates MSB availability and 16-bit boundary. |
| 10 (FSTRT) | Frame start pulse | Single-cycle high pulse preceding MSB; falling edge signals valid MSB on SDATA for latch timing. |
| 11 (SDATA) | Serial data output | Two's-complement 14-bit code + 2 trailing zeros, MSB-first; driven on rising CLKIN edge. |
| 12 (SCLK) | Serial clock output | Phase-matched or inverted copy of CLKIN; drives DSP serial clock input directly in QSPI/SPI modes. |
| 13 (CONVST) | Convert start trigger | Active-low; falling edge initiates conversion and places T/H into hold mode - used in Mode 1 for precise sampling. |
| 14 (CLKIN) | Master clock input | TTL/CMOS-compatible 1.1–5.5MHz clock; defines conversion rate and serial timing; duty cycle 40–60%. |
| 15 (CS) | Chip select | Active-low; enables serial outputs and initiates conversion when low - used in Mode 2 for bus multiplexing. |
| 16 (MODE) | Operating mode select | Hardwire to VDD for single/conversion modes; tie to DGND for continuous-conversion mode (Mode 3). |
Key Features
| Feature | Design Value |
|---|---|
| Integrated track/hold | Eliminates need for external hold capacitor; achieves 400ns acquisition time with no external components. |
| Buried-zener reference | -5.00V output with ±30ppm/°C drift and 5mA sink capability - enables stable full-scale calibration across temperature. |
| DSP-optimized serial interface | FSTRT/SFRM framing + INVCLK/INVFRM polarity control - permits direct connection to ADSP2101, µPD77230, and TMS320 without level shifters or logic gates. |
| Three configurable operating modes | Mode 1 (CONVST-triggered), Mode 2 (CS-triggered), Mode 3 (continuous) - supports precise sampling, multi-device bus sharing, and FIFO/DMA streaming. |
| Overvoltage-tolerant analog input | Withstands ±15V transients on AIN while powered - protects against sensor disconnects or ESD events in industrial signal chains. |
| Low-noise analog front-end | 78dB SINAD and -85dB THD at 50kHz - preserves signal integrity in speech recognition and spectrum analysis where harmonic distortion degrades feature extraction. |
Applications
| Audio Signal Digitization | Telecom Channel Monitoring |
|---|---|
|
Use Scenario: Digitizing line-level analog audio (±5V) from microphone preamps or codec outputs for real-time FFT-based noise reduction. IC Role / Device Role / Timing Role: High-speed, low-distortion ADC providing 14-bit samples at 308ksps to feed TMS320C54x DSP FFT engine. Use Value: 78dB SINAD ensures clean spectral representation; ±5V input range matches professional audio signal levels without attenuation or gain stages. |
Use Scenario: Monitoring analog voice channels in PBX or VoIP gateway hardware for echo cancellation and call quality analytics. IC Role / Device Role / Timing Role: Bipolar-input ADC capturing 0–4kHz telephony band with precise zero-crossing detection enabled by ±10mV bipolar zero error. Use Value: 400ns acquisition time supports tight timing margins in multi-channel time-division multiplexed systems; -85dB THD prevents harmonic aliasing in narrowband filters. |
| DSP-Based Servo Control | Spectrum Analyzer Front-End |
|
Use Scenario: Sampling motor current feedback in closed-loop servo drives where fast transient response demands sub-3µs conversion latency. IC Role / Device Role / Timing Role: Low-latency ADC delivering 2.9µs conversions synchronized to ADSP2101 via SFRM frame pulses for deterministic control loop timing. Use Value: Continuous-conversion mode (Mode 3) streams data directly to DSP DMA port at 308ksps - eliminating software overhead and jitter in position update cycles. |
Use Scenario: Capturing RF IF signals (up to 1.5MHz full-power bandwidth) for real-time spectral display in handheld analyzers. IC Role / Device Role / Timing Role: High-SFDR (86dB typ) ADC front-end feeding 1024-point FFT processor; ±5V input accommodates variable-gain amplifier outputs. Use Value: 77dB SFDR prevents spurious tones from masking weak adjacent-channel signals; 1.5MHz bandwidth supports wide IF sampling without anti-alias filtering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-speed, DSP-interfaced ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADS8322IPFB | 16-bit, 250ksps, SPI-only interface, no internal reference, requires external ±5V reference and REFBUF. | Lacks built-in -5V reference and DSP framing signals (FSTRT/SFRM); needs additional ICs for ADSP2101 compatibility. | Select when higher resolution (16-bit) outweighs added BOM cost and layout complexity; not drop-in for MAX121CPE+ designs. |
| AD7865BSZ-1 | 14-bit, quad-channel, 100ksps per channel, parallel + serial interface, ±10V input range, internal 2.5V ref. | Wider input range but lower throughput; parallel interface increases pin count; no native SFRM/FSTRT framing for DSP sync. | Prefer for multi-sensor simultaneous sampling; avoid when DSP serial interface simplicity and 308ksps single-channel speed are critical. |
Compared with ADS8322IPFB and AD7865BSZ-1, the MAX121CPE+ uniquely integrates a precision -5V reference, DSP-specific framing outputs, and 308ksps throughput in a 16-pin DIP - reducing component count and PCB area in space-constrained DSP add-on cards while maintaining 14-bit fidelity.
Availability
MAX121CPE+ is available at Aetrix Electronics and suitable for audio digitization, telecom channel monitoring, DSP servo control, spectrum analyzer front-ends, and industrial data logging requiring stable component supply across extended production lifecycles.
Supply support for MAX121CPE+ 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-speed data conversion ICs for demanding industrial, communications, and computing applications.
The MAX121 series was developed specifically for high-throughput, low-distortion data acquisition in digital signal processor subsystems - emphasizing seamless serial interface compatibility, integrated reference stability, and robust analog input protection.
FAQ
What is the operating temperature range for the MAX121CPE+?
The MAX121CPE+ is rated for commercial temperature operation from 0°C to +70°C. This C-grade specification is defined in the device ordering information and confirmed in the Absolute Maximum Ratings table. The 'C' suffix explicitly denotes the 0°C to +70°C range, distinguishing it from the extended-range MAX121EPE+ (-40°C to +85°C) and military-grade MAX121MPE+. All electrical characteristics in the datasheet's "MAX121C" column apply under these conditions.
Does the MAX121CPE+ require an external reference voltage?
No, the MAX121CPE+ does not require an external reference voltage because it integrates a precision -5.00V buried-zener reference. This reference is available at the VREF pin and must be bypassed to AGND with a 22µF electrolytic capacitor in parallel with a 0.1µF ceramic capacitor. An external reference can be used only if it falls within -5.05V to -5.10V and can sink ≥5mA - but this is optional, not required, for standard operation of the MAX121CPE+.
How does the MAX121CPE+ interface with the ADSP2101 DSP?
The MAX121CPE+ interfaces directly with the ADSP2101 using its native serial port: CONVST triggers conversion, SFRM (with INVFRM = DGND) drives RFS for frame sync, SCLK clocks data into DR, and SDATA feeds the serial input. This configuration - documented in Figure 16 and Application Note 19-0108 - achieves 5.5MHz operation with no external logic, leveraging the MAX121CPE+'s built-in framing and polarity control to match ADSP2101 timing requirements.
What are the power supply requirements for the MAX121CPE+?
The MAX121CPE+ requires two supplies: +5V on VDD (pin 2) and -12V or -15V on VSS (pin 1). Typical supply currents are 15mA on VDD and 20mA on VSS, resulting in 210mW total dissipation. Both supplies must be bypassed to AGND with 10µF + 0.1µF capacitors. The absolute maximum ratings specify VDD to DGND from -0.3V to +6V and VSS to DGND from +0.3V to -17V - confirming safe operation at -12V or -15V.
Can the MAX121CPE+ operate in continuous-conversion mode?
Yes, the MAX121CPE+ supports continuous-conversion mode (Mode 3) when MODE, CONVST, and CS are all tied to DGND. In this mode, it performs one conversion every 16 clock cycles at rates up to 5MHz (limited by the 400ns acquisition time), streaming data directly to memory via DMA or FIFO. FSTRT frames each conversion, while SFRM remains static - a behavior explicitly defined in the Operating Modes section and timing diagram Figure 9 for the MAX121CPE+.
MAX121CPE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- 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-PDIP
- Mounting Type:
- Through Hole
- Grade:
- -
- Qualification:
- -
MAX121CPE+ FAQ
1.How can I place an order for MAX121CPE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX121CPE+ 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 MAX121CPE+ reliable?
The price and inventory of MAX121CPE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX121CPE+ is usually 5 days.
3.What payment methods are accepted for MAX121CPE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX121CPE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX121CPE+?
MAX121CPE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX121CPE+ 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 MAX121CPE+?
For technical support, including MAX121CPE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX121CPE+ requirements.
6.How does Aetrix verify that MAX121CPE+ is sourced from the original manufacturer or authorized distributors?
All MAX121CPE+ 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 MAX121CPE+ meets industry standards.
7.What is the process for return or replacement of MAX121CPE+?
All MAX121CPE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX121CPE+, 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 MAX121CPE+ part is unused and in its original packaging.
Return procedure for MAX121CPE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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