MAX1321ECM+ - 14-Bit 4-Channel 357ksps Simultaneous-Sampling ADC | Maxim Integrated
MPN: MAX1321ECM+ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $11.7396 | $11.74 |
| 10 | $10.8 | $108.00 |
| 100 | $9.65 | $965.00 |
| 500 | $8.55 | $4,275.00 |
| 1,000 | $7.95 | $7,950.00 |
MAX1321ECM+ Overview
What is an SAR ADC? A successive-approximation-register analog-to-digital converter is a sampling architecture that uses an internal DAC and a comparator to perform a binary search over multiple clock cycles, one bit at a time, yielding a snapshot conversion. SAR ADCs sit within the broader hierarchy of ADC technology -> data converter -> mixed-signal IC -> semiconductor device. The simultaneous-sampling capability of the MAX1321ECM+ makes it distinct from multiplexed ADCs: every enabled channel acquires its analog input at the same instant through per-channel track-and-hold amplifiers, eliminating channel-to-channel skew that would otherwise corrupt multi-phase measurements.
Key specifications include ±10 V true-differential inputs (over-voltage protected to ±25 V), 357 ksps aggregate throughput with internal or external clock, an internal 2.5 V or external reference, and per-channel T/H amplifiers. The device interfaces through a 20 MHz SPI/QSPI/MICROWIRE-compatible serial port with a dedicated RDY/INT output for conversion-complete indication. Bipolar and unipolar input modes are software-selected without external hardware changes.
The MAX1321ECM+ uses a charge-redistribution SAR core with input protection networks on each analog channel. The built-in T/H front-end and ±25 V over-voltage clamps allow direct connection to industrial ±10 V or ±15 V signal sources without external resistor dividers, while a digital noise-rejection filter rejects mains-frequency interference. Internal or external reference flexibility lets designers balance absolute accuracy against board area.
Typical applications include multiphase motor control (simultaneous current and voltage sampling), power-grid synchronization and power-factor correction (three-phase voltage and current monitoring), vibration and waveform analysis (multi-axis accelerometers), and industrial data acquisition requiring coherent sampling across channels. The 5 V analog supply and ±10 V input range directly interface with current transformers, shunts, and line-voltage transducers.
Design consideration: Place analog and digital grounds on split planes joined at a single point beneath the exposed pad of the LQFP-48. Use 0.1 µF ceramic decoupling on AVDD, DVDD, and AVDD2 pins; decoupling value and topology should follow the manufacturer datasheet reference schematic.
This page consolidates distributor pricing, drop-in alternatives, and layout guidance not always present in the manufacturer datasheet, giving procurement and design engineers a single reference for evaluation, second-sourcing, and PCB integration.
Drop-in alternatives for MAX1321ECM+ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MAX1321ECM+ (same form factor and footprint) — differing in Package, Number of Channels, Resolution, Analog Supply Voltage, Digital Interface.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1322ECM+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1320ECM+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1318ECM+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1316ECM+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1319ECM+
✅ Drop-In✓ In Stock
$7.2 / Unit
View Datasheet →MAX1324ECM+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1321ECM+ Maximum Ratings & Electrical Characteristics
| Resolution | 14 bit |
| Number of Channels | 4 (simultaneous sampling; also supports 2/8 channel modes in family) |
| Conversion Type | SAR (Successive Approximation) |
| Maximum Throughput | 357 ksps aggregate |
| Analog Input Range | ±10 V, ±5 V, or 0 to +5 V (software-selectable, true differential) |
| Input Over-Voltage Protection | ±25 V |
| Reference | Internal 2.5 V or external |
| Digital Interface | SPI/QSPI/MICROWIRE-compatible, up to 20 MHz |
| Conversion-Complete Output | RDY/INT pin |
| Operating Temperature Range | Industrial, -40C to +85C |
| Package | 48-LQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
MAX1321ECM+ 48-lqfp (7x7 mm) Pin Configuration Guide
Pin configuration for MAX1321ECM+ (48-lqfp (7x7 mm) package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for MAX1321ECM+.
Refer to the datasheet for full pin configuration.
Typical Applications
MAX1321ECM+ is suitable for 6 applications: Multiphase Motor Control, Power-Factor Correction and Power-Grid Synchronization, Vibration and Waveform Analysis, Industrial Data Acquisition Systems, Battery Cell Monitoring and Management, Audio and Acoustic Test Equipment.
Multiphase Motor Control
The MAX1321ECM+ is a strong fit for three-phase motor control because it provides four true-differential input channels that sample all phase currents and the DC-bus voltage simultaneously through per-channel track-and-hold amplifiers, eliminating skew that would otherwise produce field-weakening errors at higher PWM duty cycles. With ±10 V true-differential inputs and ±25 V over-voltage protection, the ADC connects directly to current-shunt amplifiers and DC-link resistor dividers without external scaling. Used between the gate-driver sense resistors and the MCU's SPI port, the 357 ksps throughput supports PWM frequencies well above 20 kHz while the 14-bit resolution delivers the dynamic range needed for torque-ripple minimization and field-oriented control loops. The drawback vs the faster MAX1322ECM+ is that 357 ksps is best suited to industrial inverter PWM rates below ~50 kHz rather than ultra-high-speed servo drives.
Recommended
Power-Factor Correction and Power-Grid Synchronization
Three-phase power-quality monitoring requires that voltage and current on each leg be captured in the same instant so that phase-angle relationships are preserved, which is the primary reason the MAX1321ECM+ matches this application. Its 4-channel simultaneous sampling, software-selectable ±10 V/±5 V/0-5 V inputs, and internal 2.5 V reference let designers connect line-voltage transducers and current transformers without external signal conditioning. At 357 ksps aggregate, the part samples at more than 7 ksps per channel at the typical 14.4 ksps (720 samples/cycle @ 50 Hz) required for Class-A power meters. Unlike sigma-delta ADCs that need settling time, the SAR architecture delivers a single-snapshot conversion that simplifies FFT-based harmonic analysis of the grid signal.
Recommended
Vibration and Waveform Analysis
Two- or three-axis MEMS accelerometer arrays benefit from the MAX1321ECM+'s simultaneous-sampling architecture because the part captures all axes at one instant, preserving the cross-axis correlation needed for modal-analysis and shock-vector reconstruction. With ±10 V input range and 14-bit resolution the ADC handles piezo-sensor outputs through charge amplifiers and IEPE conditioning chains without further attenuation. The 357 ksps throughput supports 50+ kHz sampling per channel for vibration-bandwidth analysis on turbomachinery and structural-health monitoring. Compared with multiplexed ADCs that introduce inter-channel skew of one conversion cycle, the MAX1321ECM+'s per-channel T/H front-end keeps skew well below 10 ns, which is critical for beamforming and modal-extraction algorithms.
Recommended
Industrial Data Acquisition Systems
Distributed I/O modules and process-control front-ends use the MAX1321ECM+ to digitize multiple 4-20 mA or ±10 V transducer loops simultaneously with a single device, reducing the per-channel BOM cost relative to a stack of single-channel ADCs. The SPI-compatible digital interface lets the part hang directly off an MCU or industrial Ethernet controller without glue logic, and the 48-LQFP surface-mount package accommodates hand-rework during prototyping. Its ±25 V input protection allows direct termination of industrial field wiring without external TVS diodes in many applications, while the software-selectable input range lets one board design serve ±10 V, ±5 V, and unipolar 0-5 V transducer families by register setting alone.
Recommended
Battery Cell Monitoring and Management
The MAX1321ECM+ suits multi-cell battery stacks because its 4-channel simultaneous-sampling inputs let a single IC scan four series cells at the same instant, eliminating measurement skew that would cause balancing algorithms to misjudge state-of-charge. The ±5 V or ±10 V input ranges cover typical 4.2 V Li-ion cells when used in true-differential mode, and the internal 2.5 V reference removes the need for a separate precision reference per cell tap. Operated near a BMS controller through SPI, the 357 ksps throughput is sufficient to refresh all four cells within hundreds of microseconds, supporting aggressive cell-balancing scheduling. The trade-off vs dedicated battery monitor ICs is the absence of integrated cell-balancing FETs, so the MAX1321ECM+ pairs with an external balance-MOSFET driver for production designs.
Recommended
Audio and Acoustic Test Equipment
Multi-microphone acoustic-test rigs such as beamforming arrays and noise-source localization benches benefit from the MAX1321ECM+'s simultaneous capture because phase relationships between microphone channels must be preserved to within nanoseconds for accurate direction-of-arrival estimation. The 14-bit resolution and ±10 V input range accommodate standard microphone preamp outputs at +20 dBu levels with 10 dB of headroom, while the SPI-compatible interface streams four channels of audio data to a DSP or FPGA at sufficient aggregate rate to cover the full 20 kHz audio band per channel. Versus high-resolution sigma-delta audio ADCs, the SAR architecture provides a single-snapshot acquisition that avoids the group-delay artifacts of decimation filters, which is important when correlating against reference microphones.
Recommended
Recommended Products Summary
Engineering reference data for MAX1321ECM+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1322ECM+ | MAX1320ECM+ | MAX1318ECM+ | MAX1316ECM+ |
|---|---|---|---|---|---|
| Brand | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated |
| Package | 48-LQFP (7x7) | 48-LQFP (7x7) - same | 48-LQFP (7x7) - same | 48-LQFP (7x7) - same | 48-LQFP (7x7) - same |
| Resolution | 14 bit | 14 bit | 14 bit | 14 bit | 14 bit |
| Number of Channels | 4 | 4 | 2 | 8 | 6 |
| Maximum Throughput | 357 ksps | 1.4 Msps | 357 ksps | 357 ksps | 357 ksps |
| Input Range | ±10 V / ±5 V / 0 to +5 V | ±10 V / ±5 V / 0 to +5 V | ±10 V / ±5 V / 0 to +5 V | ±10 V / ±5 V / 0 to +5 V | ±10 V / ±5 V / 0 to +5 V |
| Conversion Architecture | SAR | SAR | SAR | SAR | SAR |
| Digital Interface | SPI/QSPI/MICROWIRE up to 20 MHz | SPI/QSPI/MICROWIRE up to 20 MHz | SPI/QSPI/MICROWIRE up to 20 MHz | SPI/QSPI/MICROWIRE up to 20 MHz | SPI/QSPI/MICROWIRE up to 20 MHz |
| Over-Voltage Protection | ±25 V | ±25 V | ±25 V | ±25 V | ±25 V |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
Key Differentiators
- True ±10 V differential inputs without external dividers (vs MAX1322ECM+)
- 4 channels for typical 3-phase + DC-bus sensing (vs MAX1320ECM+)
- Per-channel track-and-hold enables simultaneous sampling (vs MAX1318ECM+ (8-channel variant))
Design Notes
Place 0.1 µF ceramic decoupling capacitors as close as possible to each AVDD and DVDD pin, with a 10 µF bulk cap at the regulator output supplying the analog plane. Split the ground plane into analog (AGND) and digital (DGND) sections joined at a single point beneath the exposed thermal pad of the 48-LQFP. Estimated: a properly implemented split-plane layout typically reduces ADC noise by 6-10 dB versus a unified ground; the exact number is layout-dependent and should be measured on the prototype.
Per the MAX1321 datasheet reference schematic, the exposed thermal pad on the 48-LQFP must be soldered to the AGND plane to meet the package thermal performance and to provide a stable reference for the analog inputs. Recommended land pattern is provided in the datasheet mechanical drawing. Use a 4-mil soldermask-dam fence around thermal vias if higher reliability is required.
Avoid routing the SPI clock and data lines across or adjacent to the analog input traces; the digital SPI transitions can couple into the high-impedance analog inputs and degrade AC performance. Adding a digital-isolation barrier (such as a 74HC125 buffer or digital isolator) between the MCU and the ADC interface when the MCU and ADC are on different ground potentials prevents ground-loop noise injection. Always verify that CS, SCLK, and DIN are within the datasheet-specified logic thresholds for the chosen DVDD level (typically 2.7 V or 5 V operation).
For ±10 V true-differential inputs, keep the AIN+ and AIN- traces as a length-matched, tightly coupled pair from the input protection network to the IC pins; mismatched impedance causes common-mode-to-differential conversion that reduces the effective 14-bit resolution. Series input resistors (~100 Ω) plus a 1 nF to 10 nF common-mode filter capacitor to AGND attenuate RF pickup above the SAR's Nyquist frequency without materially affecting the input bandwidth.
Drive AVDD from a low-noise LDO (such as the MAX1321's own analog supply or a comparable ultra-low-noise part like TPS7A4701); the MAX1321's internal 2.5 V reference is sensitive to AVDD ripple above 1 mV. When using an external reference, buffer it with an op-amp to avoid reference-biasing errors when multiple devices share the reference rail.
Compliance Information
RoHS and lead-free compliance affirmed by Maxim Integrated/Analog Devices product page listings. AEC-Q100 qualification status not asserted in publicly available datasheet; treat as not_applicable for this part. Halogen-free and conflict-minerals status not explicitly listed in the captured data - set to unknown.
