MAX155BEPI+ - 8-Channel 8-Bit 250ksps SAR ADC | Maxim Integrated
N.º da peça: MAX155BEPI+ ⚠ Última compra| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $19.5 | $19,50 |
| 10 | $17.55 | $175,50 |
| 100 | $15.21 | $1.521,00 |
| 500 | $13.65 | $6.825,00 |
| 1.000 | $12.35 | $12.350,00 |
MAX155BEPI+ Visão geral
A SAR ADC is a type of analog-to-digital converter that converts an analog input into a digital code using a binary-search successive-approximation register. SAR ADCs sit in the broader hierarchy: ADC -> data converter -> mixed-signal IC -> integrated circuit. They are favored over delta-sigma and pipeline ADCs when the application needs low latency, deterministic acquisition time, and moderate-to-high sampling rates without pipeline delay, making them common in industrial multiplexing, motor control, and instrumentation loops.
The key differentiating features of the MAX155 are its eight simultaneous track/hold amplifiers (one per channel) that eliminate channel-to-channel sampling skew, the internal precision 2.5V reference (saving board space and BOM cost), and a flexible parallel data interface compatible with most microcontrollers and DSPs. Each input channel can be configured as single-ended or differential, and an analog multiplexer under software control selects which channel the SAR core digitizes while all eight T/Hs sample at the same instant.
Architecturally, the device combines an 8:1 input MUX, eight dedicated sample-and-hold capacitors, a single shared SAR core, an internal reference buffer, and a parallel output register. This "MUX + simultaneous T/H" topology trades simultaneous-snapshot timing accuracy (typically <50 ns channel-to-channel skew) for the throughput ceiling of one ADC core. The "B" grade offers the fastest conversion time in the MAX155 family.
Typical applications for the MAX155BEPI+ include industrial process control data acquisition boards, multi-axis motor position feedback, multiplexed thermocouple or strain-gauge signal chains, simultaneous-sampling vibration/acoustic analyzers, and embedded instrumentation front-ends. The DIP-28 package is friendly to breadboard prototyping, legacy through-hole designs, and educational lab work where surface-mount packages are inconvenient.
When designing with this part, ensure the analog inputs remain within the supply rails (typically +/-5V or 0-5V with VDD=+5V, VSS=-5V) and add a 10 nF ceramic bypass on the reference pin to maintain low-noise conversions. Because the part is now in Last Time Buy status per distributor listings, consider the MAX155BEWI+ (SOIC-28) or other drop-in-compatible ADC alternatives listed below for new production runs.
This page synthesizes distributor pricing, drop-in compatible 8-channel SAR ADC alternatives, and practical layout/design notes not aggregated in the manufacturer datasheet alone.
Alternativas drop-in para MAX155BEPI+ — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
MAX155AEPI+
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MAX155BCPI+
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MAX156BEPI+
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MAX1062AEUB+
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MAX155BEPI+ Classificações máximas e características elétricas
| Number of Bits | 8 |
| Taxa de amostragem | 250 ksamples/s |
| Number of Input Channels | 4 or 8 (software-selectable) |
| Input Type | Differential, Single-Ended |
| Architecture | SAR (Successive Approximation) |
| Data Interface | Parallel |
| Configuration | S/H-MUX-ADC |
| Ratio S/H:ADC | 8:1 |
| Number of A/D Converters | 1 |
| Internal Reference | 2.5 V (on-chip) |
| Simultaneous Track/Hold | Yes (one T/H per channel) |
| Encapsulamento | 28-PDIP (Plastic DIP, through-hole) |
| Faixa de temperatura de operação | -40 C to +85 C (industrial, "EPI" suffix) |
| Status RoHS | unknown (PDIP-28 likely non-RoHS per legacy Maxim data) |
Configuração de pinos do MAX155BEPI+
| Pino 1 | AIN1 — Analog input channel 1 |
| Pino 2 | AIN2 — Analog input channel 2 |
| Pino 3 | AIN3 — Analog input channel 3 |
| Pino 4 | AIN4 — Analog input channel 4 |
| Pino 5 | AIN5 — Analog input channel 5 |
| Pino 6 | AIN6 — Analog input channel 6 |
| Pino 7 | AIN7 — Analog input channel 7 |
| Pino 8 | AIN8 — Analog input channel 8 |
| Pino 9 | AGND — Analog ground |
| Pino 10 | REF — Reference pin (internal 2.5V reference, bypass with capacitor) |
| Pino 11 | VDD — Positive supply |
| Pino 12 | VSS — Negative supply (or GND for single-supply operation) |
| Pino 13 | MODE — Input mode select (single-ended / differential) |
| Pino 14 | CLK — External clock input |
| Pino 15 | /WR — Write control input (active low) |
| Pino 16 | /RD — Read control input (active low) |
| Pino 17 | /CS — Chip select (active low) |
| Pino 18 | /INT — Interrupt output (active low) |
| Pino 19 | DGND — Digital ground |
| Pino 20 | D0 — Data bit 0 (LSB) |
| Pino 21 | D1 — Data bit 1 |
| Pino 22 | D2 — Data bit 2 |
| Pino 23 | D3 — Data bit 3 |
| Pino 24 | D4 — Data bit 4 |
| Pino 25 | D5 — Data bit 5 |
| Pino 26 | D6 — Data bit 6 |
| Pino 27 | D7 — Data bit 7 (MSB) |
| Pino 28 | VDD — Positive supply (duplicate) |
Aplicações típicas
MAX155BEPI+ é adequado para 6 aplicaçãos: Industrial Multi-Channel Data Acquisition, Multi-Axis Motor Position Feedback, Vibration and Acoustic Analyzers, Multiplexed Thermocouple / Strain-Gauge Front-End, Embedded Instrumentation and Bench Test Equipment, Legacy Through-Hole Industrial Backplanes.
Industrial Multi-Channel Data Acquisition
The MAX155BEPI+ fits industrial data-acquisition front-ends because its eight simultaneous track/holds capture all sensor inputs at the same instant, eliminating channel-to-channel timing skew that would otherwise corrupt multi-axis measurements. With 250 ksps throughput and 8-bit resolution, the device digitizes multiplexed analog signals from thermocouples, strain gauges, pressure sensors, and 4-20 mA loops without external sample-and-hold stages. The internal reference saves BOM, while the parallel bus glues directly to most microcontrollers and DSPs. At TTL of -40C to +85C it survives factory-floor temperatures, and the simultaneous T/H topology ensures deterministic acquisition across all eight channels per sample cycle.
Recomendado
Multi-Axis Motor Position Feedback
For multi-axis servo loops, the MAX155BEPI+ provides simultaneous sampling of position sensors (encoders, resolvers, Hall-effect sensors) on all axes at the same instant, ensuring deterministic control-loop latency across the entire machine. The 250 ksps rate is adequate for current-loop update rates up to ~10 kHz per axis, while 8-bit resolution suits coarse position readback and current sensing. The parallel interface connects to a DSP or FPGA without handshake overhead, and the differential-input capability rejects common-mode noise from motor PWM edges. Designers pair it with op-amp signal conditioning and use the simultaneous T/H to ensure the controller sees a coherent snapshot across all axes.
Recomendado
Vibration and Acoustic Analyzers
The MAX155BEPI+ is well suited to vibration and acoustic analysis equipment that requires simultaneous sampling of multiple accelerometers or microphones to preserve phase relationships. Each of the eight T/H amplifiers captures its input at the same instant (typically <50 ns skew), preserving relative phase between channels - critical for modal analysis, FFT-based beamforming, and acoustic source identification. The 250 ksps rate supports vibration analysis up to ~100 kHz (Nyquist) per channel when channels are time-shared, and the parallel bus enables direct DMA into a DSP. The internal 2.5V reference and on-chip MUX simplify the front-end to just op-amp buffers plus the ADC.
Recomendado
Multiplexed Thermocouple / Strain-Gauge Front-End
In thermocouple and strain-gauge signal chains, the MAX155BEPI+ provides eight differential input channels that digitize low-level analog signals with simultaneous sampling, eliminating timing-skew-induced errors when comparing sensor readings. Cold-junction compensation and bridge excitation can be implemented externally; the internal 2.5V reference powers the excitation regulators. Eight channels per ADC keep board space low, and multiple MAX155 devices can be paralleled for higher channel-count systems. The industrial -40C to +85C temperature range suits process-control cabinets, and the DIP-28 package is friendly to through-hole industrial backplanes.
Recomendado
Embedded Instrumentation and Bench Test Equipment
For embedded oscilloscopes, logic-analyzer analog probes, and bench-test instruments, the MAX155BEPI+ offers 250 ksps simultaneous-sampling across eight channels, ideal for capturing repetitive waveforms with precise inter-channel phase relationships. The parallel interface supports DMA into the host microcontroller or FPGA buffer memory, and the 8-bit resolution suits general-purpose test gear. The DIP-28 package makes breadboard prototyping straightforward for educational labs and proof-of-concept designs, while the internal 2.5V reference minimizes external components. Designers use it for low-bandwidth signal integrity debug, audio-bandwidth oscilloscope front-ends, and educational DSP labs.
Recomendado
Legacy Through-Hole Industrial Backplanes
The MAX155BEPI+ remains valuable for legacy through-hole backplane designs where surface-mount ADC packages are impractical - industrial PLC backplanes, educational lab boards, and retrofit/repair scenarios for older equipment. The 28-PDIP package fits standard DIP sockets, allowing field replacement without SMT equipment. The SAR ADC architecture provides deterministic acquisition latency needed for closed-loop control, the internal reference simplifies the BOM, and the simultaneous T/H preserves timing on legacy sensor networks. For new designs, the MAX155BEWI+ (SOIC-28) is the surface-mount counterpart with identical silicon but different footprint.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para MAX155BEPI+ — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | MAX155AEPI+ | MAX155BCPI+ | MAX156BEPI+ |
|---|---|---|---|---|
| Brand | Analog Devices (formerly Maxim Integrated) | Analog Devices | Analog Devices | Analog Devices |
| Package | 28-PDIP (through-hole) | 28-PDIP - same | 28-PDIP - same | 28-PDIP - same |
| Resolution | 8 bits | 8 bits | 8 bits | 8 bits |
| Sampling Rate | 250 ksps (B grade) | 125 ksps (A grade, ~50% slower) | 250 ksps (B grade, same) | 250 ksps (B grade, same) |
| Number of Input Channels | 8 (4 or 8 SE/Diff) | 8 (same) | 8 (same) | 4 (50% fewer channels) |
| Simultaneous Track/Hold | Yes (8 T/Hs) | Yes (8 T/Hs) | Yes (8 T/Hs) | Yes (4 T/Hs) |
| Internal Reference | 2.5 V on-chip | 2.5 V on-chip | 2.5 V on-chip | 2.5 V on-chip |
| Temperature Grade | Industrial -40C to +85C | Industrial -40C to +85C | Commercial 0C to +70C | Industrial -40C to +85C |
| Lifecycle Status | Last Time Buy | Last Time Buy | Last Time Buy | Last Time Buy |
Principais diferenciais
- Fastest B-grade sampling in the MAX155 family (vs MAX155AEPI+)
- Industrial temperature range for harsh environments (vs MAX155BCPI+)
- 8-channel simultaneous sampling for coherent multi-axis data (vs MAX156BEPI+)
- Through-hole PDIP for legacy and educational designs (vs MAX155BEWI+)
Notas de projeto
The MAX155BEPI+ typically operates from VDD = +5V and VSS = -5V for bipolar +/-5V analog input range, or from VDD = +5V with VSS = 0V for unipolar 0-5V inputs. Decouple VDD/VSS with 10uF tantalum plus 100 nF ceramic placed within 5 mm of the supply pins. Add a 10 nF NPO/C0G ceramic capacitor directly on the REF pin (pin 10) - the internal 2.5V reference drives the SAR DAC and noise here degrades ENOB. Estimated: typical 5V supply current is on the order of 5-15 mA during conversion; confirm with datasheet for the latest figure.
Place the 28-PDIP device so that analog and digital grounds are joined at a single star point near the AGND pin (pin 9). Keep the parallel digital bus (D0-D7) and control lines (/CS, /RD, /WR) routed away from the analog inputs (AIN1-AIN8) and the REF pin. Use a ground plane on the component side under the analog section and a separate digital ground pour under the bus to limit switching-noise coupling. For through-hole PDIP-28 boards, add bypass ceramics right at the IC pins rather than at the socket.
Common pitfalls with the MAX155BEPI+ include: (1) exceeding the analog input range beyond VDD/VSS rails causes latch-up and permanent damage; (2) forgetting to bypass the REF pin results in noisy conversions (kHz-range spur tones appear in the spectrum); (3) using long wires from sensors to AIN pins without op-amp buffers picks up 50/60 Hz mains noise that aliases into the conversion; (4) clocking the part faster than the rated 250 ksps B-grade rate returns incorrect codes; (5) leaving /CS floating may cause spurious reads - tie it high via 100 kohm to VDD when unused.
The simultaneous T/H topology preserves channel-to-channel phase, but absolute aperture accuracy depends on a clean CLK source. Drive CLK from a low-jitter source (crystal oscillator or MCU timer output) and avoid routing CLK near the analog inputs. For differential inputs, route AIN+ and AIN- as a tightly coupled pair with matched lengths to preserve common-mode rejection. If source impedances exceed ~1 kohm, add an op-amp buffer per channel - the SAR core samples 25 pF of input capacitance and produces a charge kick that causes settling errors with high-impedance sources.
Informações de conformidade
PDIP-28 legacy Maxim package - RoHS/lead-free status not confirmed in provided data; typical legacy Maxim PDIP products are non-RoHS, but check the device label or manufacturer documentation. Not AEC-Q100 qualified (industrial temp grade only).
