MAX156BCNG - 8-Ch 8-Bit 250ksps ADC w/ T/H | Maxim Integrated
MPN: MAX156BCNG ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.5 | $7.50 |
| 10 | $6.8 | $68.00 |
| 100 | $5.95 | $595.00 |
| 500 | $5.2 | $2,600.00 |
| 1,000 | $4.65 | $4,650.00 |
MAX156BCNG Overview
A successive-approximation ADC is a type of data converter that resolves each conversion one bit at a time using an internal binary-search algorithm, offering a favorable trade-off between speed, resolution, and die size compared to flash or sigma-delta architectures. SAR ADCs sit in the hierarchy: ADC -> data converter -> mixed-signal IC -> semiconductor. The MAX156's 8-bit resolution and 250 ksps throughput place it in the mid-speed data-acquisition tier used for instrumentation, video digitizing, and DSP front-ends where 8-bit dynamic range is acceptable.
Key features include 8 input channels (software-configurable as 2 or 4 single-ended inputs or differential pairs), simultaneous track-and-hold for paired channels, internal +2.5V reference with external override option, single +5V analog supply plus digital 5V supply, and a parallel interface compatible with most microprocessors. The device guarantees no missing codes over the full operating temperature range and provides ±1 LSB linearity.
Typical applications include multichannel data-acquisition systems, simultaneous-sampling instrumentation, DSP front-end analog input stages, industrial process control with multiple sensors, and portable or benchtop test equipment. The internal reference simplifies BOM and layout while keeping the device suitable for cost-sensitive multi-channel designs.
Drop-in alternatives for MAX156BCNG — 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 MAX156BCNG (same form factor and footprint) — differing in Package, Resolution, Input Voltage Range, Number of Channels, Operating Temperature Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX156BCNG+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX155ACNG
✅ Drop-In📋 Reference alternative (not in catalog)
MAX128BCNG
✅ Drop-In✓ In Stock
$10.27 / Unit
View Datasheet →MAX1270BENG
✅ Drop-In✓ In Stock
$19.85 / Unit
View Datasheet →MAX120ENG
✅ Drop-In📋 Reference alternative (not in catalog)
MAX132CNG
✅ Drop-In✓ In Stock
$13.7 / Unit
View Datasheet →MAX156BCNG Maximum Ratings & Electrical Characteristics
| Resolution | 8 bit |
| Number of Channels | 8 (configurable as 2/4 inputs) |
| Sampling Rate | 250 ksps |
| ADC Architecture | SAR (Successive Approximation) |
| Input Configuration | 2 or 4 single-ended / differential |
| Track-and-Hold | Simultaneous T/H on paired channels |
| Internal Reference Voltage | 2.5 V |
| Analog Supply Voltage | +5 V |
| Digital Supply Voltage | +5 V |
| Data Interface | Parallel |
| Operating Temperature Range | 0C to +70C (commercial) |
| Package | 24-pin PDIP (NG suffix, 0.300 inch) |
| Mounting Type | Through-Hole |
| RoHS Status | Non-compliant (NG suffix, lead-bearing) |
| Number of Pins | 24 |
MAX156BCNG Pin Configuration
| Pin 1 | VREF — Reference voltage input/output (2.5V internal) |
| Pin 2 | REFADJ — Reference adjust |
| Pin 3 | AGND — Analog ground |
| Pin 4 | CH1 — Analog input channel 1 |
| Pin 5 | CH2 — Analog input channel 2 |
| Pin 6 | CH3 — Analog input channel 3 |
| Pin 7 | CH4 — Analog input channel 4 |
| Pin 8 | CH5 — Analog input channel 5 |
| Pin 9 | CH6 — Analog input channel 6 |
| Pin 10 | CH7 — Analog input channel 7 |
| Pin 11 | CH8 — Analog input channel 8 |
| Pin 12 | AGND — Analog ground |
| Pin 13 | VDD — +5V analog supply |
| Pin 14 | VLOGIC — +5V digital supply |
| Pin 15 | DGND — Digital ground |
| Pin 16 | D0 — Data output bit 0 (LSB) |
| Pin 17 | D1 — Data output bit 1 |
| Pin 18 | D2 — Data output bit 2 |
| Pin 19 | D3 — Data output bit 3 |
| Pin 20 | D4 — Data output bit 4 |
| Pin 21 | D5 — Data output bit 5 |
| Pin 22 | D6 — Data output bit 6 |
| Pin 23 | D7 — Data output bit 7 (MSB) |
| Pin 24 | CS — Chip select / read strobe |
Typical Applications
MAX156BCNG is suitable for 6 applications: Multichannel Data-Acquisition Systems, Simultaneous-Sampling Instrumentation, DSP Front-End Analog Input Stage, Industrial Process Control, Portable Test and Measurement Equipment, Legacy Replacement and EOL Bridging.
Multichannel Data-Acquisition Systems
The MAX156BCNG's 8 input channels and 250 ksps throughput make it ideal for multichannel data-acquisition boards where multiple analog signals must be digitized at a common time reference. The 8-bit resolution suits instrumentation front-ends measuring temperature, pressure, strain-gauge, or general-purpose sensor arrays where 8 bits of dynamic range (256 levels) is sufficient and cost is a primary concern. Its parallel interface pairs cleanly with 8051-family microcontrollers and DSPs for high-throughput sample transfer.
Recommended
Simultaneous-Sampling Instrumentation
The MAX156BCNG integrates simultaneous track-and-hold amplifiers that capture paired channels at exactly the same instant, eliminating inter-channel aperture skew. This makes it a strong fit for vibration analysis, three-phase power monitoring, and vector measurement systems where phase relationships between channels carry information. Engineers select the MAX156 specifically when inter-channel timing alignment is more important than raw resolution.
Recommended
DSP Front-End Analog Input Stage
The MAX156BCNG serves as the analog front-end for DSP-based systems that need 8-bit conversion at moderate speeds without sacrificing board area. Its 250 ksps sampling rate comfortably supports audio-bandwidth DSP (e.g., 48 kS/s oversampled) and motor-control loop rates. The internal +2.5V reference reduces BOM and the parallel data output integrates with DSPs that have a parallel peripheral interface.
Recommended
Industrial Process Control
In factory automation, the MAX156BCNG's 8 channels enable a single IC to monitor multiple sensor lines such as thermocouples, pressure transducers, or 4-20 mA loops. The through-hole PDIP package suits legacy industrial control boards that prioritize mechanical robustness and field-replaceability over surface-mount density. The internal reference simplifies calibration and the parallel interface fits older industrial PLC architectures.
Recommended
Portable Test and Measurement Equipment
The MAX156BCNG's 8 single +5V analog supply and on-chip reference make it well-suited for portable benchtop instruments and handheld multimeters where board space and power budget matter. The 250 ksps rate supports oscilloscope-style capture of low-frequency signals up to ~125 kHz, and the 24-pin PDIP allows through-hole assembly for low-volume or hand-prototyped builds favored in test-equipment design.
Recommended
Legacy Replacement and EOL Bridging
Because the MAX156BCNG is in NRND status, engineers maintaining older Maxim-based boards can use this part as a documented drop-in replacement for the original MAX156, MAX155, and earlier 8-bit Maxim ADC designs. The 24-pin PDIP form factor allows direct socket swap, the parallel interface matches legacy firmware, and the Maxim/Analog Devices continuity of supply protects long-life-cycle programs (aerospace, medical, industrial) from re-qualification churn.
Recommended
Recommended Products Summary
Engineering reference data for MAX156BCNG — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX156BCNG+ | MAX155ACNG | MAX128BCNG |
|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 24-pin PDIP | 24-pin PDIP - same | 24-pin PDIP - same | 24-pin PDIP - same |
| Resolution | 8 bit | 8 bit | 8 bit | 12 bit |
| Channels | 8 (configurable 2/4) | 8 (configurable 2/4) | 8 (configurable 2/4) | 8 |
Key Differentiators
- On-chip simultaneous track-and-hold eliminates inter-channel skew (vs MAX120ENG)
- 8 input channels in a single 24-pin PDIP (vs MAX128BCNG)
- Internal +2.5V reference reduces BOM (vs MAX132CNG (14-bit DAC))
Design Notes
The MAX156BCNG requires two separate +5V supplies - VDD (analog) and VLOGIC (digital) - plus an analog ground and digital ground. Decouple each supply pin with a 0.1uF ceramic capacitor placed as close to the IC as possible, and add a bulk 10uF tantalum or ceramic on each supply rail. Keeping VLOGIC noise out of VDD via separate decoupling prevents digital switching noise from coupling into the SAR comparator and degrading ADC linearity.
Use a star-ground topology with the AGND and DGND pins tied at a single point near the IC. Route analog input traces away from the parallel digital output bus to minimize digital-to-analog crosstalk. Place the 24-pin PDIP in a socket if field-replaceability matters; the through-hole package is preferred for hand-prototyped and legacy industrial designs.
Do not exceed the absolute maximum analog input voltage range on CH1-CH8 or the internal reference will be damaged. When using the internal 2.5V reference, decouple VREF with at least 1uF; bypassing with smaller capacitance may cause reference oscillation and degraded ADC linearity. Ensure CS timing follows the datasheet - the MAX156 uses CS as a combined chip-select and read strobe in some modes, which can confuse firmware written for a generic parallel ADC.
Compliance Information
MAX156BCNG (NG suffix) is the lead-bearing variant and is RoHS non-compliant; the MAX156BCNG+ (plus suffix) is the RoHS-compliant lead-free variant. NRND status per distributor listings.
