MAX1245BEAP - 12-Bit 8-Ch 100ksps +3.3V ADC | Maxim Integrated
MPN: MAX1245BEAP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $16.19 | $16.19 |
| 10 | $14.57 | $145.70 |
| 100 | $13.2 | $1,320.00 |
| 500 | $12.1 | $6,050.00 |
| 1,000 | $11.05 | $11,050.00 |
MAX1245BEAP Overview
An ADC (analog-to-digital converter, also written A/D converter or A-to-D) is a mixed-signal integrated circuit that samples a continuous-time analog voltage and converts it into a discrete digital code that a microcontroller or DSP can process. The MAX1245 family belongs to the SAR (successive approximation register) sub-type, which internally performs a binary-search algorithm using an internal DAC and comparator. Within the broader taxonomy, this part sits under data converter -> ADC -> precision SAR ADC -> low-power multi-channel ADC -> power-management-aware signal-chain IC. SAR ADCs are favored when deterministic latency, low latency, and simplicity are required.
Key features include 8 single-ended analog input channels (or 4 differential pairs via software control), an internal track/hold with >2 MHz input bandwidth, a 3-wire SPI/QSPI/MICROWIRE-compatible serial interface, hardware- and software-controlled power-down modes (1 µA max), and an internal 2.5V reference that can also be overdriven by an external reference for higher-accuracy applications.
Typical applications include portable 2.5V and 3.3V data-acquisition systems, battery-powered instrumentation, pen digitizers, patient monitoring, and process-control I/O modules where multiple sensors share a single ADC. The low 1 mW (typ) power dissipation at 3V and the 1 µA power-down current make it ideal for power-constrained designs.
When designing with the MAX1245BEAP, ensure the analog input range stays within the supply rails (rail inputs without overdrive damage), use a 0.1 µF ceramic bypass close to the supply, and observe the maximum 10 MHz SCLK limit of the SPI interface to maintain linearity. The internal reference settles within 1 ms after power-up, so a short delay is required before the first conversion. As of 2026-10-14, distributor pricing starts around $16.19 per 1ku list price from Maxim Integrated. This page synthesizes distributor pricing, drop-in same-package alternatives (MAX1245AEAP, MAX1245BCAP), and design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for MAX1245BEAP — 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 MAX1245BEAP (same form factor and footprint) — differing in Interface, Resolution, Sampling Rate, Supply Voltage.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1245AEAP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1245BCAP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1245BEAP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1245BEAP+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1145BEAP+
✅ Drop-In✓ In Stock
$5.95 / Unit
View Datasheet →MAX1245BEAP Maximum Ratings & Electrical Characteristics
| Resolution | 12 bit |
| Number of Channels | 8 single-ended / 4 differential |
| Architecture | SAR (Successive Approximation) |
| Sampling Rate | 100 ksps |
| Supply Voltage | +2.375 V to +3.3 V |
| Supply Current (active) | 1.3 mA typ |
| Supply Current (power-down) | 1 µA max |
| Input Bandwidth (track/hold) | >2 MHz |
| Interface | 3-wire SPI / QSPI / MICROWIRE-compatible serial |
| Internal Reference | 2.5 V |
| External Reference Range | 1.0 V to VDD |
| Package | 20-pin SSOP |
| Operating Temperature Range | -40 C to +85 C (E grade) |
| MSL Level | 1 |
| RoHS Status | Compliant |
MAX1245BEAP Pin Configuration
| Pin 1 | VDD — +2.375 V to +3.3 V supply |
| Pin 2 | AIN0 — Analog input channel 0 |
| Pin 3 | AIN1 — Analog input channel 1 |
| Pin 4 | AIN2 — Analog input channel 2 |
| Pin 5 | AIN3 — Analog input channel 3 |
| Pin 6 | AIN4 — Analog input channel 4 |
| Pin 7 | AIN5 — Analog input channel 5 |
| Pin 8 | AIN6 — Analog input channel 6 |
| Pin 9 | AIN7 — Analog input channel 7 |
| Pin 10 | GND — Analog/digital ground |
| Pin 11 | REF — Reference input/output in/out |
| Pin 12 | REFADJ — Reference adjust / bypass |
| Pin 13 | SCLK — Serial clock input |
| Pin 14 | DOUT — Serial data output |
| Pin 15 | DIN — Serial data input |
| Pin 16 | CS — Chip select (active low) |
| Pin 17 | SHDN — Shutdown (active low) |
| Pin 18 | AGND — Analog ground |
| Pin 19 | DGND — Digital ground |
| Pin 20 | VDD — +2.375 V to +3.3 V supply |
Typical Applications
MAX1245BEAP is suitable for 6 applications: Portable Battery-Powered Data Acquisition, Industrial Process Control I/O Modules, Patient Monitoring and Medical Instrumentation, Pen Digitizers and Touch Panels, Battery Cell Monitoring and Management, Sensor Signal Conditioning Hubs.
Portable Battery-Powered Data Acquisition
The MAX1245BEAP suits portable battery-powered data-acquisition front ends because it draws only 1.3 mA active and 1 µA in power-down, and operates directly from a +2.375 V to +3.3 V supply rail that matches a single Li-ion cell or two alkaline cells. Its 8 single-ended channels scan multiple sensor outputs (temperature, pressure, battery voltage) sequentially through one SPI port to a low-power MCU. Unlike higher-speed SAR ADCs it adds no significant quiescent load, extending runtime in field instruments and pen digitizers.
Recommended
Industrial Process Control I/O Modules
In 4-20 mA loop-powered or PLC I/O modules, the MAX1245BEAP multiplexes up to eight analog sensor inputs into one SAR ADC, reducing BOM cost and board area compared to one ADC per channel. The internal 2.5 V reference sets the input span, but an external precision reference (1.0 V to VDD) can be overdriven for tighter absolute accuracy in closed-loop PID control. The 100 ksps throughput supports sub-millisecond loop times, while the SPI/QSPI/MICROWIRE-compatible serial interface glues directly to most microcontrollers and DSPs.
Recommended
Patient Monitoring and Medical Instrumentation
The MAX1245BEAP's low power dissipation and small 20-pin SSOP package fit medical patient-monitoring designs (pulse oximetry, blood-pressure cuffs, glucose meters) where board area is tight and battery life matters. The 8-channel multiplexer can scan multiple sensor bridges or bioelectric signals through one ADC, and the 1 µA power-down current is critical for sleep modes between measurements. Unlike higher-power continuous ADCs, the MAX1245BEAP can be duty-cycled on to extend battery life in portable, low-power clinical devices.
Recommended
Pen Digitizers and Touch Panels
Pen-digitizer and resistive touch-panel controllers digitize X/Y position and pen pressure from a 4-wire or 5-wire touch stack. The MAX1245BEAP's 4-differential-channel mode (via software) directly captures X+, X-, Y+, Y- from the touch panel through one ADC, while the 8-channel mode handles additional pen-pressure inputs. The 100 ksps throughput sustains >50 Hz update rates for smooth handwriting capture, and the low-power shutdown between samples extends battery life in wireless stylus designs.
Recommended
Battery Cell Monitoring and Management
The MAX1245BEAP is well-suited to multi-cell battery-monitoring boards in 2.5 V-3.3 V Li-ion or 2-cell alkaline packs, where each cell or pack voltage is multiplexed into the ADC. The internal 2.5 V reference scales to a 0-2.5 V input span via a resistive divider, and the 1 µA shutdown current minimizes quiescent drain between scans. Unlike dedicated battery monitors, this SAR ADC adds diagnostic-read flexibility for the IM and current sensing on a shared bus.
Recommended
Sensor Signal Conditioning Hubs
In sensor-hub designs that aggregate thermistors, photodiodes, strain gauges, and gas-sensor outputs, the MAX1245BEAP multiplexes up to 8 analog inputs through a single SPI port, eliminating per-signal ADCs and reducing PCB area. The internal track/hold with >2 MHz input bandwidth preserves transient signal fidelity, while the 1 µA power-down mode enables aggressive duty cycling. The MAX16197 is a recommended companion for system-level health monitoring and watchdog timing on the same bus.
Recommended
Recommended Products Summary
Engineering reference data for MAX1245BEAP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1245AEAP+ | MAX1245BCAP+ | MAX1245BEAP+ | MAX1245BEAP+T | MAX1145BEAP+ |
|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | SSOP-20 | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Supply Voltage | +2.375 V to +3.3 V | +2.375 V to +3.3 V | +2.375 V to +3.3 V | +2.375 V to +3.3 V | +2.375 V to +3.3 V | 3.3 V only |
| Linearity Grade | B grade | A grade (tighter) | B grade | B grade | B grade | B grade |
| Internal Reference | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V |
| Interface | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI |
Key Differentiators
- Optimized for low-voltage 2.5 V-3.3 V portable operation (vs MAX147)
- Internal 2.5 V reference with external override capability (vs MAX1245AEAP+)
- 8 single-ended / 4 differential channel multiplexer with software switching (vs MAX1145BEAP+)
Design Notes
Decouple the VDD pin (pin 1 and pin 20) with a 0.1 µF ceramic capacitor placed within 3 mm of each supply pin, and add a 10 µF bulk tantalum/ceramic at the supply entry point. The MAX1245BEAP draws 1.3 mA active and 1 µA power-down, so a low-ESR bypass is critical to avoid supply droop during SCLK-driven charge kickback events that would otherwise degrade linearity.
Keep analog input traces short and routed over a continuous analog ground plane to minimize charge-injection noise. The internal track/hold has >2 MHz input bandwidth, so stray capacitance beyond 20 pF at the AIN pin can attenuate the sampled-and-held voltage and increase conversion error. For high-impedance sources, add a 1 nF to 10 nF ceramic capacitor at each AIN pin to absorb sampled-charge kickback.
Do not exceed the maximum SCLK frequency of 10 MHz - faster clocks will degrade linearity and produce bit errors. Wait at least 1 ms after power-up (or after exiting shutdown) before initiating the first conversion to allow the internal 2.5 V reference to settle. Driving REFADJ low disables the internal reference, so use that mode only when an external reference is connected. Failure to obey these rules is the most common cause of noisy or stuck readings.
When using the internal 2.5 V reference, bypass REF (pin 11) with a 4.7 µF low-ESR ceramic or tantalum capacitor to AGND. For higher-accuracy designs, drive REF with an external low-drift reference (e.g. MAX6126 or equivalent) instead of the internal one, but disable the internal reference via REFADJ first. The serial interface (SCLK/DOUT/DIN/CS) should be routed away from the analog input traces to avoid digital coupling into the analog path.
Compliance Information
RoHS and REACH compliant per Maxim Integrated product page. Not AEC-Q100 qualified - this part is not designed for automotive applications. Lead-free + suffix variants available (MAX1245BEAP+, MAX1245BEAP+T).
