Analog Devices Inc./Maxim Integrated MAX1295BCEI+T

Overview

MAX1295BCEI+T from Maxim Integrated is a 12-bit, 265ksps successive-approximation ADC with internal +2.5V reference, software-configurable 6-channel single-ended / 3-channel pseudo-differential analog input, and parallel 12-bit interface. It operates from a single +2.7V to +3.6V supply, consumes only 1.9mA at full speed, and features fast 2µs wake-up from shutdown - ideal for portable patient monitoring and battery-powered data-acquisition systems.

For engineers reviewing the MAX1295BCEI+T datasheet, MAX1295BCEI+T pinout, MAX1295BCEI+T application, or MAX1295BCEI+T equivalent, key selection criteria include its ±1 LSB INL accuracy, QSOP-28 package compatibility, unipolar/bipolar software configuration, and support for internal/external clock and acquisition modes in low-power industrial sensing.

Technical Context

The MAX1295BCEI+T implements a charge-redistribution SAR architecture with integrated track/hold (3MHz full-power bandwidth), on-chip 3MHz oscillator, and configurable control-byte interface (D7–D0) for channel selection (A2–A0), SGL/DIF, UNI/BIP, ACQMOD, and PD1/PD0 power-down modes. Its analog front-end supports COM-referenced single-ended inputs or pseudo-differential pairs with ±0.5 LSB COM stability requirement during conversion.

Timing is governed by either internal clock (3.6µs conversion time) or external clock (100kHz–4.8MHz, 30–70% duty cycle); WR rising edge initiates acquisition in internal mode or terminates it in external mode, while INT asserts low upon data readiness. The device tri-states INT when CS goes high and uses a 12-bit parallel bus (D0–D11) with three-state digital I/O.

Key Specifications

Pinout & Package

MAX1295BCEI+T is housed in a 28-pin QSOP package with exposed pad (not thermally enhanced). Pin functions are electrically validated per Maxim's official datasheet Rev 3 (12/02) and support direct µP interfacing via parallel bus and control lines.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit parallel ADC applications.

Compared with MAX1295ACEI+T, the MAX1295BCEI+T trades 0.5 LSB linearity for lower cost in volume production; versus ADS7822U, it delivers 33% higher throughput and integrated timing at the expense of footprint and interface flexibility.

Availability

MAX1295BCEI+T is available at Aetrix Electronics and suitable for industrial process monitoring, portable medical devices, and smart energy metering requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for MAX1295BCEI+T 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 power-management ICs for demanding industrial, medical, and communications applications.

The MAX1295 series targets low-power, high-accuracy data acquisition in space- and energy-constrained systems, emphasizing integrated functionality (reference, clock, MUX) to minimize external components and layout complexity.

FAQ

What is the guaranteed INL specification for MAX1295BCEI+T across its operating temperature range?

The MAX1295BCEI+T guarantees ±1 LSB integral nonlinearity over its full 0°C to +70°C operating temperature range, as specified in the Electrical Characteristics table of the official datasheet Rev 3. This B-grade accuracy applies under standard conditions: VDD = +2.7V to +3.6V, fCLK = 4.8MHz, and unipolar single-ended input mode. The MAX1295BCEI+T achieves this without requiring external trimming or calibration circuits.

Does MAX1295BCEI+T support both internal and external clock modes, and how is the selection made?

Yes, MAX1295BCEI+T supports both internal and external clock modes. Selection is controlled by bits D7 and D6 in the 8-bit control byte written to D7–D0: D7=1 and D6=0 selects internal clock mode (3.6µs conversion time), while D7=1 and D6=1 selects external clock mode (100kHz–4.8MHz). The device powers up in external clock mode by default, and the CLK pin must be tied high or low in internal clock mode to prevent floating.

How many analog input channels does MAX1295BCEI+T support, and what configurations are available?

The MAX1295BCEI+T supports six analog input channels (CH0–CH5) in single-ended mode or three pseudo-differential channel pairs (CH0/CH1, CH2/CH3, CH4/CH5) - all selectable via the A2–A0 address bits and SGL/DIF bit (D4) in the control byte. In pseudo-differential mode, only the positive input (IN+) is sampled, while the negative input (IN−) must remain stable to ±0.5 LSB relative to GND during conversion.

What power-down modes are available on MAX1295BCEI+T, and what are their typical current draws?

MAX1295BCEI+T offers two software-selectable power-down modes controlled by PD1/PD0 bits: Standby mode draws ~10µA and retains register state, while Full Power-Down mode draws ~2µA and resets internal logic. Both modes are entered between conversions; wake-up occurs in 2µs upon next WR pulse. At 10ksps sampling, supply current drops to 400µA, enabling ultra-low average power in duty-cycled systems.

Is MAX1295BCEI+T pin-compatible with other devices in the MAX1295/MAX1297 family?

Yes, MAX1295BCEI+T is pin-compatible with all MAX1295 variants (e.g., MAX1295ACEI+T, MAX1295AEEI+T) in the 28-pin QSOP package. It is not pin-compatible with MAX1297 variants (24-pin QSOP) or with +5V counterparts like MAX1294/MAX1296. Pin compatibility extends to identical pin functions, spacing, and thermal pad layout - allowing drop-in replacement within the MAX1295 grade family without PCB revision.