Analog Devices Inc./Maxim Integrated MAX953ESA+T

Overview

MAX953ESA+T from Maxim Integrated is an ultra-low-power, single-supply analog IC integrating a unity-gain-stable op amp, rail-to-rail comparator, and no internal reference in an 8-pin SO package. It operates from 2.4V to 7V with 5μA typical supply current, supports common-mode input down to VSS and within 1.6V of VDD, and delivers rail-to-rail outputs - ideal for battery-powered smoke detector sensor preamplification and alarm triggering.

For engineers reviewing the MAX953ESA+T datasheet, MAX953ESA+T pinout, MAX953ESA+T application, or MAX953ESA+T equivalent, key selection criteria include its 5μA quiescent current, absence of internal reference (enabling flexible external reference use), unity-gain stability, rail-to-rail output swing, and −40°C to +85°C industrial temperature range.

Technical Context

The MAX953ESA+T integrates two independent signal chains: a micropower CMOS op amp with unity-gain compensation and 20kHz gain-bandwidth product, and a comparator with ±3mV internal hysteresis, 22μs propagation delay at 10mV overdrive, and continuous 40mA sourcing capability. Both share a common 2.4V–7V supply and rail-to-rail I/O architecture.

Its input stage features high-impedance CMOS inputs (typical 0.003nA bias current), common-mode range from VSS to VDD−1.6V, and robust ESD tolerance (±300mV beyond rails). The comparator eliminates supply glitches during logic transitions and avoids crowbar currents, enhancing system-level noise immunity without external bypassing.

Key Specifications

Pinout & Package

MAX953ESA+T is housed in an 8-pin SO (Small Outline) package, 3.9mm × 4.9mm, RoHS-compliant, with standard JEDEC MS-012AC footprint. Pin 1 marked by beveled corner or dot.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar op amp + comparator applications.

Compared with MAX951ESA+T, MAX953ESA+T trades internal reference convenience for 2.8× lower supply current and design flexibility; compared with TLV2304IDR + TLV3701, it consolidates three functions into one die with guaranteed timing correlation and reduced PCB footprint.

Availability

MAX953ESA+T is available at Aetrix Electronics and suitable for battery-powered systems, low-frequency local-area alarms/detectors, and photodiode preamps requiring stable component supply, long-term lifecycle support, and industrial-grade temperature performance.

Supply support for MAX953ESA+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 industrial, medical, communications, and consumer applications.

The MAX951–MAX954 family was engineered for ultra-low-power, single-supply sensor signal conditioning and threshold detection - targeting portable instrumentation, safety sensors, and energy-constrained remote controls.

FAQ

Does MAX953ESA+T include an internal voltage reference?

No, MAX953ESA+T does not include an internal voltage reference. Unlike MAX951/MAX952, its COMPIN− pin is unconnected internally and requires an external reference or feedback network. This design choice reduces supply current to 5μA and provides flexibility for custom threshold setting - critical in applications like smoke detectors where reference accuracy and drift must be independently controlled. MAX953ESA+T relies entirely on external circuitry for comparator reference voltage.

What is the maximum capacitive load the op amp in MAX953ESA+T can drive while remaining stable?

The op amp in MAX953ESA+T is unity-gain stable and capable of driving up to 1000pF load capacitance without external compensation. This is confirmed in the datasheet under "Op Amp Capable of Driving up to 1000pF Load" and validated in the "MAX951/MAX953 Op Amp Percent Overshoot vs. Capacitive Load" graph (TOC12), which shows stable response up to 1000pF at unity gain. For loads exceeding 1000pF, a small series resistor (e.g., 10–50Ω) at the output is recommended to isolate capacitance.

Can MAX953ESA+T operate from a 2.4V supply, and what performance changes occur at minimum voltage?

Yes, MAX953ESA+T is fully specified down to 2.4V supply voltage. At 2.4V, the op amp maintains unity-gain stability and rail-to-rail output swing (VSS+50mV to VDD−500mV), while comparator propagation delay increases to ~30μs (vs. 22μs at 5V) due to reduced slew rate. Supply current remains near 5μA. This makes MAX953ESA+T suitable for end-of-life battery operation in devices powered by two alkaline cells (nominal 3.0V, dropping to 2.4V).

How does the comparator hysteresis in MAX953ESA+T improve noise immunity?

MAX953ESA+T incorporates ±3mV internal hysteresis, creating a 6mV input voltage window between upper and lower switching thresholds. This prevents output oscillation ("chatter") when input signals hover near the trip point - common with slow-moving sensor outputs like ionization chamber voltages in smoke detectors. The hysteresis is inherent and requires no external components, reducing BOM count and layout complexity while ensuring clean, glitch-free digital output transitions even with noisy or drifting analog inputs.

Is MAX953ESA+T pin-compatible with other devices in the MAX951–MAX954 family?

Yes, MAX953ESA+T shares identical 8-pin SO package pinout and footprint with MAX951ESA+T, MAX952ESA+T, and MAX954ESA+T. All four variants use the same pin configuration: Pin 1 = AMPOUT, Pin 2 = AMPIN−, Pin 3 = AMPIN+, Pin 4 = VSS, Pin 5 = COMPIN+, Pin 6 = COMPIN−, Pin 7 = COMPOUT, Pin 8 = VDD. This allows drop-in replacement within the same package variant, provided the functional differences (e.g., reference presence, gain stability) are accounted for in the schematic.