Analog Devices Inc./Maxim Integrated MAX709RCSA

Overview

MAX709RCSA from Maxim Integrated is a precision power-supply monitor IC with active-low reset output, designed for +3V and +3.3V systems. It asserts RESET when VCC falls below 2.63V (±0.08V), holds reset for ≥140ms after VCC recovers, operates down to 1V supply, consumes only 35µA typical supply current, and is housed in an 8-pin SO package. It ensures reliable µP reset during brownout, power-up, and power-down in embedded controllers.

For engineers reviewing the MAX709RCSA datasheet, MAX709RCSA pinout, MAX709RCSA application, or MAX709RCSA equivalent, key selection criteria include reset threshold accuracy (2.63V), guaranteed minimum reset timeout (140ms), low quiescent current (35µA), immunity to short VCC transients (<40µs at 100mV overdrive), and compatibility with 3V/3.3V microprocessor reset inputs.

Technical Context

The MAX709RCSA integrates a precision voltage comparator with hysteresis, a 140ms monostable timer, and an open-drain RESET driver. Its reset threshold is factory-trimmed to 2.63V with ±3% tolerance over temperature, and the internal timer guarantees minimum assertion time independent of VCC slew rate.

It features dual-stage reset generation: immediate assertion on VCC drop below threshold, followed by fixed-duration hold after VCC recovery. The RESET output remains valid (low) with VCC as low as 1V, and its open-drain structure allows wired-OR configuration with other reset sources.

Key Specifications

Pinout & Package

MAX709RCSA is supplied in an 8-pin SO (Small Outline) package, 3.9mm × 4.9mm body, 1.27mm pitch, JEDEC MS-012AC compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power-supply monitor applications.

Compared with MAX706RCSA and TPS3808G18DBVR, the MAX709RCSA provides optimal balance of industrial temperature range, SO package standardization, and cost-effective reset supervision without manual reset overhead-ideal for fixed-function 3V/3.3V µP systems where pin count and BOM simplicity are prioritized.

Availability

MAX709RCSA is available at Aetrix Electronics and suitable for industrial PLC controllers, medical sensor nodes, automotive body control modules, and IoT edge gateways requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX709RCSA 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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and computing applications.

The MAX709 belongs to Maxim's µP supervisory circuits product line, engineered specifically to replace discrete reset solutions in 3V/3.3V microprocessor systems with guaranteed timing, precision thresholds, and robust transient immunity.

FAQ

What is the exact reset threshold voltage of the MAX709RCSA?

The MAX709RCSA has a nominal reset threshold of 2.63V, with a guaranteed range of 2.55V to 2.70V over the full -40°C to +85°C operating temperature range. This value is factory-trimmed and specified in the Electrical Characteristics table under "RESET Threshold, VTH" for suffix R. It is optimized for reliable reset assertion in 3V and 3.3V systems before logic levels become invalid.

Does the MAX709RCSA require external components to function?

No, the MAX709RCSA requires no external resistors, capacitors, or trimming components to perform basic reset supervision. A 0.1µF ceramic bypass capacitor on VCC (pin 2) is recommended for transient immunity but is not strictly required for functional operation. Its internal precision reference, comparator, and timer eliminate the need for external calibration or timing elements-reducing BOM count and board space.

Can the MAX709RCSA drive a microprocessor reset pin directly?

Yes, the MAX709RCSA can drive most µP reset pins directly via its open-drain RESET output (pin 7), provided an external pull-up resistor (typically 10kΩ to VCC) is used. It sinks ≥1.2mA at minimum VTH (2.55V), sufficient for standard CMOS and TTL reset inputs. For µPs with bidirectional reset I/O (e.g., Motorola 68HC11), a 4.7kΩ series resistor is recommended to prevent contention, as documented in Maxim's application note.

What is the minimum VCC voltage at which the MAX709RCSA guarantees correct RESET output state?

The MAX709RCSA guarantees correct RESET output state (active low) down to VCC = 1.0V. Below 1.0V, the RESET output becomes high-impedance (open-circuit). For applications requiring valid RESET down to 0V, a pull-down resistor (e.g., 100kΩ to GND) on the RESET line is advised to prevent floating logic states during deep undervoltage conditions.

Is the MAX709RCSA pin-compatible with other MAX709 variants like MAX709SCSA or MAX709MCSA?

Yes, all MAX709 variants-including MAX709RCSA, MAX709SCSA, and MAX709MCSA-are fully pin-compatible within the same package type (e.g., 8-pin SO). They share identical pinout, package dimensions, and electrical interface. Only the reset threshold voltage differs (2.63V, 2.93V, and 4.40V respectively); all other timing, current, and functional specifications remain consistent across the family.