Analog Devices Inc./Maxim Integrated MAX708RCSA+T

Overview

MAX708RCSA+T from Maxim Integrated is a +3V microprocessor supervisory circuit providing active-low RESET and active-high RESET outputs, 2.63V reset threshold, 200ms reset pulse width, and 1.25V power-fail comparator input - used for reliable power-up/power-down sequencing in battery-powered portable instruments and embedded controllers.

For engineers reviewing the MAX708RCSA+T datasheet, MAX708RCSA+T pinout, MAX708RCSA+T application, or MAX708RCSA+T equivalent, key selection criteria include dual-reset polarity support, guaranteed RESET assertion down to VCC = 1V, absence of watchdog timer (distinguishing it from MAX706 variants), SO-8 package compatibility, and operation across 0°C to +70°C industrial temperature range.

Technical Context

The MAX708RCSA+T integrates dual-reset generation with independent power-fail monitoring: its internal voltage detector triggers both RESET (active-low) and RESET (active-high) simultaneously when VCC falls below 2.63V or MR is asserted, with a fixed 200ms deassertion delay after recovery. The 1.25V precision reference enables external resistive-divider-based PFI threshold configuration for early power-fail warning.

No watchdog timer is present - unlike MAX706/706A families - eliminating WDI/WDO pins and simplifying timing-critical designs where watchdog supervision is unnecessary. The device guarantees valid reset output behavior down to VCC = 1V and supports TTL/CMOS-compatible manual reset with 500ns minimum pulse width at 3V supply.

Key Specifications

Pinout & Package

MAX708RCSA+T is housed in an 8-pin SOIC (Small Outline Integrated Circuit) package, pin-compatible with industry-standard SO-8 footprints and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX708RCSA+T, MAX708SCSA+ raises reset threshold by 300mV for improved noise margin in noisy 3.3V rails, while MAX708TCSA+ further increases threshold to 3.08V - making both alternatives suitable for tighter supply regulation but requiring validation against actual system brownout points.

Availability

MAX708RCSA+T is available at Aetrix Electronics and suitable for battery-powered equipment, portable instruments, industrial controllers, and embedded computer BIOS initialization requiring stable component supply across commercial temperature grades.

Supply support for MAX708RCSA+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 and mixed-signal ICs for power management, sensing, and interface applications in industrial, computing, and consumer markets.

The MAX708 family delivers low-cost, integrated µP supervisory functions - specifically engineered for +3V/+3.3V embedded systems needing dual-polarity reset, power-fail warning, and manual reset capability without watchdog complexity.

FAQ

What is the reset threshold voltage of the MAX708RCSA+T?

The MAX708RCSA+T has a precise reset threshold of 2.63V (typical) with ±1.5% tolerance over temperature. This value is specified for VCC falling conditions and ensures reliable reset assertion before most +3.3V microprocessors enter undefined operation. The threshold is factory-trimmed and does not require external calibration. MAX708RCSA+T maintains this specification across its full 0°C to +70°C operating range.

Does the MAX708RCSA+T include a watchdog timer function?

No, the MAX708RCSA+T does not include a watchdog timer. Unlike the MAX706/706A series, the MAX708 family omits WDI and WDO pins entirely - simplifying design for applications where software supervision is handled externally or not required. This absence is reflected in the 8-pin SO package having a No-Connect (N.C.) on pin 6 instead of WDI, and no WDO pin present. MAX708RCSA+T focuses exclusively on voltage monitoring and dual-reset generation.

How does the MAX708RCSA+T generate both active-low and active-high reset signals?

The MAX708RCSA+T integrates two independent reset drivers: pin 7 (RESET) is active-low, and pin 8 (RESET) is active-high. Both outputs assert simultaneously when VCC drops below 2.63V or MR is pulled low, and both deassert after the 200ms internal timer expires post-recovery. This dual-output architecture eliminates external inverters in systems requiring both logic polarities - for example, driving a µP reset pin (active-low) and a CPLD configuration enable (active-high). MAX708RCSA+T guarantees co-timed behavior with no skew between outputs.

Can the MAX708RCSA+T monitor voltages other than VCC?

Yes, the MAX708RCSA+T includes a dedicated PFI (Power-Fail Input) pin referenced to an internal 1.25V comparator threshold. By connecting PFI to a resistive divider from any DC supply - including unregulated rails, negative voltages, or auxiliary supplies like +12V or -5V - designers can configure custom undervoltage detection. PFO asserts low when the divided voltage falls below 1.25V. MAX708RCSA+T supports this function without additional components, enabling early-warning power-fail interrupts independent of the main VCC rail.

What is the minimum VCC level at which MAX708RCSA+T guarantees reset assertion?

The MAX708RCSA+T guarantees RESET and RESET outputs remain asserted down to VCC = 1.0V (for commercial-grade parts), ensuring robust brownout protection during deep battery discharge or slow power-down sequences. Below 1.0V, the RESET output becomes high-impedance (open-drain), but the device continues asserting RESET until VCC reaches 1.0V. This specification is tested and guaranteed - not typical - and applies across the full 0°C to +70°C temperature range. MAX708RCSA+T's behavior below 1V avoids false releases during final capacitor discharge.