Analog Devices Inc./Maxim Integrated MAX708SCPA

Overview

MAX708SCPA from Maxim Integrated is a +3V microprocessor supervisory circuit with active-high and active-low reset outputs, 2.93V reset threshold, 200ms reset pulse width, 100µA quiescent current, and power-fail comparator (1.25V threshold) - used in battery-powered instruments to ensure reliable µP startup and brownout recovery.

For engineers reviewing the MAX708SCPA datasheet, MAX708SCPA pinout, MAX708SCPA application, or MAX708SCPA equivalent, key selection considerations include dual-reset polarity support, absence of watchdog timer, PDIP-8 package compatibility, and guaranteed RESET assertion down to VCC = 1V for low-voltage system integrity.

Technical Context

The MAX708SCPA implements a precision voltage monitor with fixed 2.93V reset threshold (±1.5% over temperature), internal 200ms one-shot timer for reset deassertion delay, and independent 1.25V reference-based power-fail comparator with PFO output. It lacks watchdog functionality-distinguishing it from MAX706-series variants.

All logic inputs (MR, PFI) are TTL/CMOS-compatible across 3.0V–5.5V VCC range; RESET and RESET outputs drive CMOS loads with guaranteed VOL ≤ 0.3V at ISINK = 500µA (VCC < 3.6V) and VOH ≥ 0.8×VCC under same conditions.

Key Specifications

Pinout & Package

MAX708SCPA is housed in an 8-pin plastic DIP (PDIP) package (package code P8-1), with 0.3-inch body width and standard through-hole footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX708RCPA and MAX708TCPA, the MAX708SCPA offers the mid-point 2.93V threshold ideal for 3.3V systems with moderate brownout margin, balancing early fault detection against noise-induced false triggers without altering PCB layout or firmware.

Availability

MAX708SCPA is available at Aetrix Electronics and suitable for battery-powered equipment, portable instruments, and industrial controllers requiring stable component supply across commercial temperature range and through-hole assembly.

Supply support for MAX708SCPA 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, sensing, and interface applications - with emphasis on reliability and integration for embedded systems.

The MAX708 family delivers cost-effective, single-chip µP supervision for +3V systems, targeting applications where dual-reset polarity, low IQ, and guaranteed low-VCC operation are critical - especially in portable and industrial instrumentation.

FAQ

What is the reset threshold voltage of the MAX708SCPA?

The MAX708SCPA has a factory-trimmed reset threshold of 2.93V ±1.5% over temperature. This value is specified for VCC falling conditions and ensures reliable reset assertion before a 3.3V supply drops below the operational minimum of most µPs. The threshold is fixed and not user-adjustable - unlike the PFI comparator, which uses the same 1.25V internal reference but accepts external resistor dividers for custom trip points.

Does the MAX708SCPA include a watchdog timer function?

No, the MAX708SCPA does not include a watchdog timer. It belongs to the MAX708 series, which provides dual-reset outputs (RESET and RESET) and power-fail detection (PFI/PFO) but omits the WDI/WDO pins and associated timing circuitry found in MAX706-series devices. This makes MAX708SCPA appropriate for systems where reset supervision is required without autonomous watchdog behavior - such as safety-certified or externally monitored applications.

What is the purpose of the N.C. pin on the MAX708SCPA?

Pin 8 of the MAX708SCPA is designated N.C. (No Connection) and is not internally bonded. It must remain unconnected in the circuit - neither tied to VCC, GND, nor left floating with capacitive coupling. Connecting this pin may cause unpredictable behavior or damage, as confirmed in the official Maxim datasheet Pin Description table and Functional Diagrams. All MAX708 variants share this N.C. pin configuration in PDIP, SO, and µMAX packages.

How does the MAX708SCPA guarantee reset assertion down to VCC = 1V?

The MAX708SCPA guarantees that both RESET and RESET outputs remain asserted for VCC ≥ 1V, as verified in the Absolute Maximum Ratings and Electrical Characteristics tables. Internally, the reset generator remains functional and drives outputs actively (not high-impedance) down to this voltage - unlike many supervisors that release reset prematurely. This ensures deterministic µP behavior during deep brownout, provided external pull-down resistors are used on RESET if interfacing with high-impedance CMOS inputs below 1V.

Can the MAX708SCPA be used with a 5V supply?

Yes, the MAX708SCPA operates over a VCC range of 1.2V to 5.5V and is fully specified at 5V. At 5V, its RESET and RESET outputs meet VOH ≥ VCC − 1.5V (min 3.5V) at ISOURCE = 800µA and VOL ≤ 0.4V at ISINK = 1.2mA - compatible with standard TTL and 5V CMOS logic families. The 2.93V reset threshold remains valid, making it suitable for hybrid 3.3V/5V systems where the supervisor monitors the 3.3V rail while powered from 5V.