Renesas X40010S8-AT1

Overview

X40010S8-AT1 from Intersil is a dual-voltage supervisor IC with integrated CPU reset control, watchdog timer, and programmable voltage thresholds. It monitors VCC (V1MON) and a secondary supply (V2MON), asserts active-HIGH RESET on VCC brownout, provides 200ms default power-on reset timeout, and supports I²C-compatible 400kHz serial interface for configuration. Used in network servers to ensure reliable boot sequencing and power-fail detection.

For engineers reviewing the X40010S8-AT1 datasheet, X40010S8-AT1 pinout, X40010S8-AT1 application, or X40010S8-AT1 equivalent, key selection criteria include its dual-threshold programmability, 25µA standby current with watchdog enabled, VCC operation down to 1V, and support for 0.9V–5V monitoring ranges across both inputs.

Technical Context

The X40010S8-AT1 implements independent comparators for VCC (V1MON) and V2MON, each with user-programmable trip points via high-voltage programming sequence on WDO/SDA/SCL. Its reset logic generates an active-HIGH RESET signal with selectable tPURST (50/200/400/800ms) and includes a fault detection register tracking LV1F, LV2F, and WDF events.

Watchdog functionality uses SDA edge detection synchronized with SCL toggling to restart a nonvolatile timer with four intervals (25ms/200ms/1.4s/off). The device operates as an I²C slave (7-bit address 0xA0) with open-drain SDA/SCL, active-LOW WDO and V2FAIL outputs, and CMOS RESET output - all functional with VCC ≥1V.

Key Specifications

Pinout & Package

8-pin SOIC package (S8 suffix), 150 mil width, JEDEC MS-012AC compliant. RoHS-compliant, Pb-free lead finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-voltage supervisor applications.

Compared with MAX6816EPA+ and TPS3808G33DBVR, the X40010S8-AT1 uniquely delivers dual-rail visibility, nonvolatile threshold programming, and integrated fault logging - enabling deterministic root-cause analysis in multi-rail embedded systems where reliability and debuggability are critical.

Availability

X40010S8-AT1 is available at Aetrix Electronics and suitable for network servers, disk arrays, and industrial PLCs requiring stable component supply, long-term lifecycle support, and traceable sourcing for production programs.

Supply support for X40010S8-AT1 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

Intersil Corporation (now part of Renesas Electronics) is a U.S.-based semiconductor company specializing in precision analog, power management, and interface ICs for industrial, communications, and computing markets.

The X40010 family was designed as a highly integrated CPU supervisor targeting multi-rail embedded systems needing coordinated reset timing, watchdog protection, and field-programmable voltage thresholds without external components.

FAQ

What is the default power-on reset timeout for X40010S8-AT1, and how is it configured?

The X40010S8-AT1 ships with a factory-default power-on reset timeout (tPURST) of 200ms. This value is stored in nonvolatile PUP1/PUP0 bits within the Control Register (address 0x1FF) and can be changed to 50ms, 400ms, or 800ms via I²C write sequence. Configuration requires first setting WEL and RWEL bits, then writing the desired PUP combination - a process documented in the FN8111 datasheet section "Writing to the Control Registers". The X40010S8-AT1 retains this setting across power cycles.

Does X40010S8-AT1 support monitoring of sub-1.8V core voltages like 1.2V or 1.0V?

Yes, the X40010S8-AT1 supports monitoring of voltages as low as 0.9V on both V1MON (VCC) and V2MON inputs. Its programmable VTRIP1 and VTRIP2 thresholds allow precise adjustment for 1.2V or 1.0V rails using the high-voltage programming sequence on the WDO pin. The device's comparator architecture maintains accuracy across the full 0.9V–4.75V range, making X40010S8-AT1 suitable for modern low-voltage SoC and FPGA core supply supervision.

How does the watchdog timer in X40010S8-AT1 get restarted, and what are the timing requirements?

The X40010S8-AT1 watchdog timer is restarted by a specific I²C event: a HIGH-to-LOW transition on SDA while SCL is toggled from HIGH to LOW, followed immediately by a STOP condition. This sequence must occur within the selected timeout interval (25ms/200ms/1.4s/off). The timer is implemented with nonvolatile WD1/WD0 bits and remains active even after power cycling. Failure to issue this restart sequence causes WDO to assert LOW, signaling a firmware hang condition that can be captured in the Fault Detection Register (FDR) of the X40010S8-AT1.

Can X40010S8-AT1 generate a reset signal when V2MON falls below its threshold, or is reset only triggered by VCC (V1MON) undervoltage?

The X40010S8-AT1 asserts its primary RESET output only in response to VCC (V1MON) falling below VTRIP1. However, the V2FAIL output is independently asserted when V2MON drops below VTRIP2, and this signal can be externally OR'd with RESET using a pull-up resistor and diode to create a combined reset condition. The device does not internally combine these signals - the X40010S8-AT1 provides discrete, configurable outputs to enable flexible system-level reset architectures.

What package type and footprint does X40010S8-AT1 use, and is it compatible with automated PCB assembly?

The X40010S8-AT1 uses an 8-pin SOIC (Small Outline Integrated Circuit) package designated "S8", with 150 mil body width and standard 1.27mm pitch. It complies with JEDEC MS-012AC and is fully compatible with industry-standard reflow soldering profiles, pick-and-place machines, and AOI inspection systems. The AT1 suffix indicates tape-and-reel packaging optimized for SMT production lines, and the device's RoHS-compliant, Pb-free finish meets IPC-J-STD-020 moisture sensitivity level 1 requirements.