X4005

Features:

• Selectable watchdog timer
-Select 200ms, 600ms, 1.4s, off
• Low VCC detection and reset assertion
-Five standard reset threshold voltages
nominal 4.62V, 4.38V, 2.92V, 2.68V, 1.75V
-Adjust low VCC reset threshold voltage using
special programming sequence
-Reset signal valid to V_CC = 1V
• Low power CMOS
-12A typical standby current, watchdog on
-800nA typical standby current watchdog off
-3mA active current
• 400kHz I2C interface
• 1.8V to 5.5V power supply operation
• Available packages
-8 Ld SOIC
-8 Ld MSOP
• Pb-free plus anneal available (RoHS compliant)




Specifications

Temperature under bias ................... -65 to +135
Storage temperature ........................ -65 to +150
Voltage on any pin with
respect to V_SS ...................................... -1.0V to +7V
D.C. output current ...............................................5mA
Lead temperature (soldering, 10s) .................... 300




Description

The X4005 combine three popular functions, Power-on Reset Control, Watchdog Timer, and Supply Voltage Supervision. This combination lowers system cost, reduces board space requirements, and increases reliability. Applying power to the device activates the power-on reset circuit which holds RESET/RESET active for a period of time. This allows the power supply and oscillator to stabilize before the processor can execute code. The Watchdog Timer of X4005 provides an independent protection mechanism for microcontrollers. When the microcontroller fails to restart a timer within a selectable time out interval, the device activates the RESET/RESET signal. The user selects the interval from three preset values. Once selected, the interval does not change, even after cycling the power. The devices low VCC detection circuitry protects the users system from low voltage conditions, resetting the system when VCC falls below the minimum VCC trip point. RESET/RESET is asserted until VCC returns to proper operating level and stabilizes. Five industry standard VTRIP thresholds are available; however, X4005 unique circuits allow the threshold to be reprogrammed to meet custom requirements, or to fine-tune the threshold for applications requiring higher precision.