Features: • Extended Power-On Reset (800ms Nominal)
• Selectable Watchdog Timer
• Low Vcc Detection and Reset Assertion -Five Standard Reset Threshold Voltages -Re-program Low Vcc Reset Threshold Voltage using special programming sequence -Reset Signal Valid to Vcc=1V
• Determine Watchdog or Low Voltage Reset with a Volatile Flag bit
• Long Battery Life With Low Power Consumption -<50 mA Max Standby Current, Watchdog On -<1 mA Max Standby Current, Watchdog Off -<400 mA Max Active Current during Read
• 16Kbits of EEPROM
• Built-in Inadvertent Write Protection -Power-Up/Power-Down Protection Circuitry -Protect 0, 1/4, 1/2 or all of EEPROM Array with Block LockTM Protection -In Circuit Programmable ROM Mode
• 2MHz SPI Interface Modes (0,0 & 1,1)
• Minimize EEPROM Programming Time -32 Byte Page Write Mode -Self-Timed Write Cycle -5ms Write Cycle Time (Typical)
• 1.8V to 3.6V, 2.7V to 5.5V and 4.5V to 5.5V Power Supply Operation
• Available Packages -14-Lead TSSOP, 8-Lead SOIC
Pinout
SpecificationsTemperature under Bias ........................65°C to +135°C
Storage Temperature .............................65°C to +150°C
Voltage on any Pin with Respect to VSS....... 1.0V to +7V
D.C. Output Current ....................................................5mA
Lead Temperature (Soldering, 10 seconds)............300°CDescriptionThis X51638 combines four popular functions, Power-on Reset Control, Watchdog Timer, Supply Voltage Supervision, and Block Lock™ Protect Serial EEPROM in one package. This combination lowers system cost, reduces board space requirements, and increases reliability. Applying power to the device activates a power on reset circuit which holds RESET active for a period of time. This allows the power supply and oscillator to stabilize before the processor can execute code. This device allows 800ms before releasing the controller.
The Watchdog Timer 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 signal. The user selects the interval from three preset values. Once selected, the interval does not change, even after cycling the power.
The X51638 low Vcc detection circuitry protects the user's system from low voltage conditions, resetting the system when Vcc falls below the minimum Vcc trip point. RESET is asserted until Vcc returns to proper operating level and stabilizes. Five industry standard VTRIP thresholds are available, however, Xicor's unique circuits allow the thresold to be reprogrammed to meet custom requirements or to fine-tune the threshold for applications requiring higher precision.
X51638 Data Sheet
