These devices combine four popular functions, Power-on

Reset Control, Watchdog Timer, Supply Voltage Supervision,

and Block Lock Protect Serial EEPROM Memory in one

package. 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 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 device’s 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/RESET is

asserted until VCC returns to proper operating level and

stabilizes. Five industry standard VTRIP thresholds are

available, however, Intersil’s unique circuits allow the

threshold to be reprogrammed to meet custom requirements

or to fine-tune the threshold for applications requiring higher

precision.

特性 Features

? 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

- <50μA max standby current, watchdog on

- <1μA max standby current, watchdog off

- <400μA 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

Lock? 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)

? 2.7V to 5.5V and 4.5V to 5.5V power supply operation

? Available packages: 14 Ld TSSOP, 8 Ld SOIC, 8 Ld PDIP

? Pb-free plus anneal available (RoHS compliant)