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X25325 Dataheets PDF



Part Number X25325
Manufacturers Xicor
Logo Xicor
Description Programmable Watchdog Timer & V CC Supervisory Circuit w/Serial E 2 PROM
Datasheet X25325 DatasheetX25325 Datasheet (PDF)

64K 32K 16K FEATURES X25643/45 X25323/25 X25163/65 DESCRIPTION 8K x 8 Bit 4K x 8 Bit 2K x 8 Bit Programmable Watchdog Timer & VCC Supervisory Circuit w/Serial E2PROM • Programmable Watchdog Timer • Low Vcc Detection and Reset Assertion —Reset Signal Valid to Vcc=1V • Save Critical Data With Block LockTM Protection —Block LockTM Protect 0, 1/4, 1/2 or all of Serial E2PROM Memory Array • In Circuit Programmable ROM Mode • Long Battery Life With Low Power Consumption —<50µA Max Standby Current, .

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64K 32K 16K FEATURES X25643/45 X25323/25 X25163/65 DESCRIPTION 8K x 8 Bit 4K x 8 Bit 2K x 8 Bit Programmable Watchdog Timer & VCC Supervisory Circuit w/Serial E2PROM • Programmable Watchdog Timer • Low Vcc Detection and Reset Assertion —Reset Signal Valid to Vcc=1V • Save Critical Data With Block LockTM Protection —Block LockTM Protect 0, 1/4, 1/2 or all of Serial E2PROM Memory Array • In Circuit Programmable ROM Mode • Long Battery Life With Low Power Consumption —<50µA Max Standby Current, Watchdog On —<1µA Max Standby Current, Watchdog Off —<5mA Max Active Current during Write —<400µA Max Active Current during Read • 1.8V to 3.6V, 2.7V to 5.5V and 4.5V to 5.5V Power Supply Operation • 2MHz Clock Rate • Minimize Programming Time —32 Byte Page Write Mode —Self-Timed Write Cycle —5ms Write Cycle Time (Typical) • SPI Modes (0,0 & 1,1) • Built-in Inadvertent Write Protection —Power-Up/Power-Down Protection Circuitry —Write Enable Latch —Write Protect Pin • High Reliability • Available Packages —14-Lead SOIC (X2564x) —14-Lead TSSOP (X2532x, X2516x) —8-Lead SOIC (X2532x, X2516x) BLOCK DIAGRAM SI SO SCK CS DATA REGISTER COMMAND DECODE & CONTROL LOGIC RESET CONTROL X - DECODE LOGIC These devices combine three popular functions, Watchdog Timer, Supply Voltage Supervision, and Serial E2PROM Memory in one package. This combination lowers system cost, reduces board space requirements, and increases reliability. The Watchdog Timer provides an independent protection mechanism for microcontrollers. During a system failure, the device will respond with a RESET/RESET signal after a selectable time-out interval. The user selects the interval from three preset values. Once selected, the interval does not change, even after cycling the power. The user’s system is protected from low voltage conditions by the device’s low Vcc detection circuitry. When Vcc falls below the minimum Vcc trip point, the system is reset. RESET/RESET is asserted until Vcc returns to proper operating levels and stabilizes. The memory portion of the device is a CMOS Serial E2PROM array with Xicor’s Block LockTM Protection. The array is internally organized as x 8. The device features a Serial Peripheral Interface (SPI) and software protocol allowing operation on a simple four-wire bus. The device utilizes Xicor’s proprietary Direct WriteTM cell, providing a minimum endurance of 100,000 cycles per sector and a minimum data retention of 100 years. PAGE DECODE LOGIC 32 SERIAL E2PROM ARRAY 8 RESET/RESET STATUS REGISTER VCC LOW VOLTAGE SENSE WATCHDOG TIMER WP PROGRAMMING, BLOCK LOCK & ICP ROM CONTROL HIGH VOLTAGE CONTROL Characteristics subject to change without notice 7036 FRM 01 ©Xicor, Inc. 1994, 1995, 1996 Patents Pending 7049 -1.0 6/20/97 T0/C0/D0 SH 1 X25643/45 X25323/25 X25163/65 PIN DESCRIPTIONS Serial Output (SO) SO is a push/pull serial data output pin. During a read cycle, data is shifted out on this pin. Data is clocked out by the falling edge of the serial clock. Serial Input (SI) SI is a serial data input pin. All opcodes, byte addresses, and data to be written to the memory are input on this pin. Data is latched by the rising edge of the serial clock. Serial Clock (SCK) The Serial Clock controls the serial bus timing for data input and output. Opcodes, addresses, or data present on the SI pin are latched on the rising edge of the clock input, while data on the SO pin change after the falling edge of the clock input. Chip Select (CS) When CS is HIGH, the device is deselected and the SO output pin is at high impedance and unless a nonvolatile write cycle is underway, the device will be in the standby power mode. CS LOW enables the device, placing it in the active power mode. It should be noted that after power-up, a HIGH to LOW transition on CS is required prior to the start of any operation. Write Protect (WP) When WP is low and the nonvolatile bit WPEN is “1”, nonvolatile writes to the device’s Status Register are disabled, but the part otherwise functions normally. When WP is held high, all functions, including nonvolatile writes to the Status Register operate normally. If an internal Status Register Write Cycle has already been initiated, WP going low while WPEN is a “1” will have no effect on this write. Subsequent write attempts to the Status Register under these conditions will be disabled. The WP pin function is blocked when the WPEN bit in the Status Register is “0”. This allows the user to install the device in a system with WP pin grounded and still be able to program the Status Register. The WP pin functions will be enabled when the WPEN bit is set to a “1”. Reset (RESET/RESET) RESET/RESET is an active LOW/HIGH, open drain output which goes active whenever Vcc falls below the minimum Vcc sense level. It will remain active until Vcc rises above the minimum Vcc sense level for 200ms. RESET/ RESET will also go active if the Watchdog Timer is enabled and CS remains either HIGH or LOW longer than the selectable Watchdog.


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