X4285 XICOR [Xicor Inc.], X4285 Datasheet

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X4285

Manufacturer Part Number
X4285
Description
CPU Supervisor with 128K EEPROM
Manufacturer
XICOR [Xicor Inc.]
Datasheets
Preliminary Information
128K
FEATURES
• Selectable watchdog timer
• Low V
• Low power CMOS
• 128Kbits of EEPROM
• Built-in inadvertent write protection
• 400kHz 2-wire interface
• 2.7V to 5.5V power supply operation
• Available packages
BLOCK DIAGRAM
REV 1.17 11/27/00
—Four standard reset threshold voltages
—Adjust low V
—Reset signal valid to V
—<20µA max standby current, watchdog on
—<1µA standby current, watchdog OFF
—3mA active current
—64 byte page write mode
—Self-timed write cycle
—5ms write cycle time (typical)
—Power-up/power-down protection circuitry
—Protect 0, 1/4, 1/2, all or 64, 128, 256 or 512
—8-lead SOIC
—8-lead TSSOP
SDA
SCL
V
WP
special programming sequence
bytes of EEPROM array with programmable
Block Lock
S0
S1
CC
CC
detection and reset assertion
CC
protection
reset threshold voltage using
V
Reset logic
CC
Command
Decode &
Register
Control
Data
Logic
Threshold
CC
Watchdog Transition
CPU Supervisor with 128K EEPROM
= 1V
Detector
V
TRIP
EEPROM Array
X4283/85
Protect Logic
www.xicor.com
Register
+
Status
-
DESCRIPTION
The X4283/85 combines four popular functions,
Power-on Reset Control, Watchdog Timer, Supply Volt-
age Supervision, and Block Lock protect serial
EEPROM memory in one package. This combination
lowers system cost, reduces board space require-
ments, 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 oscilla-
tor to stabilize before the processor can execute code.
The Watchdog Timer provides an independent protec-
tion mechanism for microcontrollers. When the micro-
controller 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 V
user’s system from low voltage conditions, resetting
the system when V
trip point. RESET/RESET is asserted until V
to proper operating level and stabilizes. Four industry
Power on and
Timer Reset
Low Voltage
Generation
Watchdog
Watchdog
Timebase
Reset &
Reset
Characteristics subject to change without notice.
CC
CC
falls below the set minimum V
detection circuitry protects the
16K x 8 Bit
RESET (X4283)
RESET (X4285)
CC
returns
1 of 22
CC

Related parts for X4285

X4285 Summary of contents

Page 1

... Protect Logic Status Register EEPROM Array Watchdog Power on and Low Voltage + Generation - V TRIP www.xicor.com 16K x 8 Bit detection circuitry protects the CC falls below the set minimum RESET (X4283) RESET (X4285) Reset & Timebase Reset Characteristics subject to change without notice. CC returns ...

Page 2

X4283/85 – Preliminary Information standard Vtrip thresholds are available, however, Xicor’s unique circuits allow the threshold to be reprogrammed to meet custom requirements or to fine-tune the thresh- old for applications requiring higher precision. The memory portion of the device ...

Page 3

X4283/85 – Preliminary Information PRINCIPLES OF OPERATION Power On Reset Application of power to the X4283/85 activates a Power On Reset Circuit that pulls the RESET/RESET pin active. This signal provides several benefits. – It prevents the system microprocessor from ...

Page 4

X4283/85 – Preliminary Information Setting the V Voltage TRIP This procedure is used to set the V lower voltage value necessary to reset the trip point before setting the new value. To set the new V voltage, start ...

Page 5

X4283/85 – Preliminary Information Figure 4. V Programming Sequence TRIP New V Applied = CC Old V Applied + Error CC Emax = Maximum Allowed V Control Register The Control Register provides the user a mechanism for changing the Block ...

Page 6

X4283/85 – Preliminary Information The state of the Control Register can be read at any time by performing a random read at address FFFFh. Only one byte is read by each register read operation. The X4283/85 resets itself after the ...

Page 7

X4283/85 – Preliminary Information Table 1. Write Protect Enable Bit and WP Pin Function Memory Array not WP WPEN Block Protected LOW X Writes OK HIGH 0 Writes OK HIGH 1 Writes OK Writing to the Control Register Changing any ...

Page 8

X4283/85 – Preliminary Information Serial Start Condition All commands are preceded by the start condition, which is a HIGH to LOW transition of SDA when SCL is HIGH. The device continuously monitors the SDA and SCL lines for the start ...

Page 9

X4283/85 – Preliminary Information Serial Write Operations B W YTE RITE For a write operation, the device requires the Slave Address Byte and a Word Address Byte. This gives the master access to any one of the words in the ...

Page 10

X4283/85 – Preliminary Information Figure 10. Writing 12 bytes to a 64-byte page starting at location 60. 8 Bytes Address = 7 The master terminates the Data Byte loading by issuing a stop condition, which causes the device to begin ...

Page 11

X4283/85 – Preliminary Information Serial Read Operations Read operations are initiated in the same manner as write operations with the exception that the R/W bit of the Slave Address Byte is set to one. There are three basic read operations: ...

Page 12

X4283/85 – Preliminary Information There is a similar operation, called “Set Current Address” where the device does no operation, but enters a new address into the address counter if a stop is issued instead of the second start shown in ...

Page 13

X4283/85 – Preliminary Information Figure 15. X4283/85 Addressing Device Identifier (X1) D7 Operational Notes The device powers-up in the following state: – The device is in the low power standby state. – The WEL bit is set ...

Page 14

X4283/85 – Preliminary Information ABSOLUTE MAXIMUM RATINGS Temperature under bias ................... -65°C to +135°C Storage temperature ........................ -65°C to +150°C Voltage on any pin with respect to V .......................................-1.0V to +7V SS D.C. output current ............................................... 5mA Lead temperature (soldering, ...

Page 15

X4283/85 – Preliminary Information CAPACITANCE (T = 25° 1.0 MHz Symbol (4) C Output Capacitance (SDA, RST/RST) OUT (4) C Input Capacitance (SCL, WP) IN Note: (4) This parameter is periodically sampled and not 100% tested. ...

Page 16

X4283/85 – Preliminary Information TIMING DIAGRAMS Bus Timing t F SCL t SU:STA t HD:STA SDA IN SDA OUT WP Pin Timing START SCL SDA IN WP Write Cycle Timing SCL th SDA 8 Bit of Last Byte Nonvolatile Write ...

Page 17

... X4283/85 – Preliminary Information Power-Up and Power-Down Timing V TRIP Volts t R RESET (X4285) RESET (X4283) RESET Output Timing Symbol V Reset Trip Point Voltage, X4283/85-4.5A TRIP Reset Trip Point Voltage, X4283/85 Reset Trip Point Voltage, X4283/85-2.7A Reset Trip Point Voltage, X4283/85-2.7 ...

Page 18

X4283/85 – Preliminary Information RESET Output Timing Symbol Parameter t Watchdog Time Out Period, WDO WD1 = 1, WD0 = 0 WD1 = 0, WD0 = 1 WD1 = 0, WD0 = 0 (factory setting) t Reset Time Out RST ...

Page 19

X4283/85 – Preliminary Information PACKAGING INFORMATION 8-Lead Plastic Small Outline Gull Wing Package Type S Pin 1 Index 0.010 (0.25) 0.020 (0.50) 0° - 8° 0.016 (0.410) 0.037 (0.937) NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) REV 1.17 ...

Page 20

X4283/85 – Preliminary Information PACKAGING INFORMATION 0° – 8° Detail A (20X) See Detail “A” NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) REV 1.17 11/27/00 8-Lead Plastic, TSSOP, Package Type V .025 (.65) BSC .169 (4.3) .177 (4.5) ...

Page 21

... Part Number RESET (Active HIGH) X4285S8–4.5A X4285S8I–4.5A X4285V8–4.5A X4285V8I–4.5A X4285S8 X4285S8I X4285V8 X4285V8I X4285S8–2.7A X4285S8I–2.7A X4285V8–2.7A X4285V8I–2.7A X4285S8–2.7 X4285S8I–2.7 X4285V8–2.7 X4285V8I–2.7 X4283/85 X Blank = 8-Lead SOIC XX Characteristics subject to change without notice ...

Page 22

X4283/85 – Preliminary Information LIMITED WARRANTY Devices sold by Xicor, Inc. are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only. Xicor, Inc. makes no warranty, express, statutory, implied description regarding the ...

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