X40421V14I-A [INTERSIL]
Dual Voltage Monitor with Integrated CPU Supervisor and System Battery Switch; 双电压监控器，集成了CPU监控系统和电池开关
| 型号： | X40421V14I-A |
| 厂家： | 
Intersil |
| 描述： | Dual Voltage Monitor with Integrated CPU Supervisor and System Battery Switch |
| 文件： | 总25页 (文件大小：382K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
X40420, X40421
®
4kbit EEPROM
Data Sheet
March 28, 2005
FN8117.0
PRELIMINARY
• Memory Security
• Battery Switch Backup
Dual Voltage Monitor with Integrated CPU
Supervisor and System Battery Switch
• V
5mA to 50mA
OUT
FEATURES
APPLICATIONS
• Dual voltage detection and reset assertion
—Three standard reset threshold settings
(4.6V/2.9V, 4.6V/2.6V, 2.9V/1.6V)
• Communications Equipment
—Routers, Hubs, Switches
—Disk arrays
• Industrial Systems
—Process Control
—Intelligent Instrumentation
• Computer Systems
—Desktop Computers
—Network Servers
—V
Programmable down to 0.9V
TRIP2
—Adjust low voltage reset threshold voltages
using special programming sequence
—Reset signal valid to V = 1V
CC
—Monitor two voltages or detect power fail
• Battery Switch Backup
• V
V
: 5mA to 50mA from V ; or 250µA from
OUT
BATT
CC
X40420/21
• Fault detection register
Standard VTRIP1 Level Standard VTRIP2 Level Suffix
• Selectable power-on reset timeout
(0.05s, 0.2s, 0.4s, 0.8s)
• Selectable watchdog timer interval
(25ms, 200ms, 1.4s, off)
• Debounced manual reset input
• Low power CMOS
4.6V (+/-1%)
4.6V (+/-1%)
2.9V(+/-1.7%)
2.9V(+/-1.7%)
2.6V (+/-2%)
1.6V (+/-3%)
-A
-B
-C
See “Ordering Information” for more details
For Custom Settings, call Intersil.
—25µA typical standby current, watchdog on
—6µA typical standby current, watchdog off
—1µA typical battery current in backup mode
• 4Kbits of EEPROM
—16 byte page write mode
—Self-timed write cycle
—5ms write cycle time (typical)
• Built-in inadvertent write protection
—Power-up/power-down protection circuitry
—Block lock protect 0 or 1/2, of EEPROM
• 400kHz 2-wire interface
• 2.7V to 5.5V power supply operation
• Available packages
DESCRIPTION
The X40420/21 combines power-on reset control,
watchdog timer, supply voltage supervision, and sec-
ondary supervision, manual reset, and Block Lock
protect serial EEPROM in one package. This combi-
nation lowers system cost, reduces board space
requirements, and increases reliability.
™
Applying voltage to V
activates the power-on reset
CC
circuit which holds RESET/RESET active for a period of
time. This allows the power supply and system oscilla-
tor to stabilize before the processor can execute code.
—14-lead SOIC, TSSOP
• •Monitor Voltages: 5V to 1.6V
BLOCK DIAGRAM
VOUT
+
-
V2FAIL
WDO
V2MON
VTRIP2
V2 Monitor
Logic
Watchdog
and
Reset Logic
Fault Detection
Register
Data
Register
SDA
VOUT
Status
Register
WP
Command
Decode Test
& Control
EEPROM
Array
MR
RESET
X40420
Logic
SCL
Power-on,
Manual Reset
Low Voltage
Reset
VOUT
RESET
X40421
+
VCC
(V1MON)
VTRIP1
Generation
VCC Monitor
-
Logic
BATT-ON
LOWLINE
System
Battery
VOUT
Switch
VBATT
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-352-6832 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2005. All Rights Reserved
1
All other trademarks mentioned are the property of their respective owners.
X40420, X40421
Low V detection circuitry protects the user’s system
from low voltage conditions, resetting the system
Once selected, the interval does not change, even
after cycling the power.
CC
when V
RESET/RESET is active until V
falls below the minimum V
point.
CC
TRIP1
The memory portion of the device is a CMOS Serial
EEPROM array with Intersil’s Block Lock protection.
The array is internally organized as x 8. The device
features an 2-wire interface and software protocol
allowing operation on a two-wire bus.
returns to proper
CC
operating level and stabilizes. A second voltage moni-
tor circuit tracks the unregulated supply to provide a
power fail warning or monitors different power supply
voltage. Three common low voltage combinations are
available, however, Intersil’s unique circuits allows the
threshold for either voltage monitor to be repro-
grammed to meet special needs or to fine-tune the
threshold for applications requiring higher precision.
™
The device utilizes Intersil’s proprietary Direct Write
cell, providing a minimum endurance of 100,000
cycles and a minimum data retention of 100 years.
Example Application
A manual reset input provides debounce circuitry for
minimum reset component count.
Unreg.
Supply
5V
REG
A battery switch circuit compares V with V
input
BATT
CC
and connects V
to whichever is higher. This pro-
OUT
vides voltage to external SRAM or other circuits in the
event of main power failure. The X40420/21 can drive
BATT-ON
CC
Enable
SRAM
V
V
V
OUT
BATT
50mA from V to 250µA from V
. The device only
CC
BATT
Addr
+
X40420/21
V2MON
switches to V
voltage threshold and V
when V drops below the low V
BATT
CC CC
Addr
uC
.
BATT
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 WDO signal.
The user selects the interval from three preset values.
NMI
V
V2FAIL
CC
VDO
RESET
MR
IRQ
RESET
Manual
Reset
SCL SDA
2
I C
PIN CONFIGURATION
X40421
X40420
14-Pin SOIC, TSSOP
14-Pin SOIC, TSSOP
VCC
V2FAIL
V2MON
LOWLINE
WDO
VCC
V2FAIL
V2MON
1
2
3
4
14
13
12
11
1
2
3
4
14
13
12
11
BATT-ON
VOUT
VBATT
WP
BATT-ON
VOUT
VBATT
WP
LOWLINE
WDO
MR
RESET
VSS
MR
RESET
VSS
5
6
7
10
9
8
5
6
7
10
9
8
SCL
SCL
SDA
SDA
PIN DESCRIPTION
Pin
Name
Function
1
V2FAIL
V2 Voltage Fail Output. This open drain output goes LOW when V2MON is less than VTRIP2 and
goes HIGH when V2MON exceeds VTRIP2. There is no power-up reset delay circuitry on this pin.
2
V2MON
V2 Voltage Monitor Input. When the V2MON input is less than the VTRIP2 voltage, V2FAIL goes
LOW. This input can monitor an unregulated power supply with an external resistor divider or can
monitor a second power supply with no external components. Connect V2MON to VSS or V when
CC
not used.
3
4
5
LOWLINE Early Low VCC Detect. This open drain output signal goes LOW when V < VTRIP1.
CC
When V > VTRIP1, this pin is pulled high with the use of an external pull up resistor.
CC
WDO
MR
WDO Output. WDO is an active LOW, open drain output which goes active whenever the watchdog
timer goes active.
Manual Reset Input. Pulling the MR pin LOW initiates a system reset. The RESET/RESET pin will remain
HIGH/LOW until the pin is released and for the tPURST thereafter. It has an internal pull up resistor.
March 28, 2005
2
X40420, X40421
PIN DESCRIPTION (Continued)
Pin
Name
Function
6
RESET/
RESET
RESET Output. (X40421) This open drain pin is an active LOW output which goes LOW whenever
VCC falls below VTRIP1 voltage or if manual reset is asserted. This output stays active for the pro-
grammed time period (tPURST) on power-up. It will also stay active until manual reset is released and
for tPURST thereafter.
RESET Output. (X40420) This pin is an active HIGH open drain output which goes HIGH whenever
VCC falls below VTRIP1 voltage or if manual reset is asserted. This output stays active for the pro-
grammed time period (tPURST) on power-up. It will also stay active until manual reset is released and
for tPURST thereafter.
7
8
VSS
Ground
SDA
Serial Data. SDA is a bidirectional pin used to transfer data into and out of the device. It has an open
drain output and may be wire ORed with other open drain or open collector outputs. This pin requires
a pull up resistor and the input buffer is always active (not gated).
Watchdog Input. A HIGH to LOW transition on the SDA (while SCL is toggled from HIGH to LOW
and followed by a stop condition) restarts the Watchdog timer. The absence of this transition within
the watchdog time out period results in WDO going active.
9
SCL
WP
Serial Clock. The Serial Clock controls the serial bus timing for data input and output.
10
Write Protect. WP HIGH prevents writes to any location in the device (including all the registers). It
has an internal pull down resistor. (>10MΩ typical)
11
12
VBATT
Battery Supply Voltage. This input provides a backup supply in the event of a failure of the
primary VCC voltage. The VBATT voltage typically provides the supply voltage necessary to
maintain the contents of SRAM and also powers the internal logic to “stay awake.” If the battery is not
used, connect VBATT to ground.
VOUT
Output Voltage. (V)
VOUT = VCC if VCC > VTRIP1
IF VCC < VTRIP1
.
then VOUT = VCC if VCC > VBATT + 0.03V
else VOUT = VBATT (ie if VCC < VBATT - 0.03V)
Note: There is hysteresis around VBATT ± 0.03V point to avoid oscillation at or near the
switchover voltage. A capacitance of 0.1µF must be connected to VOUT to ensure stability.
13
14
BATT-ON Battery On. This CMOS output goes HIGH when the VOUT switches to VBATT and goes LOW when
VOUT switches to VCC. It is used to drive an external PNP pass transistor when VCC = VOUT and current
requirements are greater than 50mA.
The purpose of this output is to drive an external transistor to get higher operating currents when the
V
CC supply is fully functional. In the event of a VCC failure, the battery voltage is applied to the VOUT
pin and the external transistor is turned off. In this “backup condition,” the battery only needs to supply
enough voltage and current to keep SRAM devices from losing their data–there is no communication
at this time.
VCC
Supply Voltage
March 28, 2005
3
X40420, X40421
PRINCIPLES OF OPERATION
Power-on Reset
Low Voltage V2 Monitoring
The X40420/21 also monitors a second voltage level and
asserts V2FAIL if the voltage falls below a preset mini-
Applying power to the X40420/21 activates a Power-
on Reset Circuit that pulls the RESET/RESET pins
active. This signal provides several benefits.
mum V
. The V2FAIL signal is either ORed with
TRIP2
RESET to prevent the microprocessor from operating in
a power fail or brownout condition or used to interrupt the
microprocessor with notification of an impending power
failure. The V2FAIL signal remains active until the V
drops below 1V (V falling). It also remains active until
– It prevents the system microprocessor from starting
to operate with insufficient voltage.
CC
CC
– It prevents the processor from operating prior to sta-
bilization of the oscillator.
V2MON returns and exceeds V
.
TRIP2
V2MON voltage monitor is powered by V
If V
CC
OUT.
– It allows time for an FPGA to download its configura-
tion prior to initialization of the circuit.
and V
go away, V2MON cannot be monitored.
BATT
– It prevents communication to the EEPROM, greatly
reducing the likelihood of data corruption on power-up.
Figure 2. Two Uses of Multiple Voltage Monitoring
VOUT
When V exceeds the device V
threshold value
CC
TRIP1
X40420
for t
(selectable) the circuit releases the RESET
PURST
(X40421) and RESET (X40420) pin allowing the system
to begin operation.
5V
Unreg.
Supply
VCC
System
Reset
Reg
RESET
R
Figure 1. Connecting a Manual Reset Push-Button
V2MON
V2FAIL
R
X40420/21
System
Reset
Resistors selected so 3V appears on V2MON when unregulated
supply reaches 6V.
RESET
VOUT
MR
Manual
Reset
X40421
Unreg.
Supply
5V
Reg
VCC
RESET
V2FAIL
System
Reset
3V
Reg
V2MON
Manual Reset
By connecting a push-button directly from MR to
ground, the designer adds manual system reset capa-
bility. The MR pin is LOW while the push-button is
closed and RESET/RESET pin remains LOW for
Notice: No external components required to monitor two voltages.
tPURST or till the push-button is released and for t
thereafter. A weak pull up resistor is connected to the
MR pin.
PURST
WATCHDOG TIMER
The Watchdog Timer circuit monitors the microproces-
sor activity by monitoring the SDA and SCL pins. A
standard read or write sequence to any slave address
byte restarts the watchdog timer and prevents the
WDO signal to go active. A minimum sequence to
reset the watchdog timer requires four microprocessor
instructions namely, a Start, Clock Low, Clock High
and Stop. The state of two nonvolatile control bits in
the Status Register determine the watchdog timer
period. The microprocessor can change these watch-
dog bits by writing to the X40420/21 control register.
Low Voltage V1 Monitoring
During operation, the X40420/21 monitors the V
CC
level and asserts RESET if supply voltage falls below
a preset minimum V . The RESET signal prevents
TRIP1
the microprocessor from operating in a power fail or
brownout condition. The V1FAIL signal remains active
until the voltage drops below 1V. It also remains active
until V returns and exceeds V
for tPURST.
CC
TRIP1
March 28, 2005
4
X40420, X40421
Figure 3. V
Set/Reset Conditions
TRIPX
V
(X = 1, 2)
V
/V2MON
TRIPX
CC
V
P
0
WDO
0
7
0
7
7
SCL
SDA
t
WC
A0h
00h
Figure 4. Watchdog Restart
The STOP bit following a valid write operation initiates
the programming sequence. Pin WDO must then be
brought LOW to complete the operation.
.6µs
1.3µs
SCL
SDA
To check if the V
has been set, set VXMON to a
TRIPX
value slightly greater than V
(that was previously
TRIPX
set). Slowly ramp down VXMON and observe when the
corresponding outputs (LOWLINE and V2FAIL) switch.
Start
Stop
WDT Reset
The voltage at which this occurs is the V
(actual).
TRIPX
V1 AND V2 THRESHOLD PROGRAM PROCEDURE
(OPTIONAL)
CASE A
The X40420/21 is shipped with standard V1 and V2
Now if the desired V
is greater than the V
TRIPX
TRIPX
threshold (V
V
) voltages. These values will not
(actual), then add the difference between V
(desired) - V (actual) to the original V
TRIP1, TRIP2
TRIPX
desired.
TRIPX
change over normal operating and storage conditions.
However, in applications where the standard thresholds
are not exactly right, or if higher precision is needed in
the threshold value, the X40420 trip points may be
adjusted. The procedure is described below, and uses
the application of a high voltage control signal.
TRIPX
This is your new V
that should be applied to
TRIPX
VXMON and the whole sequence should be repeated
again (see Figure 5).
CASE B
Now if the V
(actual), is higher than the V
TRIPX
TRIPX
Setting a V
Voltage (x = 1, 2)
TRIPx
(desired), perform the reset sequence as described in
the next section. The new V voltage to be applied
to VXMON will now be: V
There are two procedures used to set the threshold volt-
ages (V ), depending if the threshold voltage to be
TRIPX
TRIPx
(desired) - (V
TRIPX
TRIPX
stored is higher or lower than the present value. For
example, if the present V is 2.9 V and the new
(actual) - V
(desired)).
TRIPX
TRIPx
Note: 1. This operation does not corrupt the memory
V
is 3.2 V, the new voltage can be stored directly
TRIPx
array.
2. Set V
into the V
cell. If however, the new setting is to be
TRIPx
= 5V, when V
is being pro-
lower than the present setting, then it is necessary to
“reset” the V voltage before setting the new value.
CC
TRIP2
grammed
TRIPx
Setting a Higher V
Voltage (x = 1, 2)
Setting a Lower V
Voltage (x = 1, 2)
TRIPx
TRIPx
To set a V
threshold to a new voltage which is
In order to set V
present value, then V
ing to the procedure described below. Once V
to a lower voltage than the
TRIPx
TRIPx
higher than the present threshold, the user must apply
the desired threshold voltage to the
must first be “reset” accord-
TRIPx
V
TRIPx
TRIPx
corresponding input pin (Vcc(V1MON) or V2MON).
Then, a program-ming voltage (Vp) must be applied to
the WDO pin before a START condition is set up on
SDA. Next, issue on the SDA pin the Slave Address A0h,
has been “reset”, then V
can be set to the desired
TRIPx
voltage using the procedure described in “Setting a
Higher V Voltage”.
TRIPx
followed by the Byte Address 01h for V
, and 09h for
TRIP1
V
, and a 00h Data Byte in order to program V
.
TRIP2
TRIPx
March 28, 2005
5
X40420, X40421
Resetting the V
Voltage
TRIPx
Condition
Mode of Operation
Normal Operation
To reset a V
voltage, apply the programming volt-
TRIPx
VCC > VTRIP1
age (Vp) to the WDO pin before a START condition is set
up on SDA. Next, issue on the SDA pin the Slave
Address A0h followed by the Byte Address 03h for
VCC > VTRIP1
VBATT = 0
&
Normal Operation without battery
backup capability
0 ≤ VCC ≤ VTRIP1
and VCC < VBATT signal is asserted. No communica-
Battery Backup mode; RESET
V
and 0Bh for V
, followed by 00h for the Data
TRIP1
TRIP2
Byte in order to reset V
. The STOP bit following a
TRIPx
tion to the device is allowed.
valid write operation initiates the programming sequence.
Pin WDO must then be brought LOW to complete the
operation.
Control Register
The Control Register provides the user a mechanism for
changing the Block Lock and Watchdog Timer settings.
The Block Lock and Watchdog Timer bits are nonvolatile
and do not change when power is removed.
After being reset, the value of V
value of 1.7V or lesser.
becomes a nominal
TRIPx
Note: This operation does not corrupt the memory array.
The Control Register is accessed with a special pream-
ble in the slave byte (1011) and is located at address
1FFh. It can only be modified by performing a byte write
operation directly to the address of the register and only
one data byte is allowed for each register write operation.
Prior to writing to the Control Register, the WEL and
RWEL bits must be set using a two step process, with
the whole sequence requiring 3 steps. See "Writing to
the Control Registers" on page 8.
System Battery Switch
As long as V exceeds the low voltage detect threshold
CC
V
, V
is connected to V through a 5Ω (typical)
TRIP
OUT CC
switch. When the V has fallen below V1
, then V
CC
CC
TRIP
is applied to V
if V is or equal to or greater than
OUT
CC
V
- 0.03V. When V
drops to less than V
-
BATT
CC
BATT
0.03V, then V
is connected to V
through an 80Ω
OUT
BATT
(typical) switch. V
typically supplies the system static
OUT
RAM voltage, so the switchover circuit operates to pro-
tect the contents of the static RAM during a power failure.
The user must issue a stop, after sending this byte to
the register, to initiate the nonvolatile cycle that stores
WD1, WD0, PUP1, PUP0, and BP. The X40420 will not
acknowledge any data bytes written after the first byte
is entered.
Typically, when V
has failed, the SRAMs go into a
CC
lower power state and draw much less current than in
their active mode. When V returns, V switches
CC
OUT
back to V when V exceeds V + 0.03V. There is
CC
CC
BATT
The state of the Control Register can be read at any time
by performing a random read at address 01Fh, using the
special preamble. Only one byte is read by each register
read operation. The master should supply a stop condi-
tion to be consistent with the bus protocol, but a stop is
not required to end this operation.
a 60mV hysteresis around this battery switch threshold to
prevent oscillations between supplies.
While V
is connected to V
the BATT-ON pin is
CC
OUT
pulled LOW. The signal can drive an external PNP tran-
sistor to provide additional current to the external circuits
during normal operation.
7
6
5
4
3
2
1
0
PUP1 WD1 WD0
BP
0
RWEL WEL PUP0
Operation
The device is in normal operation with V as long as
CC
RWEL: Register Write Enable Latch (Volatile)
V
> V
. It switches to the battery backup mode
CC
TRIP1
when V goes away.
The RWEL bit must be set to “1” prior to a write to the
Control Register.
CC
Figure 5. Sample V
Reset Circuit
TRIP
VP
Adjust
V2FAIL
RESET
µC
1
6
2
7
14
13
Run
9
X40420
VTRIP1
Adj.
8
SCL
VTRIP2
Adj.
4.7K
SDA
March 28, 2005
6
X40420, X40421
Figure 6. V
Set/Reset Sequence (X = 1, 2)
TRIPX
Vx = VCC, VxMON
VTRIPX Programming
Note: X = 1, 2
Let: MDE = Maximum Desired Error
Desired
No
VTRIPX
<
MDE+
Acceptable
Present Value
Desired Value
YES
Error Range
MDE–
Execute
TRIPX Reset Sequence
V
Error = Actual - Desired
Set VX = desired VTRIPX
New VX applied =
Old VX applied + | Error |
Execute
Set Higher VX Sequence
New VX applied =
Old VX applied - | Error |
Apply VCC and Voltage
Execute Reset VTRIPX
Sequence
> Desired VTRIPX to
VX
NO
Decrease
VX
Output Switches?
YES
V
Error < MDE–
Error > MDE+
Actual
TRIPX -
VTRIPX
Desired
| Error | < | MDE |
DONE
WEL: Write Enable Latch (Volatile)
Once set, WEL remains set until either it is reset to 0
(by writing a “0” to the WEL bit and zeroes to the other
bits of the control register) or until the part powers up
again. Writes to the WEL bit do not cause a high volt-
age write cycle, so the device is ready for the next
operation immediately after the stop condition.
The WEL bit controls the access to the memory and to
the Register during a write operation. This bit is a vola-
tile latch that powers up in the LOW (disabled) state.
While the WEL bit is LOW, writes to any address,
including any control registers will be ignored (no
acknowledge will be issued after the Data Byte). The
WEL bit is set by writing a “1” to the WEL bit and
zeroes to the other bits of the control register.
March 28, 2005
7
X40420, X40421
BP: Block Protect Bit (Nonvolatile)
– Write a one byte value to the Control Register that
has all the control bits set to the desired state. The
Control register can be represented as qxys 001r in
binary, where xy are the WD bits, and st are the BP
bits and qr are the power-up bits. This operation pro-
ceeded by a start and ended with a stop bit. Since
this is a nonvolatile write cycle it will take up to 10ms
to complete. The RWEL bit is reset by this cycle and
the sequence must be repeated to change the non-
volatile bits again. If bit 2 is set to ‘1’ in this third step
(qxys 011r) then the RWEL bit is set, but the WD1,
WD0, PUP1, PUP0, and BP bits remain unchanged.
Writing a second byte to the control register is not
allowed. Doing so aborts the write operation and
returns a NACK.
The Block Protect Bits BP determines which blocks of
the array are write protected. A write to a protected
block of memory is ignored. The block protect bit will
prevent write operations to half the array segment.
Protected Addresses
(Size)
Memory
Array Lock
0
1
None
None
100h – 1FFh (256 bytes)
Upper Half of
Memory Array
PUP1, PUP0: Power-uppower-up Bits (Nonvolatile)
The Power-up bits, PUP1 and PUP0, determine the
tPURST time delay. The nominal power-up times are
shown in the following table.
– A read operation occurring between any of the previ-
ous operations will not interrupt the register write
operation.
PUP1 PUP0
Power-on Reset Delay (tPURST)
– The RWEL bit cannot be reset without writing to the
nonvolatile control bits in the control register, power
cycling the device or attempting a write to a write
protected block.
0
0
1
1
0
1
0
1
50ms
200ms (default)
400ms
800ms
To illustrate, a sequence of writes to the device con-
sisting of [02H, 06H, 02H] will reset all of the nonvola-
tile bits in the Control Register to 0. A sequence of
[02H, 06H, 06H] will leave the nonvolatile bits
unchanged and the RWEL bit remains set.
WD1, WD0: Watchdog Timer Bits
The bits WD1 and WD0 control the period of the
Watchdog Timer. The options are shown below.
Note: 1. t
is set to 200ms as factory default.
PURST
WD1
WD0
Watchdog Time Out Period
1.4 seconds
2. Watchdog timer bits are shipped disabled.
0
0
1
1
0
1
0
1
200 milliseconds
Fault Detection Register (FDR)
25 milliseconds
The Fault Detection Register provides the user the
status of what causes the system reset active. The
Manual Reset Fail, Watchdog Timer Fail and Three
Low Voltage Fail bits are volatile
disabled (factory default)
Writing to the Control Registers
Changing any of the nonvolatile bits of the control and
trickle registers requires the following steps:
7
6
5
4
3
2
1
0
LV1F LV2F
0
WDF MRF
0
0
0
– Write a 02H to the Control Register to set the Write
Enable Latch (WEL). This is a volatile operation, so
there is no delay after the write. (Operation pre-
ceded by a start and ended with a stop).
The FDR is accessed with a special preamble in the
slave byte (1011) and is located at address 0FFh. It
can only be modified by performing a byte write opera-
tion directly to the address of the register and only one
data byte is allowed for each register write operation.
– Write a 06H to the Control Register to set the
Register Write Enable Latch (RWEL) and the WEL
bit. This is also a volatile cycle. The zeros in the data
byte are required. (Operation proceeded by a start
and ended with a stop).
There is no need to set the WEL or RWEL in the con-
trol register to access this fault detection register.
March 28, 2005
8
X40420, X40421
Figure 7. Valid Data Changes on the SDA Bus
SCL
SDA
Data Stable
Data Change
Data Stable
At power-up, the Fault Detection Register is defaulted
to all “0”. The system needs to initialize this register to
all “1” before the actual monitoring take place. In the
event of any one of the monitored sources failed. The
corresponding bits in the register will change from a
“1” to a “0” to indicate the failure. At this moment, the
system should perform a read to the register and
noted the cause of the reset. After reading the register
the system should reset the register back to all “1”
again. The state of the Fault Detection Register can be
read at any time by performing a random read at
address 0FFh, using the special preamble.
Interface Conventions
The device supports a bidirectional bus oriented proto-
col. The protocol defines any device that sends data
onto the bus as a transmitter, and the receiving device
as the receiver. The device controlling the transfer is
called the master and the device being controlled is
called the slave. The master always initiates data
transfers, and provides the clock for both transmit and
receive operations. Therefore, the devices in this fam-
ily operate as slaves in all applications.
Serial Clock and Data
Data states on the SDA line can change only during
SCL LOW. SDA state changes during SCL HIGH are
reserved for indicating start and stop conditions. See
Figure 7.
The FDR can be read by performing a random read at
0FFh address of the register at any time. Only one
byte of data is read by the register read operation.
MRF, Manual Reset Fail Bit (Volatile)
Serial Start Condition
The MRF bit will set to “0” when Manual Reset input
goes active.
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 condition and will not
respond to any command until this condition has been
met. See Figure 8.
WDF, Watchdog Timer Fail Bit (Volatile)
The WDF bit will set to “0” when WDO goes active.
LV1F, Low V Reset Fail Bit (Volatile)
CC
The LV1F bit will be set to “0” when V
(V1MON)
CC
Serial Stop Condition
falls below V
.
TRIP1
All communications must be terminated by a stop con-
dition, which is a LOW to HIGH transition of SDA when
SCL is HIGH. The stop condition is also used to place
the device into the Standby power mode after a read
sequence. A stop condition can only be issued after the
transmitting device has released the bus. See Figure 8.
LV2F, Low V2MON Reset Fail Bit (Volatile)
The LV2F bit will be set to “0” when V2MON falls
below V
.
TRIP2
March 28, 2005
9
X40420, X40421
Figure 8. Valid Start and Stop Conditions
SCL
SDA
Start
Stop
Serial Acknowledge
detected. The master must then issue a stop condition
to return the device to Standby mode and place the
device into a known state.
Acknowledge is a software convention used to indi-
cate successful data transfer. The transmitting device,
either master or slave, will release the bus after trans-
mitting eight bits. During the ninth clock cycle, the
receiver will pull the SDA line LOW to acknowledge
that it received the eight bits of data. See Figure 9.
Serial Write Operations
Byte Write
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
array. After receipt of the Word Address Byte, the
device responds with an acknowledge, and awaits the
next eight bits of data. After receiving the 8 bits of the
Data Byte, the device again responds with an
acknowledge. The master then terminates the transfer
by generating a stop condition, at which time the
device begins the internal write cycle to the nonvolatile
memory. During this internal write cycle, the device
inputs are disabled, so the device will not respond to any
requests from the master. The SDA output is at high
impedance. See Figure 12.
The device will respond with an acknowledge after
recognition of a start condition and if the correct
Device Identifier and Select bits are contained in the
Slave Address Byte. If a write operation is selected,
the device will respond with an acknowledge after the
receipt of each subsequent eight bit word. The device
will acknowledge all incoming data and address bytes,
except for the Slave Address Byte when the Device
Identifier and/or Select bits are incorrect.
In the read mode, the device will transmit eight bits of
data, release the SDA line, then monitor the line for an
acknowledge. If an acknowledge is detected and no
stop condition is generated by the master, the device
will continue to transmit data. The device will terminate
further data transmissions if an acknowledge is not
A write to a protected block of memory will suppress
the acknowledge bit.
Figure 9. Acknowledge Response From Receiver
SCL from
Master
1
8
9
Data Output
from
Data Output
from Receiver
Start
Acknowledge
March 28, 2005
10
X40420, X40421
Figure 10. Byte Write Sequence
S
t
a
r
S
t
o
p
Signals from
the Master
Byte
Address
Slave
Address
Data
t
SDA Bus
0
A
C
K
A
C
K
A
C
K
Signals from
the Slave
Page Write
This means that the master can write 16 bytes to the
page starting at any location on that page. If the master
begins writing at location 10, and loads 12 bytes, then
the first 6 bytes are written to locations 10 through 15,
and the last 6 bytes are written to locations 0 through 5.
Afterwards, the address counter would point to location
6 of the page that was just written. If the master sup-
plies more than 16 bytes of data, then new data over-
writes the previous data, one byte at a time.
The device is capable of a page write operation. It is
initiated in the same manner as the byte write opera-
tion; but instead of terminating the write cycle after the
first data byte is transferred, the master can transmit
an unlimited number of 8-bit bytes. After the receipt of
each byte, the device will respond with an acknowl-
edge, and the address is internally incremented by
one. The page address remains constant. When the
counter reaches the end of the page, it “rolls over” and
goes back to ‘0’ on the same page.
Figure 11. Page Write Operation
(1 ≤ n ≤ 16)
S
S
t
o
p
t
a
r
Signals from
the Master
Byte
Address
Slave
Address
Data
(1)
Data
(n)
t
SDA Bus
1 0 1
0 0
0
A
C
K
A
C
K
A
C
K
A
C
K
Signals from
the Slave
Figure 12. Writing 12 bytes to a 16-byte page starting at location 10.
6 Bytes
6 Bytes
address pointer
ends here
Addr = 6
address
10
address
= 5
address
n-1
The master terminates the Data Byte loading by issuing
a stop condition, which causes the device to begin the
nonvolatile write cycle. As with the byte write operation,
all inputs are disabled until completion of the internal
write cycle. See Figure 11 for the address, acknowl-
edge, and data transfer sequence.
March 28, 2005
11
X40420, X40421
Stops and Write Modes
Figure 13. Acknowledge Polling Sequence
Stop conditions that terminate write operations must
be sent by the master after sending at least 1 full data
byte plus the subsequent ACK signal. If a stop is
issued in the middle of a data byte, or before 1 full
data byte plus its associated ACK is sent, then the
device will reset itself without performing the write. The
contents of the array will not be effected.
Byte Load Completed
by Issuing STOP.
Enter ACK Polling
Issue START
Acknowledge Polling
Issue Slave Address
Byte (Read or Write)
Issue STOP
The disabling of the inputs during high voltage cycles
can be used to take advantage of the typical 5ms write
cycle time. Once the stop condition is issued to indi-
cate the end of the master’s byte load operation, the
device initiates the internal high voltage cycle.
Acknowledge polling can be initiated immediately. To
do this, the master issues a start condition followed by
the Slave Address Byte for a write or read operation. If
the device is still busy with the high voltage cycle then
no ACK will be returned. If the device has completed
the write operation, an ACK will be returned and the
host can then proceed with the read or write operation.
See Figure 13.
NO
ACK
Returned?
YES
High Voltage Cycle
Complete. Continue
Command Sequence?
Issue STOP
NO
YES
Continue Normal
Read or Write
Serial Read Operations
Command Sequence
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: Current Address Reads, Ran-
dom Reads, and Sequential Reads.
PROCEED
It should be noted that the ninth clock cycle of the read
operation is not a “don’t care.” To terminate a read
operation, the master must either issue a stop condi-
tion during the ninth cycle or hold SDA HIGH during
the ninth clock cycle and then issue a stop condition.
Current Address Read
Internally the device contains an address counter that
maintains the address of the last word read incre-
mented by one. Therefore, if the last read was to
address n, the next read operation would access data
from address n+1. On power-up, the address of the
address counter is undefined, requiring a read or write
operation for initialization.
Random Read
Random read operation allows the master to access any
memory location in the array. Prior to issuing the Slave
Address Byte with the R/W bit set to one, the master
must first perform a “dummy” write operation. The master
issues the start condition and the Slave Address Byte,
receives an acknowledge, then issues the Word Address
Bytes. After acknowledging receipts of the Word Address
Bytes, the master immediately issues another start con-
dition and the Slave Address Byte with the R/W bit set to
one. This is followed by an acknowledge from the device
and then by the eight bit word. The master terminates the
read operation by not responding with an acknowledge
and then issuing a stop condition. See Figure 15 for the
address, acknowledge, and data transfer sequence.
Upon receipt of the Slave Address Byte with the R/W
bit set to one, the device issues an acknowledge and
then transmits the eight bits of the Data Byte. The
master terminates the read operation when it does not
respond with an acknowledge during the ninth clock
and then issues a stop condition. See Figure 14 for the
address, acknowledge, and data transfer sequence.
March 28, 2005
12
X40420, X40421
A similar operation called “Set Current Address” where
SERIAL DEVICE ADDRESSING
the device will perform this operation if a stop is issued
instead of the second start shown in Figure 15. The
device will go into standby mode after the stop and all
bus activity will be ignored until a start is detected.
This operation loads the new address into the address
counter. The next Current Address Read operation will
read from the newly loaded address. This operation
could be useful if the master knows the next address it
needs to read, but is not ready for the data.
Memory Address Map
CR, Control Register, CR7: CR0
Address: 1FF
hex
FDR, Fault DetectionRegister, FDR7: FDR0
Address: 0FF
hex
General Purpose Memory Organization, A8:A0
Address: 00h to 1FFh
Sequential Read
General Purpose Memory Array Configuration
Sequential reads can be initiated as either a current
address read or random address read. The first Data
Byte is transmitted as with the other modes; however,
the master now responds with an acknowledge, indicat-
ing it requires additional data. The device continues to
output data for each acknowledge received. The master
terminates the read operation by not responding with an
acknowledge and then issuing a stop condition.
Memory Address
A8:A0
000h
Lower 256 bytes
0FFh
100h
Upper 256 bytes
Block Protect Option
1FFh
Slave Address Byte
The data output is sequential, with the data from
address n followed by the data from address n + 1. The
address counter for read operations increments through
all page and column addresses, allowing the entire
memory contents to be serially read during one opera-
tion. At the end of the address space the counter “rolls
Following a start condition, the master must output a
Slave Address Byte. This byte consists of several parts:
– a device type identifier that is always “1010” when
accessing the array and “1011” when accessing the
control register and fault detection register.
over” to address 0000 and the device continues to out-
H
– two bits of “0”.
put data for each acknowledge received. See Figure 17
for the acknowledge and data transfer sequence.
– one bit that becomes the MSB of the memory
address X .
4
– last bit of the slave command byte is a R/W bit. The
R/W bit of the Slave Address Byte defines the oper-
ation to be performed. When the R/W bit is a one,
then a read operation is selected. A zero selects a
write operation. See Figure 16.
Figure 14. Current Address Read Sequence
S
Slave
Address
t
a
r
S
t
o
p
Signals from
the Master
t
SDA Bus
1 0 1
0 0
1
A
Signals from
the Slave
C
Data
K
March 28, 2005
13
X40420, X40421
Figure 15. Random Address Read Sequence
S
S
S
t
o
p
t
a
r
Slave
Address
Byte
Address
Slave
Address
t
a
r
Signals from
the Master
t
t
SDA Bus
1
1 0 1 0 0
0
A
C
K
A
C
K
A
C
K
Signals from
the Slave
Data
Figure 16. X40410/11 Addressing
Slave Byte
General Purpose Memory
Control Register
1
1
1
0
0
0
1
1
1
0
1
1
0
0
0
0
R/W
R/W
R/W
A8
0
0
1
0
Fault Detection Register
Word Address
General Purpose Memory
Control Register
A0
1
A7 A6 A5 A4 A3 A2 A1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Fault Detection Register
1
Word Address
Data Protection
The word address is either supplied by the master or
obtained from an internal counter.
The following circuitry has been included to prevent
inadvertent writes:
– The WEL bit must be set to allow write operations.
Operational Notes
– The proper clock count and bit sequence is required
prior to the stop bit in order to start a nonvolatile
write cycle.
The device powers-up in the following state:
– The device is in the low power standby state.
– The WEL bit is set to ‘0’. In this state it is not possi-
ble to write to the device.
– A three step sequence is required before writing into
the Control Register to change Watchdog Timer or
Block Lock settings.
– SDA pin is the input mode.
– The WP pin, when held HIGH, prevents all writes to
the array and all the Register.
– RESET/RESET Signal is active for tPURST
.
Figure 17. Sequential Read Sequence
S
t
Slave
Address
Signals from
the Master
o
A
C
K
A
C
K
A
C
K
p
SDA Bus
1
A
C
K
Signals from
the Slave
Data
(2)
Data
(n-1)
Data
(1)
Data
(n)
(n is any integer greater than 1)
March 28, 2005
14
X40420, X40421
ABSOLUTE MAXIMUM RATINGS
COMMENT
Temperature under bias.................... -65°C to +135°C
Storage temperature ......................... -65°C to +150°C
Voltage on any pin with
Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only; functional operation of the
device (at these or any other conditions above those
listed in the operational sections of this specification) is
not implied. Exposure to absolute maximum rating con-
ditions for extended periods may affect device reliability.
respect to V ...................................... -1.0V to +7V
SS
D.C. output current...............................................5mA
Lead temperature (soldering, 10 seconds)........ 300°C
RECOMMENDED OPERATING CONDITIONS
Temperature
Commercial
Industrial
Min.
0°C
Max.
70°C
Monitored
Version ChipSupplyVoltage
Voltages*
2.6 to 5.5V
1.6V to 3.6V
-A or -B
-C
2.7V to 5.5V
2.7V to 5.5V
-40°C
+85°C
*See ordering Info
D.C. OPERATING CHARACTERISTICS
(Over the recommended operating conditions unless otherwise specified)
(5)
Symbol
Parameter
Active Supply Current (V ) Read
Min.
Typ.
Max.
Unit
Test Conditions
(1)
ICC1
1.5
mA
VIL = V x 0.1
CC
CC
(Excludes IOUT
)
VIH = V x 0.9,
CC
(1)
fSCL = 400kHz
ICC2
Active Supply Current (V ) Write Non
3.0
10
mA
CC
Volatile Memory (Excludes IOUT
)
(1)(7)
ISB1
Standby Current (V ) AC (WDT off)
6
µA VIL = V x 0.1
CC
CC
VIH = V x 0.9
CC
fSCL, fSDA = 400kHz
(2)(7)
ISB2
Standby Current (V ) DC (WDT on)
25
30
µA VSDA = VSCL = V
CC
CC
Others = GND or V
CC
(3)(7)
IBATT1
VBATT Current (Excludes IOUT
)
0.4
1
6
µA VOUT = V
CC
µA VBATT = 2.8V
VOUT = Open
(7)
IBATT2
VBATT Current (Excludes IOUT
(Battery Backup Mode)
)
(7)
VOUT1
Output Voltage (VCC > VBATT + 0.03V or
VCC > VTRIP1
V
CC-0.05V
V
IOUT = 5mA (4.5-5.5V)
IOUT = 50mA (4.5-5.5V)
)
VCC-0.5V
(7)
VOUT2
Output Voltage (VCC < VBATT – 0.03V and
VCC < VTRIP1) {Battery Backup}
VBATT-0.2
V
IOUT = 250µA
VOLB
VOHB
Output (BATT-ON) LOW Voltage
Output (BATT-ON) HIGH Voltage
Battery Switch Hysteresis
0.4
V
V
IOL = 3.0mA (4.5-5.5V)
IOH = -0.4mA (4.5-5.5V)
VOUT-0.8
(7)
VBSH
30
-30
mV Power-up
Power-down
(VCC < VTRIP1
)
ILI
Input Leakage Current (SCL, MR, WP)
10
10
µA VIL = GND to V
CC
ILO
Output Leakage Current (SDA, V2FAIL,
WDO, RESET)
µA
VSDA = GND to V
CC
Device is in Standby(2)
(3)
VIL
Input LOW Voltage (SDA, SCL, MR, WP)
Input HIGH Voltage (SDA, SCL, MR, WP)
-0.5
x 0.7
V
x 0.3
V
V
CC
(3)
VIH
V
V
+ 0.5
CC
CC
March 28, 2005
15
X40420, X40421
D.C. OPERATING CHARACTERISTICS (Continued)
(Over the recommended operating conditions unless otherwise specified)
(5)
Symbol
Parameter
Min.
Typ.
Max.
Unit
Test Conditions
(7)
VHYS
Schmitt Trigger Input Hysteresis
• Fixed input level
0.2
.05 x V
V
V
• V related level
CC
CC
VOL
Output LOW Voltage (SDA, RESET/
RESET, LOWLINE, V2FAIL, WDO)
0.4
V
I
OL = 3.0mA (2.7-5.5V)
IOL = 1.8mA (2.4-3.6V)
V
CC Supply
(6)
VTRIP1
V
Reset Trip Point Voltage Range
2.0
4.75
4.65
2.95
5
V
CC
4.55
2.85
4.6
2.9
A, B Version
C Version
(7)
tRPDL
µS
V
VTRIP1 to LOWLINE
Second Supply Monitor
(6)
VTRIP2
V2MON Reset Trip Point Voltage Range
0.9
3.5
2.95
2.65
1.65
5
2.85
2.55
1.55
2.9
2.6
1.6
A Version
B Version
C Version
(7)
tRPD2
µS
VTRIP2 to V2FAIL
Notes: (1) The device enters the Active state after any start, and remains active until: 9 clock cycles later if the Device Select Bits in the Slave
Address Byte are incorrect; 200ns after a stop ending a read operation; or tWC after a stop ending a write operation.
(2) The device goes into Standby: 200ns after any stop, except those that initiate a high voltage write cycle; tWC after a stop that initiates a
high voltage cycle; or 9 clock cycles after any start that is not followed by the correct Device Select Bits in the Slave Address Byte.
(3) Negative numbers indicate charging current, positive numbers indicate discharge current.
(4) VIL Min. and VIH Max. are for reference only and are not tested.
(5) At 25°C, VCC = 3V.
(6) See ordering information for standard programming levels. For custom programming levels, contact factory.
(7) Based on characterization data only.
EQUIVALENT INPUT CIRCUIT FOR VxMON (x = 1, 2)
∆V = 100mV
R
∆V
VREF
VxMON
+
–
Output
VREF
C
tRPDX = 5µs worst case
March 28, 2005
16
X40420, X40421
CAPACITANCE
Symbol
Parameter
Max.
Unit
Test Conditions
OUT = 0V
(1)
COUT
Output Capacitance (SDA, RESET, RESET/LOWLINE,
V2FAIL, WDO)
8
pF
V
(1)
CIN
Input Capacitance (SCL, WP)
6
pF
VIN = 0V
Note: (1) This parameter is not 100% tested.
EQUIVALENT A.C. OUTPUT LOAD CIRCUIT FOR
SYMBOL TABLE
V
= 5V
CC
WAVEFORM
INPUTS
OUTPUTS
VOUT
5V
V2MON
Must be
steady
Will be
steady
4.6kΩ
4.6kΩ
2.06kΩ
May change
from LOW
Will change
from LOW
to HIGH
RESET
WDO/LOWLINE
SDA
V2FAIL
30pF
May change
from HIGH
to LOW
Will change
from HIGH
to LOW
30pF
30pF
Don’t Care:
Changes
Allowed
Changing:
State Not
Known
A.C. TEST CONDITIONS)
N/A
Center Line
is High
Impedance
Input pulse levels
V
x 0.1 to V x 0.9
CC
CC
Input rise and fall times
Input and output timing levels
Output load
10ns
V
x 0.5
CC
Standard output load
March 28, 2005
17
X40420, X40421
A.C. CHARACTERISTICS
Symbol
400kHz
Parameter
Min.
Max.
Unit
kHz
ns
µs
µs
µs
µs
µs
µs
ns
µs
µs
ns
ns
ns
µs
µs
pF
fSCL
tIN
SCL Clock Frequency
400
Pulse width Suppression Time at inputs
SCL LOW to SDA Data Out Valid
Time the bus free before start of new transmission
Clock LOW Time
50
0.1
1.3
1.3
0.6
0.6
0.6
100
0
tAA
0.9
tBUF
tLOW
tHIGH
tSU:STA
tHD:STA
tSU:DAT
tHD:DAT
tSU:STO
tDH
Clock HIGH Time
Start Condition Setup Time
Start Condition Hold Time
Data In Setup Time
Data In Hold Time
Stop Condition Setup Time
Data Output Hold Time
0.6
50
tR
SDA and SCL Rise Time
SDA and SCL Fall Time
WP Setup Time
20 +.1Cb(1)
20 +.1Cb(1)
300
300
tF
tSU:WP
tHD:WP
Cb
0.6
0
WP Hold Time
Capacitive load for each bus line
400
Note: (1) Cb = total capacitance of one bus line in pF.
TIMING DIAGRAMS
Bus Timing
tF
tHIGH
tLOW
tR
SCL
SDA IN
tSU:DAT
tSU:STA
tHD:DAT
tSU:STO
tHD:STA
tAA tDH
tBUF
SDA OUT
March 28, 2005
18
X40420, X40421
WP Pin Timing
START
SCL
Clk 1
Clk 9
Slave Address Byte
SDA IN
WP
tSU:WP
tHD:WP
Write Cycle Timing
SCL
8th Bit of Last Byte
ACK
SDA
tWC
Stop
Start
Condition
Condition
Nonvolatile Write Cycle Timing
Symbol
(1)
Parameter
Write Cycle Time
Min.
Typ.
Max.
Unit
(1)
tWC
5
10
ms
Note: (1) tWC is the time from a valid stop condition at the end of a write sequence to the end of the self-timed internal nonvolatile write cycle. It is
the minimum cycle time to be allowed for any nonvolatile write by the user, unless Acknowledge Polling is used.
Power Fail Timings
VTRIPX
tRPDL
tRPDX
tRPDL
tRPDX
VCC or
tRPDL
tRPDX
V2MON
tF
tR
LOWLINE or
V2FAIL
VRVALID
X = 1, 2
March 28, 2005
19
X40420, X40421
RESET/RESET/MR Timings
VTRIP1
VCC
tPURST
tPURST
tRPD1
tF
tR
RESET
VRVALID
RESET
MR
tMD
LOW VOLTAGE AND WATCHDOG TIMINGS PARAMETERS (@25°C, VCC = 5V)
Symbol
Parameters
Min.
Typ.
Max.
Unit
(1)
tRPD1
VTRIP1 to RESET/RESET (Power-down only)
VTRIP1 to LOWLINE
5
µs
tRPDL
(1)
tLR
LOWLINE to RESET/RESET delay (Power-down only) [= tRPD1-tRPDL
]
500
ns
µs
(1)
tRPD2
VTRIP2 to V2FAIL
5
tPURST
Power-on Reset delay:
PUP1=0, PUP0=0
PUP1=0, PUP0=1 (factory default)
PUP1=1, PUP0=0
50(1)
200
ms
ms
ms
ms
400(1)
800(1)
PUP1=1, PUP0=1
tF
VCC, V2MON Fall Time
VCC, V2MON Rise Time
20
20
1
mV/µs
mV/µs
V
tR
VRVALID Reset Valid VCC
t MD MR to RESET/ RESET delay (activation only)
tin1
500
50
ns
Pulse width Suppression Time for MR
ns
tWDO
Watchdog Timer Period:
WD1=0, WD0=0
WD1=0, WD0=1
1.4(1)
200(1)
25
s
ms
ms
WD1=1, WD0=0
WD1=1, WD0=1 (factory default)
OFF
tRST1
Watchdog Reset Time Out Delay
WD1=0, WD0=0
100
200
300
ms
WD1=0, WD0=1
tRST2
tRSP
Watchdog Reset Time Out Delay WD1=1, WD0=0
Watchdog timer restart pulse width
12.5
1
25
37.5
ms
µs
Note: (1) Based on characterization data.
March 28, 2005
20
X40420, X40421
Watchdog Time Out For 2-Wire Interface
Start
Start
Clockin (0 or 1)
tRSP
< tWDO
SCL
SDA
tRST
tWDO
tRST
WDO
WDT
Restart
Start
Minimum Sequence to Reset WDT
SCL
SDA
V
Set/Reset Conditions
TRIPX
(VTRIPX
)
VCC/V2MON
tTHD
VP
tTSU
WDO
tVPS
tVPO
tVPH
7
SCL
SDA
0
0
7
0
7
tWC
A0h
00h
Start
resets VTRIP1
resets VTRIP2
01h*
09h*
03h*
0Bh*
sets VTRIP1
sets VTRIP2
* all others reserved
March 28, 2005
21
X40420, X40421
V
, V
Programming Specifications: V = 2.0-5.5V; Temperature = 25°C
TRIP1
TRIP2
CC
Parameter
tVPS
Description
WDO Program Voltage Setup time
WDO Program Voltage Hold time
VTRIPX Level Setup time
Min.
10
10
10
10
10
Max. Unit
µs
µs
tVPH
tTSU
µs
tTHD
VTRIPX Level Hold (stable) time
VTRIPX Program Cycle
µs
tWC
ms
ms
tVPO
Program Voltage Off time before next cycle
Programming Voltage
1
VP
15
18
4.75
3.5
V
V
VTRAN1
VTRAN2
Vtv
VTRIP1 Set Voltage Range
2.0
0.9
-25
10
VTRIP2 Set Voltage Range
V
VTRIPX Set Voltage variation after programming (0-75°C).
WDO Program Voltage Setup time
+25
mV
µs
tVPS
VTRIPX programming parameters are periodically sampled and are not 100% tested.
March 28, 2005
22
X40420, X40421
PACKAGING INFORMATION
14-Lead Plastic Small Outline Gullwing Package Type S
0.150 (3.80) 0.228 (5.80)
0.158 (4.00) 0.244 (6.20)
Pin 1 Index
Pin 1
0.014 (0.35)
0.020 (0.51)
0.336 (8.55)
0.345 (8.75)
(4X) 7°
0.053 (1.35)
0.069 (1.75)
0.004 (0.10)
0.010 (0.25)
0.050 (1.27)
0.050"Typical
0.010 (0.25)
X 45°
0.020 (0.50)
0.050"Typical
0° - 8°
0.250"
0.0075 (0.19)
0.010 (0.25)
0.016 (0.410)
0.037 (0.937)
0.030"Typical
14 Places
FOOTPRINT
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
March 28, 2005
23
X40420, X40421
PACKAGING INFORMATION
14-Lead Plastic, TSSOP, Package Type V
.025 (.65) BSC
.169 (4.3)
.177 (4.5)
.252 (6.4) BSC
.193 (4.9)
.200 (5.1)
.047 (1.20)
.0075 (.19)
.0118 (.30)
.002 (.05)
.006 (.15)
.010 (.25)
Gage Plane
0° - 8°
Seating Plane
.019 (.50)
.029 (.75)
Detail A (20X)
.031 (.80)
.041 (1.05)
See Detail “A”
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
March 28, 2005
24
X40420, X40421
ORDERING INFORMATION
Operating
Temperature
Range
Monitored
Supplies
V
Part Number
with RESET
Part Number
with RESET
TRIP1
V
Range
V
Range
Package
CC
TRIP2
2.9-5.5
2.6-5.5
1.6-3.6
4.6V±50mV
2.9V±50mV
2.6V±50mV
1.6V±50mV
14L SOIC
0oC - 70oC
-40oC - 85oC
0oC - 70oC
-40oC - 85oC
0oC - 70oC
-40oC - 85oC
0oC - 70oC
-40oC - 85oC
0oC - 70oC
-40oC - 85oC
0oC - 70oC
-40oC - 85oC
X40420S14-A
X40420S14I-A
X40420V14-A
X40420V14I-A
X40420S14-B
X40420S14I-B
X40420V14-B
X40420V14I-B
X40420S14-C
X40421S14-A
X40421S14I-A
X40421V14-A
X40421V14I-A
X40421S14-B
X40421S14I-B
X40421V14-B
X40421V14I-B
X40421S14-C
14L TSSOP
14L SOIC
4.6V±50mV
2.9V±50mV
14L TSSOP
14L SOIC
X40420S14I-C X40421S14I-C
X40420V14-C X40421V14-C
X40420V14I-C X40421V14I-C
14L TSSOP
PART MARK INFORMATION
14-Lead SOIC
0/1
X4042XX
YYWWXX
Package - S/V
A, B, or C
I – Industrial
Blank – Commercial
WW – Workweek
YY – Year
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
March 28, 2005
25
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