MAX8211CSA+T ,Microprocessor Voltage Monitors with Programmable Voltage DetectionELECTRICAL CHARACTERISTICS (continued)(V+ = 5V, T = +25°C, unless otherwise noted.)AMAX8211 MAX8212 ..
MAX8211CSA-T ,Microprocessor Voltage Monitors with Programmable Voltage Detectionblock diagrams of Figures 1 and 2, theMAX8211 and MAX8212 each contain a 1.15V refer-ence, a compar ..
MAX8211CUA ,Microprocessor Voltage Monitors with Programmable Voltage Detectionfeatures include the following:' On-Board Gating of Chip-Enable Signals1) µP reset: Assertion of RE ..
MAX8211CUA+ ,Microprocessor Voltage Monitors with Programmable Voltage DetectionMAX8211/MAX821219-0539; Rev 4; 9/02Microprocessor Voltage Monitors with Programmable Voltage Detect ..
MAX8211EPA ,Microprocessor Voltage Monitors with Programmable Voltage DetectionMAX792/MAX82019-0147; Rev. 2; 6/98Microprocessor and Non-VolatileMemory Supervisory Circuits
MAX8211ESA ,Microprocessor Voltage Monitors with Programmable Voltage DetectionELECTRICAL CHARACTERISTICS(V = 2.65V to 5.5V, T = T to T , unless otherwise noted.)CC A MIN MAXPARA ..
MB81464- ,MOS 262144 Bit DRAMfeatures page mode which allows high speed
random access of up to 256 bits within the same tow.
..
MB81C81A-35 ,CMOS 256K-BIT HIGH-SPEED SRAMMay 1990 00
Edition1.0 FUJITSU
M38 1 C8 1A-25/-35
CMOS 256K-BI T HIGH-SPEED SRAM
256K Words ..
MB81F643242C-10FN ,4 x 512K x 32 bit synchronous dynamic RAMFUJITSU SEMICONDUCTORADVANCED INFO. AE0.1EDATA SHEETMEMORYCMOS4 · 512 K · 32 BITSYNCHRONOUS DYNAMIC ..
MB81F643242C-10FN ,4 x 512K x 32 bit synchronous dynamic RAMfeatures a fully synchronous operation referenced to a positive edge clock whereby all operations a ..
MB81N643289-60FN ,8 x 256K x 32 bit double data rate FCRAMapplications where large memory density and high effective bandwidth arerequired and where a simple ..
MB8264A-10 , MOS 65536-BIT DYNAMIC RANDOM ACCESS MEMORY
MAX8211CPA+-MAX8211CSA+-MAX8211CSA+T-MAX8211CSA-T-MAX8211CUA+-MAX8211ESA+-MAX8211ESA+T-MAX8211IPA-MAX8211MSA/PR-MAX8211MTV/883B-MAX8212CSA+-MAX8212CUA+-MAX8212ESA+-MAX8212ESA+T
Microprocessor Voltage Monitors with Programmable Voltage Detection
________________General DescriptionMaxim’s MAX8211 and MAX8212 are CMOS micropower
voltage detectors that warn microprocessors (µPs) of
power failures. Each contains a comparator, a 1.5V
bandgap reference, and an open-drain N-channel output
driver. Two external resistors are used in conjunction with
the internal reference to set the trip voltage to the desired
level. A hysteresis output is also included, allowing the user
to apply positive feedback for noise-free output switching.
The MAX8211 provides a 7mA current-limited output sink
whenever the voltage applied to the threshold pin is less
than the 1.5V internal reference. In the MAX8212, a voltage
greater than 1.5V at the threshold pin turns the output
stage on (no current limit).
The CMOS MAX8211/MAX8212 are plug-in replacements
for the bipolar ICL8211/ICL8212 in applications where the
maximum supply voltage is less than 16.5V. They offer sev-
eral performance advantages, including reduced supply
current, a more tightly controlled bandgap reference, and
more available current from the hysteresis output.
________________________ApplicationsµP Voltage Monitoring
Undervoltage Detection
Overvoltage Detection
Battery-Backup Switching
Power-Supply Fault Monitoring
Low-Battery Detection
____________________________FeaturesµP Power-Fail WarningImproved 2nd Source for ICL8211/ICL8212Low-Power CMOS Design5µA Quiescent CurrentOn-Board Hysteresis Output±40mV Threshold Accuracy (±3.5%)2.0V to 16.5V Supply-Voltage RangeDefine Output Current Limit (MAX8211)High Output Current Capability (MAX8212)
_______________Ordering Information
MAX8211/MAX8212
Microprocessor Voltage Monitors
with Programmable Voltage Detection
___________________Pin Configuration
___________Typical Operating Circuit19-0539; Rev 4; 9/02
Ordering Information continued on last page.*Contact factory for dice specifications.
MAX8211/MAX8212
Microprocessor Voltage Monitors
with Programmable Voltage DetectionSupply Voltage.......................................................-0.5V to +18V
Output Voltage.......................................................-0.5V to +18V
Hysteresis...................+0.5V to -18V with respect to (V+ + 0.5V)
Threshold Input Voltage...............................-0.5V to (V+ + 0.5V)
Current into Any Terminal.................................................±50mA
Continuous Power Dissipation (TA = +70°C)
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C).....727mW
8-Pin SO (derate 5.88mW/°C above +70°C)..................471mW
8-Pin CERDIP (derate 8.00mW/°C above +70°C)..........640mW
8-Pin TO-99 (derate 6.67mW/°C above +70°C).............533mW
Operating Temperature Ranges
MAX821_C_ _.......................................................0°C to +70°C
MAX821_E_ _.....................................................-40°C to +85°C
MAX821_M_ _..................................................-55°C to +125°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(V+ = 5V, TA= +25°C, unless otherwise noted.)
MAX8211/MAX8212
Microprocessor Voltage Monitors
with Programmable Voltage Detection
Note 1:The maximum output current of the MAX8211 is limited by design to 30mA under any operating condition. The output voltage
may be sustained at any voltage up to +16.5V as long as the maximum power dissipation of the device is not exceeded.
Note 2:The maximum output current of the MAX8212 is not defined, and systems using the MAX8212 must therefore ensure that the
output current does not exceed 50mA and that the maximum power dissipation of the device is not exceeded.
ELECTRICAL CHARACTERISTICS (continued)(V+ = 5V, TA= +25°C, unless otherwise noted.)
_______________Detailed DescriptionAs shown in the block diagrams of Figures 1 and 2, the
MAX8211 and MAX8212 each contain a 1.15V refer-
ence, a comparator, an open-drain N-channel output
transistor, and an open-drain P-channel hysteresis out-
put. The MAX8211 output N-channel turns on when the
voltage applied to the THRESH pin is less than the
internal reference (1.15V). The sink current is limited to
7mA (typical), allowing direct drive of an LED without a
series resistor. The MAX8212 output turns on when the
voltage applied to THRESH is greater than the internal
reference. It is not current limited, and will typically sink
35mA.
Compatibility with ICL8211/ICL8212The CMOS MAX8211/MAX8212 are plug-in replacements
for the bipolar ICL8211/ICL8212 in most applications.
The use of CMOS technology has several advantages.
The quiescent supply current is much less than in the
bipolar parts. Higher-value resistors can also be used
Figure 1. MAX8211 Block Diagram
MAX8211/MAX8212
Microprocessor Voltage Monitors
with Programmable Voltage DetectionFigure 3. Basic Overvoltage/Undervoltage Circuit
in the networks that set up the trip voltage, since the
comparator input (THRESH pin) is a low-leakage
MOSFET transistor. This further reduces system current
drain. The tolerance of the internal reference has also
been significantly improved, allowing for more precise
voltage detection without the use of potentiometers.
The available current from the HYST output has been
increased from 21µA to 10mA, making the hysteresis
feature easier to use. The disparity between the HYST
output and the voltage required at THRESH to switch
the OUT pin has also been reduced in the MAX8211
from 8mV to 0.1mV to eliminate output “chatter” or
oscillation.
Most voltage detection circuits operate with supplies of
15V or less; in these applications, the MAX8211/
MAX8212 will replace ICL8211/ICL8212s with the per-
formance advantages described above. However, note
that the CMOS parts have an absolute maximum sup-
ply-voltage rating of 18V, and should never be used in
applications where this rating could be exceeded.
Exercise caution when replacing ICL8211/ICL8212s in
closed-loop applications such as programmable
zeners. Although neither the ICL8211/ICL8212 nor the
MAX8211/MAX8212 are internally compensated, the
CMOS parts have higher gain and may not be stable
for the external compensation-capacitor values used in
lower-gain ICL8211/ICL8212 circuits.
__________Applications Information
Basic Voltage DetectorsFigure 3 shows the basic circuit for both undervoltage
detection (MAX8211) and overvoltage detection
(MAX8212). For applications where no hysteresis is
needed, R3 should be omitted. The ratio of R1 to R2 is
then chosen such that, for the desired trip voltage at VIN,
1.15V is applied to the THRESH pin. Since the com-
parator inputs are very low-leakage MOSFET transis-
tors, the MAX8211/MAX8212 can use much higher
resistors values in the attenuator network than can the
bipolar ICL8211/ICL8212. See Table 1 for switching
delays.
Table 1. Switching Delays
Voltage Detectors with HysteresisTo ensure noise-free output switching, hysteresis is
frequently used in voltage detectors. For both the
MAX8211 and MAX8212 the HYST output is on for
threshold voltages greater than 1.15V. R3 (Figure 3)
controls the amount of current (positive feedback) sup-
plied from the HYST output to the mid-point of the resis-
tor divider, and hence the magnitude of the hysteresis,
or dead-band.
Figure 2. MAX8212 Block Diagram
Calculate resistor values for Figure 3 asfollows:Choose a value for R1. Typical values are in
the 10kΩ to 10MΩ range.Calculate R2for the desired upper trip point using the formula:Calculate R3 for the desired amount of
hysteresis, where VL is the lower trip point:
or, if V+= VIN:
Figure 5 shows an alternate circuit, suitable only when the
voltage being detected is also the power-supply voltage
for the MAX8211 or MAX8212.
Calculate resistor values for Figure5 asfollows:Choose a value for R1. Typical values are in
the 10kΩ to 10MΩ range.Calculate R2:Calculate R3:
Low-Voltage Detector for Logic SupplyThe circuit of Figure 5 will detect when a 5.0V (nominal)
supply goes below 4.5V, which is the VMINnormally
specified in logic systems. The selected resistor values
ensure that false undervoltage alarms will not be gener-
ated, even with worst-case threshold trip values and
resistor tolerances. R3 provides approximately 75mV of
hysteresis.
MAX8211/MAX8212
Microprocessor Voltage Monitors
with Programmable Voltage DetectionFigure 4. MAX8211/MAX8212 Threshold Trip Voltage vs.
Ambient Temperature
Figure 5. MAX8211 Logic-Supply Low-Voltage Detector
MAX8211/MAX8212
Microprocessor Voltage Monitors
with Programmable Voltage Detection
_Ordering Information (continued)
_____________________________________________Pin Configurations (continued)*Contact factory for dice specifications.
