MAX1253BEUE ,Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD MonitorELECTRICAL CHARACTERISTICS(V = +2.7V to +3.6V (MAX1253), V = +4.5V to +5.5V (MAX1254), V = +2.5V (M ..
MAX1253BEUE+T ,Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD MonitorApplications Ordering InformationSystem SupervisionPART TEMP RANGE PIN-PACKAGERemote Telecom Networ ..
MAX1254BEUE ,Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD MonitorApplications Ordering InformationSystem SupervisionPART TEMP RANGE PIN-PACKAGERemote Telecom Networ ..
MAX12555ETL+ ,14-Bit, 95Msps, 3.3V ADCfeatures a 300µW power-down mode to ±0.35V to ±1.10Vconserve power during idle periods.♦ Common-Mod ..
MAX12557ETK ,Dual, 65Msps, 14-Bit, IF/Baseband ADCApplications(Msps) (Bits)IF and Baseband Communication ReceiversMAX12557 65 14Cellular, LMDS, Point ..
MAX1257BETM ,2.5 V, 12-bit, multichannel ADC/DAC with FIFO, temperature sensing, and GPIO portFeaturesage from +2.7V to +3.6V (MAX1221/MAX1223/MAX1257)and from +4.75V to +5.25V (MAX1220/MAX1222 ..
MAX367CWN ,Signal-Line Circuit ProtectorsGeneral Description ________
MAX367EWN ,Signal-Line Circuit ProtectorsFeaturesThe MAX366 and MAX367 are multiple, two-terminal circuit' ±40V Overvoltage Protectionprotec ..
MAX367EWN ,Signal-Line Circuit ProtectorsApplicationsMAX367 available after January 1, 1995.* Dice are tested at T = +25°C only.Process Cont ..
MAX367EWN+ ,Signal Line Circuit Protector with Three Independent ProtectorsMAX366/MAX36719-0326; Rev 0; 12/94Signal-Line Circuit Protectors_______________
MAX3680EAI ,+3.3V / 622Mbps / SDH/SONET 1:8 Deserializer with TTL OutputsELECTRICAL CHARACTERISTICS(V = +3.0V to +3.6V, T = -40°C to +85°C, unless otherwise noted. Typical ..
MAX3680EAI ,+3.3V / 622Mbps / SDH/SONET 1:8 Deserializer with TTL OutputsApplications622Mbps SDH/SONET Transmission Systems________________Ordering Information622Mbps ATM/S ..
MAX1253BEUE-MAX1254BEUE
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor
General DescriptionThe MAX1253/MAX1254 are stand-alone, 10-channel (8
external, 2 internal) 12-bit system monitor ADCs with
internal reference. A programmable single-ended/dif-
ferential mux accepts voltage and remote-diode tem-
perature-sensor inputs. These devices independently
monitor the input channels without microprocessor
interaction and generate an interrupt when any variable
exceeds user-defined limits. The MAX1253/MAX1254
configure both high and low limits, as well as the num-
ber of fault cycles allowed, before generating an inter-
rupt. These ADCs can also perform recursive data
averaging for noise reduction. Programmable wait inter-
vals between conversion sequences allow the selection
of the sample rate.
At the maximum sampling rate of 94ksps (auto mode,
single channel enabled), the MAX1253 consumes only
5mW (1.7mA at 3V). AutoShutdownTMreduces supply
current to 190µA at 2ksps and to less than 8µA at 50sps.
Stand-alone operation, combined with ease of use in a
small package (16-pin TSSOP), makes the MAX1253/
MAX1254 ideal for multichannel system-monitoring
applications. Low power consumption also makes
these devices a good fit for hand-held and battery-pow-
ered applications.
ApplicationsSystem Supervision
Remote Telecom Networks
Server Farms
Remote Data Loggers
FeaturesMonitor 10 Signals Without Processor
InterventionEight External Channels Programmable as
Temperature or Voltage MonitorsIntelligent Circuitry for Reliable Autonomous
Measurement
Programmable Digital Averaging Filter
Programmable Fault CounterPrecision Measurements
12-Bit Resolution
±1 LSB INL, ±1 LSB DNL
±0.75°C Temperature Accuracy (typ)Flexible
Automatic Channel Scan Sequencer with
Programmable Intervals
Programmable Inputs: Single Ended/Differential,
Voltage/Temperature
Programmable Wait StateInternal 2.5V/4.096V Reference
(MAX1253/MAX1254)Remote Temperature Sensing Up to 10m
(Differential Mode)Single 3V or 5V Supply OperationSmall 16-Pin TSSOP Package
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitor
Selector Guide19-2838; Rev 0; 4/03
*Future product—contact factory for availability.
*Future product—contact factory for availability.
Typical Application Circuit appears at end of data sheet.AutoShutdown is a trademark of Maxim Integrated Products, Inc.
Pin Configuration
Ordering Information
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitor
ABSOLUTE MAXIMUM RATINGSStresses 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.
VDDto GND.............................................................-0.3V to +6V
Analog Inputs to GND (AIN0–AIN7, REF) ...-0.3V to (VDD+ 0.3V)
Digital Inputs to GND (DIN, SCLK, CS) ....-0.3V to (VDD+ 0.3V)
Digital Outputs to GND (DOUT, INT) ........-0.3V to (VDD+ 0.3V)
Digital Outputs Sink Current .............................................25mA
Maximum Current into Any Pin ..........................................50mA
Continuous Power Dissipation (TA= +70°C)
16-Pin TSSOP (derate 8.7mW/°C above +70°C).........696mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
ELECTRICAL CHARACTERISTICS(VDD= +2.7V to +3.6V (MAX1253), VDD= +4.5V to +5.5V (MAX1254), VREF= +2.5V (MAX1253), VREF= +4.096V (MAX1254), fSCLK
= 10MHz (50% duty cycle), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitor
ELECTRICAL CHARACTERISTICS (continued)(VDD= +2.7V to +3.6V (MAX1253), VDD= +4.5V to +5.5V (MAX1254), VREF= +2.5V (MAX1253), VREF= +4.096V (MAX1254), fSCLK
= 10MHz (50% duty cycle), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitor
ELECTRICAL CHARACTERISTICS (continued)(VDD= +2.7V to +3.6V (MAX1253), VDD= +4.5V to +5.5V (MAX1254), VREF= +2.5V (MAX1253), VREF= +4.096V (MAX1254), fSCLK
= 10MHz (50% duty cycle), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitorhave been calibrated.
Note 2:Offset nulled.
Note 3:In reference mode 00, the reference system powers up for each temperature measurement. In reference mode 01, the ref-
erence system powers up once per sequence of channels scanned. If a sample wait <80µs is programmed, the reference
system is on all the time. In reference mode 10, the reference system is on all the time (see Table 7).
Note 4:No external capacitor on REF.
Note 5:The operational input voltage range for each individual input of a differentially configured pair (AIN0–AIN7) is from GND to
VDD. The operational input voltage difference is from -VREF/2 to +VREF/2.
Note 6:See Figure 3 and the Sampling Error vs. Input Source Impedance graph in the Typical Operating Characteristicssection.
Note 7:Grade A tested at +10°C and +55°C. -20°C to +85°C and -40°C to +85°C specifications guaranteed by design. Grade B
tested at +25°C. TMINto TMAXspecification guaranteed by design.
Note 8:External temperature measurement mode using an MMBT3904 (Diodes Inc.) as a sensor. External temperature sensing
from -40°C to +85°C; MAX1253/MAX1254 held at +25°C.
Note 9:Performing eight single-ended external channels’ temperature measurements, an internal temperature measurement, and
an internal VDDmeasurement with no sample wait results in a conversion rate of 2ksps per channel.
Note 10:Performing eight single-ended voltage measurements, an internal temperature measurement, and an internal VDDmeasure-
ment with no sample wait results in a conversion rate of 7ksps per channel.
Note 11:Performing eight single-ended voltage measurements, an internal temperature measurement, and an internal VDDmeasure-
ment with maximum sample wait results in a conversion rate of 3ksps per channel.
Note 12:Defined as the shift in the code boundary as a result of supply voltage change. VDD= min to max; full-scale input, mea-
sured using external reference.
TIMING CHARACTERISTICS(VDD= +2.7V to +3.6V (MAX1253), VDD= +4.5V to +5.5V (MAX1254), TA= TMINto TMAX, unless otherwise noted.) (Figures 1, 2, and 4)
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitor
Typical Operating Characteristics(VDD= +3V, VREF= 2.5V (MAX1253); VDD= 5V, VREF= 4.096V (MAX1254); fSCLK= 10MHz, CREF= 0.1µF, TA= +25°C, unless oth-
erwise noted.)
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitorypical Operating Characteristics (continued)(VDD= +3V, VREF= 2.5V (MAX1253); VDD= 5V, VREF= 4.096V (MAX1254); fSCLK= 10MHz, CREF= 0.1µF, TA= +25°C, unless oth-
erwise noted.)
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitor
TEMPERATURE ERROR vs. INTERCONNECT
CAPACITANCE (EXTERNAL SENSOR)MAX1253/54 toc19
INTERCONNECT CAPACITANCE (pF)
TEMPERATURE (
°C)101001000
SAMPLING ERROR
vs. INPUT SOURCE IMPEDANCEMAX1253/54 toc20
SOURCE IMPEDANCE (Ω)
SAMPLING ERROR (LSB)
100010010,000
TURN ON THERMAL TRANSIENT,
CONTINUOUS CONVERSION
VDD = 3.0VMAX1253/54 toc21
TIME (s)
TEMPERATURE SHIFT (2015105
Typical Operating Characteristics (continued)
(VDD= +3V, VREF= 2.5V (MAX1253); VDD= 5V, VREF= 4.096V (MAX1254); fSCLK= 10MHz, CREF= 0.1µF, TA= +25°C, unless oth-
erwise noted.)
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitor
Pin Description
Block Diagram
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitor
Detailed DescriptionThe MAX1253/MAX1254 are precision-monitoring inte-
grated circuit systems specifically intended for stand-
alone operation. They can monitor diverse types of
inputs, such as those from temperature sensors and
voltage signals from pressure, vibration, and accelera-
tion sensors, and digitize these input signals. The digi-
tal values are then compared to preprogrammed
thresholds and, if the thresholds are exceeded, the
processor is alerted by an interrupt signal. No interac-
tion by the CPU or microcontroller (µC) is required until
one of the programmed limits is exceeded (Figures 3
and 4).
Voltages on all the inputs are converted to 12-bit values
sequentially and stored in the current data registers.
Note that eight of these inputs are external and two are
internal. One of the internal inputs monitors the VDD
voltage supply, while the other monitors the internal IC
temperature. AIN0 to AIN7 can be configured as either
single ended (default) or differential. In addition, these
inputs can be configured for single-ended or differen-
tial temperature measurements. In the temperature
configuration, the device provides the proper bias nec-
essary to measure temperature with a diode-connected
transistor sensor. The user enables which inputs are
measured (both external and internal) and sets the
delay between each sequence of measurements dur-
ing the initial setup of the device.
The values stored in the current data registers are com-
pared to the user-preprogrammed values in the thresh-
old registers (upper and lower thresholds) and, if
exceeded, activate the interrupt output and generate an
alarm condition. If desired, the device can be pro-
grammed to average the results of many measurements
before comparing to the threshold value. This reduces
the sensitivity to external noise in the measured signal.
In addition, the user can set the number of times the
threshold is exceeded (fault cycles) before generating
an interrupt. This feature reduces falsely triggered
alarms caused by undesired, random spurious impulses.
When the fault cycle criterion is exceeded, an alarm
condition is created. The device writes the fault condi-
tion into the alarm register to indicate the alarmed input
channel.
Converter OperationThe MAX1253/MAX1254 ADCs use a fully differential
successive-approximation register (SAR) conversion
technique and an on-chip track-and-hold (T/H) block to
convert temperature and voltage signals into a 12-bit
digital result. Both single-ended and differential config-
urations are supported with a unipolar signal range for
single-ended mode and bipolar or unipolar ranges for
differential mode. Figure 5 shows the equivalent input
circuit for the MAX1253/MAX1254. Configure the input
channels according to Tables 5 and 6 (see the Input
Configuration Registersection).
In single-ended mode, the positive input (IN+) is con-
nected to the selected input channel and the negative
input (IN-) is connected to GND. In differential mode,
IN+ and IN- are selected from the following pairs:
AIN0/AIN1, AIN2/AIN3, AIN4/AIN5, and AIN6/AIN7.
Once initiated, voltage conversions require 10.6µs (typ)
to complete.
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitorDuring the acquisition interval, IN+ and IN- charge both
a positive (CHOLDP) and a negative (CHOLDN) sam-
pling capacitor. After completing the acquisition inter-
val, the T/H switches open, storing an accurate sample
of the differential voltage between IN+ and IN-. This
charge is then transferred to the ADC and converted.
Finally, the conversion result is transferred to the cur-
rent data register.
Temperature conversions require 46µs (typ) and mea-
sure the difference between two sequential voltage
measurements (see the Temperature Measurement
section for a detailed description).
Fully Differential Track/Hold (T/H)The T/H acquisition interval begins with the rising edge
of CS(for manually triggered conversions) and is inter-
nally timed to 1.5µs (typ). The accuracy of the input sig-
nal sample is a function of the input signal’s source
impedance and the T/H’s capacitance. In order to
achieve adequate settling of the T/H, limit the signal
source impedance to a maximum of 1kΩ.
Input BandwidthThe ADC’s input tracking circuitry has a 1MHz small-
signal bandwidth. To avoid high-frequency signals
aliasing into the frequency band of interest, anti-alias
prefiltering of the input signals is recommended.
Analog Input ProtectionInternal protection diodes, which clamp the analog
inputs to VDDand GND, allow the channel input pins to
swing from (GND - 0.3V) to (VDD+ 0.3V) without dam-
age. However, for accurate conversions near full scale,
the inputs must not exceed VDDby more than 50mV or
be lower than GND by 50mV. If the analog input range
must exceed 50mV beyond the supplies, limit the input
current.
Single Ended/DifferentialThe MAX1253/MAX1254 use a fully differential ADC for
all conversions. Through the input configuration regis-
ter, the analog inputs can be configured for either dif-
ferential or single-ended conversions. When sampling
signal sources close to the MAX1253/MAX1254, single-
ended conversion is generally sufficient. Single-ended
conversions use only one analog input per signal
source, internally referenced to GND.
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitor
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitorIn differential mode, the T/H samples the difference
between two analog inputs, eliminating common-mode
DC offsets and noise. See the Input Configuration
Registersection and Tables 5 and 6 for more details on
configuring the analog inputs.
Unipolar/BipolarWhen performing differential conversions, the input
configuration register (Tables 5 and 6) also selects
between unipolar and bipolar operation. Unipolar mode
sets the differential input range from 0 to VREF. A nega-
tive differential analog input in unipolar mode causes
the digital output code to be zero. Selecting bipolar
mode sets the differential input range to ±VREF/2. The
digital output code is straight binary in unipolar mode
and two’s complement in bipolar mode (see the
Transfer Functionsection).
In single-ended mode, the MAX1253/MAX1254 always
operate in unipolar mode. The analog inputs are inter-
nally referenced to GND with a full-scale input range
from 0 to VREF.
Digital InterfaceThe MAX1253/MAX1254 digital interface consists of
five signals: CS, SCLK, DIN, DOUT, and INT. CS,
SCLK, DIN, and DOUT comprise an SPI™-compatible
serial interface (see the Serial Digital Interfacesection).
INT is an independent output that provides an indica-
tion that an alarm has occurred in the system (see the
INT Interrupt Outputsection).
Serial Digital InterfaceThe MAX1253/MAX1254 feature a serial interface com-
patible with SPI, QSPI™, and MICROWIRE™ devices.
For SPI/QSPI, ensure that the CPU serial interface runs
in master mode so it generates the serial clock signal.
Select a serial clock frequency of 10MHz or less, and
set clock polarity (CPOL) and phase (CPHA) in the µP
control registers to the same value, one or zero. The
MAX1253/MAX1254 support operation with SCLK idling
high or low, and thus operate with CPOL = CPHA = 0 or
CPOL = CPHA = 1.
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitorClock pulses on SCLK shift data into DIN on the rising
edge of the SCLK and out of DOUT on the falling edge
of SCLK.
Data transfers require a logic low on CS. A high-to-low
transition of CSmarks the beginning of a data transfer. A
logic high on CSat any time resets the serial interface.
See Figure 6 and the Timing Characteristicstable for
detailed serial-interface timing information.
Input Data FormatSerial communications always begin with an 8-bit com-
mand word, serially loaded from DIN. A high-to-low
transition on CSinitiates the data input operation. The
command word and the subsequent data bytes (for
write operations) are clocked from DIN into the
MAX1253/MAX1254 on the rising edges of SCLK. The
first rising edge on SCLK, after CSgoes low, clocks in
the MSB of the command word (see the Command
Wordsection). The next seven rising edges on SCLK
complete the loading of the command word into the
internal command register. After the 8-bit command
word is entered, transfer 0 to 20 bytes of data, depend-
ing on the command. Table 2 shows the number of
data bytes for each command.
Output Data FormatOutput data from the MAX1253/MAX1254 is clocked
onto DOUT on the falling edge of SCLK. Single-ended
and unipolar differential measurements are output in
straight binary MSB first, with two 8-bytes-per-conver-
sion result, and the last 4 bits padded with zeros. For
temperature and bipolar differential voltage measure-
ments, the output is two’s complement binary in the
same 2-byte format. The MSB of the output data from a
read command transitions at DOUT after the falling
edge of the 8th SCLK clock pulse following the CS
high-to-low transition. Table 2 shows the number of
bytes to be read from DOUT for a given read com-
mand.
Command WordThe command word (Table 1) controls all serial com-
munications and configuration of the MAX1253/
MAX1254, providing access to the 44 on-chip registers.
The first 4 MSBs of the command word specify the
command (Table 2), while the last 4 bits provide
address information.
The first rising edge on SCLK, after CSgoes low, trans-
fers the command word MSB into DIN. The next seven
rising edges on SCLK shift the remaining 7 bits into the
internal command register (see the Serial Digital
Interfacesection).
MAX1253/MAX1254
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and VDDMonitor
Manually Triggered Conversion
(Command Code = 0000)Before beginning a manual conversion, ensure the
scan mode bit in the setup register is zero, because a
logic 1 disables manual conversions. The address bits
in a Manually Triggered Conversion command select
the input channel for conversion (see Table 3). When
performing a differential conversion, use the even chan-
nel address (AIN0, AIN2, AIN4, AIN6); the command is
ignored if odd channel addresses (AIN1, AIN3, AIN5,
AIN7) are used for a differential conversion.
After issuing a Manually Triggered Conversion com-
mand, bring CShigh to begin the conversion. To obtain
a correct conversion result, CSmust remain high for a
period longer than the reference power-up time (if in
power-down mode) plus the conversion time for the
selected channel configured conversion type (voltage
or temperature). The conversion’s result can then be
read at DOUT by issuing a Read Current Data Register
for Selected Channel command, addressing the con-
verted channel. See Table 3 for channel addresses.
