19-2838; Rev 0; 4/03
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and V
DD
Monitor
General Description
The 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). AutoShutdown
TM
reduces 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.
Features
o
Monitor 10 Signals Without Processor
Intervention
o
Eight External Channels Programmable as
Temperature or Voltage Monitors
o
Intelligent Circuitry for Reliable Autonomous
Measurement
Programmable Digital Averaging Filter
Programmable Fault Counter
o
Precision Measurements
12-Bit Resolution
±1 LSB INL, ±1 LSB DNL
±0.75°C Temperature Accuracy (typ)
o
Flexible
Automatic Channel Scan Sequencer with
Programmable Intervals
Programmable Inputs: Single Ended/Differential,
Voltage/Temperature
Programmable Wait State
o
Internal 2.5V/4.096V Reference
(MAX1253/MAX1254)
o
Remote Temperature Sensing Up to 10m
(Differential Mode)
o
Single 3V or 5V Supply Operation
o
Small 16-Pin TSSOP Package
MAX1253/MAX1254
Applications
System Supervision
Remote Telecom Networks
Server Farms
Remote Data Loggers
PART
MAX1253AEUE*
MAX1253BEUE
MAX1254AEUE*
MAX1254BEUE
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
16 TSSOP
16 TSSOP
16 TSSOP
16 TSSOP
*Future
product—contact factory for availability.
Selector Guide
PART
MAX1253AEUE*
MAX1253BEUE
MAX1254AEUE*
MAX1254BEUE
INL (LSB)
±1
±1
±1
±1
TEMP
ERROR (°C)
±1.0
±3.0
±1.0
±2.5
SUPPLY
VOLTAGE (V)
2.7 to 3.6
2.7 to 3.6
4.5 to 5.5
4.5 to 5.5
Pin Configuration
TOP VIEW
AIN0 1
AIN1 2
AIN2 3
AIN3 4
AIN4 5
AIN5 6
AIN6 7
16 CS
15 SCLK
14 DIN
MAX1253
MAX1254
13 V
DD
12 GND
11 DOUT
10 INT
9
REF
*Future
product—contact factory for availability.
Typical Application Circuit appears at end of data sheet.
AutoShutdown is a trademark of Maxim Integrated Products, Inc.
AIN7 8
16 TSSOP
1
________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and V
DD
Monitor
MAX1253/MAX1254
ABSOLUTE MAXIMUM RATINGS
VDD to GND .............................................................-0.3V to +6V
Analog Inputs to GND (AIN0–AIN7, REF) ... -0.3V to (V
DD
+ 0.3V)
Digital Inputs to GND (DIN, SCLK,
CS)
.... -0.3V to (V
DD
+ 0.3V)
Digital Outputs to GND (DOUT, INT) ........ -0.3V to (V
DD
+ 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
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.
ELECTRICAL CHARACTERISTICS
(V
DD
= +2.7V to +3.6V (MAX1253), V
DD
= +4.5V to +5.5V (MAX1254), V
REF
= +2.5V (MAX1253), V
REF
= +4.096V (MAX1254), f
SCLK
= 10MHz (50% duty cycle), T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DC ACCURACY
Resolution
Integral Nonlinearity (Note 1)
Differential Nonlinearity
Offset Error
Gain Error (Note 2)
Offset Error Tempco
Gain and Temperature Coefficient
Channel-to-Channel Offset Matching
V
DD
Monitor Accuracy
Internal reference
External reference
Internal reference
External reference
Internal reference
±5
±2
±30
±0.1
±2.5
RES
INL
DNL
Grade A
Grade B
No missing codes overtemperature
12
±1.0
±1.0
±1.0
±4.0
±4.0
2.0
Bits
LSB
LSB
LSB
LSB
%FSR
ppm/°C
ppm/°C
LSB
%
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DYNAMIC ACCURACY
(10kHz sine-wave input, 2.5V
P-P
(MAX1253), 4.096V
P-P
(MAX1254), 64ksps, f
SCLK
= 10MHz, bipolar input mode)
Signal-to-Noise Plus Distortion
Total Harmonic Distortion
Spurious-Free Dynamic Range
Full-Power Bandwidth
Full Linear Bandwidth
CONVERSION RATE
Voltage measurement, all ref modes
Conversion Time (Note 3)
Single-Channel Throughput
Power-Up Time
ANALOG INPUT
(AIN0–AIN7)
Input Voltage Range (Note 5)
Common-Mode Range
Common-Mode Rejection
Unipolar, single-ended, or differential inputs
Bipolar, differential inputs
Differentially configured inputs
Differentially configured inputs, V
CM
= 0 to V
DD
0
-V
REF
/ 2
0
-90
+V
REF
+V
REF
/ 2
V
DD
V
V
dB
t
PU
t
CONV
Temp-sensor ref modes 01, 10
Temp-sensor ref mode 00
Manual trigger, voltage measurement
Internal reference (Note 4)
70
40
45
10.6
46
73
11.7
50.7
80
ksps
µs
µs
SINAD
THD
SFDR
-3dB point
S / (N + D) > 68dB
Up to the 5th harmonic
70
-76
72
1
100
dB
dB
dB
MHz
kHz
2
_______________________________________________________________________________________
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and V
DD
Monitor
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +2.7V to +3.6V (MAX1253), V
DD
= +4.5V to +5.5V (MAX1254), V
REF
= +2.5V (MAX1253), V
REF
= +4.096V (MAX1254), f
SCLK
= 10MHz (50% duty cycle), T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Input Leakage Current
Input Capacitance
TEMPERATURE MEASUREMENTS
Grade A
MAX1253
MAX1254
Internal Sensor Measurement Error
(Note 7)
Grade B
MAX1253
Grade B
MAX1254
Differential
External Sensor Measurement
Error (Note 8)
Single ended
T
A
= -20°C to +85°C
T
A
= -40°C to +85°C
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= +25°C
±0.5
±0.75
±0.3
±1.2
±0.7
±1.2
±0.7
±2
±1
±5
±2
0.3
0.1
0.125
Low
High
PSR
Differentially configured inputs and internal
sensor
Single-ended configured, external sensor
INTERNAL REFERENCE
REF Output Voltage
REF Temperature Coefficient
REF Output Resistance
REF Output Noise
REF Power-Supply Rejection Ratio
EXTERNAL REFERENCE
REF Input Voltage Range
REF Input Current
V
REF
I
REF
V
REF
= +2.5V; f
SAMPLE
= 94ksps
In power-down
1.0
15
V
DD
+ 0.05
40
±1
V
µA
PSRR
MAX1253
MAX1254
MAX1253
MAX1254
V
REF
TC
REF
MAX1253
MAX1254
Grade A
Grade B
2.456
4.024
2.500
4.096
±8
±30
7
200
160
-70
-70
-50
-50
2.544
4.168
V
ppm/°C
kΩ
µV
RMS
dB
4
66
0.3
0.1
°C/LSB
µA
°C
°C
±3.0
±2.5
°C
±1.0
±1.5
SYMBOL
(Note 6)
CONDITIONS
On-/off-leakage, V
IN
= 0 or V
DD
18
MIN
TYP
MAX
±1
UNITS
µA
pF
MAX1253/MAX1254
Temperature Measurement Noise
Temperature Resolution
External Sensor Bias Current
Differentially configured inputs and internal
sensor
Single-ended configured, external sensor
Power-Supply Rejection
°C/V
_______________________________________________________________________________________
3
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and V
DD
Monitor
MAX1253/MAX1254
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +2.7V to +3.6V (MAX1253), V
DD
= +4.5V to +5.5V (MAX1254), V
REF
= +2.5V (MAX1253), V
REF
= +4.096V (MAX1254), f
SCLK
= 10MHz (50% duty cycle), T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DIGITAL INPUTS
(SCLK, DIN,
CS)
Input Voltage Low
Input Voltage High
Input Hysteresis
Input Leakage Current
Input Capacitance
DIGITAL OUTPUTS
(INT, DOUT)
Output Voltage Low
Output Voltage High
Tri-State Leakage Current
Tri-State Output Capacitance
POWER REQUIREMENTS
Positive Supply Voltage
V
DD
MAX1253
MAX1254
MAX1253 internal reference (Note 9)
MAX1253 internal reference (Note 10)
MAX1253 external reference (Note 10)
Supply Current
I
DD
MAX1254 internal reference (Note 9)
MAX1254 internal reference (Note 10)
MAX1254 external reference (Note 10)
Both internal reference, mode 01 (Note 11)
Full Power-Down Supply Current
Power-Supply Rejection Ratio
I
SHDN
PSRR
Full power-down state
MAX1253
MAX1254
8
480
860
±0.4
±1.6
2.7
4.5
3.6
5.5
3.3
2.9
2.2
5.0
4.0
3.0
µA
nA
mV/V
mA
V
V
OL
V
OH
I
L
C
OUT
I
SINK
= 8mA, DOUT
I
SINK
= 2mA, INT
I
SOURCE
= 8mA, DOUT
I
SOURCE
= 2mA, INT
CS
= V
DD
CS
= V
DD
5
V
DD
- 0.5
V
DD
- 0.5
±10
0.5
0.5
V
V
µA
pF
V
IL
V
IH
V
HYST
I
IN
C
IN
V
IN
= 0 or V
DD
2
V
DD
x 0.7
200
±10
V
DD
x 0.3
V
V
mV
µA
pF
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Analog inputs at full scale (Note 12)
4
_______________________________________________________________________________________
Stand-Alone, 10-Channel, 12-Bit System Monitors
with Internal Temperature Sensor and V
DD
Monitor
TIMING CHARACTERISTICS
(V
DD
= +2.7V to +3.6V (MAX1253), V
DD
= +4.5V to +5.5V (MAX1254), T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Figures 1, 2, and 4)
PARAMETER
SCLK Clock Period
SCLK Pulse Width High Time
SCLK Pulse Width Low Time
DIN to SCLK Setup Time
DIN to SCLK Hold Time
CS
Fall to SCLK Rise Setup
SCLK Rise to
CS
Rise Hold
SCLK Fall to DOUT Valid
CS
Rise to DOUT Disable
CS
Fall to DOUT Enable
CS
Pulse Width High
SYMBOL
t
CP
t
CH
t
CL
t
DS
t
DH
t
CSS
t
CSH
t
DOV
t
DOD
t
DOE
t
CSW
C
L
= 30pF
C
L
= 30pF
C
L
= 30pF
40
CONDITIONS
MIN
100
45
45
25
0
25
50
50
40
40
TYP
0.5
MAX
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
MAX1253/MAX1254
Note 1:
Relative accuracy is the deviation of the analog value at any code from its theoretical value after the gain and offset errors
have 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
V
DD
. 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 Characteristics
section.
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. T
MIN
to T
MAX
specification 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 V
DD
measurement 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 V
DD
measure-
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 V
DD
measure-
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. V
DD
= min to max; full-scale input, mea-
sured using external reference.
_______________________________________________________________________________________
5
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