SOT23 (Ordering Information contains “#”).................+245°C
SOT23 (Ordering Information contains “-”)..................+240°C
Note 1:
It is not recommended to operate the device above +125°C for extended periods of time.
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
CC
= +3.0V to +5.5V, T
A
= -55°C to +125°C, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.) (Notes
2 and 3)
PARAMETER
TEMPERATURE
T
A
= room temp, V
CC
= +3.3V
0°C ≤ T
A
≤ +70°C, V
CC
= +3.3V
-20°C ≤ T
A
≤ +85°C, V
CC
= +3.3V
Accuracy
-20°C ≤ T
A
≤ +100°C, V
CC
= +3.3V
-40°C ≤ T
A
≤ +125°C, V
CC
= +3.3V
T
A
≥ -55°C, V
CC
= +3.3V
T
A
= +150°C, V
CC
= +3.3V
Power-Supply Sensitivity
Resolution
Time Between Conversion
Starts
Conversion Time
POWER SUPPLY
Supply Voltage Range
Supply Current, SCK Idle
V
CC
I
SD
I
IDLE
I
CONV
Average Operating Current
Power-On Reset (POR)
Threshold
I
CC
Shutdown (Note 3), V
CC
= +0.8V
ADC idle (Figure 2),
CS
= low
ADC converting (Figure 2)
MAX6629, MAX6630
MAX6631, MAX6632
V
CC
falling
6
360
200
32
1.6
3.0
5.5
5
20
650
400
50
µA
V
µA
V
t
SAMPLE
t
CONV
MAX6629, MAX6630,
CS
high
MAX6631, MAX6632,
CS
high
PSS
0.0625
0.37
5.9
180
0.5
8
250
0.65
10.5
320
-0.8
-1.0
-1.6
-2.3
-3.2
-1.0
-5.0
±0.2
±0.2
+0.3
+0.5
+0.8
+1.5
+1.5
0.2
+0.8
+1.0
+1.6
+2.3
+3.2
+3.5
+6.5
0.6
°C/V
°C
s
ms
°C
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
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2
MAX6629–MAX6632
12-Bit + Sign Digital Temperature Sensors
with Serial Interface
Electrical Characteristics (continued)
(V
CC
= +3.0V to +5.5V, T
A
= -55°C to +125°C, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.) (Notes
2 and 3)
PARAMETER
LOGIC INPUTS (CS, SCK)
Logic Input Low Voltage
Logic Input High Voltage
Input Leakage Current
LOGIC OUTPUTS (SO)
Output Low Voltage
Output High Voltage
Serial Clock Frequency
SCK Pulse Width High
SCK Pulse Width Low
CS
Fall to SCK Rise
CS
Fall to Output Enable
CS
Rise to Output Disable
SCK Fall to Output Data Valid
V
OL
V
OH
f
SCL
t
CH
t
CL
t
CSS
t
DV
t
TR
t
DO
C
LOAD
= 10pF
C
LOAD
= 10pF
C
LOAD
= 10pF
C
LOAD
= 10pF
100
100
80
80
50
80
I
SINK
= 1.6mA
I
SOURCE
= 1.6mA
V
CC
- 0.4
5
0.4
V
V
MHz
ns
ns
ns
ns
ns
ns
V
IL
V
IH
I
LEAK
V
IN
= V
GND
or +5.5V
0.7 x
V
CC
±1
±5
0.3 x
V
CC
V
V
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
TIMING CHARACTERISTICS (Notes 4 and 5)
Note 2:
Tested at a single temperature. Specifications over temperature are guaranteed by design.
Note 3:
The MAX6629–MAX6632 are not specifically equipped with a shutdown function. Their low supply current permits powering
them from the output of a logic gate. This specification is given to ensure that the MAX6629–MAX6632 do not draw exces-
sive currents at low supply voltages, ensuring reliable operation from a gate output.
Note 4:
Timing characteristics are guaranteed by design and are not production tested.
Note 5:
C
LOAD
= total capacitance of one bus line in picofarads.
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│
3
MAX6629–MAX6632
12-Bit + Sign Digital Temperature Sensors
with Serial Interface
Typical Operating Characteristics
(V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
OPERATING SUPPLY CURRENT
vs. TEMPERATURE
MAX6629-32 toc01
MAX6629-32 toc02
POWER-ON RESET THRESHOLD (V)
V
CC
= +5.5V V
CC
= +4.5V
TEMPERATURE ERROR (∞C)
350
SUPPLY CURRENT (µA)
300
250
200
150
100
V
CC
= +3.3V
V
CC
= +3.0V
V
CC
= +5.0V
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
-55 -30
-5
20
45
70
95
2
1
0
-1
-2
-3
-4
MAX6629
-55 -30
-5
20
45
70
95
V
CC
= +3.6V
MAX6629
-55 -30
-5
20
45
70
95
120 145
TEMPERATURE (°C)
120 145
120 145
TEMPERATURE (°C)
TEMPERATURE (°C)
MAX6629-32 toc04
10
TEMPERATURE ERROR (°C)
8
6
4
2
0
V
IN
= SQUARE WAVE
APPLIED TO V
CC
WITH NO
0.1µF CAPACITOR
125
100
TEMPERATURE (°C)
75
50
25
0
V
IN
= 250mV
P-P
10
100
1k
10k
100k
1M
10M 100M
-2
0
2
4
6
TIME (s)
8
10
12
14
FREQUENCY (Hz)
Pin Description
PIN
MAX6629
MAX6631
1
2
3
4
5
6
—
MAX6630
MAX6632
2
1
3
4
5
6
—
NAME
N.C.
GND
V
CC
SCK
CS
SO
EP
FUNCTION
No Connect. Connect to ground plane for better thermal performance to the PC board.
Ground
Supply Voltage Input. Bypass V
CC
to GND with a 0.1µF capacitor. V
CC
can also be
powered from a logic output as long as the voltage level is greater than 3.0V and the logic
output is not noisy. Setting the logic output low provides a hardware shutdown mode.
Serial Clock Input
Chip-Select Input. Enables the interface. A rising edge off
CS
initiates the next conversion.
Pulling
CS
low initiates an idle state.
Serial Data Output
Exposed Pad (TDFN only). Connect to GND or leave unconnected.
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MAX6629-32 toc05
12
TEMPERATURE ERROR
vs. POWER-SUPPLY NOISE FREQUENCY
RESPONSE TO THERMAL SHOCK
MAX6629-32 toc03
400
2.6
POWER-ON RESET (POR)
THRESHOLD vs.TEMPERATURE
3
TEMPERATURE ERROR
vs. TEMPERATURE
MAX6629–MAX6632
12-Bit + Sign Digital Temperature Sensors
with Serial Interface
Detailed Description
The MAX6629–MAX6632 are local digital temperature
sensors with a serial bus. The MAX6629–MAX6632 are
typically interfaced to a μC in temperature sensing and
control applications. The MAX6629–MAX6632 convert
temperature to a 12-bit + sign word with a 0.0625°C LSB.
The data is communicated through a simple serial inter-
face with a
CS
(chip select) line, SO (data) line, and SCK
(clock) line. This interface can be directly connected to,
and is fully compatible with, SPI interfaces. This interface
can also be connected to virtually any processor, which
has at least three general-purpose input/output (GPIO)
lines available to implement software “bit banging.”
The high resolution of the MAX6629–MAX6632 makes
them especially useful in thermal control loops, HVAC
systems, or in any system where quick anticipation of
temperature trends is useful. The MAX6629–MAX6632
can produce temperature data in excess of +150°C,
although they are specified for a maximum operating
temperature of +150°C. The low power consumption is
also ideal in battery-operated and portable applications.
The MAX6631/MAX6632 are optimized for minimum
power consumption with their 8s conversions. The
MAX6629/MAX6630 provide faster conversions, 0.5s, at
the expense of power consumption. The low quiescent
supply current enables the device to be powered from
a logic line or the output of a gate where the high level
exceeds 3V, as shown in Figure 1. While the MAX6629–
MAX6632 are not specifically equipped with a software
shutdown mode, the hardware shutdown can easily be
implemented by setting the gate output to low. Pulling
CS
low without a clock also puts the device in idle mode.
Take care to ensure that the logic output is not noisy, as
excessive noise on V
CC
can affect temperature measure-
ment accuracy.
MAX6629
MAX6630
CONVERSION PERIOD
0.5s
LOGIC LINE WHERE V
LOGIC
> 3V
V
CC
MAX6629
MAX6630
MAX6631
MAX6632
SO
SCK
CS
GND
Figure 1. Powering the Sensor from a Logic Gate
ADC Conversion Sequence
The MAX6629–MAX6632 continuously convert tempera-
ture to digital data. Setting
CS
low stops any conversion
in progress, places the device in idle mode, and makes
data available for reading. Setting
CS
high starts a new
conversion.
CS
must remain high for at least 0.3s to allow
for the conversion to be completed. Figure 2 shows the
timing relationship between conversion time and conver-
sion rate.
SPI Digital Interface
The MAX6629–MAX6632 are compatible with SPI serial-
interface standards (Figure 3) and are designed to be
read-only devices.
CS’s
rising edge always starts a new
conversion and resets the interface.
CS
must stay high
for a minimum of 300ms to allow the conversion to finish.
CS’s
falling edge stops any conversion in progress, and
data is latched into the shift register. Then the data clocks