Page 1
General Description
The MAX6629–MAX6632 are local digital temperature
sensors with an SPI™-compatible serial interface. The
temperature is converted to a 12-bit + sign word with a
resolution of 0.0625°C/LSB. An extended temperature
range provides useful readings up to +150°C.
These sensors are 3-wire serial interface SPI compatible, allowing the MAX6629–MAX6632 to be readily connected to a variety of microcontrollers (µCs). The
MAX6629–MAX6632 are read-only devices, simplifying
their use in systems where only temperature data is
required.
All four digital temperature sensors require very little
supply current, making them ideal for portable systems.
The MAX6631/MAX6632 perform a temperature-to-digital conversion once every 8s and require minimal average supply current, 32µA (typ). The MAX6629/
MAX6630 perform a conversion once every 0.5s and
require only 200µA (typ) supply current. Any of these
temperature sensors can perform conversions more
often—up to approximately four conversions per second by reading the conversion results more often.
Applications
Features
♦ Low Power Consumption
32µA typ (MAX6631/MAX6632)
200µA typ (MAX6629/MAX6630)
♦ 12-Bit + Sign Resolution with 0.0625°C/LSB
♦ Accuracy
±1°C (max) from 0°C to +70°C
♦ +150°C Extended Temperature Range
♦ SPI-Compatible Serial Interface
♦ +3.0V to +5.5V Supply Range
♦ 6-Pin TDFN and SOT23 Packages
♦ Lead-Free Version Available (TDFN Package)
MAX6629–MAX6632
12-Bit + Sign Digital Temperature Sensors
with Serial Interface
________________________________________________________________
Maxim Integrated Products
1
Pin Configurations
19-2047; Rev 4; 5/10
Ordering Information
SPI is a trademark of Motorola, Inc.
V
CC
SO
GND
SCK
μC
+3V TO +5.5V
0.1μF
MAX6629
MAX6630
MAX6631
MAX6632
CS
Typical Application Circuit
Cellular
Hard Disk Drive
HVAC
Automotive
Industrial Control
Systems
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
*
EP = Exposed pad.
PART TEMP RANGE PIN-PACKAGE
MAX6629MTT+ -55°C to +125°C 6 TDFN-EP*
MAX6629MUT -55°C to +125°C 6 SOT23-6
MAX6630MTT+ -55°C to +125°C 6 TDFN-EP*
MAX6630MUT -55°C to +125°C 6 SOT23-6
MAX6631MTT+ -55°C to +125°C 6 TDFN-EP*
MAX6631MUT -55°C to +125°C 6 SOT23-6
MAX6632MTT+ -55°C to +125°C 6 TDFN-EP*
MAX6632MUT -55°C to +125°C 6 SOT23-6
TOP VIEW
16SO
N.C.
GND
MAX6629
2
MAX6631
34
CC
SOT23
TDFN TDFN
CS
5
SCKV
16SO
GND
N.C.
MAX6630
2
MAX6632
34
CC
SOT23
CS
5
SCKV
Page 2
MAX6629–MAX6632
12-Bit + Sign Digital Temperature Sensors
with Serial Interface
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.
All Voltages Referenced to GND
V
CC
...........................................................................-0.3V, +6.0V
SO, SCK, CS ....................................................-0.3V, V
CC
+ 0.3V
SO .......................................................................-1mA to +50mA
Current into Any Pin ............................................................10mA
Continuous Power Dissipation (T
A
= +70°C)
6-Pin SOT23 (derate 9.10mW/°C above +70°C)..........727mW
6-Pin TDFN (derate 24.4mW/°C above +70°C) .........1951mW
Junction Temperature......................................................+150°C
Operating Temperature Range (Note 1) ...........-55°C to +150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow)
TDFN............................................................................+260°C
SOT23 (Ordering Information contains “#”) .................+245°C
SOT23 (Ordering Information contains “-”)..................+240°C
ELECTRICAL CHARACTERISTICS
(VCC= +3.0V to +5.5V, TA= -55°C to +125°C, unless otherwise noted. Typical values are at VCC= +3.3V and TA= +25°C.) (Notes 2
and 3)
Note: It is not recommended to operate the device above +125°C for extended periods of time.
TEMPERATURE
Accuracy
Power-Supply Sensitivity PSS 0.2 0.6 °C/V
Resolution 0.0625 °C
Time Between Conversion
Starts
Conversion Time t
POWER SUPPLY
Supply Voltage Range VCC 3.0 5.5 V
Supply Current, SCK Idle
Average Operating Current I
Power-On Reset (POR)
Threshold
PARAMETER S YMBOL CONDITIONS MIN TYP MAX UNITS
TA = room temp, VCC = +3.3V -0.8 ±0.2 +0.8
0°C TA +70°C, VCC = +3.3V -1.0 ±0.2 +1.0
-20°C TA +85°C, VCC = +3.3V -1.6 +0.3 +1.6
-20°C TA +100°C, VCC = +3.3V -2.3 +0.5 +2.3 °C
-40°C TA +125°C, VCC = +3.3V -3.2 +0.8 +3.2
TA -55°C, VCC = +3.3V -1.0 +1.5 +3.5
= +150°C, VCC = +3.3V -5.0 +1.5 +6.5
T
A
t
SAMPLE
CONV
ISD Shutdown (Note 3), VCC = +0.8V 5
I
IDLE
I
CONV
CC
MAX6629, MAX6630, CS high 0.37 0.5 0.65
MAX6631, MAX6632, CS high 5.9 8 10.5
180 250 320 ms
ADC idle (Figure 2), CS = low 6 20
ADC converting (Figure 2) 360 650
MAX6629, MAX6630 200 400
MAX6631, MAX6632 32 50
V
falling 1.6 V
CC
s
μA
μA
Page 3
MAX6629–MAX6632
12-Bit + Sign Digital Temperature Sensors
with Serial Interface
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +3.0V to +5.5V, TA= -55°C to +125°C, unless otherwise noted. Typical values are at VCC= +3.3V and TA= +25°C.) (Notes 2
and 3)
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
excessive 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.
LOGIC INPUTS (CS, SCK)
Logic Input Low Voltage VIL
Logic Input High Voltage V
Input Leakage Current I
LOGIC OUTPUTS (SO)
Output Low Voltage VOL I
Output High Voltage VOH I
TIMING CHARACTERISTICS (Notes 4 and 5)
Serial Clock Frequency f
SCK Pulse Width High tCH 100 ns
SCK Pulse Width Low tCL 100 ns
CS Fall to SCK Rise t
CS Fal l to Output Enable tDV C
CS Ri se to Output Disable tTR C
SCK Fal l to Output Data Valid tDO C
PARAMETER S YMBOL CONDITIONS MIN TYP MAX UNITS
0.3 x
V
CC
IH
VIN = V
LEAK
SINK
SOURCE
5 MHz
SCL
C
CSS
LOAD
LOAD
LOAD
LOAD
or + 5.5V ±1 ±5 μA
GND
= 1.6mA 0.4 V
= 1.6mA VCC - 0.4 V
= 10pF 80 ns
= 10pF 80 ns
= 10pF 50 ns
= 10pF 80 ns
0.7 x
V
V
CC
V
Page 4
MAX6629–MAX6632
12-Bit + Sign Digital Temperature Sensors
with Serial Interface
4 _______________________________________________________________________________________
Typical Operating Characteristics
(V
CC
= +3.3V, TA= +25°C, unless otherwise noted.)
100
200
150
300
250
400
350
-55 -5 20 45-30 70 95 120 145
OPERATING SUPPLY CURRENT
vs. TEMPERATURE
MAX6629-32 toc01
TEMPERATURE (°C)
SUPPLY CURRENT (μA)
MAX6629
VCC = +5.5V
VCC = +4.5V
VCC = +5.0V
VCC = +3.0V
VCC = +3.3V
VCC = +3.6V
0.6
1.0
0.8
1.4
1.2
1.8
1.6
2.0
2.4
2.2
2.6
-55 -5 20 45-30 70 95 120 145
POWER-ON RESET (POR)
THRESHOLD vs.TEMPERATURE
MAX6629-32 toc02
TEMPERATURE (°C)
POWER-ON RESET THRESHOLD (V)
-4
-2
-3
0
-1
2
1
3
-55 -5 20 45-30 70 95 120 145
TEMPERATURE ERROR
vs. TEMPERATURE
MAX6629-32 toc03
TEMPERATURE (°C)
TEMPERATURE ERROR (°C)
MAX6629
10 100k 10M1k100 10k 1M 100M
TEMPERATURE ERROR
vs. POWER-SUPPLY NOISE FREQUENCY
MAX6629-32 toc04
FREQUENCY (Hz)
TEMPERATURE ERROR (°C)
0
4
2
6
8
10
12
V
IN
= SQUARE WAVE
APPLIED TO V
CC
WITH NO
0.1μF CAPACITOR
VIN = 250mV
P-P
0
25
50
75
100
125
-2 20 4 6 8 10 12 14
RESPONSE TO THERMAL SHOCK
MAX6629-32 toc05
TIME (s)
TEMPERATURE (°C)
Pin Description
PIN NAME FUNCTION
MAX6629
MAX6631
MAX6630
MAX6632
1 2 N.C. No Connect. Connect to ground plane for better thermal performance to the PC board.
2 1 GND Ground
3 3 V
CC
Supply Voltage Input. Bypass VCC to GND with a 0.1μF capacitor. VCC can also be
powered from a logic output as long as the vo ltage level is greater than 3.0V and the
logic output is not noisy. Setting the logic output low provides a hardware shutdown
mode.
4 4 SCK Serial Clock Input
5 5 CS
Chip-Select Input. Enables the interface. A rising edge off CS initiates the next
convers ion. Pulling CS low initiates an idle state.
6 6 SO Serial Data Output
— — EP Exposed Pad (TDFN only). Connect to GND or leave unconnected.
Page 5
MAX6629–MAX6632
12-Bit + Sign Digital Temperature Sensors
with Serial Interface
_______________________________________________________________________________________ 5
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
interface 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. This extended temperature
range makes it especially useful in automotive underhood applications. 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 tem-
perature measurement accuracy.
ADC Conversion Sequence
The MAX6629–MAX6632 continuously convert temperature 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 conversion 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
Figure 2. Conversion Time and Rate Relationships
Figure 1. Powering the Sensor from a Logic Gate
LOGIC LINE WHERE V
LOGIC
> 3V
V
CC
GND
MAX6629
MAX6630
MAX6631
MAX6632
SO
SCK
CS
MAX6629
MAX6629
MAX6630
0.25s ADC CONVERSION TIME
MAX6631
MAX6632
0.25s ADC CONVERSION TIME
MAX6630
CONVERSION PERIOD
0.5s
MAX6631
MAX6632
CONVERSION PERIOD
8s
Page 6
MAX6629–MAX6632
12-Bit + Sign Digital Temperature Sensors
with Serial Interface
6 _______________________________________________________________________________________
finish. CS’s falling edge stops any conversion in
progress, and data is latched into the shift register.
Then the data clocks out at SO on SCK’s falling edge
with the sign bit (D15) first, followed by the MSB. Data
is sent in one 16-bit word, and CS must remain low until
all 16 bits are transferred. If CS goes high in the middle
of a transmission, it is necessary to wait the conversion
time (less than 300ms) before attempting a new read.
The serial data is composed of 12 + 1 data bits
(D15–D3) and 3 trailing bits (D2–D0). D2 is always low,
serving as the confirmation bit that the device has been
communicated with. The last 2 bits, D0 and D1, are
undefined and are always in high-impedance mode
(Table 1). The power-up state for SO is high impedance. Figure 3 shows the detailed serial timing specifications for the SPI port. The temperature data format is
in two's complement format (Table 2).
Power Shutdown Mode
The MAX6629–MAX6632 do not have a built-in power
software shutdown mode. However, a power shutdown
mode is easily implemented utilizing an unused logic
gate. A typical CMOS or TTL logic output has enough
drive capability to serve as the power source if its output voltage level exceeds 3V, as shown in Figure 1.
Drive the logic output low to provide a hardware shutdown mode.
Idle Mode
The MAX6629–MAX6632 can be put into idle mode by
pulling CS low. Data can be clocked out when the
device is in idle mode.
Power-On Reset (POR)
The POR supply voltage of the MAX6629–MAX6632 is
typically 1.6V. Below this supply voltage, the interface
is inactive and the data register is set to the POR state,
0°C.
When power is first applied and VCCrises above 1.6V
(typ), the device starts to convert, although temperature
reading is not recommended at VCClevels below 3.0V.
Figure 3. SPI Timing Diagram
Table 1. Data Output Format
Table 2. Temperature Data Format
(Two’s Complement)
t
CSS
CS
SCK
t
DV
SO
D15 D0D1D2D3
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Sign
MSB
Data
t
DO
LSB
Data
t
TR
Low High-Z High-Z
TEMPERATURE
(°C)
150 0,1001,0110,0000 0 XX
125 0,0111,1101,0000 0 XX
25 0,0001,1001,0000 0 XX
0.0625 0,0000,0000,0001 0 XX
0 0,0000,0000,0000 0 XX
-0.0625 1,1111,1111,1111 0 XX
-25 1,1110,0111,0000 0 XX
-55 1,1100,1001,0000 0 XX
DIGITAL OUTPUT (BINARY)
D15–D3 D2 D1, D0
Page 7
Applications Information
Thermal Considerations
The key to accurate temperature monitoring is good
thermal contact between the MAX6629–MAX6632 package and the object being monitored. In some applications, the 6-pin SOT23 package is small enough to fit
underneath a socketed µP, allowing the device to monitor the µP’s temperature directly. Accurate temperature
monitoring depends on the thermal resistance between
the object being monitored and the MAX6629–MAX6632
die. Heat flows in and out of plastic packages primarily
through the leads. If the sensor is intended to measure
the temperature of a heat-generating component on the
circuit board, it should be mounted as close as possible
to that component and should share supply and ground
traces (if they are not noisy) with that component where
possible. This maximizes the heat transfer from the component to the sensor.
The MAX6629/MAX6630 supply current is typically
200µA, and the MAX6631/MAX6632 supply current is
typically 32µA. When used to drive high-impedance
loads, the device dissipates negligible power.
Therefore, the die temperature is essentially the same
as the package temperature.
The rise in die temperature due to self-heating is given
by the following formula:
ΔT
J
= P
DISSIPATION
x θ
JA
where P
DISSIPATION
is the power dissipated by the
MAX6629–MAX6632, and θJAis the package’s thermal
resistance.
The typical thermal resistance is +110°C/W for the
6-pin SOT23 package. To limit the effects of self-heating, minimize the output currents. For example, if the
MAX6629–MAX6632 sink 1mA, the output voltage is
guaranteed to be less than 0.4V. Therefore, an additional 0.4mW of power is dissipated within the IC. This
corresponds to a 0.044°C shift in the die temperature in
the 6-pin SOT23.
Chip Information
PROCESS: BiCMOS
Package Information
For the latest package outline information and land patterns,
go to www.maxim-ic.com/packages
. Note that a “+”, “#”, or
“-” in the package code indicates RoHS status only. Package
drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
MAX6629–MAX6632
12-Bit + Sign Digital Temperature Sensors
with Serial Interface
_______________________________________________________________________________________ 7
Functional Diagram
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
6 SOT23 U6FH-6
21-0058
6 TDFN-EP T633+2
21-0137
MAX6629
MAX6630
MAX6631
MAX6632
TEMPERATURE
SENSOR
12-BIT + SIGN
∑Δ ADC
SPI-COMPATIBLE
INTERFACE
VOLTAGE
REFERENCE
CS
SCK
SO
Page 8
MAX6629–MAX6632
12-Bit + Sign Digital Temperature Sensors
with Serial Interface
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
8
_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
0 5/01 Initial relea se of MAX6629 —
1 7/01
2 4/04
3 8/05 Added the TDFN package 1, 2, 9
4 5/10
REVISION
DATE
DESCRIPTION
Init ial release of MAX3360, MAX3361, and MAX3362; changed I
to 650μA (max) in the Electrical Characteristics table
Changed the lead temperature in the Absolute Maximum Ratings section, replacing Note
2 with +300°C (removed the JEDEC solder reflow boi ler plating due to high temp solder
paste for flip chips now in production)
Added “+” to TDFN packages in the Ordering Information table 1
Added soldering information to the Absolute Maximum Ratings section 2
Added the TDFN exposed pad information to the Pin Description table 4
from 600μA (max)
CONV
PAGES
CHANGED
1, 2
2
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