TI UC1730

UC1730
UC2730
UC3730
Thermal Monitor
FEATURES
DESCRIPTION
•
On-Chip Temperature Transducer
•
Temperature Comparator Gives
Threshold Temperature Alarm
•
Power Reference Permits Airflow
Diagnostics
•
Precision 2.5V Power Reference
Permits Airflow Diagnostics
The UC1730 family of integrated circuit devices are designed to be used in
a number of thermal monitoring applications. Each IC combines a temperature transducer, precision reference, and temperature comparator allowing
the device to respond with a logic output if temperatures exceed a user programmed level. The reference on these devices is capable of supplying in
excess of 250mA of output current − by setting a level of power dissipation
the rise in die temperature will vary with airflow past the package, allowing
the IC to respond to airflow conditions
•
Transducer Output is Easily Scaled
for Increased Sensitivity
•
Low 2.5mA Quiescent Current
BLOCK DIAGRAM
These devices come in an 8-Pin DIP, plastic or ceramic, a 5-Pin TO-220 or a
PLCC-20 version. In the 8-Pin version, a PTAT (proportional to absolute
temperature) output reports die temperature directly. This output is configured such that its output level can be easily scaled up with two external gain
resistors. A second PTAT source is internally referenced to the temperature
comparator. The other input to this comparator can then be externally programmed to set a temperature threshold. When this temperature threshold
is exceeded an alarm delay output is activated. Following the activation of
the delay output, a separate open collector output is turned on. The delay
pin can be programmed with an external RC to provide a time separation
between activation of the delay pin and the alarm pin, permitting shutdown
diagnostics in applications where the open collector outputs of multiple parts
are wire OR’ed together.
The 5-Pin version in the TO-220 package is well suited for monitoring
heatsink temperatures. Enhanced airflow sensitivities can be obtained with
this package by mounting the device to a small heatsink in the airstream.
This version of the device does not include the PTAT output or the open collector alarm output.
Pin numbers shown for 8-Pin DIP, ( ) number for 5-Pin TO-220.
10/94
UC1730
UC2730
UC3730
ABSOLUTE MAXIMUM RATINGS
T, 5-Pin Plastic DIP TO-220 . . . . . . . . . . . . . . . . . . . . 65°C/W
Thermal Resistance Junction to Case
N, 8-Pin Plastic DIP. . . . . . . . . . . . . . . . . . . . . . . . . . . 60°C/W
J, 8-Pin Ceramic DIP. . . . . . . . . . . . . . . . . . . . . . . . . . 40°C/W
T, 5-Pin Plastic TO-220 . . . . . . . . . . . . . . . . . . . . . . . . . 5°C/W
Operating Junction Temperature . . . . . . . . . -55°C to +150°C
Storage Temperature . . . . . . . . . . . . . . . . . . -65°C to +150°C
Lead Temperature (Soldering, 10 Seconds). . . . . . . . . 300°C
Note 1: Voltages are referenced to ground. Currents are positive into, negative out of, the specified terminals.
Note 2: Consult Packaging section of Databook for thermal
limitations and considerations of package.
Input Supply Voltage, (+VIN). . . . . . . . . . . . . . . . . . . . . . . 40V
Alarm Output Voltage (8-Pin Version Only) . . . . . . . . . . . 40V
Alarm Delay Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10V
Alarm Threshold Set Voltage . . . . . . . . . . . . . . . . . . . . . . 10V
2.5V Reference Output Current . . . . . . . . . . . . . . . . . -400 mA
Alarm Output Current (8-Pin Version Only) . . . . . . . . . . 0 mA
Power Dissipation at TA = 25°C (Note 2) . . . . . . . . . 1000 mW
Power Dissipation at TC = 25°C (Note 2) . . . . . . . . . 2000 mW
Thermal Resistance Junction to Ambient
N, 8-Pin Plastic DIP . . . . . . . . . . . . . . . . . . . . . . . . . 110°C/W
J, 8-Pin Ceramic DIP . . . . . . . . . . . . . . . . . . . . . . . . 110°C/W
CONNECTION DIAGRAMS
DIL-8 (TOP VIEW)
N or J Package
PLCC-20 (TOP VIEW)
Q Package
PACKAGE PIN FUNCTION
5-PIN TO-220 (TOP VIEW)
T Package
FUNCTION
PIN
N/C
ALARM DELAY
ALARM OUTPUT
+VIN
GND
N/C
PTAT+
PTAT2.5V REFERENCE
2.5V REFERENCE
ALARM
THRESHOLD SET
N/C
1-3
4
5
6
7
8-13
14
15
16
17
18
19-20
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TJ = 0°C to +100°C for the
UC3730, -25°C to + 100°C for the UC2730 and -55°C to +125°C for the UC1730,
+VIN = + 5V, and PTAT– = 0V. TA = TJ.
PARAMETERS
INPUT SUPPLY
Supply Current
TEST CONDITIONS
MIN
TYP
MAX UNITS
+VIN = 35V
2.8
4.0
mA
+VIN = 5V
2.3
3.5
mA
2.5
2.525
V
REFERENCE
Output Voltage
TJ = 25°C
2.475
2.46
Load Regulation
Over Temperature
IOUT = 0 to 250mA
Line Regulation
+VIN = 5 to 25V
2.54
V
8.0
25
mV
1.0
5.0
mV
1.50
1.525
V
10
°C
0.005
0.02
%/V
3.0
2.0
8.0
5.0
15
°C
mV
TEMPERATURE COMPARATOR
Temperature Comparator Threshold at 300°K (26.85°C), Nominally 5mV/°K,
VINPUT High to Low
Temperature Error
1.475
-10
Threshold Line Regulation
+VIN = 5 to 25V
Temperature Linearity
Threshold Hysteresis
Note 2
Input Bias Current
VINPUT at 1.5V
-0.5
-0.1
µA
Max Output Current
VOUT = 1V
1.2
3.0
mA
Output Sat Voltage
IOUT = 100µA
0.05
2
0.25
V
UC1730
UC2730
UC3730
Unless otherwise stated, these specifications apply for TJ = 0°C to +100°C for the UC3730,
ELECTRICAL
CHARACTERISTICS (cont): -25°C to + 100°C for the UC2730 and -55°C to +125°C for the UC1730, +VIN = + 5V, and
PTAT– = 0V. TA = TJ.
PARAMETERS
TEMPERATURE COMPARATOR (cont.)
Output Leakage Current
TEST CONDITIONS
MIN
TYP
MAX
UNIT
0.01
1.0
µA
1.460
1.50
1.54
V
14.6
-12
15
15.4
12
V
°C
VOUT = 1V
PTAT BUFFER (8-Pin N, or J Version Only)
Output Voltage
at 300°K (26.85°C), Nominally 5mV/°K
In 10X Config. + VIN = 25V
Temperature Error
Temperature Linearity (Note 2)
Line Regulation
Load Regulation
Dropout Voltage
2.0
5.0
°C
+VIN = 5 to 25V
0.02
0.04
%/V
IOUT = 0 to 2mA
PTAT + TO +VIN
1.0
3.0
mV
1.9
2.5
Input Bias Current at PTAT– Input
V
µA
-3.0
-1.0
1.1
Threshold Hysteresis Voltage
Input Bias Current
Alarm Delay Input Low to High
Alarm Delay Voltage > VTH
Alarm Delay Voltage < VTH
1.2
100
0.1
1.3
250
0.5
V
mV
µA
Max Output Current
VOUT = 1V
7.0
Output Sat Voltage
IOUT = 3mA
15
0.25
0.45
mA
V
0.1
2.0
µA
ALARM BUFFER COMPARATOR (8-Pin N, or J Version Only)
Threshold Voltage (VTH)
Output Leakage
VOUT = 35V
Note 2: This parameter is guaranteed by design and is not tested in production.
APPLICATIONS AND OPERATION INFORMATION
Scaling the PTAT Output (8 Pin Version Only)
 R2 
VOUT = 5 x 1+  mV ⁄ ° K
 R1 
(Recommended Range for R1 is 2k to 4k)
VREF Maximum Output Current vs Input Supply
Junction Temperature Rise vs Airflow UC3730N (8Pin Plastic Dip)
3
UC1730
UC2730
UC3730
APPLICATIONS AND OPERATION INFORMATION (Cont.)
Setting a Temperature Threshold
Temperature Threshold (°C)
2.5V
R2
=(
− 273.15
)x
0.005
R1+R2
Note:For airflow monitoring a power dissipation
level can be set with a resistive load, RL, on the
reference output. PD = (+ VIN - 2.5V)2/RL.
Dual Speed Fan Control
2.5V
R2
x
− 273.15
0.005 R1+R2
2.5V
RX
TL(°C) =
x
− 273.15
0.005 R1+RX
R3
Where: RX = R2 ×
R2 + R3
TH(°C) =
UNITRODE INTEGRATED CIRCUITS
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4
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