ADT14GP AD [Analog Devices], ADT14GP Datasheet

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ADT14GP

Manufacturer Part Number
ADT14GP
Description
Quad Setpoint, Programmable Temperature Monitor and Controller
Manufacturer
AD [Analog Devices]
Datasheet
a
GENERAL DESCRIPTION
The ADT14 is a temperature sensor and controller that generates
an output voltage proportional to temperature and provides four
temperature trip points. The four trip points, or temperature
setpoints, and their hysteresis are determined by voltage levels set
by the user. An on-chip voltage reference provides an easy method
for setting the temperature trip points.
The ADT14 consists of a bandgap voltage reference combined
with four matched comparators. The reference provides both a
temperature-stable 2.5 V output, and a voltage proportional to
absolute temperature (VPTAT) which has a precise temperature
coefficient of 5 mV/K = 5 mV/( C +273.15). The VPTAT out-
put is nominally 1.49 V at +25 C. The comparators determine
whether the VPTAT output is above the voltages set up by
external resistive dividers (temperature trip points) and generate
an open-collector output signal when one of their respective
thresholds has been exceeded.
Hysteresis is programmed by a user-selected voltage at the hys-
teresis pin. This voltage adjusts the hysteresis current which is
used to generate a hysteresis offset voltage. The comparator’s
noninverting inputs are connected in parallel, which guarantees
that there is no hysteresis overlap and eliminates erratic transi-
tions between adjacent trip zones.
Using a proprietary thin-film resistor process in conjunction
with production laser trimming, a temperature accuracy of 3 C
at 25 C is guaranteed. The open-collector outputs are capable
of sinking 5 mA, and provide TTL/CMOS logic compatibility
with an external pull-up resistor. Operating from a single 5 V
supply, the quiescent current is 600 A max.
The ADT14 is available in the 16-lead epoxy DIP and SO
(small outline) packages.
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
FEATURES
Four Programmable Temperature Setpoints
Programmable Thermal Hysteresis
Accuracy
Temperature Output Scale Factor = 5 mV/K
Resistor Programmable Temperature Setpoints
5 mA Open-Collector Setpoint Outputs
Internal 2.5 V Reference
600 A Max Quiescent Current at +5 V
APPLICATIONS
Power Supply Monitor and Control System
Multiple Fan Controller System
Workstation Thermal Management System
3 C Typ from –40 C to +125 C
Temperature Monitor and Controller
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
Quad Setpoint, Programmable
SET 1
SET 2
SET 3
SET 4
V
GND
2.5V
REF
V+
FUNCTIONAL BLOCK DIAGRAM
REFERENCE
VOLTAGE
SENSOR
SETPOINT 1
SETPOINT 2
AND
OUTPUT 1
OUTPUT 2
GROUND
PIN CONFIGURATIONS
VPTAT
World Wide Web Site: http://www.analog.com
NC
NC
COMPARATORS
CURRENT
WINDOW
MIRROR
1
2
3
4
5
6
7
8
NC = NO CONNECT
DIP & SO
(Not to Scale)
TOP VIEW
ADT14
ADT14
TEMPERATURE
OUTPUT
HYSTERESIS
VOLTAGE
16
15
14
13
12
11
10
© Analog Devices, Inc., 1997
9
OUTPUT 4
SETPOINT 4
2.5V REFERENCE
V+
NC
HYSTERESIS
SETPOINT 3
OUTPUT 3
ADT14
HYSTERESIS
SETPOINT
OUTPUT 1
SETPOINT
OUTPUT 2
SETPOINT
OUTPUT 3
SETPOINT
OUTPUT 4
VPTAT

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ADT14GP Summary of contents

Page 1

FEATURES Four Programmable Temperature Setpoints Programmable Thermal Hysteresis Accuracy 3 C Typ from – +125 C Temperature Output Scale Factor = 5 mV/K Resistor Programmable Temperature Setpoints 5 mA Open-Collector Setpoint Outputs Internal 2.5 V Reference 600 ...

Page 2

... OL SINK See Figure Unloaded Unloaded at + Model/Grade ADT14GP ADT14GS NOTES 1 XIND = Plastic DIP Small Outline. THERMAL PACKAGE CHARACTERISTICS Package Type 16-Lead Plastic DIP 16-Lead SOIC –2– Min Typ Max Units ...

Page 3

WAFER TEST LIMITS ( GND = Parameter INPUTS SET HIGH, SET LOW Input Bias Current OUTPUT VPTAT Temperature Accuracy OUTPUT V REF Nominal Value Line Regulation Load Regulation OPEN-COLLECTOR OUTPUTS OVER, UNDER Output Low ...

Page 4

ADT14 –Typical Performance Characteristics 160 TRANSITION FROM +100 C STIRRED OIL BATH TO FORCED +25 C AIR 140 V+ = +5V, NO LOAD 120 100 80 SOIC SOLDERED TO 0.6" 60 PDIP IN SOLDERTAIL SOCKET SOLDERED TO 0.8" ...

Page 5

V+ = +5V, NO LOAD 400 375 350 325 300 TEMPERATURE – C Figure 8. Supply Current vs. Temperature +1V + ...

Page 6

ADT14 APPLICATIONS INFORMATION Programming the ADT14 To program any of the four temperature trip points, simply set the voltage at the setpoint pin equal to the voltage expected at the VPTAT output at the desired trip temperature. The on- board ...

Page 7

The comparator output remains on until the voltage at the compara- tor input, now equal to VPTAT plus the hysteresis offset, has returned to the setpoint voltage. At this point ...

Page 8

ADT14 Safety Considerations In heating and cooling system design, designers should antici- pate potential system fault conditions which may result in sig- nificant safety hazards which are outside the control of, and cannot be corrected by, the ADT14 based circuit. ...

Page 9

ADT14 3 TEMP NC 14 SENSOR & VOLTAGE REFERENCE 5 12 HYSTERESIS 6 11 GENERATOR IN4001 OR EQUIVALENT CONNECT Figure 18a. Reed Relay Drive 1 2 ...

Page 10

ADT14 High Current Switching As mentioned earlier, internal dissipation due to large loads on the ADT14 outputs will cause some temperature error due to self-heating. External transistors buffer the load from the ADT14, so that virtually no power is dissipated ...

Page 11

Buffering the Temperature Output Pin The VPTAT sensor output is a low impedance dc output volt- age with a 5 mV/K temperature coefficient, and is useful in a number of measurement and control applications. In many applications, this voltage may ...

Page 12

ADT14 By connecting the VPTAT output to the input of the AD654, the 5 mV/K, temperature coefficient gives a sensitivity of 25 Hz/ C, centered around 7.5 kHz The trimming resistor, R2, is needed to calibrate the ...

Page 13

Out-of-Range Warning In Figure 25, connecting an open-collector output of the ADT14 and an inverted open-collector output together into a wired-OR configuration, a temperature “out-of-range” warning signal is generated. This can be useful in sensitive equipment calibrated to work over ...

Page 14

ADT14 P0.0 TO USER P3.2 P0.7 INPUTS P3.1 P3.0 P3.3 TO 2ND AD8403 80CL51 C P2.0 P2.1 P2.2 P2.3 P1.0/INT2 P2.4 + OUT DIS 0.1 F TLC555 THR CONT TRIG 0.1 F GND Figure 28. Typical Microcontroller ...

Page 15

Figure 30 illustrates the system described in the previous para- graph, where each trip-point output corresponds to a 25% re- duction in power when tripped. This is accomplished by the dual rail-to-rail precision OP284 op amp configured as an in- ...

Page 16

ADT14 0.210 (5.33) 0.160 (4.06) 0.115 (2.93) OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 16-Lead Plastic DIP (N-16) 0.840 (21.34) 0.745 (18.92 0.280 (7.11) 0.240 (6.10 PIN 1 0.060 (1.52) 0.015 (0.38) MAX 0.130 (3.30) ...

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