ANALOG DEVICES ADM1021 Service Manual
Low Cost Microprocessor
a
FEATURES
Improved Replacement for MAX1617
On-Chip and Remote Temperature Sensing
No Calibration Necessary
1ⴗC Accuracy for On-Chip Sensor
3ⴗC Accuracy for Remote Sensor
Programmable Over/Under Temperature Limits
Programmable Conversion Rate
2-Wire SMBus Serial Interface
Supports System Management Bus (SMBus™) Alert
70 A Max Operating Current
3 A Standby Current
3 V to 5.5 V Supply
Small 16-Lead QSOP Package
APPLICATIONS
Desktop Computers
Notebook Computers
Smart Batteries
Industrial Controllers
Telecomms Equipment
Instrumentation
FUNCTIONAL BLOCK DIAGRAM
System Temperature Monitor
ADM1021
PRODUCT DESCRIPTION
The ADM1021 is a two-channel digital thermometer and under/
over temperature alarm, intended for use in personal computers
and other systems requiring thermal monitoring and management. The device can measure the temperature of a microprocessor using a diode-connected PNP transistor, which may be
provided on-chip in the case of the Pentium
cessors, or can be a low cost discrete NPN/PNP device such as
the 2N3904/2N3906. A novel measurement technique cancels
out the absolute value of the transistor’s base emitter voltage, so
that no calibration is required. The second measurement channel measures the output of an on-chip temperature sensor, to
monitor the temperature of the device and its environment.
The ADM1021 communicates over a two-wire serial interface
compatible with SMBus
standards. Under and over temperature
limits can be programmed into the devices over the serial bus,
and an ALERT output signals when the on-chip or remote
temperature is out of range. This output can be used as an interrupt, or as an SMBus alert.
®
II or similar pro-
LOCAL TEMPERATURE
ON-CHIP TEMP.
SENSOR
D+
ANALOG MUX
D–
EXTERNAL DIODE OPEN-CIRCUIT
ADM1021
TEST
V
DD
SMBus is a trademark and Pentium is a registered trademark of Intel Corporation.
8-BIT A-TO-D
CONVERTER
BUSY RUN/STANDBY
NC GND NC NC TEST
VALUE REGISTER
REMOTE TEMPERATURE
VALUE REGISTER
GND
LOCAL TEMPERATURE
LOW LIMIT COMPARATOR
LOCAL TEMPERATURE
HIGH LIMIT COMPARATOR
REMOTE TEMPERATURE
LOW LIMIT COMPARATOR
REMOTE TEMPERATURE
HIGH LIMIT COMPARATOR
STATUS REGISTER
SDATA
SCLK ADD0 ADD1
SMBUS INTERFACE
ADDRESS POINTER
REGISTER
ONE-SHOT
REGISTER
CONVERSION RATE
REGISTER
LOCAL TEMPERATURE
LOW LIMIT REGISTER
LOCAL TEMPERATURE
HIGH LIMIT REGISTER
REMOTE TEMPERATURE
LOW LIMIT REGISTER
REMOTE TEMPERATURE
HIGH LIMIT REGISTER
CONFIGURATION
REGISTER
INTERRUPT
MASKING
STBY
ALERT
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 1998
ADM1021–SPECIFICATIONS
(TA = T
MIN
to T
, VDD = 3.0 V to 3.6 V, unless otherwise noted)
MAX
Parameter Min Typ Max Units Test Conditions/Comments
POWER SUPPLY AND ADC
Temperature Resolution 1 °C Guaranteed No Missed Codes
Temperature Error, Local Sensor ±1 °C
–3 +3 °C
Temperature Error, Remote Sensor –3 +3 °CT
= +60°C to +100°C
A
–5 +5 °C
Supply Voltage Range 3 3.6 V Note 1
Undervoltage Lockout Threshold 2.5 2.7 2.95 V V
Input, Disables ADC,
DD
Rising Edge
Undervoltage Lockout Hysteresis 25 mV
Power-On Reset Threshold 0.9 1.7 2.2 V V
, Falling Edge
DD
2
POR Threshold Hysteresis 50 mV
Standby Supply Current 3 10 µAV
= 3.3 V, No SMBus Activity
DD
4 µA SCLK at 10 kHz
Average Operating Supply Current 70 90 µA 0.25 Conversions/Sec Rate
Auto-Convert Mode, Averaged Over 4 Seconds 160 200 µA 2 Conversions/Sec Rate
Conversion Time 65 115 170 ms From Stop Bit to Conversion
Complete (Both Channels)
Remote Sensor Source Current D+ Forced to D– + 0.65 V
60 90 130 µA High Level
3.5 5.5 8 µA Low Level
D-Source Voltage 0.7 V
Address Pin Bias Current (ADD0, ADD1) 50 µA Momentary at Power-On Reset
SMBUS INTERFACE
Logic Input High Voltage, V
IH
2.2 V VDD = 3 V to 5.5 V
STBY, SCLK, SDATA
Logic Input Low Voltage, V
IL
0.8 V VDD = 3 V to 5.5 V
STBY, SCLK, SDATA
SMBus Output Low Sink Current 6 mA SDATA Forced to 0.6 V
ALERT Output Low Sink Current 1 mA ALERT Forced to 0.4 V
Logic Input Current, I
, I
IH
IL
–1 +1 µA
SMBus Input Capacitance, SCLK, SDATA 5 pF
SMBus Clock Frequency 0 100 kHz
SMBus Clock Low Time, t
SMBus Clock High Time, t
SMBus Start Condition Setup Time, t
LOW
HIGH
SU:STA
4.7 µst
4 µst
4.7 µs
Between 10% Points
LOW
Between 90% Points
HIGH
SMBus Repeat Start Condition 250 ns Between 90% and 90% Points
Setup Time, t
SMBus Start Condition Hold Time, t
SU:STA
HD:STA
4 µs Time from 10% of SDATA to
90% of SCLK
SMBus Stop Condition Setup Time, t
SU:STO
4 µs Time from 90% of SCLK to 10%
of SDATA
SMBus Data Valid to SCLK 250 ns Time from 10% or 90% of
Rising Edge Time, t
SU:DAT
SMBus Data Hold Time, t
SMBus Bus Free Time, t
BUF
HD:DAT
0 µs
4.7 µs Between Start/Stop Condition
SDATA to 10% of SCLK
SCLK Falling Edge to SDATA 1 µs Master Clocking in Data
Valid Time, t
NOTES
1
Operation at VDD = +5 V guaranteed by design, not production tested.
2
Guaranteed by design, not production tested.
Specifications subject to change without notice.
VD,DAT
–2–
REV. 0
ADM1021
ABSOLUTE MAXIMUM RATINGS*
Positive Supply Voltage (VDD) to GND . . . . . . .–0.3 V to +6 V
D+, ADD0, ADD1 . . . . . . . . . . . . . . . . –0.3 V to V
+ 0.3 V
DD
D– to GND . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +0.6 V
SCLK, SDATA, ALERT, STBY . . . . . . . . . . . .–0.3 V to +6 V
Input Current, SDATA . . . . . . . . . . . . . . . . –1 mA to +50 mA
Input Current, D– . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1 mA
ESD Rating, all pins (Human Body Model) . . . . . . . . 2000 V
Continuous Power Dissipation
Up to +70°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 mW
Derating above +70°C . . . . . . . . . . . . . . . . . . . . 6.7 mW/°C
Operating Temperature Range . . . . . . . . . . –55°C to +125°C
Maximum Junction Temperature (T
max) . . . . . . . . . +150°C
J
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature, Soldering
Vapor Phase 60 sec . . . . . . . . . . . . . . . . . . . . . . . . . +215°C
Infrared 15 sec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +200°C
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
THERMAL CHARACTERISTICS
16-Lead QSOP Package: θ
= 150°C/Watt.
JA
ORDERING GUIDE
Temperature Package Package
Model Range Description Option
ADM1021ARQ 0°C to +85°C 16-Lead QSOP RQ-16
PROTOCOL
SCL
SDA
START
CONDITION
(S)
BIT 7
MSB
(A7)
t
LOWtHIGH
t
RtF
BIT 6
(A6)
1/f
SCL
PIN FUNCTION DESCRIPTIONS
Pin No. Mnemonic Description
1, 16 TEST Test pin for factory use only. See
note.
2V
DD
Positive supply, +3 V to +5.5 V.
3 D+ Positive connection to remote tem-
perature sensor.
4 D– Negative connection to remote tem-
perature sensor.
5, 9, 13 NC No Connect.
6 ADD1 Three-state logic input, higher bit of
device address.
7, 8 GND Supply 0 V connection.
10 ADD0 Three-state logic input, lower bit of
device address.
11 ALERT Open-drain logic output used as
interrupt or SMBus alert.
12 SDATA Logic input/output, SMBus serial
data. Open-drain output.
14 SCLK Logic input, SMBus serial clock.
15 STBY Logic input selecting normal opera-
tion (high) or standby mode (low).
NOTE
Pins 1 and 16 are reserved for test purposes. Ideally these pins should be left
unconnected. If routing through these pins is required, then both should be at
the same potential (i.e., connected together).
PIN CONFIGURATION
1
TEST
2
V
DD
3
D+
4
D–
5
NC
6
ADD1
7
GND
8
GND
NC = NO CONNECT
ADM1021
TOP VIEW
(Not to Scale)
16
15
14
13
12
11
10
9
TEST
STBY
SCLK
NC
SDATA
ALERT
ADD0
NC
BIT 0
ACKNOWLEDGE
PROTOCOL
SCL
SDA
LSB
(R/W)
(A)
Figure 1. Diagram for Serial Bus Timing
STOP
CONDITION
(P)
–3–REV. 0
ADM1021–Typical Performance Characteristics
30
20
10
0
–10
–20
–30
TEMPERATURE ERROR – 8C
–40
–50
–60
1 1003.3
LEAKAGE RESISTANCE – MV
DXP TO GND
DXP TO VCC (5V)
10 30
Figure 2. Temperature Error vs. PC Board Track Resistance
6
5
4
250mV p-p REMOTE
3
2
1
TEMPERATURE ERROR – 8C
0
100mV p-p REMOTE
120
100
90
80
70
60
50
READING
40
30
20
10
0
0 11010
20 30 40 50
MEASURED TEMPERATURE
60 70 80 90 100
Figure 5. Pentium II Temperature Measurement vs.
ADM1021 Reading
25
20
15
10
5
TEMPERATURE ERROR – 8C
0
–1
50 50M500
5k
50k
FREQUENCY – Hz
500k 5M
Figure 3. Temperature Error vs. Power Supply Noise
Frequency
25
20
15
10
5
TEMPERATURE ERROR – 8C
0
–5
50 50M500
5k 50k 500k 5M
FREQUENCY – Hz
100mV p-p
50mV p-p
25mV p-p
Figure 4. Temperature Error vs. Common-Mode Noise
Frequency
–5
1102.2
3.2 4.7 7
DXP-DXN CAPACITANCE – nF
Figure 6. Temperature Error vs. Capacitance Between
D+ and D–
80
70
60
50
40
30
SUPPLY CURRENT – mA
20
10
0
0
5k 10k 25k 50k 75k 100k 250k 500k 750k
SCLK FREQUENCY – Hz
VCC = +5V
VCC = +3V
1M1k
Figure 7. Standby Supply Current vs. Clock Frequency
–4–
REV. 0
Loading...