ANALOG DEVICES AD7816 Service Manual
查询AD7816ACHIPS供应商
Single- and 4-Channel, 9 s, 10-Bit ADCs
with On-Chip Temperature Sensor
AD7816/AD7817/AD7818
FEATURES
10-Bit ADC with 9 s Conversion Time
One (AD7818) and Four (AD7817) Single-Ended Analog
Input Channels
The AD7816 Is a Temperature Measurement Only Device
On-Chip Temperature Sensor
Resolution of 0.25ⴗC
ⴞ2ⴗC Error from –40ⴗC to +85ⴗC
–55ⴗC to +125ⴗC Operating Range
Wide Operating Supply Range
2.7 V to 5.5 V
Inherent Track-and-Hold Functionality
On-Chip Reference (2.5 V ⴞ 1%)
Overtemperature Indicator
Automatic Power-Down at the End of a Conversion
Low Power Operation
4 W at a Throughput Rate of 10 SPS
40 W at a Throughput Rate of 1 kSPS
400 W at a Throughput Rate of 10 kSPS
Flexible Serial Interface
APPLICATIONS
Ambient Temperature Monitoring (AD7816)
Thermostat and Fan Control
High Speed Microprocessor
Temperature Measurement and Control
Data Acquisition Systems with Ambient Temperature
Monitoring (AD7817 and AD7818)
Industrial Process Control
Automotive
Battery Charging Applications
GENERAL DESCRIPTION
The AD7818 and AD7817 are 10-bit, single- and 4-channel
A/D converters with on-chip temperature sensor that can operate from a single 2.7 V to 5.5 V power supply. Each part contains a 9 µs successive-approximation converter based around
a capacitor DAC, an on-chip temperature sensor with an accuracy of ⫾2°C, an on-chip clock oscillator, inherent track-andhold functionality and an on-chip reference (2.5 V). The
AD7816 is a temperature monitoring only device in a SOIC/
MSOP package.
The on-chip temperature sensor of the AD7817 and AD7818
can be accessed via Channel 0. When Channel 0 is selected and
a conversion is initiated, the resulting ADC code at the end of
the conversion gives a measurement of the ambient temperature
with a resolution of ⫾0.25°C. See Temperature Measurement
section of this data sheet.
FUNCTIONAL BLOCK DIAGRAM
REF
IN
AD7817
TEMP
SENSOR
V
IN1
V
IN2
V
V
MUX
IN3
IN4
SAMPLING
CAPACITOR
V
AGND
REF
2.5V
BALANCE
DGND
V
DD
OVERTEMP
REG
CHARGE
REDISTRIBUTION
DAC
CONTROL
LOGIC
BUSY
CONVST
B
CONTROL
A > B
A
DATA
OUT
REG
CLOCK
OTI
D
OUT
D
IN
SCLK
RD/WR
CS
The AD7816, AD7817, and AD7818 have a flexible serial
interface that allows easy interfacing to most microcontrollers.
The interface is compatible with the Intel 8051, Motorola
®
and QSPI™ protocols and National Semiconductors
SPI
MICROWIRE™ protocol. For more information refer to the
Serial Interface section of this data sheet.
The AD7817 is available in a narrow body 0.15" 16-lead small
outline IC (SOIC), in a 16-lead, thin shrink small outline package (TSSOP), while the AD7816/AD7818 come in an 8-lead
small outline IC (SOIC) and an 8-lead microsmall outline IC
(MSOP).
PRODUCT HIGHLIGHTS
1. The devices have an on-chip temperature sensor that allows an
accurate measurement of the ambient temperature to be
made. The measurable temperature range is –55°C to +125°C.
2. An overtemperature indicator is implemented by carrying out a
digital comparison of the ADC code for Channel 0 (temperature sensor) with the contents of the on-chip overtemperature
register. The overtemperature indicator pin goes logic low when
a predetermined temperature is exceeded.
3. The automatic power-down feature enables the AD7816,
AD7817, and AD7818 to achieve superior power performance at slower throughput rates, e.g., 40 µW at 1 kSPS
throughput rate.
REV. C
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 that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 www.analog.com
Fax: 781/326-8703 © 2004 Analog Devices, Inc. All rights reserved.
AD7816/AD7817/AD7818
AD7817–SPECIFICATIONS
Parameter A Version *B Version *S Version Unit Test Conditions/Comments
DYNAMIC PERFORMANCE Sample Rate = 100 kSPS, Any
2
Signal to (Noise + Distortion) Ratio
Total Harmonic Distortion
Peak Harmonic or Spurious Noise2–65 –65 –65 dB max –75 dB typ
Intermodulation Distortion
2
2
Second Order Terms –67 –67 –67 dB typ
Third Order Terms –67 –67 –67 dB typ
Channel-to-Channel Isolation
2
DC ACCURACY Any Channel
Resolution 10 10 10 Bits
Minimum Resolution for Which
No Missing Codes are Guaranteed 10 10 10 Bits
Relative Accuracy
Differential Nonlinearity
Gain Error
Gain Error Match
Offset Error
2
2
2
2
2
Offset Error Match ⫾1/2 ⫾1/2 ⫾ 1/2 LSB max
TEMPERATURE SENSOR
1
Measurement Error External Reference V
Ambient Temperature 25°C ⫾2 ⫾1 ⫾2 °C max
to T
T
MIN
MAX
Measurement Error On-Chip Reference
Ambient Temperature 25°C ⫾2.25 ⫾2.25 ⫾2.25 °C max
to T
T
MIN
MAX
Temperature Resolution 1/4 1/4 1/4 °C/LSB
REFERENCE INPUT
REFIN Input Voltage Range
3, 4
3
Input Impedance 40 40 40 kΩ min
Input Capacitance 10 10 10 pF max
ON-CHIP REFERENCE
Temperature Coefficient
CONVERSION RATE
Track/Hold Acquisition Time
5
3
4
Conversion Time
Temperature Sensor 27 27 27 µs max
Channels 1 to 4 9 9 9 µs max
POWER REQUIREMENTS
V
DD
I
DD
Normal Operation 2 2 2 mA max 1.6 mA typ
Using External Reference 1.75 1.75 1.75 mA max 2.5 V External Reference Connected
Power-Down (V
Power-Down (V
= 5 V) 10 10 12.5 µA max 5.5 µA typ
DD
= 3 V) 4 4 4.5 µA max 2 µA typ
DD
Auto Power-Down Mode V
10 SPS Throughput Rate 6.4 6.4 6.4 µW typ See Power vs. Throughput Section for
1 kSPS Throughput Rate 48.8 48.8 48.8 µW typ Description of Power Dissipation in
10 kSPS Throughput Rate 434 434 434 µW typ Auto Power-Down Mode
Power-Down 12 12 13.5 µW max Typically 6 µW
58 58 58 dB min
–65 –65 –65 dB max –75 dB typ
–80 –80 –80 dB typ fIN = 20 kHz
⫾1 ⫾1 ⫾1LSB max
⫾1 ⫾1 ⫾1LSB max
⫾2 ⫾2 ⫾2LSB max External Reference
⫾10 ⫾10 +20/–10 LSB max Internal Reference
⫾1/2 ⫾1/2 ⫾ 1/2 LSB max
⫾2 ⫾2 ⫾2LSB max
⫾3 ⫾2 ⫾3 °C max
⫾3 ⫾3 ⫾6 °C max
2.625 2.625 2.625 V max 2.5 V + 5%
2.375 2.375 2.375 V min 2.5 V – 5%
80 80 150 ppm/°C typ
400 400 400 ns max Source Impedance < 10 Ω
5.5 5.5 5.5 V max For Specified Performance
2.7 2.7 2.7 V min
(VDD = 2.7 V to 5.5 V, GND = 0 V, REFIN = 2.5 V unless otherwise noted)
Channel, fIN = 20 kHz
fa =19.9 kHz, fb = 20.1 kHz
Nominal 2.5 V
Logic Inputs = 0 V or V
= 3 V
DD
= 2.5 V
REF
DD
1
REV. C–2–
AD7816/AD7817/AD7818
1
AD7816/AD78186–SPECIFICATIONS
Parameter A Version Unit Test Conditions/Comments
DYNAMIC PERFORMANCE (AD7818 Only) Sample Rate = 100 kSPS, Any Channel,
Signal to (Noise + Distortion) Ratio
Total Harmonic Distortion
Peak Harmonic or Spurious Noise
Intermodulation Distortion
2
2
Second Order Terms –67 dB typ
Third Order Terms –67 dB typ
Channel-to-Channel Isolation
DC ACCURACY (AD7818 Only) Any Channel
Resolution 10 Bits
Minimum Resolution for Which
No Missing Codes are Guaranteed 10 Bits
Relative Accuracy
Differential Nonlinearity
Gain Error
Offset Error
TEMPERATURE SENSOR
2
2
2
2
1
Measurement Error External Reference V
Ambient Temperature 25°C ⫾2 °C max
to T
T
MIN
MAX
Measurement Error On-Chip Reference
Ambient Temperature 25°C ⫾2 °C max
to T
T
MIN
MAX
Temperature Resolution 1/4 °C/LSB
REFERENCE INPUT
Input Voltage Range
REF
IN
3, 4
(AD7816 Only)
3
Input Impedance 50 kΩ min
Input Capacitance 10 pF max
ON-CHIP REFERENCE
Temperature Coefficient
5
3
CONVERSION RATE
Track/Hold Acquisition Time
Conversion Time
Temperature Sensor 27 µs max
Channel 1 9 µs max (AD7818 Only)
POWER REQUIREMENTS
V
DD
I
DD
Normal Operation 2 mA max 1.3 mA typ
Using External Reference 1.75 mA max 2.5 V External Reference Connected
Power-Down (V
Power-Down (V
= 5 V) 10.75 µA max 6 µA typ
DD
= 3 V) 4.5 µA max 2 µA typ
DD
Auto Power-Down Mode V
10 SPS Throughput Rate 6.4 µW typ See Power vs. Throughput Section for
1 kSPS Throughput Rate 48.8 µW typ Description of Power Dissipation in
10 kSPS Throughput Rate 434 µW typ Auto Power-Down Mode
Power-Down 13.5 µW max Typically 6 µW
2
2
2
57 dB min
–65 dB max –75 dB typ
–67 dB typ –75 dB typ
–80 dB typ fIN = 20 kHz
⫾1 LSB max
⫾1 LSB max
⫾10 LSB max
⫾4 LSB max
⫾3 °C max
⫾3 °C max
2.625 V max 2.5 V + 5%
2.375 V min 2.5 V – 5%
30 ppm/°C typ
4
400 ns max Source Impedance < 10 Ω
5.5 V max For Specified Performance
2.7 V min
(VDD = 2.7 V to 5.5 V, GND = 0 V, REFIN = 2.5 V unless
otherwise noted)
fIN = 20 kHz
fa = 19.9 kHz, fb = 20.1 kHz
= 2.5 V
REF
Nominal 2.5 V
Logic Inputs = 0 V or V
= 3 V
DD
DD
REV. C
–3–
AD7816/AD7817/AD7818–SPECIFICATIONS
Parameter A Version *B Version *S Version Unit Test Conditions/Comments
ANALOG INPUTS
Input Voltage Range V
Input Leakage ⫾1 ⫾1 ⫾ 1 µA min
Input Capacitance 10 10 10 pF max
LOGIC INPUTS
Input High Voltage, V
Input Low Voltage, V
Input High Voltage, V
Input Low Voltage, V
Input Current, I
Input Capacitance, C
LOGIC OUTPUTS
Output High Voltage, V
Output Low Voltage, V
High Impedance Leakage Current ⫾1 ⫾1 ⫾ 1 µA max
High Impedance Capacitance 15 15 15 pF max
NOTES
*B and S Versions apply to AD7817 only. For operating temperature ranges, see Ordering Guide.
1
AD7816 and AD7817 temperature sensors specified with external 2.5 V reference, AD7818 specified with on-chip reference. All other specifications with external
and on-chip reference (2.5 V). For VDD = 2.7 V, TA = 85°C max and temperature sensor measurement error = ⫾3°C.
2
See Terminology.
3
The accuracy of the temperature sensor is affected by reference tolerance. The relationship between the two is explained in the section titled Temperature Measurement Error Due to Reference Error.
4
Sample tested during initial release and after any redesign or process change that may affect this parameter.
5
On-chip reference shuts down when external reference is applied.
6
All specifications are typical for AD7818 at temperatures above 85°C and with VDD greater than 3.6 V.
7
Refers to the input current when the part is not converting. Primarily due to reverse leakage current in the ESD protection diodes.
Specifications subject to change without notice.
7
REF
V
REF
V
REF
V max
(AD7817 and AD7818)
0 00V min
4
INH
INL
INH
INL
IN
IN
4
OH
OL
2.4 2.4 2.4 V min VDD = 5 V ⫾ 10%
0.8 0.8 0.8 V max VDD = 5 V ⫾ 10%
2 22V minV
= 3 V ⫾ 10%
DD
0.4 0.4 0.4 V max VDD = 3 V ⫾ 10%
⫾3 ⫾3 ⫾ 3 µA max Typically 10 nA, VIN = 0 V to V
10 10 10 pF max
I
= 200 µA
4 44V minV
2.4 2.4 2.4 V min V
0.4 0.4 0.4 V max V
0.2 0.2 0.2 V max V
SOURCE
= 5 V ⫾ 10%
DD
= 3 V ⫾ 10%
DD
I
= 200 µA
SINK
= 5 V ⫾ 10%
DD
= 3 V ⫾ 10%
DD
DD
V
DD
OVERTEMP
REG
CHARGE
REDISTRIBUTION
DAC
CONTROL
LOGIC
CONVST
B
CONTROL
A > B
A
DATA
OUT
REG
CLOCK
AD7816
TEMP
SENSOR
MUX
REF
REF
2.5V
SAMPLING
CAPACITOR
V
BALANCE
AGND
IN
Figure 1. AD7816 Functional Block Diagram
OTI
D
OUT
IN/
SCLK
RD/WR
V
DD
AD7818
TEMP
SENSOR
V
MUX
IN1
REF
2.5V
SAMPLING
CAPACITOR
V
BALANCE
AGND
OVERTEMP
REG
CHARGE
REDISTRIBUTION
DAC
CONTROL
LOGIC
CONVST
Figure 2. AD7818 Functional Block Diagram
A > B
B
A
DATA
OUT
CONTROL
REG
CLOCK
GENERATOR
OTI
D
OUT
IN/
SCLK
RD/WR
REV. C–4–
AD7816/AD7817/AD7818
TIMING CHARACTERISTICS
(VDD = 2.7 V to 5.5 V, GND = 0 V, REFIN = 2.5 V. All specifications T
1, 2
otherwise noted)
MIN
to T
MAX
unless
Parameter A, B Versions Unit Test Conditions/Comments
t
POWER-UP
t
1a
t
1b
t
2
t
3
t
4
t
5
t
6
t
7
t
8
t
9
t
10
t
11
3
t
12
3
t
13
3, 4
t
14a
3, 4
t
14b
t
15
t
16
t
17
NOTES
1
Sample tested during initial release and after any redesign or process change that may affect this parameter. All input signals are measured with tr = tf = 1 ns (10% to
90% of 5 V) and timed from a voltage level of 1.6 V.
2
See Figures 16, 17, 20 and 21.
3
These figures are measured with the load circuit of Figure 3. They are defined as the time required for D
or 2 V for VDD = 3 V ⫾ 10%, as quoted on the specifications page of this data sheet.
4
These times are derived from the measured time taken by the data outputs to change 0.5 V when loaded with the circuit of Figure 3. The measured number is then
extrapolated back to remove the effects of charging or discharging the 50 pF capacitor. This means that the times quoted in the timing characteristics are the true bus
relinquish times of the part and as such are independent of external bus loading capacitances.
Specifications subject to change without notice.
2 µs max Power-Up Time from Rising Edge of CONVST
9 µs max Conversion Time Channels 1 to 4
27 µs max Conversion Time Temperature Sensor
20 ns min CONVST Pulse Width
50 ns max CONVST Falling Edge to BUSY Rising Edge
0 ns min CS Falling Edge to RD/WR Falling Edge Setup Time
0 ns min RD/WR Falling Edge to SCLK Falling Edge Setup
10 ns min DIN Setup Time before SCLK Rising Edge
10 ns min DIN Hold Time after SCLK Rising Edge
40 ns min SCLK Low Pulse Width
40 ns min SCLK High Pulse Width
0 ns min CS Falling Edge to RD/WR Rising Edge Setup Time
0 ns min RD/WR Rising Edge to SCLK Falling Edge Setup Time
20 ns max D
20 ns max D
30 ns max D
30 ns max D
Access Time after RD/WR Rising Edge
OUT
Access Time after SCLK Falling Edge
OUT
Bus Relinquish Time after Falling Edge of RD/WR
OUT
Bus Relinquish Time after Rising Edge of CS
OUT
150 ns max BUSY Falling Edge to OTI Falling Edge
40 ns min RD/WR Rising Edge to OTI Rising Edge
400 ns min SCLK Rising Edge to CONVST Falling Edge (Acquisition Time of T/H)
to cross 0.8 V or 2.4 V for VDD = 5 V ⫾ 10% and 0.4 V
OUT
I
OL
1.6V
I
OL
TO
OUTPUT
PIN
50pF
200A
C
L
200A
Figure 3. Load Circuit for Access Time and Bus Relinquish Time
REV. C
–5–
AD7816/AD7817/AD7818
ABSOLUTE MAXIMUM RATINGS
(
TA = 25°C unless otherwise noted)
1
VDD to AGND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V
to DGND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V
V
DD
Analog Input Voltage to AGND
to V
V
IN1
Reference Input Voltage to AGND
Digital Input Voltage to DGND . . . . . . –0.3 V to V
Digital Output Voltage to DGND . . . . . –0.3 V to V
. . . . . . . . . . . . . . . . . . . –0.3 V to VDD + 0.3 V
IN4
2
. . . –0.3 V to V
DD
DD
DD
+ 0.3 V
+ 0.3 V
+ 0.3 V
Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C
TSSOP, Power Dissipation . . . . . . . . . . . . . . . . . . . . 450 mW
Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 120°C/W
θ
JA
Lead Temperature, Soldering . . . . . . . . . . . . . . . . . . 260°C
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
16-Lead SOIC Package, Power Dissipation . . . . . . . . 450 mW
Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 100°C/W
θ
JA
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
8-Lead SOIC Package, Power Dissipation . . . . . . . . . . 450 mW
Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 157°C/W
θ
JA
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
µSOIC Package, Power Dissipation . . . . . . . . . . . . . . 450 mW
θ
Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 206°C/W
JA
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
NOTES
1
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those listed in the operational sections
of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
2
If the Reference Input Voltage is likely to exceed VDD by more than 0.3 V (e.g.,
during power-up) and the reference is capable of supplying 30 mA or more, it is
recommended to use a clamping diode between the REFIN pin and VDD pin. The
diagram below shows how the diode should be connected.
BAT81
V
DD
REF
IN
AD7816/AD7817
REV. C–6–
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