NSC SCANSTA476

SCANSTA476
Eight Input IEEE 1149.1 Analog Voltage Monitor
General Description
Features
The SCANSTA476 is a low power, Analog Voltage Monitor
used for sampling or monitoring up to 8 analog/mixed-signal
input channels. Analog Voltage Monitors are valuable during
product development, environmental test, production, and
field service for verifying and monitoring power supply and
reference voltages. In a supervisory role, the ’STA476 is
useful for card or system-level health monitoring and prognostics applications.
Instead of requiring an external microcontroller with a GPIO
interface, the ’STA476 features a common IEEE 1149.1
(JTAG) interface to select the analog input, initiate a measurement, and access the results - further extending the
capabilities of an existing JTAG infrastructure.
The SCANSTA476 uses the VREF input as a reference. This
enables the SCANSTA476 to operate with a full-scale input
range of 0 to VDD, which can range from +2.7V to +5.5V.
The SCANSTA476 is packaged in a 16-lead non-pullback
LLP package that provides an extremely small footprint for
applications where space is a critical consideration. This
product operates over the industrial temperature range of
−40˚C to +85˚C.
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Eight selectable Analog input channels
Analog full-scale input range 0V to VDD
Typical accuracy of 2 mV at maximum VDD
Very low power operation
Small package footprint in 16-lead, 5 x 5 x 0.8 mm LLP
Single +2.7V to +5.5V supply operation
IEEE 1149.1 (JTAG) compliant interface
Applications
Measurement of Point Voltages
Real-time Signal Monitoring
System Health Monitoring and Prognostics
Debug, Environmental Test, Production Test, Field
Service
n Supplement In-Circuit Tester (ICT) access
n Vital in Servers, Computing, Telecommunication and
Industrial equipment
n Essential in Medical, Data Storage, and Networking
equipment
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Block Diagram
20083521
© 2005 National Semiconductor Corporation
DS200835
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SCANSTA476 Eight Input IEEE 1149.1 Analog Voltage Monitor
August 2005
SCANSTA476
Connection Diagram
20083522
DAP = GND
(Top View)
Pin Descriptions
Pin No.
Symbol
Description
ANALOG I/O
16
A0
Analog input 0. This signal can range from 0V to VREF.
15
A1
Analog input 1. This signal can range from 0V to VREF.
14
A2
Analog input 2. This signal can range from 0V to VREF.
13
A3
Analog input 3. This signal can range from 0V to VREF.
12
A4
Analog input 4. This signal can range from 0V to VREF.
11
A5
Analog input 5. This signal can range from 0V to VREF.
10
A6
Analog input 6. This signal can range from 0V to VREF.
9
A7
Analog input 7. This signal can range from 0V to VREF.
2
VREF
Analog reference voltage input. VREF must be ≤ VDD. This pin should be connected to a quiet
source (not directly to VDD) and bypassed to GND with 0.1 µF and 1 µF monolithic capacitors
located within 1 cm of the VREF pin.
DIGITAL I/O
6
TDI
Test Data Input to support IEEE 1149.1 features
5
TDO
Test Data Ouput to support IEEE 1149.1 features
7
TMS
Test Mode Select to support IEEE 1149.1 features
8
TCK
Test Clock to support IEEE 1149.1 features
4
TRST
Test Reset to support IEEE 1149.1 features
POWER SUPPLY
1,3
(Note 1)
VDD
Positive supply pin. These pins should be connected to a quiet +2.7V to +5.5V source and
bypassed to GND with 0.1 µF and 1 µF monolithic capacitors located within 1 cm of the
power pin.
GND
Ground reference for CMOS circuitry. DAP is the exposed metal contact at the bottom of the
LLP package. The DAP is used as the primary GND connection to the device. It should be
connected to the ground plane with at least 4 vias for optimal low-noise and thermal
performance.
Note 1: Note that GND is not an actual pin on the package, the GND is connected thru the DAP on the back side of the LLP package.
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2
Junction Temperature
+150˚C
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Storage Temperature
−65˚C to +150˚C
Thermal Resistance, θJA
42˚C/W
Thermal Resistance, θJC
14.3˚C/W
−0.3V to +6.5V
Supply Voltage VDD
Voltage on Any Analog Pin to GND
−0.3V to VDD+0.3V
Voltage on Any Digital Pin to GND
-0.3V to VDD+0.3V
Recommended Operating
Conditions
± 10 mA
Input Current at Any Pin (Note 4)
Operating Temperature Range
ESD Susceptibility
Human Body Model
Machine Model
8000V
> 250V
Soldering Temperature
Refer to AN-1187
−40˚C ≤ TA ≤ +85˚C
VDD Supply Voltage
+2.7V to +5.5V
Digital Input Pins Voltage Range
+0V to VDD
Analog Input Pins Voltage Range
(Note 5)
+0V to VREF
SCANSTA476 Electrical Characteristics
The following specifications apply for VDD = +2.7V to 5.5V, fTCK = 20 MHz, unless otherwise noted.
Symbol
Parameter
Conditions
Typical
Limits
Units
POWER SUPPLY CHARACTERISTICS
VDD
IDD
PD
2.7
V (min)
5.5
V (max)
5.0
mA
VDD = +2.7V to +5.5V,
fTCK = 1 MSPS
5.0
mA (max)
VDD = +5.5V, fTCK = 1 MSPS
27.5
mW (max)
0 to VREF
V
Supply Voltage
−40˚C ≤ TA ≤ 85˚C
Normal Mode (Static)
VDD = +2.7V to +5.5V,
Normal Mode (Operational)
Power Consumption, Normal Mode
(Operational)
3.5
ANALOG INPUT CHARACTERISTICS (A0-A7)
VIN
Analog Input Range
VREF
Reference Voltage Range
IDCL
DC Leakage Current
VMEAS
Analog Input Measurement Accuracy
VREF ≤ VDD
VDD
V
0.1
± 10
µA (max)
VDD = +2.7V
1
7.5
VDD = +5.5V
2
15
mV
DIGITAL INPUT CHARACTERISTICS (TDI, TMS, TCK, TRST)
VDD = +2.7V to +3.6V
2.0
VDD = +5.5V
2.1
V (min)
VIH
Input High Voltage
VIL
Input Low Voltage
VDD = +5V
0.8
V (max)
VCL
Input Clamp Voltage
ICL = -18mA
-0.8
-1.5
V (max)
IIN
Input Current
VIN = 0V or VDD
0.2
± 10
µA (max)
IILR
Input Current
TRST, TDI, TMS only
-300
µA (max)
VDD −0.2
V (min)
IOH = -4 mA, 3.0V ≤ VDD ≤ 5.5V
2.4
V (min)
IOH = -4 mA, VDD = 2.7V
2.2
V (min)
IOL = 100 µA, 2.7V ≤ VDD ≤ 5.5V
0.2
V (max)
IOL = 4 mA, 2.7V ≤ VDD ≤ 5.5V
0.4
V (max)
-85
mA (max)
± 10
µA (max)
DIGITAL OUTPUT CHARACTERISTICS (TDO)
IOH = -100 µA, 2.7V ≤ VDD ≤ 5.5V
VOH
Output High Voltage
VOL
Output Low Voltage
IOS
Output Short Circuit Current
IOZ
TRI-STATE Leakage Current
VOUT = 0V, VDD = 5.5V
Output Coding
Straight (Natural) Binary
3
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SCANSTA476
Absolute Maximum Ratings (Note 2)
SCANSTA476
SCANSTA476 Electrical Characteristics
(Continued)
The following specifications apply for VDD = +2.7V to 5.5V, fTCK = 20 MHz, unless otherwise noted.
Symbol
Parameter
Conditions
Typical
Limits
Units
1
MSPS
(max)
AC ELECTRICAL CHARACTERISTICS
FMAX
Throughput Rate
TCK = 20MHz
INPUT TIMING CHARACTERISTICS
tSET
TDI to TCK (H/L)
(Note 3)
2.0
ns (min)
tHOLD
TDI to TCK (H/L)
(Note 3)
1.5
ns (min)
tSET
TMS to TCK (H/L)
(Note 3)
2.0
ns (min)
tHOLD
TMS to TCK (H/L)
(Note 3)
2.0
ns (min)
tW
TCK Pulse Width (H/L)
(Note 3)
10.0
ns (min)
tREC
Recovery TIme TRST to TCK
(Note 3)
2.0
ns (min)
tW
TRST Pulse Width (L)
(Note 3)
2.5
ns (min)
FMAX
TCK
20
MHz (min)
Note 2: Absolute maximum ratings are limiting values, to be applied individually, and beyond which the serviceability of the circuit may be impaired. Functional
operability under any of these conditions is not implied. Exposure to maximum ratings for extended periods may affect device reliability.
Note 3: Data sheet min/max specification limits are guaranteed by design or statistical analysis.
Note 4: Except power supply pins.
Note 5: For valid measurements, the analog VIN < VREF ≤ VDD.
STARTUP MODE
When the VDD supply is first applied, the SCANSTA476
requires one dummy conversion after start-up.
Applications Information
POWER-UP TIMING
The SCANSTA476 typically requires 1 µs to power up ,
either after first applying VDD, or after an incomplete conversion shift. To return to normal, one "dummy" conversion must
be fully completed. After this first dummy conversion, the
SCANSTA476 will perform conversions properly.
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4
Instruction Shift (Channel Select)
Note the JTAG reset preamble places the JTAG TAP controller in a stable state (RTI). Both the instruction and data shifts start in - and return to - the RTI state.
Op-codes 40h to 47h select pins A0 to A7 respectively.
Timing Diagrams
20083532
SCANSTA476
5
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6
(Continued)
Data Shift (A/D Sample)
Note that Data shifts can be run back-to-back for continous sampling of a single channel, or can be interleaved with instruction shifts for rippling through all 8 channels.
D11 through D0 correspond to the 12-bit sample from the ADC Core.
Timing Diagrams
20083533
SCANSTA476
SCANSTA476 Eight Input IEEE 1149.1 Analog Voltage Monitor
Physical Dimensions
inches (millimeters) unless otherwise noted
LLP, Plastic, Dual
Order Number SCANSTA476TSD,
NS Package Number SDA16A
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves
the right at any time without notice to change said circuitry and specifications.
For the most current product information visit us at www.national.com.
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS
WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR
CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body, or
(b) support or sustain life, and whose failure to perform when
properly used in accordance with instructions for use
provided in the labeling, can be reasonably expected to result
in a significant injury to the user.
2. A critical component is any component of a life support
device or system whose failure to perform can be reasonably
expected to cause the failure of the life support device or
system, or to affect its safety or effectiveness.
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Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain
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