Datas heet
AS1524/AS1525
1 5 0 k s ps , 1 2 - B i t , 1 - C h a n n e l P s e u d o / Tru e - D i f f e r e n t i a l
and 2-Channel Single-Ended ADCs
1 General Description
The AS1524/AS1525 are low-power, 12-bit analog-to-
digital converters (ADCs) designed to operate with a sin-
gle +2.7V to +5.25V supply. Excellent dynamic perfor-
mance, low power consumption, and simplicity make
these devices perfect for portable battery-powered data-
acquisition applications.
The devices are available as the standard products
listed in
Table 1.
Table 1. Standard Products
Model
AS1524
AS1525
Input Type
1-Channel, Pseudo /
True-Differential
2-Channel, Single-
Ended
Input Voltage
0 to V
REF
/
-V
REF
/2 to V
REF
/2
0 to V
REF
2 Key Features
!
!
!
Single-Supply Operation: +2.7V to +5.25V
Automatic Shutdown Between Conversions
Low Power Consumption
- 350µA @ 150ksps
- 245µA @ 100ksps
- 24µA @ 10ksps
- 2.5µA @ 1ksps
- 200nA in Automatic Shutdown Mode
!
True-Differential Track/Hold, 150kHz Sampling Rate
Software-Configurable Unipolar/Bipolar Conversion
(AS1524)
Input Common Mode Range from GND to V
DD
3-Wire SPI-/QSPI-/MICROWIRE-Compatible Serial
Interface
Internal Conversion Clock
8-pin TDFN (3x3mm) Package
The devices feature a successive-approximation regis-
ter (SAR), automatic shutdown, fast wakeup (1.4µs),
and low-power consumption at the maximum sampling
rate of 150ksps.
Automatic shutdown (0.2µA) between conversions
results in reduced power consumption (at slower
throughput rates).
Data access are made via an external clock through the
SPI-/QSPI-/MICROWIRE-compatible 3-wire high-speed
serial interface.
The AS1525/AS1524 are available in a 8-pin TDFN
(3x3mm) package.
!
!
!
!
3 Applications
The devices are ideal for remote sensors, data-acquisi-
tion, data logging devices, lab instruments, or for any
other space-limited A/D devices with low power con-
sumption and single-supply requirements.
Figure 1. AS1524/AS1525 - Block Diagram
1
VDD
7
CNVST
8
SCLK
Control
Logic
2
AIN1/AIN+
2
AIN2/AIN-
4
REF
5
GND
Track/
Hold
12-Bit
SAR
6
DOUT
Input
Shift
Register
AS1524/AS1525
Osc
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Revision 1.02
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AS1524/AS1525
Datasheet
Contents
1 General Description
2 Key Features
3 Applications
4 Pinout
............................................................................................................................. 1
........................................................................................................................................ 1
.......................................................................................................................................... 1
................................................................................................................................................... 3
..................................................................................................................................................... 3
................................................................................................................................................... 3
Pin Assignment
Pin Description
5 Absolute Maximum Ratings
6 Electrical Characteristics
Timing Characteristics
................................................................................................................. 4
...................................................................................................................... 5
........................................................................................................ 8
.......................................................................................................... 11
.........................................................................................12
......................................................................................................................................... 7
7 Typical Operating Characteristics
8 Detailed Description
........................................................................................................................... 11
...................................................................................................................... 11
True Differential Analog Input Track/Hold
Selecting AIN1 or AIN2 (AS1525)
Input Bandwidth
Internal Clock
Selecting Unipolar or Bipolar Conversions (AS1524)
Analog Input Protection
Output Data Format
Transfer Function
..................................................................................................................................................13
......................................................................................................................................13
......................................................................................................................................................13
............................................................................................................................................13
................................................................................................................................................13
9 Application Information
External Reference
....................................................................................................................... 15
.................................................................................................................................15
....................................................................................................................................15
..........................................................................................................................15
Automatic Shutdown Mode
Performing a Conversion
.............................................................................................................................................15
Standard Interface Connections
SPI and Microwire Interface ........................................................................................................................... 15
QSPI Interface ................................................................................................................................................16
PIC16 and SSP Module and PIC17 Interface ................................................................................................17
Layout and Grounding Considerations
.............................................................................................................. 19
10 Package Drawings and Markings
11 Ordering Information
.................................................................................................... 20
........................................................................................................................ 21
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Revision 1.02
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AS1524/AS1525
Datasheet - P i n o u t
4 Pinout
Pin Assignment
Figure 2. Pin Assignments (Top View)
V
DD
1
8 SCLK
AIN1/AIN+ 2
AIN2/AIN- 3
AS1524/
AS1525
7 DOUT
6 CNVST
GND 4
5 REF
Pin Description
Table 2. Pin Description
Pin Number
1
2
3
4
5
Pin Name
VDD
AIN1/AIN+
AIN2/AIN-
GND
REF
Description
Positive Supply Voltage.
+2.7V to +5.25V.
Note:
Bypass with a 0.1µF capacitor to GND.
Analog Input Channel 1 (AS1525) or Positive Analog Input (AS1524)
Analog Input Channel 2 (AS1525) or Negative Analog Input (AS1524)
Ground
External Reference Voltage Input.
Sets the analog voltage range.
Note:
Bypass with a 4.7µF capacitor to GND.
Conversion Start.
A rising edge powers up the device and puts the track/
hold circuitry in track mode. At the falling edge of this pin, the device enters
hold mode and begins a conversion.
Note:
This pin also selects the input channel (AS1525) or input polarity
(AS1524).
Serial Data Output.
This pin transitions the falling edge of SCLK and goes
low at the start of a conversion and delivers the MSB at the completion of a
conversion.
Note:
This pin goes high impedance once data has been fully clocked out.
Serial Clock Input.
Clocks out data at DOUT with the MSB first.
6
CNVST
7
DOUT
8
SCLK
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AS1524/AS1525
Datasheet - A b s o l u t e M a x i m u m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in
Table 3
may cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other conditions beyond those indicated in
Electrical Character-
istics on page 5
is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.
Table 3. Absolute Maximum Ratings
Parameter
VDD to GND
CNVST, SCLK, DOUT, REF, AIN1/
AIN+, AIN2/AIN- to GND
Current into Any Pin
Continuous Power Dissipation
Operating Temperature Range
Storage Temperature Range
1491
-40
-60
+85
+150
Min
-0.3
-0.3
Max
+6
V
DD
+
0.3
50
Units
V
V
mA
mW
ºC
ºC
The reflow peak soldering temperature (body
temperature) specified is in accordance with
IPC/JEDEC J-STD-020D “Moisture/Reflow
Sensitivity Classification for Non-Hermetic Solid
State Surface Mount Devices”.
The lead finish for Pb-free leaded packages is
matte tin (100% Sn).
T
AMB
= +70ºC; derate 19.5mW/ºC above +70ºC
Comments
Package Body Temperature
+260
ºC
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Revision 1.02
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AS1524/AS1525
Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s
6 Electrical Characteristics
V
DD
= +2.7 to +5.25V, V
REF
= +2.5V, 4.7µF Capacitor at REF; f
SCLK
= 8MHz (50% Duty Cycle); AIN- = GND (AS1524)
T
AMB
= T
MIN
to TMAX (unless otherwise specified). Typical Values at T
AMB
= +25ºC. Unipolar Mode (AS1524).
Table 4. Electrical Characteristics
Symbol
DC Accuracy
Resolution
INL
DNL
Relative Accuracy
Differential Non-Lineraity
Offset Error
Gain Error
1
Parameter
Condition
Min
12
Typ
Max
Unit
Bits
±1.0
No Missing Codes Over Temperature
-0.99
±1
±1
±0.3
±0.3
±0.1
±0.1
+1.0
±4
±4
LSB
LSB
LSB
LSB
ppm/ºC
ppm/ºC
LSB
LSB
Gain Temp Coefficient
Offset Temp Coefficient
Channel-to-Channel Offset
Match
Channel-to-Channel Gain
Match
Dynamic Specifications –
(f
IN
(sinewave) = 10kHz, V
IN
= 2.5V
P-P
, 150ksps, f
SCLK
= 8MHz (50% duty cycle), AIN- =
GND (AS1524)
SINAD
THD
SFDR
Signal-to-Noise Plus Distortion
Total Harmonic Distortion (to
the 5th Harmonic)
Spurious-Free Dynamic Range
Full Power Bandwidth
Full Linear Bandwidth
Conversion Rate
t
CONV
t
ACQ
Conversion Time
Track/Hold Acquisition Time
Aperture Delay
f
SCLK
Max Serial Clock Frequency
Serial Clock Duty Cycle
Analog Input
V
IN
Range
2
72.5
-79.5
84
-3dB Point
-0.1dB Point
Exclusive of t
ACQ
20
400
3.3
3.7
1.4
30
8
30
Unipolar
Bipolar
No Channel Selected or Conversion
Halted
Track Mode
Hold Mode
0
-V
REF
/2
±0.01
20
5
V
DD
+
50mV
11
19
0
+2
+5
25
70
V
REF
V
REF
/2
±1
dB
dB
dB
MHz
kHz
µs
µs
ns
MHz
%
V
µA
pF
pF
Input Leakage Current
Input Capacitance
External Reference Input
V
REF
V
IN
Range
1.0
V
REF
= +2.5V @ 150ksps
V
I
REF
Input Current
V
REF
= +4.096V @ 150ksps
Acquisition Between Conversions
µA
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