Datasheet

AS3932
3D Low Frequency Wakeup Receiver
General Description
The AS3932 is a 3-channel low power ASK receiver that is able
to generate a wake-up upon detection of a data signal which
uses a LF carrier frequency between 110 - 150 kHz. The
integrated correlator can be used for detection of a
programmable 16-bit wake-up pattern. The device can operate
using one, two, or three active channels.
The AS3932 provides a digital RSSI value for each active
channel, it supports a programmable data rate. The AS3932
offers a real-time clock (RTC), which is either derived from a
crystal oscillator or the internal RC oscillator.
The programmable features of AS3932 enable to optimize its
settings for achieving a longer distance while retaining a
reliable wake-up generation. The sensitivity level of AS3932 can
be adjusted in presence of a strong field or in noisy
environments.
The device is available in 16-pin TSSOP and 16LD QFN (4×4)
packages.
Ordering Information and Content Guide appear at end of
datasheet.
Key Benefits & Features
The benefits and features of AS3932, 3D Low Frequency Wakeup
Receiver are listed below:
Figure 1:
Added Value of Using AS3932
Benefits
Features
Enables low power active tags
3-channel ASK wake-up receiver
Selectable carrier frequency
Carrier frequency range 110 - 150 kHz
One, two, or three channel operation
1-D, 2-D, or 3-D wake-up pattern detection
Highly resistant to false wake-ups
16-bit programmable wake-up pattern
Improved immunity to false wake-ups
Supporting doubling of wake-up pattern
Allows frequency only detection
Wake-up without pattern detection selectable
Improved range with best-in-class sensitivity
Wake-up sensitivity 100μVRMS (typ.)
Adjustable range
Sensitivity level adjustable
Provides tracking of false wake-ups
False wake-up counter
Ensures wake-up in a noise environment
Periodical forced wake-up supported (1s – 2h)
Extended battery life
Current consumption in 3-channel listening mode 1.7μA (typ.)
ams Datasheet
[v1-83] 2015-Mar-02
Page 1
Document Feedback
AS3932 − General Description
Benefits
Features
Flexible clock configuration
RTC based 32 kHz XTAL, RC-OSC, or external clock
Operates from a 3V battery
Operating supply range 2.4V – 3.6V (TA = 25°C)
Industrial temperature range
Operation temperature range -40°C to +85°C
Applications
The AS3932 is ideal for:
• Active RFID tags,
• Real-time location systems,
• Operator identification,
• Access control, and
• Wireless sensors.
Figure 2:
AS3932 Typical Application Diagram with Crystal Oscillator
VCC
CL
CBAT
Page 2
Document Feedback
XIN
NC
XOUT
X, Y, and Z Receiving Antennas
TX
CS
XTAL
Transmitting Antenna
TRANSMITTER
VCC
LF1P
DAT
AS3932
WAKE
LF2P
SCL
LF3P
SDO
LFN
SDI
VSS
GND
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − General Description
Figure 3:
AS3932 Typical Application Diagram with RC Oscillator
VCC
VCC
CS
XIN
NC
CBAT
LF1P
X, Y, and Z Receiving Antennas
TX
Transmitting Antenna
XOUT
TRANSMITTER
DAT
AS3932
WAKE
LF2P
SCL
LF3P
SDO
LFN
SDI
VSS
GND
Figure 4:
AS3932 Typical Application Diagram with Clock from External Source
VCC
CBAT
EXTERNAL CLOCK
VCC
CS
XIN
NC
R
C
ams Datasheet
[v1-83] 2015-Mar-02
X, Y, and Z Receiving Antennas
TX
Transmitting Antenna
XOUT
TRANSMITTER
LF1P
DAT
AS3932
WAKE
LF2P
SCL
LF3P
SDO
LFN
SDI
VSS
GND
Page 3
Document Feedback
AS3932 − Pin Assignment
Pin Assignment
TSSOP Package
Figure 5:
Pin Assignments 16-pin TSSOP Package
CS
1
16
NC
SCL
2
15
DAT
SDI
3
14
WAKE
SDO
4
13
VSS
VCC
5
12
XOUT
GND
6
11
XIN
LF3P
7
10
LFN
LF2P
8
9
LF1P
AS3932
Pin Description
Figure 6:
Pin Descriptions 16-pin TSSOP Package
Pin Name
Pin
Number
CS
1
SCL
2
SDI
3
SDO
4
Digital output /
tristate
VCC
5
Supply pad
Positive supply voltage
GND
6
Supply pad
Negative supply voltage
Page 4
Document Feedback
Pin Type
Description
Chip select
Digital input
SDI interface clock
SDI data input
SDI data output (tristate when CS is low)
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Pin Assignment
Pin Name
Pin
Number
LF3P
7
Input antenna channel three
LF2P
8
Input antenna channel two
LF1P
9
Pin Type
Description
Input antenna channel one
Analog I/O
LFN
10
Common ground for antenna one, two and three
XIN
11
Crystal oscillator input
XOUT
12
Crystal oscillator output
VSS
13
WAKE
14
Supply pad
Substrate
Wake-up output IRQ
Digital output
DAT
15
NC
16
Data output
-
Not connected
QFN Package
GND
VCC
SDO
SDI
Figure 7:
Pin Assignments 16LD QFN (4×4) Package
16
15
14
13
LF3P
1
12
SCL
LF2P
2
11
CS
LF1P
3
10
NC
LFN
4
9
DAT
ams Datasheet
[v1-83] 2015-Mar-02
5
6
7
8
XIN
XOUT
VSS
WAKE
AS3932
Page 5
Document Feedback
AS3932 − Pin Assignment
Pin Description
Figure 8:
Pin Descriptions 16LD QFN (4×4) Package
Pin Name
Pin
Number
LF3P
1
Input antenna channel three
LF2P
2
Input antenna channel two
LF1P
3
Pin Type
Description
Input antenna channel one
Analog I/O
LFN
4
Common ground for antenna one, two and three
XIN
5
Crystal oscillator input
XOUT
6
Crystal oscillator output
VSS
7
WAKE
8
Supply pad
Substrate
Wake-up output IRQ
Digital output
DAT
9
Data output
NC
10
CS
11
SCL
12
SDI
13
SDO
14
Digital output /
tristate
VCC
15
Supply pad
Positive supply voltage
GND
16
Supply pad
Negative supply voltage
-
Not connected
Chip select
Digital input
SDI interface clock
SDI data input
SDI data output (tristate when CS is low)
Note(s) and/or Footnote(s):
1. The exposed pad has to be connected to ground.
Page 6
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Absolute Maximum Ratings
Absolute Maximum Ratings
Stresses beyond those listed in Absolute Maximum Ratings may
cause permanent damage to the device. These are stress ratings
only. Functional operation of the device at these or any other
conditions beyond those indicated in Electrical Characteristics
is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
Figure 9:
Absolute Maximum Ratings
Symbol
Parameter
Min
Max
Unit
Note
Electrical Parameters
VDD
DC supply voltage
-0.5
5
V
VIN
Input pin voltage
-0.5
5
V
Input current
(latch up immunity)
-100
100
mA
ISOURCE
Norm: Jedec 78
Electrostatic Discharge
ESD
Electrostatic
discharge
±2
kV
Norm: MIL 883 E method 3015 (HBM)
Continuous Power Dissipation
Pt
Total power
dissipation
0.07
mW
All supplies and outputs
Temperature Ranges and Storage Conditions
Tstrg
Storage temperature
Tbody
Package body
temperature
RHNC
Relative Humidity
non-condensing
MSL
Moisture Sensitivity
Level
ams Datasheet
[v1-83] 2015-Mar-02
-65
150
5
3
°C
260
°C
85
%
Norm: IPC/JEDEC J-STD-020
The reflow peak soldering temperature
(body temperature) is specified
according IPC/JEDEC J-STD-020
“Moisture/Reflow Sensitivity
Classification for Non-hermetic Solid
State Surface Mount Devices”.
Represents a maximum floor life
time of 168h
Page 7
Document Feedback
AS3932 − Electrical Characteristics
Electrical Characteristics
Figure 10:
Electrical Characteristics
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
2.4
3.6
V
0
0
V
-40
85
°C
Operating Conditions
VDD
Positive supply voltage
VSS
Negative supply
voltage
TAMB
Ambient temperature
DC/AC Characteristics for Digital Inputs and Outputs
CMOS Input
VIH
High level input
voltage
0.58*
VDD
0.7*
VDD
0.83*
VDD
V
VIL
Low level input voltage
0.125*
VDD
0.2*
VDD
0.3*
VDD
V
ILEAK
Input leakage current
100
nA
CMOS Output
VOH
High level output
voltage
With a load current of 1mA
VOL
Low level output
voltage
With a load current of 1mA
VSS +
0.4
V
CL
Capacitive load
For a clock frequency of 1 MHz
400
pF
VDD - 0.4
V
Tristate CMOS Output
VOH
High level output
voltage
With a load current of 1mA
VOL
Low level output
voltage
With a load current of 1mA
VSS +
0.4
V
IOZ
Tristate leakage
current
To VDD and VSS
100
nA
Page 8
Document Feedback
VDD - 0.4
V
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Electrical Characteristics
Figure 11:
Electrical System Specifications
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
Input Characteristics
RIN
Input Impedance
In case no antenna damper is
set (R1<4>=0)
2
MΩ
Fmin
Minimum Input
Frequency
110
kHz
Fmax
Maximum Input
Frequency
150
kHz
Power Down Mode
400
nA
I1CHRC
Current Consumption
in standard listening
mode with one active
channel and
RC-oscillator as RTC
2.7
μA
I2CHRC
Current Consumption
in standard listening
mode with two active
channels and
RC-oscillator as RTC
4.2
μA
I3CHRC
Current Consumption
in standard listening
mode with three
active channels and
RC-oscillator as RTC
5.7
I3CHSCRC
Current Consumption
in scanning mode
with three active
channels and
RC-oscillator as RTC
2.7
I3CHOORC
Current Consumption
in ON/ OFF mode
with three active
channels and
RC-oscillator as RTC
Current Consumption
IPWD
I3CHXT
Current Consumption
in standard listening
mode with three
active channels and
crystal oscillator as
RTC
ams Datasheet
[v1-83] 2015-Mar-02
11% Duty Cycle
1.7
50% Duty Cycle
3.45
8.3
μA
μA
μA
6.5
8.9
μA
Page 9
Document Feedback
AS3932 − Electrical Characteristics
Symbol
Parameter
IDATA
Current Consumption
in Preamble detection
/ Pattern correlation /
Data receiving mode
(RC-oscillator)
Conditions
Min
With 125 kHz carrier
frequency and
1kbpsdata-rate. No load on
the output pins.
Typ
Max
Unit
8.3
12
μA
Input Sensitivity
SENS
Input Sensitivity on
all channels
With 125 kHz carrier
frequency, chip in default
mode, 4 half bits burst + 4
symbols preamble and single
preamble detection
100
μVrms
250
μs
32.768
kHz
Channel Settling Time
TSAMP
Amplifier settling
time
Crystal Oscillator
FXTAL
Frequency
Crystal dependent
TXTAL
Start-up Time
Crystal dependent
IXTAL
Current consumption
1
s
1
μA
1
μA
External Clock Source
IEXTCL
Current consumption
RC Oscillator
FRCNCAL
Frequency
If no calibration is performed
27
32.768
42
kHz
FRCCAL32
Frequency
If calibration with 32.768 kHz
reference signal is performed
31
32.768
34.5
kHz
FRCCALMAX
Frequency
Maximum achievable
frequency after calibration
35
kHz
FRCCALMIN
Frequency
Minimum achievable
frequency after calibration
30
kHz
Start-up time
From RC enable (R1<0> = 0)
TRC
TCALRC
IRC
Calibration time
Current consumption
Page 10
Document Feedback
200
1
s
65
Periods of
reference
clock
nA
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Typical Operating Characteristics
Typical Operating
Characteristics
Figure 12:
Sensitivity over Voltage and Temperature
120
95 oC
100
27 oC
-40 oC
Sensitivity [μVrms]
80
60
40
20
0
2.4
3
3.6
Supply Voltage [V]
Figure 13:
Sensitivity over RSSI
1000000
VIN = 2.4V
100000
Input Voltage [μVrms]
VIN = 1.5V
10000
VIN = 1.0V
1000
100
10
1
2
4
6
8
10 12 14 16 18 20 22 24 26 28 30
RSSI [dB]
ams Datasheet
[v1-83] 2015-Mar-02
Page 11
Document Feedback
AS3932 − Typical Operating Characteristics
Figure 14:
RC-Osc Frequency over Voltage (calibr.)
34.5
RC-OSC Frequency [KHz]
34
33.5
33
32.5
32
31.5
31
2.4
2.6
2.8
3
3.2
3.4
3.6
Supply Voltage [V]
Figure 15:
RC-Osc Frequency over Temperature (calibr.)
34.5
RC-OSC Frequency [KHz]
34
33.5
33
32.5
32
31.5
31
-36 -30 -20 -10
0
10
20
30
40
50
60
70
80
90
Operating Temperature [oC]
Page 12
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
The AS3932 is a three-dimensional low power low-frequency
wake-up receiver. The AS3932 is capable to detect the presence
of an inductive coupled carrier and extract the envelope of the
ON-OFF-Keying (OOK) modulated carrier. If the detected
pattern corresponds to the stored one a wake-up signal (IRQ)
is risen up. The pattern correlation can be bypassed in which
case the wake-up detection is based only on the frequency
detection.
Detailed Description
The AS3932 is made up by three independent receiving
channels, one envelop detector, one data correlator, 8
programmable registers with the main logic and a real time
clock.
The digital logic can be accessed by an SPI. The real time clock
can be based on a crystal oscillator or on an internal RC one. If
the internal RC oscillator is used, a calibration procedure can be
performed to improve its accuracy.
Figure 16:
Block Diagram of LF Wake-up Receiver AS3932
AS3932
Wake-up
IRQ
Data
LF1P
Channel
Amplifier 1
SCL
RSSI
Main Logic
SPI
SDI
SDO
Freq. OK
LF2P
Channel
Amplifier 2
Envelope Detector /
Data Slicer
Channel
Selector
Data
CS
Correlator
RSSI
Freq. OK
DAT
Data
LF3P
Channel
Amplifier 3
RSSI
Freq. OK
I/V
Bias
Xtal RTC
GND
Xin
RC RTC
LFN
VCC
ams Datasheet
[v1-83] 2015-Mar-02
Xout
Page 13
Document Feedback
AS3932 − Detailed Description
AS3932 needs the following external components:
• Power supply capacitor - CBAT - 100 nF.
• 32.768 kHz crystal with its two pulling capacitors - XTAL
and CL - (it is possible to omit these components if the
internal RC oscillator is used instead of the crystal
oscillator).
• One, two, or three LC resonators according to the number
of used channels.
In case the internal RC-oscillator is used (no crystal oscillator is
mounted), the pin XIN has to be connected to the supply, while
pin XOUT should stay floating. Application diagrams with and
without crystal are shown in Figure 2 and Figure 3.
Operating Modes
Power Down Mode
In Power Down Mode AS3932 is completely switched OFF. The
typical current consumption is 400 nA.
Listening Mode
In listening mode only the active channel amplifiers and the
RTC are running. In this mode the system detects the presence
of a carrier. In case the carrier is detected the RSSI can be
displayed.
If the three dimensional detection is not required it is possible
to deactivate one or more channels. In case only two channels
are required the deactivated channel must be the number two,
while if only one channel detection is needed the active channel
must be the number one.
Inside this mode it is possible to distinguish the following three
sub modes:
Standard Listening Mode. All channels are active at the same
time.
Scanning Mode (Low Power Mode 1). All used channels are
active, but only one per time slot, where the time slot T is
defined as 1ms. Thus, if all three channels are active the
procedure is as follows (see Figure 17): for the first millisecond
only channel one is active while channel two and three are
powered down; for the next millisecond only channel three is
active while channel one and two are powered down; finally,
channel two is active while the other two are deactivated. This
channel rotation goes on until the presence of the carrier is
detected by any of the channels; then immediately all three
channels will become active at the same time. Now AS3932 can
perform a simultaneous multidirectional evaluation (on all
three channels) of the field and evaluate which channel has the
strongest RSSI. The channel with the highest RSSI will be put
through to the demodulator.
Page 14
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
In this way it is possible to perform multidirectional monitoring
of the field with a current consumption of a single channel,
keeping the sensitivity as good as if all channels are active at
the same time.
Figure 17:
Scanning Mode
Channel 1
Channel 3
time
Channel 2
time
Presence
of carrier
time
t0
ams Datasheet
[v1-83] 2015-Mar-02
t0+T
t0+2T
t0+3 T
t0+4T
t0+5T
t1
time
Page 15
Document Feedback
AS3932 − Detailed Description
ON/OFF Mode (Low Power Mode 2). All active channels are ON
at the same time but not for the whole time (time slot T is
defined as 1ms). An ON-OFF duty-ratio is defined. This duty ratio
is programmable see R4<7:6>.
Figure 18:
ON/OFF Mode
Channel 1
Channel 2
time
Channel 3
time
Presence
of carrier
time
t0
t0+T
2 *t 0
2 *t 0 + T
3 *t 0
time
For each of these sub modes it is possible to enable a further
feature called Artificial Wake-up. The Artificial Wake-up is a
counter based on the used RTC. Three bits define a time window
see R8<2:0>. If no activity is seen within this time window the
chip will produce an interrupt on the WAKE pin that lasts 128μs.
With this interrupt the microcontroller (μC) can get feedback
on the surrounding environment (e.g. read the false wake-up
register R13<7:0>) and/or take actions in order to change the
setup.
Preamble Detection / Pattern Correlation
The preamble detection and pattern correlation are only
considered for the wake-up when the data correlator function
is enabled (see R1<1>). The correlator searches first for
preamble frequency (constant frequency of Manchester clock
defined according to bit-rate transmission, see Figure 37) and
then for data pattern.
If the pattern is matched the wake-up interrupt is displayed on
the WAKE output and the chip goes in Data receiving mode. If
the pattern fails the internal wake-up (on all active channels) is
terminated and no IRQ is produced.
Page 16
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
Data Receiving
After a successful wake-up the chip enters the data receiving
mode. In this mode the chip can be retained a normal OOK
receiver. The received data are streamed out on the pin DAT. It
is possible to put the chip back to listening mode either with a
direct command (CLEAR_WAKE (see Figure 25)) or by using the
timeout feature. This feature automatically sets the chip back
to listening mode after a certain time R7<7:5>.
System and Block Specification
Register Table
Figure 19:
Register Table
7
R0
n.a.
R1
ABS_HY
R2
S_ABSH
R3
HY_20m
R4
6
AGC_TLI
M
5
4
3
2
1
0
ON_OFF
MUX_123
EN_A2
EN_A3
EN_A1
PWD
AGC_UD
ATT_ON
EN_PAT2
EN_WPAT
EN_RTC
W_PAT_T<1:0>
HY_POS
T_OFF<1:0>
Reserved
FS_SLC<2:0>
FS_ENV<2:0>
R_VAL<1:0>
GR<3:0>
R5
TS2<7:0>
R6
TS1<7:0>
R7
T_OUT<2:0>
R8
R9
S_WU1<1:0>
T_HBIT<4:0>
n.a
n.a
T_AUTO<2:0>
Reserved
R10
n.a
RSSI1<4:0>
R11
n.a
RSSI3<4:0>
R12
n.a
RSSI2<4:0>
R13
ams Datasheet
[v1-83] 2015-Mar-02
F_WAKE
Page 17
Document Feedback
AS3932 − Detailed Description
Register Table Description and Default Values
Figure 20:
Default Values of Registers
Register
Name
Type
Default
Value
R0<5>
ON_OFF
R/W
0
ON/OFF operation mode. (Duty-cycle defined in the
register R4<7:6>
R0<4>
MUX_123
R/W
0
Scan mode enable
R0<3>
EN_A2
R/W
1
Channel 2 enable
R0<2>
EN_A3
R/W
1
Channel 3 enable
R0<1>
EN_A1
R/W
1
Channel 1 enable
R0<0>
PWD
R/W
0
Power down
R1<7>
ABS_HY
R/W
0
Data slicer absolute reference
R1<6>
AGC_TLIM
R/W
0
AGC acting only on the first carrier burst
R1<5>
AGC_UD
R/W
1
AGC operating in both direction (up-down)
R1<4>
ATT_ON
R/W
0
Antenna damper enable
R1<2>
EN_PAT2
R/W
0
Double wake-up pattern correlation
R1<1>
EN_WPAT
R/W
1
Data correlation enable
R1<0>
EN_RTC
R/W
1
Crystal oscillator enable
R2<7>
S_ABSH
R/W
0
Data slicer threshold reduction
R2<6:5>
W_PAT
R/W
00
Pattern correlation tolerance (see Figure 38)
R2<4:2>
Reserved
000
Reserved
R2<1:0>
S_WU1
R/W
00
Tolerance setting for the stage wake-up (see Figure 32)
R3<7>
HY_20m
R/W
0
Data slicer hysteresis
if HY_20m = 0 then comparator hysteresis = 40mV
if HY_20m = 1 then comparator hysteresis = 20mV
R3<6>
HY_POS
R/W
0
Data slicer hysteresis on both edges
(HY_POS = 0 → hysteresis on both edges;
HY_POS = 1 → hysteresis only on positive edges)
R3<5:3>
FS_SCL
R/W
100
Data slicer time constant (see Figure 36)
R3<2:0>
FS_ENV
R/W
000
Envelop detector time constant (see Figure 35)
Page 18
Document Feedback
Description
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
Register
Name
Type
Default
Value
Description
OFF time in ON/OFF
operation mode
R4<7:6>
T_OFF
R/W
00
T_OFF=00
1ms
T_OFF=01
2ms
T_OFF=10
4ms
T_OFF=11
8ms
R4<5:4>
D_RES
R/W
01
Antenna damping resistor (see Figure 34)
R4<3:0>
GR
R/W
0000
R5<7:0>
TS2
R/W
01101001
2nd Byte of wake-up pattern
R6<7:0>
TS1
R/W
10010110
1st Byte of wake-up pattern
R7<7:5>
T_OUT
R/W
000
R7<4:0>
T_HBIT
R/W
01011
Gain reduction (see Figure 33)
Automatic time-out (see Figure 39)
Bit rate definition (see Figure 37)
Artificial wake-up
R8<2:0>
T_AUTO
R/W
000
No artificial wake-up
T_AUTO=001
1 sec
T_AUTO=010
5 sec
T_AUTO=011
20 sec
T_AUTO=100
2 min
T_AUTO=101
15min
T_AUTO=110
1 hour
T_AUTO=111
2 hour
R9<6:0>
Reserved
R10<4:0>
RSSI1
R
RSSI channel 1
R11<4:0>
RSSI2
R
RSSI channel 2
R12<4:0>
RSSI3
R
RSSI channel 3
R13<7:0>
F_WAK
R
False wake-up register
ams Datasheet
[v1-83] 2015-Mar-02
000000
T_AUTO=000
Reserved
Page 19
Document Feedback
AS3932 − Detailed Description
Serial Data Interface (SDI)
This 4-wires interface is used by the Microcontroller (μC) to
program the AS3932. The maximum clock frequency of the SDI
is 2MHz.
Figure 21:
Serial Data Interface (SDI) Pins
Name
Signal
Signal Level
Description
CS
Digital Input with pull down
CMOS
Chip Select
SDI
Digital Input with pull down
CMOS
Serial Data input for writing registers,
data to transmit and/or writing
addresses to select readable register
SDO
Digital Output
CMOS
Serial Data output for received data or
read value of selected registers
SCLK
Digital Input with pull down
CMOS
Clock for serial data read and write
Note(s): SDO is set to tristate if CS is low. In this way more than
one device can communicate on the same SDO bus.
SDI Command Structure. To program the SDI the CS signal has
to go high. A SDI command is made up by a two bytes serial
command and the data is sampled on the falling edge of SCLK.
The Figure 22 shows how the command looks like, from the MSB
(B15) to LSB (B0). The command stream has to be sent to the
SDI from the MSB (B15) to the LSB (B0).
Figure 22:
SDI Command Structure
Register Address / Direct
Command
Mode
B15
B14
B13
B12
B11
B10
B9
Register Data
B8
B7
B6
B5
B3
B2
B1
B0
The first two bits (B15 and B14) define the operating mode.
There are three modes available (write, read, direct command)
plus one spare (not used), as shown in Figure 23.
Page 20
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
Figure 23:
SDI Command Structure
B15
B14
Mode
0
0
WRITE
0
1
READ
1
0
NOT ALLOWED
1
1
DIRECT COMMAND
In case a write or read command happens the next 6 bits (B13
to B8) define the register address which has to be written
respectively read, as shown in Figure 24.
Figure 24:
SDI Command Structure
B13
B12
B11
B10
B9
B8
Read/Write Register
0
0
0
0
0
0
R0
0
0
0
0
0
1
R1
0
0
0
0
1
0
R2
0
0
0
0
1
1
R3
0
0
0
1
0
0
R4
0
0
0
1
0
1
R5
0
0
0
1
1
0
R6
0
0
0
1
1
1
R7
0
0
1
0
0
0
R8
0
0
1
0
0
1
R9
0
0
1
0
1
0
R10
0
0
1
0
1
1
R11
0
0
1
1
0
0
R12
0
0
1
1
0
1
R13
The last 8 bits are the data that has to be written respectively
read. A CS toggle high-low-high terminates the command
mode.
ams Datasheet
[v1-83] 2015-Mar-02
Page 21
Document Feedback
AS3932 − Detailed Description
If a direct command is sent (B15-B14=11) the bits from B13 to
B8 defines the direct command while the last 8 bits are omitted.
The Figure 25 shows all possible direct commands:
Figure 25:
List of Direct Commands
COMMAND_MODE
B13
B12
B11
B10
B9
B8
clear_wake
0
0
0
0
0
0
reset_RSSI
0
0
0
0
0
1
trim_osc
0
0
0
0
1
0
clear_false
0
0
0
0
1
1
preset_default
0
0
0
1
0
0
All direct commands are explained below:
• clear_wake: clears the wake state of the chip. In case the
chip has woken up (WAKE pin is high) the chip is set back
to listening mode.
• reset_RSSI: resets the RSSI measurement.
• trim_osc: starts the trimming procedure of the internal RC
oscillator (see Figure 46).
• clear_false: resets the false wake-up register
(R13<7:0>=00).
• preset_default: sets all register in the default mode, as
shown in Figure 20.
Writing of Data to Addressable Registers (WRITE Mode). The
SDI is sampled at the falling edge of SCLK (as shown in the
following diagrams).
A CS toggling high-low-high indicates the end of the WRITE
command after register has been written. The following
example shows a write command.
Page 22
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
Figure 26:
Writing of a Single Byte (falling edge sampling)
CS
SCLK
SDI
X
0
0
Two leading
Zeros indicate
WRITE Mode
A5
A4
A3
SCLK rising
edge Data is
transfered from
μC
A2
A1
A0
D7
D6
D5
D4
D3
SCLK
falling edge
Data is
sampled
D2
D1
X
D0
CS falling
edge signals
end of
WRITE Mode
Data is moved
to Address
A5-A0
Figure 27:
Writing of Register Data with Auto-incrementing Address
CS
SCLK
SDI
A A A A A D D D D D D D D D D D D D D D D D D
X 0 0 A
5 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6
Two leading
Zeros indicate
WRITE Mode
ams Datasheet
[v1-83] 2015-Mar-02
Data is moved
to Address
<A5-A0 >
Data is moved
to Address
<A5-A0 > + 1
D D D D D D D D D D
1 0 7 6 5 4 3 2 1 0
Data is moved
to Address
<A5-A0 > + (n-1)
Data is moved
to Address
<A5-A0 > + n
X
CS falling
edge signals
end of
WRITE Mode
Page 23
Document Feedback
AS3932 − Detailed Description
Reading of Data from Addressable Registers (READ Mode)
Once the address has been sent through SDI, the data can be
fed through the SDO pin out to the microcontroller.
A CS LOW toggling high-low-high has to be performed after
finishing the read mode session, in order to indicate the end of
the READ command and prepare the Interface to the next
command control Byte.
To transfer bytes from consecutive addresses, SDI master has to
keep the CS signal high and the SCLK clock has to be active as
long as data need to be read.
Figure 28:
Reading of Single Register Byte
CS
SCLK
SDI
X
0
1
A5
SDO
A4
A3
A2
A1
X
D7
SCLK rising
edge Data is
transfered from
μC
01 pattern
indicates
READ Mode
X
A0
SCLK
falling edge
Data is
sampled
D6
D5
SCLK rising
edge Data is
moved from
Address
<A5-A0>
D4
D3
D2
D1
D0
X
CS falling
edge signals
end of READ
Mode
SCLK falling
edge Data is
transfered to
μC
Figure 29:
Send Direct COMMAND Byte
CS
SCLK
SDI
X
1
1
Two leading
ONE indicate
COMMAND
Mode
Page 24
Document Feedback
C5
C4
C3
SCLK rising
edge Data is
transfered from
μC
C2
C1
SCLK
falling edge
Data is
sampled
C0
X
CS falling edge
signals the end of
COMMAND Mode
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
SDI Timing
Figure 30:
SDI Timing Parameters
Symbol
Parameter
Conditions
Min
Typ
Max
Units
TCSCLK
Time CS to Sampling
Data
500
ns
TDCLK
Time Data to Sampling
Data
300
ns
THCL
SCLK High Time
200
ns
TCLK
SCLK period
500
ns
TCLKCS
Time Sampling Data to
CS down
500
ns
TCST
CS Toggling time
500
ns
Figure 31:
SDI Timing Diagram
TCST
CS
SPI
SCLK
SCL
t
TCSCLK
TDCLK
t
THCL
TCLKCS
t
TCLK
ams Datasheet
[v1-83] 2015-Mar-02
Page 25
Document Feedback
AS3932 − Detailed Description
Channel Amplifier and Frequency Detector
Each of the 3 channels consists of a variable gain amplifier, an
automatic gain control and a frequency detector. The latter
detects the presence of a carrier. As soon as the carrier is
detected the AGC is enabled, the gain of the VGA is reduced
and set to the right value and the RSSI can be displayed.
It is possible to enable/disable individual channels, in case not
all three channels are needed. This enables to reduce the
current consumption by 1.5 μA (typ.) per channel.
Frequency Detector / AGC
The frequency detection uses the RTC as time base. In case the
internal RC oscillator is used as RTC, it must be calibrated, but
the calibration is guaranteed for a 32.768 kHz crystal oscillator
only. The frequency detection criteria can be tighter or more
relaxed according to the setup described in R2<1:0> (see
Figure 32).
Figure 32:
Tolerance Settings for Wake-up
R2<1>
R2<0>
Tolerance
0
0
relaxed
0
1
tighter (medium)
1
0
stringent
1
1
reserved
The AGC can operate in two modes:
• AGC down only (R1<5>=0)
• AGC up and down (R1<5>=1)
As soon as the AGC starts to operate, the gain in the VGA is set
to maximum. If the AGC down only mode is selected, the AGC
can only decrease the gain. Since the RSSI is directly derived
from the VGA gain, the system holds the RSSI peak.
When the AGC up and down mode is selected, the RSSI can
follow the input signal strength variation in both directions.
Regardless which AGC operation mode is used, the AGC needs
maximum 35 carrier periods to settle.
The RSSI is available for all 3 channels at the same time and it
is stored in 3 registers (R10<4:0>, R11<4:0>, R12<4:0>)
Both AGC modes (only down or down and up) can also operate
with time limitation. This option allows AGC operation only in
time slot of 256μs following the internal wake-up. Then the AGC
(RSSI) is frozen till the wake-up or RSSI reset occurs.
Page 26
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
The RSSI is reset either with the direct command 'clear_wakeup'
or 'reset_RSSI'. The 'reset_RSSI' command resets only the AGC
setting but does not terminate wake-up condition. This means
that if the signal is still present the new AGC setting (RSSI) will
appear not later than 300μs (35 LF carrier periods) after the
command was received. The AGC setting is reset if for duration
of 3 Manchester half symbols no carrier is detected. If the
wake-up IRQ is cleared the chip will go back to listening mode.
In case the maximum amplification at the beginning is a
drawback (e.g. in noisy environment) it is possible to set a
smaller starting gain on the amplifier, according to the
Figure 33. In this way it is possible to reduce the false frequency
detection.
Figure 33:
Bit Setting of Gain Reduction
ams Datasheet
[v1-83] 2015-Mar-02
R4<3>
R4<2>
R4<1>
R4<0>
Gain
Reduction
0
0
0
0
No gain reduction
0
0
0
1
n.a.
0
0
1
0 or 1
n.a.
0
1
0
0 or 1
-4dB
0
1
1
0 or 1
-8dB
1
0
0
0 or 1
-12dB
1
0
1
0 or 1
-16dB
1
1
0
0 or 1
-20dB
1
1
1
0 or 1
-24dB
Page 27
Document Feedback
AS3932 − Detailed Description
Antenna Damper
The antenna damper allows the chip to deal with higher field
strength, it is enabled by register R1<4>. It consists of shunt
resistors which degrade the quality factor of the resonator by
reducing the signal at the input of the amplifier. In this way the
resonator sees a smaller parallel resistance (in the band of
interest) which degrades its quality factor in order to increase
the linear range of the channel amplifier (the amplifier doesn't
saturate in presence of bigger signals). Figure 34 shows the bit
setup.
Figure 34:
Antenna Damper Bit Setup
R4<5>
R4<4>
Shunt Resistor (parallel
to the resonator at 125
kHz)
0
0
1 kΩ
0
1
3 kΩ
1
0
9 kΩ
1
1
27 kΩ
Channel Selector / Demodulator / Data Slicer
When at least one of three gain channel enters initial wake-up
state the channel selector makes a decision which gain channel
to connect to the envelope detector. If only one channel is in
wake-up state the selection is obvious. If more than one channel
enters wake-up state in 256μs following the first active channel
the channel with highest RSSI value is selected. The output
signal (amplified LF carrier) of selected channel is connected to
the input of the demodulator.
The performance of the demodulator can be optimized
according to bit rate and preamble length as described in
Figure 35 and Figure 36.
Page 28
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
Figure 35:
Bit Setup for the Envelop Detector for Different Symbol
Rate
R3<2>
R3<1>
R3<0>
Symbol Rate
[Manchester
symbols/s]
0
0
0
4096
0
0
1
2184
0
1
0
1490
0
1
1
1130
1
0
0
910
1
0
1
762
1
1
0
655
1
1
1
512
If the bit rate gets higher the time constant in the envelop
detector must be set to a smaller value. This means that higher
noise is injected because of the wider band. The next table is a
rough indication of how the envelop detector looks like for
different bit rates. By using proper data slicer settings it is
possible to improve the noise immunity paying the penalty of
a longer preamble. In fact if the data slicer has a bigger time
constant it is possible to reject more noise, but every time a
transmission occurs, the data slicer need time to settle. This
settling time will influence the length of the preamble.
Figure 36 gives a correlation between data slicer setup and
minimum required preamble length.
ams Datasheet
[v1-83] 2015-Mar-02
Page 29
Document Feedback
AS3932 − Detailed Description
Figure 36:
Bit Setup for the Data Slicer for Different Preamble Length
R3<5>
R3<4>
R3<3>
Minimum Preamble
Length [ms]
0
0
0
0.8
0
0
1
1.15
0
1
0
1.55
0
1
1
1.9
1
0
0
2.3
1
0
1
2.65
1
1
0
3
1
1
1
3.5
Note(s): These times are minimum required, but it is
recommended to prolong the preamble.
The comparator of the data slicer can work only with positive
or with symmetrical threshold (R3<6>). In addition the
threshold can be 20 or 40 mV (R3<7>).
In case the length of the preamble is an issue the data slicer can
also work with an absolute threshold (R1<7>). In this case the
bits R3<2:0> would not influence the performance. It is even
possible to reduce the absolute threshold in case the
environment is not particularly noisy (R2<7>).
Page 30
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
Correlator
After frequency detection the data correlation is only
performed if the correlator is enabled (R1<1>=1).
The data correlation consists of checking the presence of a
preamble (ON/OFF modulated carrier) followed by a certain
pattern.
After the frequency detection the correlator waits 16 bits (see
bit rate definition in Figure 37) and if no preamble is detected
the chip is set back to listening mode and the false wake-up
register (R13<7:0>) is incremented by one.
To get started with the pattern correlation the correlator needs
to detect at least 4 bits of the preamble (ON/OFF modulated
carrier).
The bit duration is defined in the register R7<4:0> according to
the Figure 37 as function of the Real Time Clock (RTC) periods.
Figure 37:
Bit Rate Setup
R7<4>
R7<3>
R7<2>
R7<1>
R7<0>
Bit Duration in
RTC Clock
Periods
Bit Rate
(bits/s)
Symbol Rate
(Manchester
symbols/s)
0
0
0
1
1
4
8192
4096
0
0
1
0
0
5
6552
3276
0
0
1
0
1
6
5460
2730
0
0
1
1
0
7
4680
2340
0
0
1
1
1
8
4096
2048
0
1
0
0
0
9
3640
1820
0
1
0
0
1
10
3276
1638
0
1
0
1
0
11
2978
1489
0
1
0
1
1
12
2730
1365
0
1
1
0
0
13
2520
1260
0
1
1
0
1
14
2340
1170
0
1
1
1
0
15
2184
1092
0
1
1
1
1
16
2048
1024
1
0
0
0
0
17
1926
963
1
0
0
0
1
18
1820
910
1
0
0
1
0
19
1724
862
1
0
0
1
1
20
1638
819
ams Datasheet
[v1-83] 2015-Mar-02
Page 31
Document Feedback
AS3932 − Detailed Description
R7<4>
R7<3>
R7<2>
R7<1>
R7<0>
Bit Duration in
RTC Clock
Periods
Bit Rate
(bits/s)
Symbol Rate
(Manchester
symbols/s)
1
0
1
0
0
21
1560
780
1
0
1
0
1
22
1488
744
1
0
1
1
0
23
1424
712
1
0
1
1
1
24
1364
682
1
1
0
0
0
25
1310
655
1
1
0
0
1
26
1260
630
1
1
0
1
0
27
1212
606
1
1
0
1
1
28
1170
585
1
1
1
0
0
29
1128
564
1
1
1
0
1
30
1092
546
1
1
1
1
0
31
1056
528
1
1
1
1
1
32
1024
512
If the preamble is detected correctly the correlator keeps
searching for a data pattern. The duration of the preamble plus
the pattern should not be longer than 40 bits (see bit rate
definition in Figure 37). The data pattern can be defined by the
user and consists of two bytes which are stored in the registers
R5<7:0> and R6<7:0>. The two bytes define the pattern
consisting of 16 half bit periods. This means the pattern and the
bit period can be selected by the user. The only limitation is that
the pattern (in combination with preamble) must obey
Manchester coding and timing. It must be noted that according
to Manchester coding a down-to-up bit transition represents a
symbol "0", while a transition up-to-down represents a symbol
"1". If the default code is used (96 [hex]) the binary code is (10
01 01 10 01 10 10 01). MSB has to be transmitted first.
The user can also select (R1<2>) if single or double data pattern
is used for wake-up. In case double pattern detection is set, the
same pattern has to be repeated 2 times.
Additionally it is possible to set the number of allowed missing
zero bits (not symbols) in the received bitstream (R2<6:5>), as
shown in the Figure 38.
Page 32
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
Figure 38:
Allowed Pattern Detection Errors
R2<6>
R2<5>
Maximum Allowed Error in
the Pattern Detection
0
0
No error allowed
0
1
1 missed zero
1
0
2 missed zeros
1
1
3 missed zeros
If the pattern matches the wake-up, interrupt is displayed on
the WAKE output.
If the pattern detection fails, the internal wake-up (on all active
channels) is terminated with no signal sent to MCU and the false
wake-up register will be incremented (R13<7:0>).
Wake-up Protocol - Carrier Frequency 125 kHz
The wake-up state is terminated with the direct command
‘clear_wake’ Figure 25. This command terminates the MCU
activity. The termination can also be automatic in case there is
no response from MCU. The time out for automatic termination
is set in a register R7<7:5>, as shown in the Figure 39.
Figure 39:
Timeout Setup
ams Datasheet
[v1-83] 2015-Mar-02
R7<7>
R7<6>
R7<5>
Time Out
0
0
0
0 sec
0
0
1
50 msec
0
1
0
100 msec
0
1
1
150 msec
1
0
0
200 msec
1
0
1
250 msec
1
1
0
300 msec
1
1
1
350 msec
Page 33
Document Feedback
AS3932 − Detailed Description
Without Pattern Detection
Figure 40:
Wake-up Protocol Overview without Pattern Detection (only carrier frequency detection)
Carrier Burst
Data
Carrier Burst > 550 us
DAT
WAKE
Clear_wake
In case the data correlation is disabled (R1<1>=0) the AS3932
wakes up upon detection of the carrier frequency only as shown
in Figure 40. In order to ensure that AS3932 wakes up the carrier
burst has to last longer than 550 μs. To set AS3932 back to
listening mode there are two possibilities: either the
microcontroller sends the direct command clear_wake via SDI
or the time out option is used ( R7<7:5>). In case the latter is
chosen, AS3932 is automatically set to listening mode after the
time defined in T_OUT ( R7<7:5>), counting starts at the
low-to-high WAKE edge on the WAKE pin.
Page 34
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
Single Pattern Detection
The Figure 41 shows the wake-up protocol in case the pattern
correlation is enabled (R1<1>=1) for a 125 kHz carrier
frequency. The initial carrier burst has to be longer than 550 μs
and can last maximum 16 bits (see bit rate definition in
Figure 37). If the ON/OFF mode is used ( R1<5>=1), the
minimum value of the maximum carrier burst duration is
limited to 10 ms. This is summarized in Figure 42. In case the
carrier burst is too long the internal wake-up will be set back to
low and the false wake-up counter (R13<7:0>) will be
incremented by one. The carrier burst must be followed by a
preamble (0101... modulated carrier with a bit duration defined
in Figure 37) and the wake-up pattern stored in the registers
R5<7:0> and R6<7:0>. The preamble must have at least 4 bits
and the preamble duration together with the pattern should
not be longer than 40 bits. If the wake-up pattern is correct, the
signal on the WAKE pin goes high one bit after the end of the
pattern and the data transmission can get started. To set the
chip back to listening mode the direct command clear_wake,
as well as the time out option ( R7<7:5>) can be used.
Figure 41:
Wake-up Protocol Overview with Single Pattern Detection
Carrier Burst
1 bit Preamble
Carrier Burst > 550 μs
Carrier Burst < 16 bit duration
Preamble
Pattern
Data
1 bit Preamble
Preamble > 4 bit duration
Preamble + Pattern < 40 bit duration
DAT
WAKE
Clear_wake
ams Datasheet
[v1-83] 2015-Mar-02
Page 35
Document Feedback
AS3932 − Detailed Description
Figure 42:
Preamble Requirements in Standard Mode, Scanning Mode and ON/OFF Mode
Bit Rate
(bits/s)
Maximum Duration of The Carrier
Burst in Standard Mode and
Scanning Mode (ms)
Maximum Duration of the Carrier
Burst in ON/OFF Mode (ms)
8192
1.95
10
6552
2.44
10
5460
2.93
10
4680
3.41
10
4096
3.90
10
3640
4.39
10
3276
4.88
10
2978
5.37
10
2730
5.86
10
2520
6.34
10
2340
6.83
10
2184
7.32
10
2048
7.81
10
1926
8.30
10
1820
8.79
10
1724
9.28
10
1638
9.76
10
1560
10.25
10.25
1488
10.75
10.75
1424
11.23
11.23
1364
11.73
11.73
1310
12.21
12.21
1260
12.69
12.69
1212
13.20
13.20
1170
13.67
13.67
1128
14.18
14.18
1092
14.65
14.65
Page 36
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
Bit Rate
(bits/s)
Maximum Duration of The Carrier
Burst in Standard Mode and
Scanning Mode (ms)
Maximum Duration of the Carrier
Burst in ON/OFF Mode (ms)
1056
15.15
15.15
1024
15.62
15.62
False Wake-up Register
The wake-up strategy in the AS3932 is based on 2 steps:
1. Frequency Detection: in this phase the frequency of the
received signal is checked.
2. Pattern Correlation: here the pattern is demodulated
and checked whether it corresponds to the valid one.
If there is a disturber or noise capable to overcome the first step
(frequency detection) without producing a valid pattern, then
a false wake-up call happens.Each time this event is recognized
a counter is incremented by one and the respective counter
value is stored in a memory cell (false wake-up register). Thus,
the microcontroller can periodically look at the false wake-up
register, to get a feeling how noisy the surrounding
environment is and can then react accordingly (e.g. reducing
the gain of the LNA during frequency detection, set the AS3932
temporarily to power down etc.), as shown in the Figure 43. The
false wake-up counter is a useful tool to quickly adapt the
system to any changes in the noise environment and thus avoid
false wake-up events.
Most wake-up receivers have to deal with environments that
can rapidly change. By periodically monitoring the number of
false wake-up events it is possible to adapt the system setup to
the actual characteristics of the environment and enables a
better use of the full flexibility of AS3932.
ams Datasheet
[v1-83] 2015-Mar-02
Page 37
Document Feedback
AS3932 − Detailed Description
Figure 43:
Concept of the False Wake-up Register Together With the System
Wakeup
Level 1
Frequency Detector
Wakeup
Level 2
Pattern Correlator
WAKE
Unsuccessful
pattern
correlation
CHANGE SETUP TO
MINIMIZE THE FALSE
WAKEUP EVENTS
Register Setup
False wakeup
register
READ FALSE WAKEUP REGISTER
Microcontroller
Real Time Clock (RTC)
The RTC can be based on a crystal oscillator (R1<0>=1), the
internal RC-oscillator (R1<0>=0), or an external clock source
(R1<0>=1). The crystal oscillator has higher precision of the
frequency with higher current consumption and needs three
external components (crystal plus two capacitors). The
RC-oscillator is completely integrated and can be calibrated if
a reference signal is available for a very short time to improve
the frequency accuracy. The calibration gets started with the
trim_osc direct command. Since no non-volatile memory is
available the calibration must be done every time after the RCO
is turned OFF. The RCO is turned OFF when the chip is in power
down mode, a POR happened, or the crystal oscillator is
enabled.
Page 38
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
Since the RTC defines the time base of the frequency detection,
the selected frequency (frequency of the crystal oscillator or
the reference frequency used for calibration of the RC oscillator)
should be about one forth of the carrier frequency:
(EQ1)
F RTC ∼ F CAR∗ 0.25
Where: FCAR is the carrier frequency and F RTC is the RTC
frequency.
The third option for the RTC is the use of an external clock
source, which must be applied directly to the XIN pin (XOUT
floating).
Crystal Oscillator
Figure 44:
Characteristics of XTAL
Symbol
Parameter
Conditions
Crystal accuracy (initial)
Overall accuracy
Min
Max
Crystal motional
resistance
Units
±120
p.p.m.
60
KΩ
Frequency
32.768
kHz
Contribution of the
oscillator to the
frequency error
±5
p.p.m
1
s
Start-up Time
Duty cycle
Current consumption
ams Datasheet
[v1-83] 2015-Mar-02
Typ
Crystal dependent
45
50
1
55
%
μA
Page 39
Document Feedback
AS3932 − Detailed Description
RC-Oscillator
Figure 45:
Characteristics of RCO
Symbol
Parameter
Conditions
Min
Max
Typ
Units
If no calibration is performed
27
32.768
42
kHz
If calibration is performed
31
32.768
34.5
kHz
65
cycles
Frequency
Calibration time
Current consumption
Periods of reference clock
200
nA
To trim the RC-Oscillator, set the chip select (CS) to high before
sending the direct command trim_osc over SDI. Then 65 digital
clock cycles of the reference clock (e.g. 32.768 kHz) have to be
sent on the clock bus (SCLK), as shown in Figure 46. After that
the signal on the chip select (CS) has to be pulled down.
The calibration is effective after the 65th reference clock edge
and it will be stored in a volatile memory. In case the
RC-oscillator is switched OFF or a power-on-reset happens (e.g.
battery change) the calibration has to be repeated.
Figure 46:
RC-Oscillator Calibration via SDI
Page 40
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Detailed Description
External Clock Source
To clock the AS3932 with an external signal the crystal oscillator
has to be enabled (R1<0>=1). As shown in the Figure 4 the clock
must be applied on the pin XIN while the pin XOUT must stay
floating. The RC time constant has to be 15μs with a tolerance
of ±10% (e.g. R=680 kΩ and C=22pF). In the Figure 47 the clock
characteristics are summarized.
Figure 47:
Characteristics of External Clock
Symbol
Parameter
VI
Low level
Vh
High level
Tr
Conditions
Min
Max
Units
0
0.1 * VDD
V
0.9 * VDD
VDD
V
Rise-time
3
μs
Tf
Fall-time
3
μs
T = RC
RC Time constant
16.5
μs
13.5
Typ
15
Note(s): In power down mode the external clock has to be set
to VDD.
Channel Selection in Scanning Mode and
ON/OFF Mode
In case only 2 channels are active and one of the Low Power
modes is enabled, then the channels 1 and 3 have to be active.
If the chip works in ON-OFF mode and only one channel is active
then the active channel has to be the channel 1.
Both Low Power modes are not allowed to be enabled at the
same time.
ams Datasheet
[v1-83] 2015-Mar-02
Page 41
Document Feedback
AS3932 − Package Drawings & Mark ings
Package Drawings & Markings
The product is available in a 16-pin TSSOP package.
Figure 48:
Drawings and Dimensions (TSSOP)
AS3932 @
YYWWMZZ
Symbol
Min
Nom
Max
Symbol
Min
Nom
Max
A
A1
A2
b
c
D
E
E1
e
L
L1
0.05
0.80
0.19
0.09
4.90
4.30
0.45
-
1.00
5.00
6.40BSC
4.40
0.65BSC
0.60
1.00REF
1.20
0.15
1.05
0.30
0.20
5.10
4.50
0.75
-
R
R1
S
θ1
θ2
θ3
aaa
bbb
ccc
ddd
N
0.09
0.09
0.20
0°
-
12REF
12REF
0.10
0.10
0.05
0.20
16
8°
-
Green
RoHS
Note(s) and/or Footnote(s):
1. Dimensions and tolerancing conform to ASME Y14.5M-1994.
2. All dimensions are in millimeters. Angles are in degrees.
Figure 49:
Marking: YYWWMZZ
YY
WW
M
ZZ
@
Year (i.e. 10 for 2010)
Manufacturing
Week
Assembly plant
identifier
Assembly
traceability code
Sublot identifier
Page 42
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Package Drawings & Markings
The product is available in a 16LD QFN (4×4) package.
Figure 50:
Drawings and Dimensions (QFN)
AS3932
YYWWXZZ
@
RoHS
Green
Note(s) and/or Footnote(s):
1. Dimensioning and tolerancing conform to ASME Y14.5M-1994.
2. All dimensions are in millimeters. Angles are in degrees.
3. Dimension b applies to metallized terminal and is measured between 0.25mm and 0.30mm from terminal tip. Dimension L1
represents terminal full back from package edge up to 0.15mm is acceptable.
4. Coplanarity applies to the exposed heat slug as well as the terminal.
5. Radius on terminal is optional.
6. N is the total number of terminals.
Figure 51:
Marking: YYWWXZZ
YY
WW
X
ZZ
@
Year (i.e. 10 for 2010)
Manufacturing
Week
Assembly plant
identifier
Assembly
traceability code
Sublot identifier
ams Datasheet
[v1-83] 2015-Mar-02
Page 43
Document Feedback
AS3932 − Ordering & Contact Information
Ordering & Contact Information
The devices are available as the standard products shown in
Figure 52.
Figure 52:
Ordering Information
Ordering
Code
Type
Marking
Delivery Form(1)
Delivery Quantity
AS3932-BTST
16-pin TSSOP
AS3932
7 inches Tape & Reel
1000 pcs
AS3932-BQFT
16LD QFN (4×4)
AS3932
7 inches Tape & Reel
1000 pcs
Note(s) and/or Footnote(s):
1. Dry Pack Sensitivity Level =3 according to IPC/JEDEC J-STD-033A for full reels.
Buy our products or get free samples online at:
www.ams.com/ICdirect
Technical Support is available at:
www.ams.com/Technical-Support
Provide feedback about this document at:
www.ams.com/Document-Feedback
For further information and requests, e-mail us at:
ams_sales@ams.com
For sales offices, distributors and representatives, please visit:
www.ams.com/contact
Headquarters
ams AG
Tobelbaderstrasse 30
8141 Unterpremstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
Page 44
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − RoHS Compliant & ams Green Statement
RoHS Compliant & ams Green
Statement
RoHS: The term RoHS compliant means that ams AG products
fully comply with current RoHS directives. Our semiconductor
products do not contain any chemicals for all 6 substance
categories, including the requirement that lead not exceed
0.1% by weight in homogeneous materials. Where designed to
be soldered at high temperatures, RoHS compliant products are
suitable for use in specified lead-free processes.
ams Green (RoHS compliant and no Sb/Br): ams Green
defines that in addition to RoHS compliance, our products are
free of Bromine (Br) and Antimony (Sb) based flame retardants
(Br or Sb do not exceed 0.1% by weight in homogeneous
material).
Important Information: The information provided in this
statement represents ams AG knowledge and belief as of the
date that it is provided. ams AG bases its knowledge and belief
on information provided by third parties, and makes no
representation or warranty as to the accuracy of such
information. Efforts are underway to better integrate
information from third parties. ams AG has taken and continues
to take reasonable steps to provide representative and accurate
information but may not have conducted destructive testing or
chemical analysis on incoming materials and chemicals. ams AG
and ams AG suppliers consider certain information to be
proprietary, and thus CAS numbers and other limited
information may not be available for release.
ams Datasheet
[v1-83] 2015-Mar-02
Page 45
Document Feedback
AS3932 − Copyrights & Disclaimer
Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 30, 8141
Unterpremstaetten, Austria-Europe. Trademarks Registered. All
rights reserved. The material herein may not be reproduced,
adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner.
Devices sold by ams AG are covered by the warranty and patent
indemnification provisions appearing in its General Terms of
Trade. ams AG makes no warranty, express, statutory, implied,
or by description regarding the information set forth herein.
ams AG reserves the right to change specifications and prices
at any time and without notice. Therefore, prior to designing
this product into a system, it is necessary to check with ams AG
for current information. This product is intended for use in
commercial applications. Applications requiring extended
temperature range, unusual environmental requirements, or
high reliability applications, such as military, medical
life-support or life-sustaining equipment are specifically not
recommended without additional processing by ams AG for
each application. This product is provided by ams AG “AS IS”
and any express or implied warranties, including, but not
limited to the implied warranties of merchantability and fitness
for a particular purpose are disclaimed.
ams AG shall not be liable to recipient or any third party for any
damages, including but not limited to personal injury, property
damage, loss of profits, loss of use, interruption of business or
indirect, special, incidental or consequential damages, of any
kind, in connection with or arising out of the furnishing,
performance or use of the technical data herein. No obligation
or liability to recipient or any third party shall arise or flow out
of ams AG rendering of technical or other services.
Page 46
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Document Status
Document Status
Document Status
Product Preview
Preliminary Datasheet
Datasheet
Datasheet (discontinued)
ams Datasheet
[v1-83] 2015-Mar-02
Product Status
Definition
Pre-Development
Information in this datasheet is based on product ideas in
the planning phase of development. All specifications are
design goals without any warranty and are subject to
change without notice
Pre-Production
Information in this datasheet is based on products in the
design, validation or qualification phase of development.
The performance and parameters shown in this document
are preliminary without any warranty and are subject to
change without notice
Production
Information in this datasheet is based on products in
ramp-up to full production or full production which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade
Discontinued
Information in this datasheet is based on products which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade, but these products have been superseded and
should not be used for new designs
Page 47
Document Feedback
AS3932 − Revision Information
Revision Information
Changes from 1.7 (2013-Jun-18) to current revision 1-83 (2015-Mar-02)
Page
1.7 (2013-Jun-18) to 1-82 (2014-Nov-05)
Content was converted to latest ams design
Added benefits to Key Features
1
Added TRC (start-up time) parameter in Figure 11
9
Updated text under Detailed Description section
13
Updated Figure 30
25
1-82 (2014-Nov-05) to 1-83 (2015-Mar-02)
Updated Figure 50 (QFN (4×4) package)
43
Note(s) and/or Footnote(s):
1. Page and figure numbers for the previous version may differ from page and figure numbers in the current revision.
2. Correction of typographical errors is not explicitly mentioned.
Page 48
Document Feedback
ams Datasheet
[v1-83] 2015-Mar-02
AS3932 − Content Guide
Content Guide
ams Datasheet
[v1-83] 2015-Mar-02
1
1
2
General Description
Key Benefits & Features
Applications
4
4
4
5
6
Pin Assignment
TSSOP Package
Pin Description
QFN Package
Pin Description
7
8
11
Absolute Maximum Ratings
Electrical Characteristics
Typical Operating Characteristics
13
14
14
14
16
17
17
17
18
20
25
26
26
28
28
31
33
34
35
37
38
39
40
41
41
Detailed Description
Operating Modes
Power Down Mode
Listening Mode
Preamble Detection / Pattern Correlation
Data Receiving
System and Block Specification
Register Table
Register Table Description and Default Values
Serial Data Interface (SDI)
SDI Timing
Channel Amplifier and Frequency Detector
Frequency Detector / AGC
Antenna Damper
Channel Selector / Demodulator / Data Slicer
Correlator
Wake-up Protocol - Carrier Frequency 125 kHz
Without Pattern Detection
Single Pattern Detection
False Wake-up Register
Real Time Clock (RTC)
Crystal Oscillator
RC-Oscillator
External Clock Source
Channel Selection in Scanning Mode and ON/OFF Mode
42
44
45
46
47
48
Package Drawings & Markings
Ordering & Contact Information
RoHS Compliant & ams Green Statement
Copyrights & Disclaimer
Document Status
Revision Information
Page 49
Document Feedback