The AMIS-50051 is a small digital demodulator, specially developed to work with the AMIS-50050 spread spectrum baseband
controller. It simplifies the design of the receiver in a direct sequence spread spectrum wireless communication link.
2.0 Key Features
•
•
•
•
•
1Mbit/s demodulation (QPSK)
PN code tracking output to AMIS-50050 (Please refer to the AMIS-50050 spread spectrum baseband controller.)
Fully programmable
CMOS technology
Power-down mode
3.0 Applications
•
•
•
•
Wireless local area networks
Portable wireless communication
Digital cellular telephones
Wireless ISDN modems
The AMIS-50051 uses advanced DSP technology to demodulate the data from a BPSK/DBPSK/QPSK/DQPSK modulated signal. This
technique also provides a PN code tracking signal output, a carrier tracking signal and an automatic gain control (AGC) output signal.
The power of the AMIS-50051 reduces the complexity and component count of a DSSS receiver. The AMIS-50051 is designed to
demodulate QPSK or BPSK data from a carrier whose frequency is 11 MHz or less. Data rates can be as high as 1Mbit/s for QPSK
signals or 500Kbit/s for BPSK signals. An error signal is produced, which can be used to acquire and track the PN code of a direct
sequence spread spectrum system. This output is a voltage, which the AMIS-50050 (please refer to AMIS-50050 spread spectrum
baseband controller) uses to change the phase of the receiver’s PN code. An external despreading device is required to remove the PN
code from the received signal. This reduces the chance of false acquisition over other methods. The AMIS-50051’s internal NCO
oscillator is adjusted by a signal produced from the data demodulation process. This is used to track variations in the carrier frequency
of the received signal.
The AMIS-50051 produces a level error output. This output is pulsed high or low depending on the level of the received signal. This can
be used to form an AGC circuit.
The AMIS-50051 requires few external components. The AMIS-50051 is designed to work directly with the AMIS-50050 to simplify the
design effort of a wireless communication link.
AMI Semiconductor
– Jan. 08 – M-20718-002
www.amis.com
1
AMIS-50051:
Digital Demodulator
Wireless Products
Data Sheet
4.0 AMIS-50051 Block Diagram
Figure 1: Block Diagram of AMIS-50051
AMI Semiconductor
– Jan. 08 – M-20718-002
www.amis.com
2
AMIS-50051:
Digital Demodulator
Wireless Products
Data Sheet
5.0 Package Availability
•
32 pin LQFP
Figure 2: Package Availability
Table 1: Pin Descriptions
Number on
Pin Name
32 Pin LQFP
DVDD
11, 30
DVSS
10, 31
SDATA
32
SCLK
1
RSSI2
2
RSSI1
3
RXD0
6
RXD1
7
TRACKON
DUMP
LPF
CRYST1
CRYST0
EXT_IN
RES
AGC
RX_IN
ENABLE
AVDD
AVSS
NC
8
9
16
17
18
19
22
23
24
27
26
25
4, 5, 12, 13, 20,
21, 28, 29
Functional Description
Digital power
Digital ground
Data for serial programming interface
Clock for serial programming interface, sensitive to rising edge
RSSI 2 for AMIS-50050
RSSI 1 for AMIS-50050
Received data Bit 0
Received data Bit 1
Indicates that the AMIS-50050 is tracking the incoming signal, active
high
Activate and dump control logic input
PLL phase detector output, internal VCO output
Crystal oscillator or external reference input
Crystal oscillator
Used as digital input from external window comparator, test input not for
normal use
Active low reset
Automatic gain control
IF signal input, can also be used as digital input from external window
comparator
Active low enable for serial programming interface
Analog power
Analog ground
Type
Power
Ground
Input
Output
Output
Output
Output
Output
Input
Input
Analog
Crystal OSC/Input
Crystal OSC
Input
Input
Output
Analog/Input
Input
Power
Ground
Not connected
AMI Semiconductor
– Jan. 08 – M-20718-002
www.amis.com
3
AMIS-50051:
Digital Demodulator
Wireless Products
Data Sheet
6.0 Electrical Specifications
6.1 Absolute Maximum Ratings
Table 2: Absolute Maximum Ratings
Parameter
VDD/AVDD
Input pin voltage, all pins
Input pin current, all pins
Storage temperature
Lead temperature
Min.
-0.3
-0.3
-10
-55
Max.
5.5
VDD+0.3
10
125
300
o
Units
V
V
mA
o
C
C for 10 seconds
Note: Stresses beyond those listed under “Absolute Maximum Ratings” may cause damage to the device. This is a stress rating only and functional operation of the device at
these, or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
6.2 Operational Characteristics
Table 3: Operational Characteristics
Symbol
Parameter
VDD
ICC
ICC
IFI
IFE
RXiv
RXii
Fref
Rsol
Srte
Ta
Notes:
(1)
(2)
(3)
Min.
3
Typ.
18
8
Max.
5
Units
V
mA
mA
MHz
MHz
mVpp
kΩ
MHz
Supply voltage
Supply current (5V)
Supply current (3V)
IF frequency
IF frequency
Input voltage
Input impedance
(3)
(1)
(2)
11
25
200
300
100
2
0
1.56
0
2.5
100
70
Reference frequency
RSSI 1&2 output level
Internal sample rate
Operating Temperature
Using the internal A to D converter
Using an external A to D converter
Impedance for only the RXin pin
V
MHz
°C
AMI Semiconductor
– Jan. 08 – M-20718-002
www.amis.com
4
AMIS-50051:
Digital Demodulator
Wireless Products
Data Sheet
6.3 Supply Current for 5V Operation
Figure 3: Supply Current for 5V Operation
Note:
The frequency in MHz is the frequency of the internal clock, Fvco.
6.4 Supply Current for 3V Operation
Figure 4: Supply Current for 3V Operation
Note:
The frequency in MHz is the frequency of the internal clock, Fvco.
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