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PDF MAS9178 Data sheet ( Hoja de datos )
| Número de pieza | MAS9178 | |
| Descripción | Stand-alone am Receiver ic | |
| Fabricantes | MAS | |
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www.DataSheet4U.com
DA9178.000
22 Apr, 2003
MAS9178
AM Receiver IC
• High Sensitivity
• Very Low Power Consumption
• Wide Supply Voltage Range
• Power Down Control
• Control for AGC On
• High Selectivity by Crystal Filter
• Fast Startup Feature
DESCRIPTION
The MAS9178 AM-Receiver chip is a highly sensitive,
simple to use AM receiver specially intended to
receive time signals in the frequency range from 40
kHz to 100 kHz. Only a few external components are
required for time signal receiver. The circuit has
preamplifier, wide range automatic gain control,
demodulator and output comparator built in. The
output signal can be processed directly by an
additional digital circuitry to extract the data from the
received signal. The control for AGC (automatic gain
control) can be used to switch AGC on or off if
necessary. Unlike MAS1016A and MAS1016B,
MAS9178 does not require AGC control procedure in
WWVB and JJY systems.
MAS9178A1 has differential input and internal 0.875
pF compensation capacitor for crystal shunt
capacitance compensation.
MAS9178A5 requires external compensation
capacitor for crystal shunt capacitance compensation.
It can be used with crystals that do not match with
fixed 0.875 pF compensation capacitance of
MAS9178A1.
FEATURES
• Highly Sensitive AM Receiver, 0.4 µVRMS typ.
• Wide Supply Voltage Range from 1.1 V to 3.6 V
• Very Low Power Consumption
• Power Down Control
• Fast Startup
• Only a Few External Components Necessary
• Control for AGC On
• Wide Frequency Range from 40 kHz to 100 kHz
• High Selectivity by Quartz Crystal Filter
APPLICATIONS
• Time Signal Receiver WWVB (USA), JJY (Japan),
DCF77 (Germany) and MSF (UK)
• Receiver for ASK Modulated Data Signals
BLOCK DIAGRAM
RFP
RFM
QOP
QI QOM
AGC Amplifier
AON
Demodulator
&
OUT
Comparator
Power Supply/Biasing
VDD VSS PDN
AGC DEC
1 (8)
1 page  
www.DataSheet4U.com
DA9178.000
22 Apr, 2003
TYPICAL APPLICATION (Continued)
Note 1
Note 4
Optional
Control
for AGC on/hold
Ferrite
Antenna
RFP
RFM
QOP
QI QOM
AGC Amplifier
AON
Demodulator
&
OUT
Comparator
Receiver
Output
Figure 3
Power Supply/Biasing
VDD VSS PDN
1.4 V
AGC DEC
CAGC +
10 µF
CDEC
47 nF
Note 3
Note 2
Power Down /
Fast Startup
Control
Dual band application circuit of external compensation capacitance version MAS9178A5.
Note 1: Crystal
The crystal as well as ferrite antenna frequencies are chosen according to the time-signal system (Table 1). The
crystal shunt capacitance C0 should be matched as well as possible with the internal shunt capacitance
compensation capacitor CC=0.875 pF of MAS9178A1. External compensation pad QOM is unconnected in
MAS9178A1. MAS9178A5 does not have internal compensation capacitance CC and it requires use of external
compensation capacitor CC_EXT. It must be connected between pins QOM and QI (see figure 2). CC_EXT should
have equal value with crystal’s effective shunt capacitance C0. External compensation version MAS9178A5
should be used when fixed 0.875 pF compensation capacitance of MAS9178A1 does not match well with used
crystal’s shunt capacitance.
It should be noted that grounded crystal package has reduced shunt capacitance. This value is about 85% of
floating crystal shunt capacitance. PCB traces of crystal and external compensation capacitance should be kept
at minimum to minimize additional parasitic capacitance which can cause capacitance mismatching.
In dual band receiver the crystals can be connected in parallel thus external compensation capacitor value
CC_EXT must be sum of two crystals’ shunt capacitances. In dual band receiver it is also possible to connect other
crystal from QOP pin and the other crystal from QOM pin to common QI pin (figure 3). In this circuit configuration
no external compensation capacitor is required since the crystals compensate each other.
Time-Signal System Location
Antenna Frequency
DCF77
MSF
WWVB
JJY
Table 1
Germany
77.5 kHz
United Kingdom
60 kHz
USA
60 kHz
Japan
40 kHz and 60 kHz
Time-Signal System Frequencies
Recommended Crystal Frequency
77.503 kHz
60.003 kHz
60.003 kHz
40.003 kHz and 60.003 kHz
Note 2: AGC Capacitor
The AGC and DEC capacitors must have low leakage currents due to very small 40 nA signal currents through
the capacitors. The insulation resistance of these capacitors should be higher than 70 MΩ. Also probes with at
least 100 MΩ==impedance should be used for voltage probing of AGC and DEC pins. Electrolyte capacitors
cannot be used due to their large leakage current. Instead low leakage tantalum capacitor can be used as AGC
capacitor. DEC capacitor can be low leakage chip capacitor.
5 (8)
5 Page | ||
| Páginas | Total 8 Páginas | |
| PDF Descargar | [ Datasheet MAS9178.PDF ] | |
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