AC530 Fastrax, AC530 Datasheet - Page 16

• Manufacturer Part Number: AC530
• Description: GPS Development Tools Application Board for UC530
• Manufacturer: Fastrax

Specifications of AC530

• Rohs: yes
• Product: Application Boards
• Tool Is For Evaluation Of: UC530
• Frequency: 1.575 GHz
• Operating Supply Voltage: 3.3 V
• Interface Type: UART
• Description/function: Fastrax Application Board AC530 provides the UC530 connectivity to the Fastrax Evaluation Kit or to other evaluation purposes
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Operating Supply Current: 25 mA

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4.5
The RESET_N (active low) signal provides external override of the internally generated power up/down reset.
Normally external control of RESET_N is not necessary.
When RESET_N signal is used, it will force volatile RAM data loss. Note that Non-Volatile Backup RAM content is
not cleared and thus fast TTFF is possible. The input has internal pull up resistor 75 kohm typ. and the signal can be
left floating (not connected) if not used. Non-Volatile Backup RAM content can be cleared with NMEA command
‘Factory Reset’ $PMTK104*37<CR><LF>.
4.6
The TIMER signal provides output (Open Drain) that can be used to switch off the main VDD supply voltage by
controlling autonomously an external power switch in Backup mode, see reference application circuit diagram in
chapter 7.1.
When TIMER signal is used, pull it high by using an external resistor e.g. 1 Mohm. The signal is active high, i.e. VDD
is active; and when pulled low by the UC530, the VDD shall be switched off.
4.7
The module has an embedded GPS antenna and the signal is further amplified by internal Low Noise Amplifier
(LNA), which is available at ANT output. The antenna signal ANT shall be connected externally to RF_IN Antenna
Input signal via a short trace between pads. The ANT signal is internally AC-coupled; max DC voltage at ANT signal
is +3.6 V. Note that RF_IN signal provides DC-path to ground and thus do not apply any bias voltage to RF_IN
signal; max DC voltages at RF_IN signal is 0V and thus use an external series DC-block capacitor when needed.
The RF input signal path contains first a SAW band-pass filter before LNA, which provides excellent protection
against out-of-band GPS blocking caused by possible near-by wireless transmitters.
4.8
The customer may use an external active GPS antenna connected via an external RF-switch. It is suggested that the
active antenna has a net gain including cable loss in the range from +10 dB to +30 dB. Specified sensitivity is
measured with external low noise (NF<1dB, G>15dB) amplifier.
An active antenna requires an external antenna switch in order to select path between RF_IN input and external
GPS antenna signal. For reference see e.g. the application circuit diagram in chapter7.2 Fastrax support can also
provide other antenna switch reference circuits using discrete components.
The switch shall detect external active antenna presence for switching antenna signal path to external antenna by
using e.g. the active antenna bias current detection. Second option is to use a suitable RF-connector with build-in
switching operation. The external antenna switch must also provide a bias supply to the external active antenna
and suggestion is also to add an external short circuit and ESD protection for antenna signal.
When the module is in Standby or Backup state, the antenna switch and bias can be switched off externally by
using WAKEUP signal output, see e.g. Application Circuit Diagram.
4.8.1 Jamming Remover
Jamming Remover is an embedded HW block called AIC (Active Interference Cancellation) that tracks and removes
up to 12 pcs CW (Carrier Wave) type signals up to -80 dBm (total power signal levels). By default the AIC is disabled
and usage requires an NMEA command $PMTK286,1*23<CR><LF> to enable.
Jamming Remover can be used for solving EMI problems in the customer’s system and it is effective against e.g.
narrow band clock harmonics. When enabled, Jammer Remover will increase current drain by about 1 mA and
2012-05-03
UC530_Datasheet
Reset input
Timer output
Antenna input
External GPS antenna connectivity