Texas Instruments TRF6900 User Manual page 24

Jumper Connections
-
-
-
-
-
-
-
-
JP2
Jumper JP2 is used for testing of the mixer circuit of the TRF6900. Testing
of the mixer stage by itself is accomplished by connecting JP1–1 to JP1–2,
JP2–1 to JP2–3, and removing the 0.1-µF capacitor connecting terminal
44 (MIX_OUT) and terminal 42 (IF1_IN). The IF mixer and LNA stages
may be tested together by connecting JP1–1 to JP1–2, JP2–2 to JP2–3
(default) and removing the 0.1-µF capacitor (C3) connecting terminal 44
(MIX_OUT) and terminal 42 (IF1_IN). The LNA stage is tested by itself by
connecting JP2–1 to JP2–2. The default state for jumper JP2 is JP2–2 to
JP2–3.
JP3
Jumper JP3 is used to observe the output of IF1, the first IF amplifier, by
connecting JP3–1 to JP3–2. The default configuration of JP3–2 to JP3–3
connects the output of the first IF amplifier to the input of the second IF
amplifier.
JP4
Jumper JP4 is used to monitor RXDATA_OUT when connected as JP4–2
to JP4–3. Jumper JP4 is used to monitor RSSI_OUT when connected as
JP4–1 to JP4–2. The default state for jumper JP4 is JP4–2 to JP4–3.
JP5
Jumper JP5 is used to connect the VCO tank circuit to the loop filter of the
PLL circuit. The only reason to remove jumper JP5 is to test the tuning
range of the VCO tank circuit with an external power supply. The default
state for jumper JP5 is JP5–1 to JP5–2.
JP6
Jumper JP6 can be used to pull the MODE line up to VCC (JP6–1 to
JP6–2) or pull down to ground (JP6–2 to JP6–3), if a computer connection
is not installed. The primary purpose for JP6 is as a test point to monitor
the state of the MODE line. The default state for jumper JP6 is not con-
nected.
JP7
Jumper JP7 can be used to pull the STDBY line up to VCC (JP7–1 to
JP7–2) or pull down to ground (JP7–2 to JP7–3), if a computer connection
is not installed. The primary purpose for JP7 is as a test point to monitor
the state of the STDBY line. The default state for jumper JP7 is not con-
nected.
JP8
Jumper JP8 is used to connect the Power On LED to the output of the IC1
voltage regulator. The default state for jumper JP8 is JP8–1 to JP8–2.
BPF1 Bypass Capacitor
A 0.1-µF capacitor (C3) is used to bypass BPF1 and connect the mixer
output directly to the first IF amplifier. BPF1 is not installed on the TRF6900
evaluation board. If the user requires BPF1 to be installed, then remove
the capacitor (C3) connecting terminal 44 (MIX_OUT) and terminal 42
(IF1_IN) and connect JP1–2 to JP1–3.