TDMA T2290/T2297:
Front End IC(U10)
B4
FL10
FL30
U10
RX_800
RX_1900
X2
VCO
BUFF_VCO
RX_2.75
VCC
RX_IF
FL20
SW_QMOD_KEY
LO_CTL
800*_1900
BAND_SW
DBLR_IN
FE_EN
Description
The RX front end IC(U10) is used as a first amplifier an d downconverter for dual-band RF appl ications. It removes the RX carrier frequency to produce the RX IF signal . U10 also
has some interna l LNAs for the receive signals a nd buffe rs for the VCO signals.
U10 has two RF input ports. One is used for the 800MHz receive signal and the other is used for the 1900MHz receive signal. Both signals are amplif ied within U10 and then rout-
ed to an external filter(FL10, FL30). The signal is then inje cted into the Down Converter of U10.
In 800MHz mode, the receive signal is mi xed with the VCO and the result is the r eceive intermediate frquency(IF) signal which is filt ered by FL20 prior to entering the ZIF/ZYN
IC(U110).
In 1900MHz mode, the VCO output (
DBLR_IN
) goes through a frequency doubler internal to U10 before getting mixed with t he 1900MHz receive signal. This process allows the
1900MHz carrier frequency to be removed without the need of a second VCO.
Line 800*_1900 is used to select which frequency path will be enabled for U10. Line 800*_1900 is high in 800MHz mode and low in 190 0MHz mode.
Line
FE_EN
enabl es or disables n ormal operation of U10. A low state at
FE_EN
will disable U10. This line is use d to disable U10 when the transceiver is in it' s idle or transmit
slot state. It is also used during s leep mode conditions.
Summary of Contents for T2290
Page 1: ...DIGITAL WIRELESS TELEPHONE Service Manual Level 3 Release 1 TDMA T2290 T2297 ...
Page 26: ... 2000 Motorola Inc TDMA T2290 T2297 Cellular Overview 16 ...
Page 40: ...Motorola Confidential Proprietary TDMA T2290 T2297 TDMA Test Mode NAM Programming 30 ...
Page 68: ...Disassembly TDMA T2290 T2297 Keypad Removal Motorola Confidential Proprietary 58 ...