3.5.6 Dual band GSM power amplifier (U102)
The SKY77328 Power Amplifier Module (PAM) is designed in a low profile (1.2 mm), compact form
factor for quad-band cellular handsets comprising GSM850/900, DCS1800, and PCS1900 operation.
The PAM also supports Class 12 General Packet Radio Service (GPRS) multi-slot operation.
The module consists of separate GSM850/900 PA and DCS1800/PCS1900 PA blocks, impedance-
matching circuitry for 50 Ω input and output impedances, and a Power Amplifier Control (PAC) block
with an internal current-sense resistor. The custom BiCMOS integrated circuit provides the internal
PAC function and interface circuitry. Fabricated onto a single Gallium Arsenide (GaAs) die, one
Heterojunction Bipolar Transistor (HBT) PA block supports the GSM850/900 bands and the other
supports the DCS1800 and PCS1900 bands. Both PA blocks share common power supply pins to
distribute current. The GaAs die, the Silicon (Si) die, and the passive components are mounted on a
multi-layer laminate substrate. The assembly is encapsulated with plastic overmold.
RF input and output ports of the SKY77328 are internally matched to a 50 Ω load to reduce the
number of external components for a quad-band design. Extremely low leakage current (2.5 µA,
typical) of the dual PA module maximizes handset standby time. The SKY77328 also contains band-
select switching circuitry to select GSM (logic 0) or DCS/PCS (logic 1) as determined from the Band
Select (BS) signal. In Figure 3.5.6-1 below, the BS pin selects the PA output (DCS/PCS OUT or
GSM850/900 OUT) and the Analog Power Control (VAPC) controls the level of output power.
The VBATT pin connects to an internal current-sense resistor and interfaces to an integrated power
amplifier control (iPAC™) function, which is insensitive to variations in temperature, power supply,
process, and input power. The ENABLE input allows initial turn-on of PAM circuitry to minimize battery
drain.
3. TECHNICAL BRIEF
- 32 -
Figure 3.5.5-1 Block diagram of LMV225TLX with high resistive tap
Содержание U890
Страница 1: ...Date April 2006 Issue 1 0 Service Manual Model U890 U890c Service Manual U890 U890c ...
Страница 3: ... 4 ...
Страница 20: ...3 TECHNICAL BRIEF 21 ...
Страница 46: ...3 TECHNICAL BRIEF 47 Figure PM6650 2 Functional Block Diagram ...
Страница 70: ...4 TROUBLE SHOOTING 71 4 2 SIGNAL PATH ...
Страница 109: ...4 TROUBLE SHOOTING 110 CN600 50pin LCD connector CN901 C907 C911 FB901 FB902 ...
Страница 115: ...4 TROUBLE SHOOTING 116 C226 C227 for MIC serial capacitor ...
Страница 118: ...4 TROUBLE SHOOTING 119 Q400 Q401 Q402 VBATT GND ...
Страница 139: ...Table 2 1 1 RF Block Component 6 BLOCK DIAGRAM 140 ...
Страница 140: ...6 BLOCK DIAGRAM 141 6 2 Interface Diagram U890 Interface Diagram ...
Страница 142: ...6 BLOCK DIAGRAM 143 Top Side ...
Страница 143: ...6 BLOCK DIAGRAM 144 Bottom Side ...
Страница 152: ... 153 8 pcb layout ...
Страница 153: ... 154 8 pcb layout ...
Страница 154: ... 155 8 pcb layout ...
Страница 155: ... 156 8 pcb layout ...
Страница 156: ... 157 8 pcb layout ...
Страница 157: ... 158 8 pcb layout ...
Страница 163: ...9 CALIBRATION 164 9 3 HOT KIMCHI Example Choose_U890 ...
Страница 164: ...9 CALIBRATION 165 Click APPLY button Click START button ...
Страница 165: ...9 CALIBRATION 166 Click Run button to lunch RF AUTOTEST ...
Страница 167: ... 168 ...
Страница 191: ...Note ...
Страница 192: ...Note ...