Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – With contact or lead
Reexamination Certificate
2000-04-11
2002-06-18
Tran, Minh Loan (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
With contact or lead
C455S142000, C455S144000, C455S143000, C455S146000
Reexamination Certificate
active
06407449
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor integrated circuit for dual-band transmission/reception, in which a low noise amplifier is integrated, in a mobile terminal set for dual-band wireless communications, mainly applied to a wireless communication system for operating in two frequency bands, including a high frequency band and a low frequency band.
FIG. 4
shows an example of the construction of a terminal device to which a conventional semiconductor integrated circuit for dual-band transmission/reception (hereinbelow referred to as a “transmission/reception IC”) is applied. This is applied to a mobile terminal of a wireless communication system for operating in two different frequency bands. A transmission/reception IC
401
has a receiving mixer
403
a
for the high frequency band and a receiving mixer
403
b
for the low frequency band, applied to the dual-band wireless communication system, a next-stage mixer
404
, a variable gain amplifier
405
, a demodulator
406
, a modulator
408
, an offset PLL
409
, and a divider
407
. A local oscillation signal necessary for frequency conversion is supplied from a synthesizer
410
and the internal divider
407
. A band pass filter
411
connected to the transmission/reception IC removes out-band spurs. An amplifier
402
a
for the high frequency band and an amplifier
402
b
for the low frequency band are external devices of the IC. So far, it has been difficult to IC-incorporate the low noise amplifier due to shortage of gain in the high frequency band and noise characteristic by fT limitation of the transistor operation and the capacitance of the transistor substrate. However, the above problems have been overcome by recent improvements in fine processing, and so a low noise amplifier can be incorporated.
An example of a low noise amplifier applied to a dual-band transmission/reception IC is disclosed in “Dual-band High-Linearity Variable-Gain Low-Noise Amplifiers for Wireless Applications” by Keng Leong Fong, ISSCC 1999, pp. 224-225, p. 463. This construction, in which two low noise amplifiers for the dual-band transmission/reception IC are integrated as one chip and are sealed in a TSSOP20 pin package, does not include the entire transmission/reception system. Note that correspondences between the signal lines, the ground line and the like and the pads is unknown. Further, an example of a transmission/reception IC including a low noise amplifier is disclosed in “A Single-Chip CMOS Transceiver for DCS 1800 Wireless Communications” by Michiel Steyaert et al., ISSCC 1998, pp. 48-49, p. 411. This construction, in which a transmission/reception circuit is integrated as one chip, is not applied to dual-band communications. Correspondence between the signal lines, the ground line and the like and the pads is unknown. Further, the package used there is unknown.
SUMMARY OF THE INVENTION
In the present invention, the low noise amplifiers
402
a
and
402
b
are newly provided in the transmission/reception circuit chip
401
for the dual-band communications, as shown in FIG.
4
. In this case, problems in pin layout in the package have been found. Note that in the present invention, a Quad Flat package (hereinbelow abbreviated to “QFP”) where pins are provided along four sides is employed as the package.
As a first problem, in a layout where the low noise amplifier is bonded to a long lead pin among lead pins of the QFP with a long bonding wire, the amount of feed-back by parasitic inductance is large, and the high frequency gain and noise characteristic are degraded.
As a second problem, high-frequency characteristics of the IC are similarly degraded due to transformer coupling between IC pins and transformer coupling by wiring intersection on a multilayer substrate on which the IC is packaged.
As a third problem, oscillation may occur due to parasitic capacitance and parasitic inductance in the low noise amplifier.
It is an object of the present invention to provide a pin layout which prevents degradation of high frequency 4 characteristics of the low noise amplifier included in the IC for dual transmission/reception.
REFERENCES:
patent: 3974450 (1976-08-01), Cunningham, Jr.
patent: 4851796 (1989-07-01), Hendriks
patent: 5880601 (1999-03-01), Kanazawa et al.
patent: 5903827 (1999-05-01), Kennan et al.
“Dual-Band High-Linearity Variable-Gain Low-Noise Amplifiers for Wireless Applications”, by Keng Leong Fong, ISSCC 1999, pp. 224-225, p. 463.
“A single-chip CMOS Transceiver for DCS-1800 Wireless Communications”, by Michiel Steyaert, et al., ISSCC 1998, pp. 48-49, p. 411.
Hashimoto Takashi
Okabe Yoshiyuki
Takikawa Kumiko
Tanaka Satoshi
Antonelli Terry Stout & Kraus LLP
Dickey Thomas L.
Hitachi , Ltd.
Tran Minh Loan
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