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December 16, 1999

Hitachi Releases Single-Chip High-Frequency Signal Processing IC for
Digital Cellular Standards GSM-900, DCS-1800/1900 Dual-Band Use

- Achieved smaller and lower-cost systems by higher-integrated chip and simplified support for
GSM-900 and DCS-1800/1900 standards with using offset-PLL method etc. -

Hitachi, Ltd. (TSE: 6501) today announced the HD155131TF highly-integrated IC, 
implementing transmit/receive signal processing in RF block*1 for dual-band of digital 
cellular standards GSM-900 and DCS-1800/1900*2in a single chip.  Sample shipments will 
begin in January 2000 in Japan.

The HD155131TF incorporates a dual-PLL*3 synthesizer plus LNA*4 for 900MHz and 
1800MHz band on the receiving side, and enables the VCO*5 tuning band to be minimized 
through the use of double superheterodyne*6 technology, allowing a flexible frequency plan 
to be designed.  In addition, an offset PLL system is used for frequency conversion on the 
transmitting side, making a system antenna block duplexer*7 unnecessary, and so eliminating 
the power loss associated with a duplexer.

Use of the HD155131TF simplifies the design of a digital cellular system supporting the 
GSM-900 and DCS-1800/1900 standards, and enables system size, cost, and power 
consumption to be reduced.

The GSM-900 and DCS-1800/1900 are the standards of a digital cellular system that was 
chiefly developed and constructed in Europe, and now has an expanding market, having been 
introduced into various regions of the world including Asia, the Middle East, and Africa.

In response to the shortage of GSM channels in large cities, services have recently been 
introduced that allow both bands of the GSM-900 and DCS-1800/1900 standards to be used 
by a single terminal.  This has led to a sharp shift in demand from single terminals, which 
support separate bands individually, to dual terminals supporting both bands in one terminal.  
In 1999, a new system--GPRS (General Packet Radio System)--was standardized with the 
aim of speeding up data transfer on GSM terminals, and a GSM system service using the 
1,900 MHz band was started in cities throughout the United States, leading to hopes for the 
development of high-frequency ICs capable of handling the 900/1,800/1,900 MHz bands.

These developments have brought demands for even smaller and lighter portable phones, with 
long operating times, and also for higher levels of integration-to reduce the mounting area-
and lower cost for the electronic components installed in these phones. 

In response to these needs, Hitachi entered the market with the HD155101BF and 
HD155121F GSM high-frequency block signal processing ICs, developed jointly with GSM 
system consultants TTP Communications Ltd. of the United Kingdom.  These have now been 
followed by the development of the HD155131TF, transmit/receive signal processing IC in 
RF block capable of handling GPRS plus GSM-900 and DCS-1800/1900 standards frequency 
bands.

The HD155131TF uses a 0.35 um BiCMOS process, and integrates most of the RF block 
functions in a single chip using SOI (Silicon On Insulator) technology and a deep-groove 
separation structure.

On the transmitting side, out-of-band noise has been reduced through the use of an offset PLL 
system, the number of parts has been reduced, including the SAW filter*8 and duplexer 
previously required in the antenna block.  In addition, Gain characteristics of the PGA*9 
circuit has a 98 dB dynamic range and good linearity, enabling controlled by the baseband 
block*10 that is connected through serial interface .

In the frequency plan designed for the GSM-900 and DCS-1800/1900, the tuning band needed 
for the IF and RF oscillators has been minimized by using the same IF*11.  A low-power-
consumption design has been adopted, with a low operating voltage range of 2.7 V to 3.3 V, 
and current dissipation of 45 mA when transmitting, 60 mA when receiving, and 1 uA or less 
in power save mode.

The use of a TQFP-56 package, allowing compact mounting, enables portable phones to be 
made smaller and lighter by reducing the required mounting area.


Notes:	1. RF block: Radio Frequency block.  The block that processes high-frequency 
	   signals.
	2. GSM: Global System for Mobile Communications.  A European 900 MHz 
           band digital cellular phone system.
	   DCS-1800/1900: Digital Cellular System, 1800 MHz/1900 MHz band.  
           Cellular phone system using the same method as GSM in 1,800/1,900 MHz 
           band area.  DCS-1800 is also known as PCN (Personal Communications 
           Network).
	3. PLL: Phase Locked Loop.  A circuit technology that provides oscillation at an 
           arbitrary frequency through the configuration of a loop circuit that 
           synchronizes frequency phases.  Also refers to the circuit itself.
        4. LNA: Low Noise Amplifier
	5. VCO: Voltage Controlled Oscillator.  An oscillator whose output frequency 
           varies according to an input control voltage.  An important component that  
           affects wireless circuit quality.
	6. Double superheterodyne: A method whereby wireless frequency signals  
           undergo frequency conversion twice in the reception system of a wireless 
           device, and are converted to the baseband frequency.
	7. Duplexer: A wave divider.  Contains two filters, for the receiving frequency 
           and the transmitting frequency, and carries out mutual separation.  Versions 
           with switches are also available.
	8. SAW filter: Surface Acoustic Wave filter.  A filter that uses surface acoustic 
           waves conveyed along the surface of a piezoelectric material.  Implements a 
           filter that takes the resonance frequency and its vicinity as the pass band.
 	9. PGA: Programmable Gain Control Amplifier
       10. Baseband block: Digital signal processing block that performs codec 
           processing and system control, including voice signal AD/DA conversion, and 
           man-machine interface and transmit/receive signal channel timing.
       11. IF: Intermediate Frequency

< Typical Applications >
Digital cellular phone based on GSM-900,DCS-1800/1900 standards

< Prices in Japan >   (For Reference Only) 		
Product Code		Sample Price (Yen)		
HD155131TF		1,000				

< About TTP Communications Ltd.>
TTP Communications Ltd., based in Cambridge, U.K., undertakes worldwide consultancy on 
product development, including software and hardware.  The company has extensive 
experience in the area of GSM system development, undertaking consultancy work 
worldwide.

< Specifications >
Item									Specifications		
Operating voltage range							2.7 V to 3.3 V		
Operating temperature range						-20 to +75 degrees Celsius
Current dissipation		GSM-900, 		Receiving	60 mA typ.					
(Power supply voltage is	DCS-1800/1900		Transmitting	45 mA typ.
3V.)				mode																
				Power save mode				1 uA max.		
Operating frequency		GSM-900 mode		Receiving	925 to 960 MHz		
							Transmitting	880 to 915 MHz		
				DCS-1800/1900 		Receiving	1805 to 1990 MHz	
				mode			Transmitting	1710 to 1910 MHz	
PGA gain range								-40 to 58 dB typ.	
Transmission-side               Carrier					-40 dBc typ. -31 dBc min.				
spurious suppression 		Sideband				-40 dBc typ. -35 dBc min.
ratio												
Transmission-side 		GSM-900 mode		925 MHz		-155 dBc/Hz typ.	
out-of-band noise					935 MHz		-165 dBc/Hz typ.	
				DCS-1800/1900 mode 	1805 MHz	-156 dBc/Hz typ.	
Package									TQFP-56			


WRITTEN BY Secretary's Office
All Rights Reserved, Copyright (C) 1999, Hitachi, Ltd.