Download System Block Diagram

GENERAL DESCRIPTION
The WS2017 is a third generation Tunable
Impedance Matching Circuit. It is designed to be
inserted in the RF signal chain between the antenna
and the front-end module (FEM) of a mobile phone
and provides superior transmit and receive chain
optimization over the full 824 MHz – 2170 MHz
mobile frequency range.
WiSpry’s innovative tunable capacitor
technology enables a completely new type of RF
matching component that combines excellent RF
performance from a high-Q parallel plate capacitor
and fixed inductance network with versatile digital
control of the capacitance values. The entire TX/RX
signal chains can now be optimized resulting in
superior TRP and TIS numbers with low physical
volume antennas.
The WS2017 can be quickly re-configured to
compensate for antenna source impedance changes
due to frequency band and different external load to
cover hand, head and body effects.
Using a modem serial control interface, the
WS2017’s high-Q circuits transform mismatched and
varying antenna impedances from being poorly
matched to well-matched. The result is improved RF
performance and greater energy efficiency.
The antenna impedance match is digitally
controlled by the programmable capacitive elements
implemented in WiSpry’s CMOS-RF MEMS structure.
The WS2017 features an integrated high
voltage charge pump for electrostatic actuation and
bi-directional SPI serial control bus. The SPI mode is
compatible with most RF transceiver implementations.
The ultra low power WS2017 can be driven
by an existing single supply rail such as an LDO
regulator output or directly from the battery supply.
The charge pump, serial bus and driver circuits are
all fully integrated on the same CMOS die as the
MEMS capacitor elements, making the WS2017 a
true single chip solution for antenna impedance
matching.
The WS2017 is intended primarily for openloop impedance control. Optional closed loop mode is
achieved by adding external control and detection
circuitry.
By migrating from a compromised fixed
match that covers all frequencies from 824 MHz to
2170 MHz and possible external loadings, to a realtime optimized solution with WS2017, the overall
efficiency of the RF chain and antenna can be
improved.
FEATURES
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True single chip CMOS antenna tuner
Improved TRP and TIS from 824 – 2170 MHz
Corrects for VSWR up to 20:1
Covers GSM850, EGSM, DCS, PCS and
WCDMA I, II, III, IV*, V, VI, VIII, IX, X*, XI. **
Precise digital control with 0.125 pF step size
Ultra low harmonics and inter-modulation
Fully integrated charge pump circuit
Software control of “body effects” tuning
Bidirectional, 3 and 4-Wire SPI dual mode
serial bus
Ultra low power sleep mode
Optimized for effective PCB layout
ADS die and package models available
*Bands IV and X fall within the WS2018 frequency range
but have extremely large duplex distance and may
require a special matching methodology
**Can be used for 700 MHz/2600 MHz LTE frequency
bands, contact WiSpry Application support for guidance
System Block Diagram
APPLICATION
With a WS2017 in the signal chain, different external
and internal load variations such as head phantom,
hand phantom, open/closed flip and slide effects as
well as variations due to channel and band of
operation can be reduced or eliminated providing an
optimal antenna match regardless of operating band
and user phone position.
Handset Architecture with WS2017