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Q845 Datasheet, PDF (1/2 Pages) Skyworks Solutions Inc. – Ultra-Fast Boosting Power Supply for 3G-4G-LTE PA
PRODUCT SUMMARY
Q845: Ultra-Fast Boosting Power Supply for 3G/4G/LTE PA
Envelope Tracking
Applications
 Smartphones, tablets, data cards, mobile hotspots, and other
mobile devices that feature high-speed data
VBAT
 R99, HSPA, HSPA+, LTE 5 MHz, 10 MHz, and 20 MHz
Features
 Ultra-fast low-noise power supply for 3G/4G/LTE ET PAs:
 85% ET efficiency for 4G/LTE, 93% APT efficiency
 Supports up to LTE20 (100 RB)
 No digital predistortion (DPD) required from 1 to 100 RB
 Dynamic PA VCC voltage boost above VBAT
 20 nV/Hz output noise floor
 2.7 V to 5.25 VDC input voltage range
 Flexible, low overhead, MIPI® digital and analog control:
 MIPI RFFE digital interface compliant
 MIPI eTrak analog control interface compliant
 High-speed ET/APT transitions with only 1 RFFE write
 Cost-effective and low-area CSP package:
 2.43 mm x 1.79 mm x 0.61 mm, 24-pin package
 6 passive components for ET/APT
 Seven modes of operation:
 ET, APT, Bypass, Standby, Sleep, Deep Sleep, Shutdown
Skyworks GreenTM products are compliant with
all applicable legislation and are halogen-free.
For additional information, refer to Skyworks
Definition of GreenTM, document number
SQ04–0074.
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MIPI
Control
Interface
VBAT
VIO
SDATA
SCLK
VOUT1
VIN+
VIN+
VOUT3
VIN–
VIN–
VPA
GND
Y2126
Figure 1. Functional Block Diagram of the Q845
Description
The Q845 ultra-fast power supply is designed for envelope
tracking (ET) for 3G/4G/LTE RF PAs. It also supports average
power tracking (APT).
Using patented qBoostTM technology, the Q845 simultaneously
combines the high efficiency of a switching power supply with the
responsiveness and low noise of a linear power supply. An
innovative combining network optimizes the blend of these supply
technologies and also enables the Q845 to dynamically boost its
output voltage above its input voltage to track modulation peaks.
With this approach, the Q845 provides an efficient PA supply
voltage with a slew rate up to 100V/s, continuously adjusting the
PA supply voltage to precisely track the modulation envelope,
thus maximizing PA efficiency and peak power. This performance
is achieved while still meeting ACLR, EVM, and Receive Band
noise specifications. Where APT is adequate in the mid-power
range of the PA, the Q845 seamlessly transitions between ET and
APT as needed. Figure 1 shows a functional block diagram.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
203590A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • June 30, 2015
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