REV. C
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AD8316 Dual Output
GSM PA Controller
FEATURES
Complete RF Detector/Controller Function
Selectable Dual Outputs
49 dB Range at 0.9 GHz (–47.6 dBm to +1.5 dBm re 50 )
Accurate Scaling from 0.1 GHz to 2.5 GHz
Temperature-Stable Linear-in-dB Response
Log Slope of 22 mV/dB
True Integration Function in Control Loop
Low Power: 23 mW at 2.7 V
Power-Down to 11 W
APPLICATIONS
Single-Band, Dual-Band, and Triband Mobile Handsets
(GSM, DCS, PCS, EDGE)
Wireless Terminal Devices
Transmitter Power Control
FUNCTIONAL BLOCK DIAGRAM
OUT2
OUT1
FLT1
VSET
FLT2
10dB
COMM
OFFSET
COMPENSATION
RFIN
DET
DET
DET
DET
DET
INTERCEPT
POSITIONING
LOW NOISE
GAIN BIAS
LOW NOISE
BAND GAP
REFERENCE
OUTPUT
ENABLE
DELAY
ENBL
BSEL
VPOS
HI-Z
1.35
HI-Z
V–I
10dB
10dB
10dB
1.35
GENERAL DESCRIPTION
The AD8316 is a complete, low cost subsystem for the precise
control of dual RF power amplifiers (PAs) operating in the
frequency range 0.1 GHz to 2.5 GHz and over a typical dynamic
range of 50 dB. The device is a dual-output version of the AD8315
and intended for use in dual-band or triband cellular handsets
and other battery-operated wireless devices where a separate
power control signal is required for each band. The logarithmic
amplifier technique provides a much wider measurement range
and better accuracy than is possible using controllers based on
diode detectors. In particular, multiband and multimode cellu-
lar designs can benefit from the temperature-stable (–30
°
C to
+85
°
C) operation over all cellular telephony frequencies.
Its high sensitivity allows control at low input signal levels, thus
reducing the amount of power that needs to be coupled to the
detector. The selected output, OUT1 or OUT2, has the voltage
range and current drive to directly connect to the gain control
pin of most handset power amplifiers; the deselected output is
pulled low to ensure that the inactive PA remains off. Each
output has a dedicated integrating filter capacitor that allows
separate control loop settings for each PA. OUT1 and OUT2 can
swing from 125 mV above ground to within 100 mV below the
supply voltage. Load currents of up to 12 mA can be supported.
The setpoint control input applied to pin VSET has an operating
range of 0.25 V to 1.4 V. The input resistance of the setpoint
interface is over 100 M
, and the bias current is typically 0.5
μ
A.
The AD8316 is available in 10-lead MSOP and 16-lead LFCSP
packages and consumes 8.5 mA from a 2.7 V to 5.5 V supply.
When it is powered down, the sleep current is 4
μ
A.