ANALOG DEVICES AD8317 Service Manual

FEATURES

Wide bandwidth: 1 MHz to 10 GHz

High accuracy: ±1.0 dB over temperature

55 dB dynamic range up to 8 GHz ± 3 dB error Stability over temperature: ±0.5 dB

Low noise measurement/controller output, VOUT Pulse response time: 6 ns/10 ns (fall/rise)

Small footprint, 2 mm × 3 mm LFCSP Supply operation: 3.0 V to 5.5 V @ 22 mA Fabricated using high speed SiGe process

APPLICATIONS

RF transmitter PA setpoint control and level monitoring Power monitoring in radio link transmitters

RSSI measurement in base stations, WLANs, WiMAX, and radars

GENERAL DESCRIPTION

The AD8317 is a demodulating logarithmic amplifier, capable of accurately converting an RF input signal to a corresponding decibel-scaled output. It employs the progressive compression technique over a cascaded amplifier chain, each stage of which is equipped with a detector cell. The device can be used in either measurement or controller modes. The AD8317 maintains accurate log conformance for signals of 1 MHz to 8 GHz and provides useful operation to 10 GHz. The input dynamic range is typically 55 dB (re: 50 Ω) with less than ±3 dB error. The AD8317 has 6 ns/10 ns response time (fall time/rise time) that enables RF burst detection to a pulse rate of beyond 50 MHz. The device provides unprecedented logarithmic intercept stability vs. ambient temperature conditions. A supply of 3.0 V to 5.5 V is required to power the device. Current consumption is typically 22 mA, and it decreases to 200 μA when the device is disabled.

The AD8317 can be configured to provide a control voltage to a power amplifier or a measurement output from the VOUT pin. Because the output can be used for controller applications, special attention has been paid to minimize wideband noise. In this mode, the setpoint control voltage is applied to the VSET pin.

Rev. B

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1 MHz to 10 GHz, 55 dB Log Detector/Controller AD8317

FUNCTIONAL BLOCK DIAGRAM

		VPOS	TADJ
		GAIN	SLOPE
		BIAS		I	V	VSET
				I	V	VOUT
DET	DET	DET	DET
INHI						CLPF
INLO
			COMM			05541-001

Figure 1.

The feedback loop through an RF amplifier is closed via VOUT, the output of which regulates the output of the amplifier to a magnitude corresponding to VSET. The AD8317 provides 0 V to (VPOS − 0.1 V) output capability at the VOUT pin, suitable for controller applications. As a measurement device, VOUT is externally connected to VSET to produce an output voltage, VOUT, that is a decreasing linear-in-dB function of the RF input signal amplitude.

The logarithmic slope is −22 mV/dB, determined by the VSET interface. The intercept is 15 dBm (re: 50 Ω, CW input) using the INHI input. These parameters are very stable against supply and temperature variations.

The AD8317 is fabricated on a SiGe bipolar IC process and is available in a 2 mm × 3 mm, 8-lead LFCSP with an operating temperature range of −40°C to +85°C.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: [phone] www.analog.com Fax: [phone] ©2005–2008 Analog Devices, Inc. All rights reserved.

AD8317

TABLE OF CONTENTS
Features ..............................................................................................	1
Applications.......................................................................................	1
Functional Block Diagram ..............................................................	1
General Description .........................................................................	1
Revision History ...............................................................................	2
Specifications.....................................................................................	3
Absolute Maximum Ratings............................................................	5
ESD Caution..................................................................................	5
Pin Configuration and Function Descriptions.............................	6
Typical Performance Characteristics .............................................	7
Theory of Operation ......................................................................	10
Using the AD8317 ..........................................................................	11
Basic Connections ......................................................................	11
REVISION HISTORY
3/08—Rev. A to Rev. B
Changes to Features..........................................................................	1
Changes to General Description ....................................................	1
Changes to Measurement Mode Section.....................................	12
Changes to Equation 12 .................................................................	15
8/07—Rev. 0 to Rev. A
Changes to f = 8.0 GHz, ±1 dB Dynamic Range Parameter .......	4
Changes to Table 2............................................................................	6
Changes to Figure 20......................................................................	10
Changes to Setpoint Interface Section and Figure 22................	12
Changes Figure 27 ..........................................................................	13
Changes to Table 5..........................................................................	17
Added Die Information Section ...................................................	19
Changes to Ordering Guide ..........................................................	21
10/05—Revision 0: Initial Version

Input Signal Coupling................................................................	11
Output Interface .........................................................................	11
Setpoint Interface .......................................................................	11
Temperature Compensation of Output Voltage.....................	12
Measurement Mode ...................................................................	12
Setting the Output Slope in Measurement Mode ..................	13
Controller Mode.........................................................................	13
Output Filtering..........................................................................	15
Operation Beyond 8 GHz .........................................................	15
Evaluation Board ............................................................................	16
Die Information..............................................................................	18
Outline Dimensions .......................................................................	19
Ordering Guide ..........................................................................	19

Rev. B | Page 2 of 20

AD8317

SPECIFICATIONS

VPOS = 3 V, CLPF = 1000 pF, TA = 25°C, 52.3 Ω termination resistor at INHI, unless otherwise noted.

Table 1.

Parameter	Conditions	Min	Typ	Max	Unit
SIGNAL INPUT INTERFACE	INHI (Pin 1)
Specified Frequency Range		0.001		10	GHz
DC Common-Mode Voltage			VPOS − 0.6		V
MEASUREMENT MODE	VOUT (Pin 5) shorted to VSET (Pin 4), sinusoidal
	input signal
f = 900 MHz	RTADJ = 18 kΩ
Input Impedance			1500||0.33		Ω||pF
±1 dB Dynamic Range	TA = 25°C		50		dB
	−40°C < TA < +85°C		46		dB
Maximum Input Level	±1 dB error		−3		dBm
Minimum Input Level	±1 dB error		−53		dBm
Slope1		−25	−22	−19.5	mV/dB
Intercept1		12	15	21	dBm
Output Voltage, High Power In	PIN = −10 dBm	0.42	0.58	0.78	V
Output Voltage, Low Power In	PIN = −40 dBm	1.00	1.27	1.40	V
f = 1.9 GHz	RTADJ = 8 kΩ
Input Impedance			950||0.38		Ω||pF
±1 dB Dynamic Range	TA = 25°C		50		dB
	−40°C < TA < +85°C		48		dB
Maximum Input Level	±1 dB error		−4.00		dBm
Minimum Input Level	±1 dB error		−54		dBm
Slope1		−25	−22	−19.5	mV/dB
Intercept1		10	14	20	dBm
Output Voltage, High Power In	PIN = −10 dBm	0.35	0.54	0.80	V
Output Voltage, Low Power In	PIN = −35 dBm	0.75	1.21	1.35	V
f = 2.2 GHz	RTADJ = 8 kΩ
Input Impedance			810||0.39		Ω||pF
±1 dB Dynamic Range	TA = 25°C		50		dB
	−40°C < TA < +85°C		47		dB
Maximum Input Level	±1 dB error		−5		dBm
Minimum Input Level	±1 dB error		−55		dBm
Slope1			−22		mV/dB
Intercept1			14		dBm
Output Voltage, High Power In	PIN = −10 dBm		0.53		V
Output Voltage, Low Power In	PIN = −40 dBm		1.20		V
f = 3.6 GHz	RTADJ = 8 kΩ
Input Impedance			300||0.33		Ω||pF
±1 dB Dynamic Range	TA = 25°C		42		dB
	−40°C < TA < +85°C		40		dB
Maximum Input Level	±1 dB error		−6		dBm
Minimum Input Level	±1 dB error		−48		dBm
Slope1			−22		mV/dB
Intercept1			11		dBm
Output Voltage, High Power In	PIN = −10 dBm		0.47		V
Output Voltage, Low Power In	PIN = −40 dBm		1.16		V

Rev. B | Page 3 of 20

AD8317

Parameter	Conditions	Min	Typ	Max	Unit
f = 5.8 GHz	RTADJ = 500 Ω
Input Impedance			110||0.05		Ω||pF
±1 dB Dynamic Range	TA = 25°C		50		dB
	−40°C < TA < +85°C		48		dB
Maximum Input Level	±1 dB error		−4		dBm
Minimum Input Level	±1 dB error		−54		dBm
Slope1			−22		mV/dB
Intercept1			16		dBm
Output Voltage, High Power In	PIN = −10 dBm		0.59		V
Output Voltage, Low Power In	PIN = −40 dBm		1.27		V
f = 8.0 GHz	RTADJ = open
Input Impedance			28||0.79		Ω||pF
±1 dB Dynamic Range	TA = 25°C		44		dB
	−40°C < TA < +85°C		35		dB
Maximum Input Level	±1 dB error		−2		dBm
Minimum Input Level	±1 dB error		−46		dBm
Slope2			−22		mV/dB
Intercept2			21		dBm
Output Voltage, High Power In	PIN = −10 dBm		0.70		V
Output Voltage, Low Power In	PIN = −40 dBm		1.39		V
OUTPUT INTERFACE	VOUT (Pin 5)
Voltage Swing	VSET = 0 V, RFIN = open		VPOS − 0.1		V
	VSET = 1.7 V, RFIN = open		10		mV
Output Current Drive	VSET = 0 V, RFIN = open		10		mA
Small Signal Bandwidth	RFIN = −10 dBm, from CLPF to VOUT		140		MHz
Output Noise	RFIN = 2.2 GHz, −10 dBm, fNOISE = 100 kHz,		90		nV/√Hz
	CLPF = open
Fall Time	Input level = no signal to −10 dBm, 90% to 10%,		18		ns
	CLPF = 8 pF
	Input level = no signal to −10 dBm, 90% to 10%,		6		ns
	CLPF = open, ROUT = 150 Ω
Rise Time	Input level = −10 dBm to no signal, 10% to 90%,		20		ns
	CLPF = 8 pF
	Input level = −10 dBm to no signal, 10% to 90%,		10		ns
	CLPF = open, ROUT = 150 Ω
Video Bandwidth (or Envelope Bandwidth)			50		MHz
VSET INTERFACE	VSET (Pin 4)
Nominal Input Range	RFIN = 0 dBm, measurement mode		0.35		V
	RFIN = −50 dBm, measurement mode		1.40		V
Logarithmic Scale Factor			−45		dB/V
Input Resistance	RFIN = −20 dBm, controller mode, VSET = 1 V		40		kΩ
TADJ INTERFACE	TADJ (Pin 6)
Input Resistance	TADJ = 0.9 V, sourcing 50 μA		13		kΩ
Disable Threshold Voltage	TADJ = open		VPOS − 0.4		V
POWER INTERFACE	VPOS (Pin 7)
Supply Voltage		3.0		5.5	V
Quiescent Current		18	22	30	mA
vs. Temperature	−40°C ≤ TA ≤ +85°C		60		μA/°C
Disable Current	TADJ = VPOS		200		μA

1 Slope and intercept are determined by calculating the best-fit line between the power levels of −40 dBm and −10 dBm at the specified input frequency. 2 Slope and intercept are determined by calculating the best-fit line between the power levels of −34 dBm and −16 dBm at 8.0 GHz.

Rev. B | Page 4 of 20

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter	Rating
Supply Voltage, VPOS	5.7 V
VSET Voltage	0 V to VPOS
Input Power (Single-Ended, Re: 50 Ω)	12 dBm
Internal Power Dissipation	0.73 W
θJA	55°C/W
Maximum Junction Temperature	125°C
Operating Temperature Range	−40°C to +85°C
Storage Temperature Range	−65°C to +150°C
Lead Temperature (Soldering, 60 sec)	260°C

AD8317

Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

ESD CAUTION

Rev. B | Page 5 of 20

AD8317

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

INHI 1				8	INLO
		AD8317
COMM 2				7 VPOS
CLPF 3		TOP VIEW		6	TADJ
		(Not to Scale)
VSET 4				5	VOUT

Figure 2. Pin Configuration

05541-002

Table 3. Pin Function Descriptions

Pin No. Mnemonic

1INHI

2COMM

3CLPF

4VSET

5VOUT

6TADJ

7VPOS

8INLO Paddle

Description

RF Input. Nominal input range of −50 dBm to 0 dBm, re: 50 Ω; ac-coupled RF input. Device Common. Connect to a low impedance ground plane.

Loop Filter Capacitor. In measurement mode, this capacitor sets the pulse response time and video bandwidth. In controller mode, the capacitance on this node sets the response time of the error amplifier/integrator.

Setpoint Control Input for Controller Mode or Feedback Input for Measurement Mode.

Measurement and Controller Output. In measurement mode, VOUT provides a decreasing linear-in-dB representation of the RF input signal amplitude. In controller mode, VOUT is used to control the gain of a VGA or VVA with a positive gain sense (increasing voltage increases gain).

Temperature Compensation Adjustment. Frequency-dependent temperature compensation is set by connecting a ground-referenced resistor to this pin.

Positive Supply Voltage: 3.0 V to 5.5 V.

RF Common for INHI. AC-coupled RF common.

Internally connected to COMM; solder to a low impedance ground plane.

Rev. B | Page 6 of 20