Analog Devices AD8315 b Datasheet

50 dB GSM PA Controller

AD8315

FEATURES
Complete RF Detector/Controller Function
>50 dB Range at 0.9 GHz (–49 dBm to +2 dBm re 50 )
Accurate Scaling from 0.1 GHz to 2.5 GHz
Temperature-Stable Linear-in-dB Response
Log Slope of 23 mV/dB, Intercept at –60 dBm at 0.9 GHz
True Integration Function in Control Loop
Low Power: 20 mW at 2.7 V, 38 mW at 5 V
Power Down to 10.8 W

APPLICATIONS
Single, Dual, and Triple Band Mobile Handset

(GSM, DCS, EDGE)

Transmitter Power Control

PRODUCT DESCRIPTION

The AD8315 is a complete low cost subsystem for the precise
control of RF power amplifiers operating in the frequency range

0.1 GHz–2.5 GHz and over a typical dynamic range of 50 dB. It is
intended for use in cellular handsets and other battery-operated
wireless devices. The log amp technique provides a much wider
measurement range and better accuracy than controllers using
diode detectors. In particular, its temperature stability is excellent
over a specified range of –30∞C to +85∞C.

Its high sensitivity allows control at low signal levels, thus reduc­ing the amount of power that needs to be coupled to the detector.

For convenience, the signal is internally ac-coupled. This
high-pass coupling, with a corner at approximately 0.016 GHz,
determines the lowest operating frequency. Thus, the source
may be dc grounded.

The AD8315 provides a voltage output, VAPC, that has the
voltage range and current drive to directly connect to most hand­set power amplifiers’ gain control pin. VAPC can swing from 250
mV above ground to within 200 mV below the supply voltage.
Load currents of up to 6 mA can be supported.

The setpoint control input is applied to pin VSET and has an
operating range of 0.25 V–1.4 V. The associated circuit deter­mines the slope and intercept of the linear-in-dB measurement
system; these are nominally 23 mV/dB and –60 dBm for a 50 W
termination (–73 dBV) at 0.9 GHz. Further simplifying the
application of the AD8315, the input resistance of the setpoint
interface is over 100 MW, and the bias current is typically 0.5 mA.

The AD8315 is available in MSOP and lead frame chip scale
(LFCSP) packages and consumes 8.5 mA from a 2.7 V to 5.5 V
supply. When powered down, the sleep current is 4 mA.

FUNCTIONAL BLOCK DIAGRAM

RFIN

COMM

VPOS

ENBL

LOW NOISE

GAIN BIAS

OFFSET
COMP’N

LOW NOISE

BAND GAP

REFERENCE

10dB10dB10dB

REV. B

Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.

OUTPUT
ENABLE

DELAY

VA PC

1.35

DETDETDETDETDET

10dB

INTERCEPT

POSITIONING

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © 2003 Analog Devices, Inc. All rights reserved.

HI-Z

LOW NOISE (25nV/ Hz)
RAIL-TO-RAIL BUFFER

FLTR

VSET

V-I

23mV/dB
250mV to

1.4V = 50dB

AD8315–SPECIFICATIONS

(VS = 2.7 V, T = 25C, 52.3  termination on RFIN, unless otherwise noted.)

Parameter Conditions Min Typ Max Unit

OVERALL FUNCTION

Frequency Range

1

To Meet All Specifications 0.1 2.5 GHz

Input Voltage Range ± 1 dB Log Conformance, 0.1 GHz –57 –11 dBV

Equivalent dBm Range –44 +2 dBm
Logarithmic Slope
Logarithmic Intercept

2

2

0.1 GHz 21.5 24 25.5 mV/dB

0.1 GHz –79 –70 –64 dBV

Equivalent dBm Level –66 –57 –51 dBm

RF INPUT INTERFACE Pin RFIN

Input Resistance
Input Capacitance

3

3

0.1 GHz 2.8 kW

0.1 GHz 0.9 pF

OUTPUT Pin VAPC

Minimum Output Voltage VSET £ 200 mV, ENBL High 0.25 0.27 0.3 V

ENBL Low 0.02 V
Maximum Output Voltage R
vs. Temperature

4

General Limit 2.7 V £ VPOS £ 5.5 V, R

≥ 800 W 2.45 2.6 V

L

85∞C, V

POS

=3 V, I

=6 mA 2.54 V

OUT

= • VPOS – 0.1 V

L

Output Current Drive Source/Sink 5/200 mA/mA
Output Buffer Noise 25 nV÷ Hz
Output Noise RF Input = 2 GHz, 0 dBm, f

= 220 pF

C

FLT

Small Signal Bandwidth 0.2 V to 2.6 V Swing 30 MHz
Slew Rate 10%–90%, 1.2 V Step (V

SET

= 100 kHz, 130 nV/÷Hz

NOISE

), Open Loop

5

13 V/ms

Response Time FLTR = Open, Refer to TPC 24 150 ns

SETPOINT INTERFACE Pin VSET

Nominal Input Range Corresponding to Central 50 dB 0.25 1.4 V
Logarithmic Scale Factor 43.5 dB/V
Input Resistance 100 kW
Slew Rate 16 V/ms

ENABLE INTERFACE Pin ENBL

Logic Level to Enable Power 1.8 V

POS

V

Input Current when Enable High 20 mA
Logic Level to Disable Power 0.8 V
Enable Time Time from ENBL High to V

Final Value, V

£ 200 mV, Refer to TPC 21

SET

Disable Time Time from ENBL Low to V

Final Value, V

£ 200 mV, Refer to TPC 21

SET

Power-On/Enable Time Time from VPOS/ENBL High to V

1% of Final Value, V

£ 200 mV, Refer to

SET

within 1% of 4 5 ms

APC

within 1% of 8 9 ms

APC

within 2 3 ms

APC

TPC 26

Time from VPOS/ENBL Low to V

1% of Final Value, V

£ 200 mV, Refer to

SET

within 100 200 ns

APC

TPC 26

POWER INTERFACE Pin VPOS

Supply Voltage 2.7 5.5 V
Quiescent Current ENBL High 8.5 10.7 mA

Over Temperature –30∞C £ T

Disable Current

6

ENBL Low 4 10 mA

£ +85∞C12.9mA

A

Over Temperature –30∞C £ TA £ +85∞C13mA

NOTES

1

Operation down to 0.02 GHz is possible.

2

Mean and Standard Deviation specifications are available in Table I.

3

See TPC 9 for plot of Input Impedance vs. Frequency.

4

This parameter is guaranteed but not tested in production. Limit is –3 sigma from the mean.

5

Response time in a closed-loop system will depend upon the filter capacitor (C

6

This parameter is guaranteed but not tested in production. Maximum specified limit on this parameter is the +6 sigma value.

Specifications subject to change without notice.

) used and the response of the variable gain element.

FLT

–2–

REV. B

AD8315

Table I. Typical Specifications at Selected Frequencies at 25C (Mean and Sigma)

1 dB Dynamic Range

Slope – mV/dB Intercept – dBV Low Point – dBV High Point – dBV

Frequency – GHz Mean Sigma Mean Sigma Mean Sigma Mean Sigma

0.1 23.8 0.3 –70.1 1.8 –57.7 1.3 –10.6 0.8

0.9 23.2 0.4 –72.6 1.8 –61.0 1.3 –11.2 0.8

1.9 22.2 0.3 –73.8 1.6 –62.9 0.9 –18.5 1.7

2.5 22.3 0.4 –75.6 1.5 –64.0 1.1 –20.0 1.7

ABSOLUTE MAXIMUM RATINGS*

Supply Voltage VPOS . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5 V

Temporary Overvoltage VPOS

(100 cycles, 2 seconds duration, ENBL Low) . . . . . . .6.3 V

VAPC, VSET, ENBL . . . . . . . . . . . . . . . . . . . . . . 0 V, VPOS

RFIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 dBm

Equivalent Voltage . . . . . . . . . . . . . . . . . . . . . . . . 1.6 V rms

Internal Power Dissipation . . . . . . . . . . . . . . . . . . . . . 60 mW

(MSOP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200∞C/W

q

JA

q

(LFCSP, Paddle Soldered) . . . . . . . . . . . . . . . . . . 80∞C/W

JA

(LFCSP, Paddle not Soldered) . . . . . . . . . . . . . 200∞C/W

q

JA

Maximum Junction Temperature . . . . . . . . . . . . . . . . . 125∞C

Operating Temperature Range . . . . . . . . . . . –40∞C to +85∞C

Storage Temperature Range . . . . . . . . . . . . –65∞C to +150∞C

Lead Temperature Range (Soldering 60 sec)

MSOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300∞C

LFCSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240∞C

*Stresses above those listed under Absolute Maximum Ratings may cause perma-

nent 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.

PIN CONFIGURATION

1

RFIN

2

ENBL

3

VSET

(Not to Scale)

4

NC = NO CONNECT

AD8315

TOP VIEW

8

7

6

5

VPOS

VAPC

NC

COMMFLTR

PIN FUNCTION DESCRIPTIONS

Pin
No. Mnemonic Function

1 RFIN RF Input
2 ENBL Connect to VPOS for Normal Operation

Connect pin to ground for Disable Mode

3 VSET Setpoint Input. Nominal input range

0.25 V to 1.4 V.

4 FLTR Integrator Capacitor. Connect between

FLTR and COMM.
5 COMM Device Common (Ground)
6NCNo Connection
7 VAPC Output. Control voltage for gain control

element.
8 VPOS Positive Supply Voltage: 2.7 V to 5.5 V

ORDERING GUIDE

Model Temperature Range Package Descriptions Package Option Branding Information

AD8315ARM –30∞C to +85∞CTube, 8-Lead MSOP RM-8 J7A
AD8315ARM-REEL 13" Tape and Reel
AD8315ARM-REEL7 7" Tape and Reel
AD8315-EVAL MSOP Evaluation Board
AD8315ACP-REEL –30∞C to +85∞C 13" Tape and Reel, CP-8 J7A

8-Lead LFCSP
AD8315ACP-REEL7 7" Tape and Reel
AD8315ACP-EVAL LFCSP Evaluation Board

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although

WARNING!

the AD8315 features proprietary ESD protection circuitry, permanent damage may occur on
devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are
recommended to avoid performance degradation or loss of functionality.

REV. B

–3–

ESD SENSITIVE DEVICE

AD8315

–Typical Performance Characteristics

1

0

–10

–20

–30

–40

0.9GHz

–50

RF INPUT AMPLITUDE – dBV

–60

–70

–80

0.2

10

0

(+3dBm)

–10

–20

–30

RF INPUT

–40

AMPLITUDE – dBV

–50

(–47dBm)

–60

–70

0.1

0.4 0.6 0.8 1.0 1.2 1.4

TPC 1. Input Amplitude vs. V

+25C

0.3 0.5 0.7 0.9 1.1 1.3 1.5

1.9GHz

0.1GHz

2.5GHz

V

– V

SET

SET

–30C

+25C

+85C

–30C

ERROR AT +85C AND –30C
BASED ON DEVIATION FROM
SLOPE AND INTERCEPT AT +25C

V

– V

SET

+85C

TPC 2. Input Amplitude and Log Conformance vs. V

0.1 GHz

23

13

3

–7

–17

–27

–37

–47

RF INPUT AMPLITUDE – dBm

–57

–67

4

3

2

1

0

ERROR – dB

–1

–2

(–47dBm)

TPC 5. Input Amplitude and Log Conformance vs. V

SET

–3

–4

at

1.9 GHz

ERROR – dB

(+3dBm)

–10

–20

–30

RF INPUT

–40

AMPLITUDE – dBV

–50

–60

–70

4

3

2

1

0

–1

–2

–3

–4

0.2

0.1GHz

0.4 0.6 0.8 1.0 1.2 1.4 1.6
V

– V

SET

TPC 4. Log Conformance vs. V

10

0

+85C

+25C

+85C

0.1

–30C

0.3 0.5 0.7 0.9 1.1 1.3 1.5

–30C

+25C

ERROR AT +85C AND –30C
BASED ON DEVIATION FROM
SLOPE AND INTERCEPT AT +25C

V

– V

SET

1.9GHz

2.5GHz

SET

0.9GHz

4

3

2

1

0

–1

–2

–3

–4

SET

ERROR – dB

at

(+3dBm)

RF INPUT

(–47dBm)

10

0

–10

–20

–30

–40

AMPLITUDE – dBV

–50

–60

–70

0.3 0.5 0.7 0.9 1.1 1.3 1.5

0.1

–30C

+25C

–30C

+85C

+25C

ERROR AT +85C AND –30C
BASED ON DEVIATION FROM
SLOPE AND INTERCEPT AT +25C

V

– V

SET

+85C

TPC 3. Input Amplitude and Log Conformance vs. V

0.9 GHz

SET

4

3

2

1

0

ERROR – dB

–1

–2

–3

–4

at

10

0

(+3dBm)

–10

–30C

+85C

ERROR AT +85C AND –30C
BASED ON DEVIATION FROM
SLOPE AND INTERCEPT AT +25C

V

– V

SET

RF INPUT

(–47dBm)

–20

–30

–40

AMPLITUDE – dBV

–50

+25C

–60

–70

0.1

0.3 0.5 0.7 0.9 1.1 1.3 1.5

+25C

–30C+85C

TPC 6. Input Amplitude and Log Conformance vs. V

2.5 GHz

–4–

4

3

2

1

0

ERROR – dB

–1

–2

–3

–4

at

SET

REV. B

AD8315

(

)(

)

(

)(

)

(

)(

)

4

3

2

1

0

ERROR – dB

–1

–2

–3

–4

–80 0–70

+85C

ERROR AT +85C AND –30C
BASED ON DEVIATION FROM
SLOPE AND INTERCEPT AT +25C

–60

RF INPUT AMPLITUDE – dBV

–47dBm

–50 –40 –30 –20 –10

–30C

+3dBm

TPC 7. Distribution of Error at Temperature after Ambient
Normalization vs. Input Amplitude, 3 Sigma to Either Side
of Mean, 0.1 GHz

4

3

2

30C

4

3

2

1

0

ERROR – dB

–1

–2

ERROR AT +85C AND –30C

–3

BASED ON DEVIATION FROM
SLOPE AND INTERCEPT AT +25C

–4

–80 0–70

–30C

+85C

–50 –40 –30 –20 –10

–60

RF INPUT AMPLITUDE – dBV

–47dBm

+3dBm

TPC 10. Distribution of Error at Temperature after Ambient
Normalization vs. Input Amplitude, 3 Sigma to Either Side of
Mean, 1.9 GHz

4

3

2

–30C

1

0

ERROR – dB

–1

–2

ERROR AT +85C AND –30C

–3

BASED ON DEVIATION FROM
SLOPE AND INTERCEPT AT +25C

–4

–80 0–70

85C

–60

–50 –40 –30 –20 –10

RF INPUT AMPLITUDE – dBV

(+3dBm)(–47dBm)

TPC 8. Distribution of Error at Temperature after Ambient
Normalization vs. Input Amplitude, 3 Sigma to Either Side
of Mean, 0.9 GHz

jX
j1500
j220
j130
j110

0

–200

–400

–600

–800

–1000

–1200

X

–1400

–1600

–1800

–2000

3000

2700

2400

2100

1800

X (LFCSP)

1500

1200

RESISTANCE – 

900

600

300

0

0 2.50.5 1 1.5 2

X (MSOP)

FREQUENCY
(GHz)

0.1

0.9

1.9

2.5

FREQUENCY – GHz

2900 –

R (LFCSP)

R (MSOP)

R –

700 –
130 –
170 –

Chip Scale (LFCSP)

MSOP

jX
j1900
j240
j80
j70

R –

2700 –

730 –
460 –
440 –

R

TPC 9. Input Impedance

1

0

ERROR – dB

–1

–2

ERROR AT +85C AND –30C

–3

BASED ON DEVIATION FROM
SLOPE AND INTERCEPT AT +25C

–4

–80 0–70

–50 –40 –30 –20 –10

–60

RF INPUT AMPLITUDE – dBV

–47dBm

+85C

+3dBm

TPC 11. Distribution of Error at Temperature after Ambient
Normalization vs. Input Amplitude, 3 Sigma to Either Side of
Mean, 2.5 GHz

10

8



REACTANCE –

6

4

DECREASING

SUPPLY CURRENT – mA

2

0

1.3

V

ENBL

1.4 1.5 1.6 1.7
V

ENBL

TPC 12. Supply Current vs. V

– V

INCREASING
V

ENBL

ENBL

REV. B

–5–

AD8315

g

25

24

23

22

SLOPE – mV/dB

21

20

0

–30 C

0.5 1.0 1.5 2.0 2.5
FREQUENCY – GHz

+85 C

+25 C

TPC 13. Slope vs. Frequency; –30∞C, +25∞C, and +85∞C

24

23

SLOPE – mV/dB

22

0.1GHz

0.9GHz

1.9GHz

–66

–68

+85 C

–70

–72

+25 C

–74

INTERCEPT – dBV

–76

–78

–80

0





–30 C



0.5 1.0 1.5 2.0 2.5
FREQUENCY – GHz

TPC 16. Intercept vs. Frequency; –30∞C, +25∞C, and +85∞C

–68

–70

–72

–74

INTERCEPT – dBV

–76

0.1GHz

0.9GHz

1.9GHz

2.5GHz

21

3.0 3.5 4.0 4.5 5.0 5.5

2.5
VS – V

TPC 14. Slope vs. Supply Voltage

45
40
35
30
25
20
15
10

5
0

–5

–10

AMPLITUDE – dB

–15
–20
–25
–30
–35
–40

10

100 1k 10k 100k 1M 10M

C

= 220pF

FLT

FREQUENCY – Hz

C

= 0pF

FLT

TPC 15. AC Response from VSET to VAPC

0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
–120
–130

rees

PHASE – De

–78

–80

3.0 3.5 4.0 4.5 5.55.0

2.5

2.5GHz

VS – V

TPC 17. Intercept vs. Supply Voltage

10000

1000

100

NOISE SPECTRAL DENSITY – nV/ Hz

10

100

TPC 18. V

C

= 220PF, RF INPUT = 2GHz

FLT

RF INPUT

–51dBV

–48dBV

–33dBV

–43dBV

–23dBV

–13dBV

–53dBV AND

–63dBV

1k 10k 100k 1M 10M

FREQUENCY – Hz

Noise Spectral Density

APC

–6–

REV. B