ATF-521P8-BLK - Agilent / Hewlett-Packard

Agilent ATF-521P8 High Linearity

Enhancement Mode[1]

Pseudomorphic HEMT in

2x2 mm2 LPCC[3] Package

Data Sheet

Description

Agilent Technologies’s ATF-521P8 is a

single-voltage high linearity, low noise

E-pHEMT housed in an 8-lead JEDEC-

standard leadless plastic chip carrier

(LPCC[3]) package. The device is ideal

as a medium-power, high-linearity am-

plifier. Its operating frequency range

is from 50 MHz to 6 GHz.

The thermally efficient package mea-

sures only 2mm x 2mm x 0.75mm. Its

backside metalization provides excel-

lent thermal dissipation as well as vi-

sual evidence of solder reflow. The

device has a Point MTTF of over 300

years at a mounting temperature of

+85°C. All devices are 100% RF & DC

tested.

Features

•Single voltage operation

•High linearity and P1dB

•Low noise figure

•Excellent uniformity in product

specifications

•Small package size:

2.0 x 2.0 x 0.75 mm3

•Point MTTF > 300 years[2]

•MSL-1 and lead-free

•Tape-and-reel packaging option

available

Specifications

2 GHz; 4.5V, 200 mA (Typ.)

•42 dBm output IP3

•26.5 dBm output power at 1 dB gain

compression

•1.5 dB noise figure

•17 dB Gain

•12.5 dB LFOM[4]

Applications

•Front-end LNA Q2 and Q3, driver or

pre-driver amplifier for Cellular/

PCS and WCDMA wireless

infrastructure

•Driver amplifier for WLAN,

WLL/RLL and MMDS applications

•General purpose discrete E-pHEMT

for other high linearity applications

Pin Connections and

Package Marking

Note:

Package marking provides orientation and

identification

“2P” = Device Code

“x” = Month code indicates the month of

manufacture.

Note:

1. Enhancement mode technology employs a

single positive Vgs, eliminating the need of

negative gate voltage associated with

conventional depletion mode devices.

2. Refer to reliability datasheet for detailed

MTTF data

3. Conform to JEDEC reference outline MO229

for DRP-N

4. Linearity Figure of Merit (LFOM) is essentially

OIP3 divided by DC bias power.

Pin 1 (Source)

Pin 2 (Gate)

Pin 3

Pin 4 (Source)

Pin 8

Pin 7 (Drain)

Pin 6

Pin 5

2Px

Top View

Pin 8

Source

(Thermal/RF Gnd)

Pin 7 (Drain)

Pin 6

Pin 5

Pin 1 (Source)

Pin 2 (Gate)

Pin 3

Pin 4 (Source)

Bottom View

ATF-521P8 Absolute Maximum Ratings[1]

Absolute

Symbol Parameter Units Maximum

VDS Drain –Source Voltage [2] V7

VGS Gate –Source Voltage[2] V -5 to 1

VGD Gate Drain Voltage[2] V -5 to 1

IDS Drain Current [2] mA 500

IGS Gate Current mA 46

Pdiss Total Power Dissipation [3] W 1.5

Pin max. RF Input Power dBm 27

TCH Channel Temperature °C 150

TSTG Storage Temperature °C -65 to 150

θch_b Thermal Resistance[4] °C/W 45

Notes:

1. Operation of this device in excess of any one

of these parameters may cause permanent

damage.

2. Assumes DC quiescent conditions.

3. Board (package belly) temperatureTB is 25°C.

Derate 22 mW/°C for TB > 83°C.

4. Channel to board thermal resistance

measured using 150°C Liquid Crystal

Measurement method.

Product Consistency Distribution Charts [5, 6]

NF (dB)

Figure 2. NF @ 2 GHz, 4.5 V, 200 mA.

Nominal = 1.5 dB.

0 1.5

0.5 12.5

180

150

120

Stdev = 0.19

+3 Std-3 Std

OIP3 (dBm)

Figure 3. OIP3 @ 2 GHz, 4.5 V, 200 mA.

Nominal = 41.9 dBm, LSL = 38.5 dBm.

37 43

39 41 47

45 49

150

120

Cpk = 0.86

Stdev = 1.32

+3 Std-3 Std

GAIN (dB)

Figure 4. Gain @ 2 GHz, 4.5 V, 200 mA.

Nominal = 17.2 dB, LSL = 15.5 dB,

USL = 18.5 dB.

15 18

16 17 19

180

150

120

Cpk = 2.13

Stdev = 0.21

+3 Std-3 Std

Notes:

5. Distribution data sample size is 500 samples taken from 5 different wafers. Future wafers allocated

to this product may have nominal values anywhere between the upper and lower limits.

6. Measurements are made on production test board, which represents a trade-off between optimal

OIP3, P1dB and VSWR. Circuit losses have been de-embedded from actual measurements.

(V)

Figure 1. Typical I-V Curves.

(VGS = 0.1 V per step)

(mA)

0.5V

Vgs = 0.6V

0.7V

0.8V

0.4V

02 648

600

500

400

300

200

100

P1dB (dBm)

Figure 5. P1dB @ 2 GHz, 4.5 V, 200 mA.

Nominal = 26.5 dBm, LSL = 25 dBm.

25 26.5

25.5 26 27 27.5

300

250

200

150

100

Cpk = 4.6

Stdev = 0.11

+3 Std-3 Std

5. Device can safely handle +27dBm RF Input

Power provided IGS is limited to 46mA. IGS

at P1dB drive level is bias circuit dependent.

ATF-521P8 Electrical Specifications

TA = 25°C, DC bias for RF parameters is Vds = 4.5V and Ids = 200 mA unless otherwise specified.

Symbol Parameter and Test Condition Units Min. Typ. Max.

Vgs Operational Gate Voltage Vds = 4.5V, Ids = 200 mA V —0.62 —

Vth Threshold Voltage Vds = 4.5V, Ids = 16 mA V —0.28 —

Idss Saturated Drain Current Vds = 4.5V, Vgs = 0V µA—14.8 —

Gm Transconductance Vds = 4.5V, Gm = ∆Idss/∆Vgs; mmho —1300 —

Vgs = Vgs1 - Vgs2

Vgs1 = 0.55V, Vgs2 = 0.5V

Igss Gate Leakage Current Vds = 0V, Vgs = -4V µA -20 0.49 —

NF Noise Figure [1] f = 2 GHz dB —1.5 —

f = 900 MHz dB —1.2 —

G Gain [1] f = 2 GHz dB 15.5 17 18.5

f = 900 MHz dB —17.2 —

OIP3 Output 3rd Order f = 2 GHz dBm 38.5 42 —

Intercept Point[1] f = 900 MHz dBm —42.5 —

P1dB Output 1dB f = 2 GHz dBm 25 26.5 —

Compressed[1] f = 900 MHz dBm —26.5 —

PAE Power Added Efficiency f = 2 GHz % 45 60 —

f = 900 MHz % —56 —

ACLR Adjacent Channel Leakage Offset BW = 5 MHz dBc —-51.4 —

Power Ratio[1,2] Offset BW = 10 MHz dBc —-61.5 —

Notes:

1. Measurements obtained using production test board described in Figure 6.

2. ACLR test spec is based on 3GPP TS 25.141 V5.3.1 (2002-06)

– Test Model 1

– Active Channels: PCCPCH + SCH + CPICH + PICH + SCCPCH + 64 DPCH (SF=128)

– Freq = 2140 MHz

– Pin = -5 dBm

– Chan Integ Bw = 3.84 MHz

Input

50 Ohm

Transmission

Line Including

Gate Bias T

(0.3 dB loss)

Input

Matching Circuit

Γ_mag = 0.55

Γ_ang = -166°

(1.1 dB loss)

Output

Matching Circuit

Γ_mag = 0.35

Γ_ang = 168°

(0.9 dB loss)

DUT

50 Ohm

Transmission

Line and

Drain Bias T

(0.3 dB loss)

Output

Figure 6. Block diagram of the 2 GHz production test board used for NF, Gain, OIP3 , P1dB and PAE and ACLR measurements. This circuit achieves a

trade-off between optimal OIP3, P1dB and VSWR. Circuit losses have been de-embedded from actual measurements.

Gamma Load and Source at Optimum OIP3 and P1dB Tuning Conditions

The device’s optimum OIP3 and P1dB measurements were determined using a Maury load pull system at

4.5V, 200 mA quiesent bias:

Optimum OIP3

Freq Gamma Source Gamma Load OIP3 Gain P1dB PAE

(GHz) Mag Ang (deg) Mag Ang (deg) (dBm) (dB) (dBm) (%)

0.9 0.413 10.5 0.314 179.0 42.7 16.0 27.0 54.0

20.368 162.0 0.538 -176.0 42.5 15.8 27.5 55.3

2.4 0.318 169.0 0.566 -169.0 42.0 14.1 27.4 53.5

3.9 0.463 -134.0 0.495 -159.0 40.3 9.6 27.3 43.9

Optimum P1dB

Freq Gamma Source Gamma Load OIP3 Gain P1dB PAE

(GHz) Mag Ang (deg) Mag Ang (deg) (dBm) (dB) (dBm) (%)

0.9 0.587 12.7 0.613 -172.1 39.1 14.5 29.3 49.6

20.614 126.1 0.652 -172.5 39.5 12.9 29.3 49.5

2.4 0.649 145.0 0.682 -171.5 40.0 12.0 29.4 46.8

3.9 0.552 -162.8 0.670 -151.2 38.1 9.6 27.9 39.1

Figure 7. Simplified schematic of production test board. Primary purpose is to show 15 Ohm series resistor placement in

gate supply. Transmission line tapers, tee intersections, bias lines and parasitic values are not shown.

RF Input

1.5 pF

3.9 nH

1.5 pF

RF Outpu

50 Ohm

.02 λ

110 Ohm

.03 λ

110 Ohm

.03 λ

50 Ohm

.02 λ

DUT

1 pF

12 nH

15 Ohm

2.2 µF

Gate

Supply

47 nH

2.2 µF

Drain

Supply

ATF-521P8 Typical Performance Curves (at 25°C unless specified otherwise)

Tuned for Optimal OIP3

Note:

Bias current for the above charts are quiescent

conditions. Actual level may increase depending

on amount of RF drive.

Figure 8. OIP3 vs. Ids and Vds at 2 GHz.

4.5V

Id (mA)

OIP3 (dBm)

100 400200150 300 350250

Figure 9. OIP3 vs. Ids and Vds at 900 MHz.

Id (mA)

OIP3 (dBm)

100 400200150 300 350250

4.5V

Figure 10. OIP3 vs. Ids and Vds at 3.9 GHz.

Id (mA)

OIP3 (dBm)

100 400200150 300 350250

4.5V

Figure 11. P1dB vs. Idq and Vds at 2 GHz.

Idq (mA)

P1dB (dBm)

100 400200150 300 350250

4.5V

Figure 12. P1dB vs. Idq and Vds at 900 MHz.

4.5V

Idq (mA)

P1dB (dBm)

100 400200150 300 350250

Figure 13. P1dB vs. Idq and Vds at 3.9 GHz.

4.5V

Idq (mA)

P1dB (dBm)

100 400200150 300 350250

Figure 14. Small Signal Gain vs Ids and Vds

at 2 GHz.

Id (mA)

GAIN (dBm)

100 400200150 300 350250

4.5V

Figure 15. Small Signal Gain vs Ids and Vds

at 900 MHz.

Id (mA)

GAIN (dBm)

100 400200150 300 350250

4.5V

Figure 16. Small Signal Gain vs Ids and Vds

at 3.9 GHz.

Id (mA)

GAIN (dBm)

100 400200150 300 350250

4.5V

ATF-521P8 Typical Performance Curves, continued (at 25°C unless specified otherwise)

Tuned for Optimal OIP3

Note:

Bias current for the above charts are quiescent

conditions. Actual level may increase depending

on amount of RF drive.

Figure 17. PAE @ P1dB vs. Idq and Vds

at 2 GHz.

(mA)

PAE (%)

100 400200150 300 350250

4.5V

Figure 18. PAE @ P1dB vs. Idq and Vds

at 900 MHz.

(mA)

PAE (%)

100 400200150 300 350250

4.5V

Figure 19. PAE @ P1dB vs. Idq and Vds

at 3.9 GHz.

(mA)

PAE (%)

100 400200150 300 350250

4.5V

Figure 20. OIP3 vs. Temp and Freq

tuned for optimal OIP3 at 4.5V, 200 mA.

FREQUENCY (GHz)

OIP3 (dBm)

0.5 43.51.51 2.5 32

85°C

25°C

-40°C

Figure 21. P1dB vs. Temp and Freq

tuned for optimal OIP3 at 4.5V, 200 mA.

FREQUENCY (GHz)

P1dB (dBm)

0.5 43.51.51 2.5 32

85°C

25°C

-40°C

Figure 22. Gain vs. Temp and Freq

tuned for optimal OIP3 at 4.5V, 200 mA.

FREQUENCY (GHz)

GAIN (dB)

0.5 43.51.51 2.5 32

85°C

25°C

-40°C

Figure 23. PAE vs Temp and Freq

tuned for optimal OIP3 at 4.5V, 200 mA.

FREQUENCY (GHz)

PAE (%)

0.5 43.51.51 2.5 32

85°C

25°C

-40°C

ATF-521P8 Typical Performance Curves (at 25°C unless specified otherwise)

Tuned for Optimal P1dB

Note:

Bias current for the above charts are quiescent

conditions. Actual level may increase depending

on amount of RF drive.

Figure 24. OIP3 vs. Ids and Vds at 2 GHz.

Id (mA)

OIP3 (dBm)

100 400200150 300 350250

4.5V

200150 300 350250

4.5V

Figure 25. OIP3 vs. Ids and Vds at 900 MHz.

4.5V

Id (mA)

OIP3 (dBm)

100 400

Figure 27. P1dB vs. Idq and Vds at 2 GHz.

4.5V

Idq (mA)

P1dB (dBm)

100 400200150 300 350250

Figure 28. P1dB vs. Idq and Vds at 900 MHz.

4.5V

Idq (mA)

P1dB (dBm)

100 400

200

150 300 350250

Figure 29. P1dB vs. Idq and Vds at 3.9 GHz.

4.5V

Idq (mA)

P1db (dBm)

100 400200150 300 350250

Figure 30. Gain vs Ids and Vds at 2 GHz.

4.5V

Id (mA)

GAIN (dBm)

100 400200150 300 350250

Figure 31. Gain vs Ids and Vds at 900 MHz.

4.5V

Id (mA)

GAIN (dBm)

100 400200150 300 350250

Figure 32. Gain vs Ids and Vds at 3.9 GHz.

Id (mA)

GAIN (dBm)

100 400200150 300 350250

4.5V

Figure 26. OIP3 vs. Ids and Vds at 3.9 GHz.

4.5V

Id (mA)

OIP3 (dBm)

100 400200150 300 350250

ATF-521P8 Typical Performance Curves, continued (at 25°C unless specified otherwise)

Tuned for Optimal P1dB

Note:

Bias current for the above charts are quiescent

conditions. Actual level may increase depending

on amount of RF drive.

Figure 33. PAE @ P1dB vs. Idq and Vds

at 2 GHz.

Idq (mA)

PAE (%)

100 400350200150 300250

4.5V

Idq (mA)

PAE (%)

100 400350200150 300250

Figure 34. PAE @ P1dB vs. Idq and Vds

at 900 MHz.

4.5V

Figure 35. PAE @ P1dB vs. Idq and Vds

at 3.9 GHz.

Idq (mA)

PAE (%)

100 400200150 300 350250

4.5V

Figure 36. OIP3 vs. Temp and Freq

tuned for optimal P1dB at 4.5V, 200 mA.

FREQUENCY (GHz)

OIP3 (dBm)

0.5 43.51.5

12.5 32

85°C

25°C

-40°C

Figure 38. Gain vs. Temp and Freq

tuned for optimal P1dB at 4.5V, 200 mA.

FREQUENCY (GHz)

GAIN (dB)

0.5 43.51.51 2.5 32

85°C

25°C

-40°C

Figure 39. PAE vs Temp and Freq

tuned for optimal P1dB at 4.5V.

FREQUENCY (GHz)

PAE (%)

00.5 4

85°C

25°C

-40°C

3.51.51 2.5 32

Figure 37. P1dB vs. Temp and Freq

(tuned for optimal P1dB at 4.5V, 200 mA).

FREQUENCY (GHz)

P1dB (dBm)

0.5 43.5

1.5

12.5 32

85°C

25°C

-40°C

ATF-521P8 Typical Scattering Parameters at 25°C, VDS = 4.5V, IDS = 280 mA

Freq. S11 S21 S12 S22

MSG/MAG

GHz Mag. Ang. dB Mag. Ang. dB Mag. Ang. Mag. Ang. dB

0.1 0.613 -96.9 33.2 45.79 141.7 -39.5 0.011 51.3 0.317 -108.3 36.2

0.2 0.780 -131.8 30.0 31.50 121.6 -36.7 0.015 37.1 0.423 -138.5 33.2

0.3 0.831 -147.2 27.3 23.26 111.0 -36.2 0.015 30.6 0.466 -152.4 31.9

0.4 0.855 -156.4 25.1 18.04 104.1 -35.4 0.017 28.2 0.483 -159.9 30.3

0.5 0.860 -162.0 23.5 14.98 99.7 -35.2 0.017 27.4 0.488 -163.8 29.5

0.6 0.878 -166.7 22.0 12.62 95.6 -35.0 0.018 26.1 0.496 -167.0 28.5

0.7 0.888 -170.2 20.8 10.95 92.8 -34.6 0.019 27.4 0.497 -169.9 27.6

0.8 0.887 -172.6 19.7 9.63 90.0 -34.3 0.019 28.9 0.500 -171.7 27.0

0.9 0.894 -174.5 18.7 8.65 87.9 -33.7 0.021 28.5 0.501 -173.6 26.1

1.0 0.886 -177.2 17.9 7.82 85.4 -33.8 0.020 30.3 0.502 -175.7 25.9

1.5 0.892 175.0 14.3 5.20 76.3 -32.8 0.023 34.6 0.502 178.8 23.5

2.0 0.883 168.7 12.1 4.01 68.4 -31.2 0.027 36.7 0.492 173.6 20.2

2.5 0.890 162.8 10.2 3.24 61.5 -30.0 0.032 36.8 0.490 169.8 18.5

3.0 0.884 157.2 8.6 2.71 54.5 -28.9 0.036 39.2 0.494 165.7 16.2

4.0 0.890 146.6 6.1 2.02 40.6 -27.0 0.045 36.1 0.505 157.8 13.8

5.0 0.893 137.0 4.1 1.60 27.6 -25.5 0.053 32.4 0.529 150.3 11.9

6.0 0.896 127.9 2.3 1.31 15.4 -24.2 0.061 28.2 0.551 142.9 10.4

7.0 0.906 119.5 0.9 1.11 3.7 -22.9 0.071 22.9 0.570 135.5 9.6

8.0 0.882 105.6 -0.8 0.92 -9.8 -21.3 0.086 14.5 0.567 127.3 6.8

9.0 0.887 96.4 -1.7 0.82 -22.2 -20.1 0.098 7.2 0.585 117.8 6.2

10.0 0.887 84.6 -2.9 0.72 -33.6 -19.3 0.109 -1.0 0.593 107.3 5.0

11.0 0.882 72.3 -3.9 0.64 -45.8 -18.5 0.119 -10.5 0.617 97.1 3.9

12.0 0.878 62.2 -5.0 0.56 -57.0 -18.0 0.126 -19.8 0.636 86.0 2.8

13.0 0.894 52.0 -6.4 0.48 -67.8 -17.8 0.130 -28.6 0.662 74.7 2.1

14.0 0.888 42.0 -7.6 0.42 -76.2 -17.3 0.137 -36.1 0.697 67.5 0.9

15.0 0.884 34.6 -8.3 0.38 -84.3 -16.6 0.147 -42.9 0.732 58.7 0.3

16.0 0.830 24.7 -9.5 0.34 -92.8 -16.1 0.156 -52.4 0.752 51.9 -1.8

17.0 0.708 11.0 -9.0 0.35 -99.5 -15.4 0.169 -63.8 0.816 46.1 -2.2

18.0 0.790 -12.7 -10.3 0.31 -93.1 -16.4 0.152 -82.8 0.660 41.2 -4.3

Freq Fmin Γopt Γopt RnGa

GHz dB Mag. Ang. dB

0.5 1.20 0.47 170.00 2.8 22.8

1.0 1.30 0.53 -177.00 2.6 20.1

2.0 1.61 0.61 -166.34 2.7 17.3

3.0 1.68 0.69 -155.85 4.0 14.4

4.0 2.12 0.67 -146.98 8.4 11.6

5.0 2.77 0.71 -134.35 19.0 9.9

6.0 2.58 0.79 -125.22 26.7 8.8

7.0 2.85 0.82 -115.35 47.2 7.5

8.0 3.35 0.73 -105.76 65.2 5.7

Notes:

1. Fmin values at 2 GHz and higher are based on measurements while the Fmins below 2 GHz have been extrapolated. The Fmin values are based on a set of

16 noise figure measurements made at 16 different impedances using an ATN NP5 test system. From these measurements a true Fmin is calculated.

Refer to the noise parameter application section for more information.

2. S and noise parameters are measured on a microstrip line made on 0.025 inch thick alumina carrier. The input reference plane is at the end of the gate

lead. The output reference plane is at the end of the drain lead.

Typical Noise Parameters at 25°C, VDS = 4.5V, IDS = 280 mA

Figure 40. MSG/MAG and |S

vs.

Frequency at 4.5V, 280 mA.

MAG

FREQUENCY (GHz)

MSG/MAG and

(dB)

02010515

40.0

30.0

20.0

10.0

0.0

-10.0

-20.0

MSG

Freq Fmin Γopt Γopt RnGa

GHz dB Mag. Ang. dB

0.5 0.60 0.30 130.00 2.8 20.2

1.0 0.72 0.35 150.00 2.6 18.4

2.0 0.96 0.47 -175.47 1.9 16.5

3.0 1.11 0.57 -162.03 2.1 13.8

4.0 1.44 0.62 -150.00 4.5 11.2

5.0 1.75 0.69 -136.20 10.0 9.8

6.0 1.99 0.74 -127.35 17.0 8.7

7.0 2.12 0.80 -116.83 28.5 7.5

8.0 2.36 0.69 -108.38 35.6 5.7

Notes:

1. Fmin values at 2 GHz and higher are based on measurements while the Fmins below 2 GHz have been extrapolated. The Fmin values are based on a set of

16 noise figure measurements made at 16 different impedances using an ATN NP5 test system. From these measurements a true Fmin is calculated.

Refer to the noise parameter application section for more information.

2. S and noise parameters are measured on a microstrip line made on 0.025 inch thick alumina carrier. The input reference plane is at the end of the gate

lead. The output reference plane is at the end of the drain lead.

Typical Noise Parameters, VDS = 4.5V, IDS = 200 mA

Figure 41. MSG/MAG and |S

vs.

Frequency at 4.5V, 200 mA.

MAG

FREQUENCY (GHz)

MSG/MAG and

(dB)

02010515

40.0

30.0

20.0

10.0

0.0

-10.0

-20.0

MSG

ATF-521P8 Typical Scattering Parameters, VDS = 4.5V, IDS = 200 mA

Freq. S11 S21 S12 S22

MSG/MAG

GHz Mag. Ang. dB Mag. Ang. dB Mag. Ang. Mag. Ang. dB

0.1 0.823 -89.9 34.4 52.21 135.6 -37.9 0.013 46.2 0.388 -113.0 36.0

0.2 0.873 -128.7 30.5 33.39 115.7 -35.6 0.017 32.0 0.478 -143.2 32.9

0.3 0.879 -145.5 27.6 23.90 106.3 -34.9 0.018 27.0 0.507 -156.0 31.2

0.4 0.885 -155.1 25.2 18.25 100.5 -34.7 0.018 25.8 0.518 -163.1 30.1

0.5 0.883 -161.1 23.6 15.12 96.6 -34.4 0.019 24.8 0.519 -166.7 29.0

0.6 0.897 -165.9 22.1 12.66 92.9 -34.1 0.020 24.2 0.525 -169.6 28.0

0.7 0.895 -169.5 20.8 10.95 90.5 -33.7 0.021 24.2 0.526 -172.2 27.2

0.8 0.894 -171.9 19.6 9.59 88.0 -33.6 0.021 25.3 0.528 -174.0 26.6

0.9 0.900 -174.7 18.7 8.64 86.2 -33.1 0.022 26.2 0.528 -175.6 25.9

10.893 -176.6 17.8 7.78 83.7 -33.1 0.022 27.6 0.529 -177.7 25.5

1.5 0.894 175.3 14.3 5.17 75.7 -32.1 0.025 32.6 0.527 177.2 23.2

20.889 168.5 12.0 4.00 67.8 -30.8 0.029 33.6 0.516 172.1 21.4

2.5 0.888 162.6 10.2 3.22 61.3 -29.8 0.032 35.2 0.514 168.1 18.4

30.892 157.0 8.6 2.69 54.5 -28.6 0.037 35.6 0.517 164.0 16.7

40.884 146.5 6.0 2.00 40.7 -26.8 0.046 34.4 0.526 156.0 13.5

50.891 137.0 4.0 1.59 28.3 -25.2 0.055 30.5 0.548 148.3 11.9

60.889 127.9 2.3 1.30 16.4 -24.0 0.063 26.4 0.568 141.0 10.1

70.902 119.6 0.9 1.11 4.8 -22.8 0.072 21.0 0.584 133.5 9.4

80.881 105.6 -0.9 0.90 -8.8 -21.3 0.086 13.3 0.580 124.9 6.7

90.891 96.0 -1.7 0.83 -20.1 -20.2 0.098 5.6 0.594 115.8 6.4

10 0.876 83.9 -2.9 0.72 -32.1 -19.3 0.108 -3.2 0.600 105.3 4.6

11 0.885 73.1 -3.6 0.66 -43.7 -18.5 0.119 -12.1 0.622 95.0 4.2

12 0.885 60.9 -4.8 0.57 -54.1 -18.0 0.126 -21.6 0.641 84.1 3.0

13 0.893 53.0 -6.3 0.48 -66.2 -17.7 0.131 -29.9 0.663 73.1 2.1

14 0.889 42.2 -7.2 0.44 -74.0 -17.2 0.138 -36.7 0.698 65.7 1.2

15 0.894 34.3 -7.8 0.41 -80.6 -16.9 0.143 -44.1 0.732 57.4 1.0

16 0.840 25.0 -8.4 0.38 -83.4 -16.2 0.154 -54.3 0.750 51.0 -0.8

17 0.719 9.1 -10.0 0.32 -90.1 -15.4 0.171 -64.8 0.815 44.5 -3.2

18 0.794 -8.1 -12.2 0.25 -102.3 -16.7 0.147 -84.1 0.655 40.4 -5.9

Freq Fmin Γopt Γopt RnGa

GHz dB Mag. Ang. dB

0.5 0.60 0.19 162.00 3.0 20.0

1.0 0.72 0.30 164.00 2.6 18.3

2.0 0.81 0.44 176.97 2.0 15.9

3.0 0.92 0.56 -164.98 2.0 13.6

4.0 1.24 0.59 -155.51 3.4 11.1

5.0 1.50 0.70 -136.55 11.1 9.7

6.0 1.60 0.75 -128.59 16.0 8.7

7.0 1.88 0.81 -117.31 24.0 7.6

8.0 2.02 0.68 -109.54 28.8 5.6

Typical Noise Parameters, VDS = 4.5V, IDS = 120 mA

Figure 42. MSG/MAG and |S

vs.

Frequency at 4.5V, 120 mA.

MAG

FREQUENCY (GHz)

MSG/MAG and

(dB)

02010515

40.0

30.0

20.0

10.0

0.0

-10.0

-20.0

MSG

ATF-521P8 Typical Scattering Parameters, VDS = 4.5V, IDS = 120 mA

Freq. S11 S21 S12 S22

MSG/MAG

GHz Mag. Ang. dB Mag. Ang. dB Mag. Ang. Mag. Ang. dB

0.1 0.913 -84.6 34.2 51.26 135.4 -36.4 0.015 49.0 0.423 -106.6 35.3

0.2 0.900 -125.0 30.3 32.80 115.4 -33.9 0.020 31.2 0.499 -139.4 32.1

0.3 0.896 -142.0 27.4 23.39 106.1 -33.4 0.021 25.3 0.522 -153.4 30.5

0.4 0.893 -152.3 25.1 17.89 100.3 -32.9 0.023 23.5 0.530 -161.1 28.9

0.5 0.882 -158.4 23.4 14.75 96.3 -32.6 0.023 22.5 0.531 -165.0 28.1

0.6 0.895 -164.2 21.8 12.36 92.9 -32.7 0.023 20.6 0.537 -168.4 27.3

0.7 0.893 -167.8 20.6 10.71 90.5 -32.4 0.024 20.4 0.537 -171.2 26.5

0.8 0.895 -170.8 19.5 9.39 88.0 -32.3 0.024 21.1 0.539 -173.1 25.9

0.9 0.897 -173.0 18.5 8.44 86.1 -32.2 0.025 22.1 0.539 -174.8 25.3

10.895 -175.5 17.6 7.59 83.6 -31.8 0.026 23.0 0.540 -176.9 24.7

1.5 0.893 176.0 14.1 5.07 75.3 -31.1 0.028 25.5 0.538 177.4 22.6

20.889 169.2 11.8 3.89 67.8 -30.0 0.032 27.9 0.528 172.2 20.8

2.5 0.882 163.6 10.0 3.15 61.2 -29.0 0.036 30.2 0.526 168.1 19.4

30.888 157.9 8.4 2.62 54.6 -28.2 0.039 30.2 0.528 163.9 16.9

40.883 146.8 5.9 1.97 40.7 -26.5 0.047 29.7 0.536 155.7 13.6

50.885 137.7 3.8 1.55 28.2 -25.2 0.055 26.3 0.556 148.1 11.6

60.892 128.0 2.1 1.28 16.7 -24.0 0.063 21.9 0.576 140.5 10.2

70.894 120.4 0.6 1.08 5.1 -22.8 0.072 18.2 0.591 133.1 8.9

80.880 105.7 -1.0 0.89 -8.7 -21.2 0.087 10.6 0.585 124.3 6.6

90.876 96.5 -1.9 0.81 -20.8 -20.1 0.099 3.2 0.602 114.9 5.7

10 0.879 84.4 -3.0 0.71 -32.7 -19.3 0.108 -5.2 0.605 104.5 4.7

11 0.889 72.8 -3.8 0.65 -44.3 -18.6 0.118 -13.5 0.624 94.2 4.3

12 0.881 62.4 -5.2 0.55 -56.0 -18.1 0.125 -23.1 0.642 83.4 2.7

13 0.893 54.0 -6.3 0.48 -66.6 -17.7 0.130 -31.4 0.664 72.4 2.2

14 0.891 42.1 -7.2 0.44 -72.6 -17.3 0.136 -38.4 0.697 65.1 1.2

15 0.888 34.1 -8.3 0.39 -79.2 -16.8 0.144 -45.9 0.732 56.7 0.4

16 0.845 25.3 -9.1 0.35 -89.6 -16.1 0.157 -55.0 0.751 50.4 -1.5

17 0.828 13.2 -11.2 0.28 -95.9 -15.6 0.167 -64.2 0.821 44.0 -3.9

18 0.827 -10.2 -11.0 0.28 -92.5 -16.6 0.147 -86.1 0.654 39.9 -4.3

Notes:

1. Fmin values at 2 GHz and higher are based on measurements while the Fmins below 2 GHz have been extrapolated. The Fmin values are based on a set of

16 noise figure measurements made at 16 different impedances using an ATN NP5 test system. From these measurements a true Fmin is calculated.

Refer to the noise parameter application section for more information.

2. S and noise parameters are measured on a microstrip line made on 0.025 inch thick alumina carrier. The input reference plane is at the end of the gate

lead. The output reference plane is at the end of the drain lead.

Freq Fmin Γopt Γopt RnGa

GHz dB Mag. Ang. dB

0.5 0.67 0.21 155.00 2.8 20.1

1.0 0.74 0.30 164.00 2.6 18.4

2.0 0.96 0.46 -176.61 2.1 16.4

3.0 1.24 0.57 -162.19 2.8 13.9

4.0 1.44 0.62 -152.18 4.5 11.4

5.0 1.62 0.69 -135.43 10.0 10.0

6.0 1.83 0.74 -127.94 17.0 8.7

7.0 1.99 0.82 -117.20 27.7 7.7

8.0 2.21 0.71 -108.96 35.3 5.9

Typical Noise Parameters, VDS = 4V, IDS = 200 mA

Figure 43. MSG/MAG and |S

vs.

Frequency at 4V, 200 mA.

MAG

FREQUENCY (GHz)

MSG/MAG and

(dB)

02010515

40.0

30.0

20.0

10.0

0.0

-10.0

-20.0

MSG

ATF-521P8 Typical Scattering Parameters, VDS = 4V, IDS = 200 mA

Freq. S11 S21 S12 S22

MSG/MAG

GHz Mag. Ang. dB Mag. Ang. dB Mag. Ang. Mag. Ang. dB

0.1 0.843 -90.5 34.3 51.89 134.8 -37.7 0.013 46.5 0.408 -118.1 36.0

0.2 0.879 -129.3 30.3 32.88 115.0 -35.4 0.017 32.1 0.507 -146.1 32.9

0.3 0.888 -146.1 27.4 23.48 105.8 -35.1 0.018 26.0 0.539 -158.3 31.2

0.4 0.892 -155.6 25.1 17.91 100.1 -34.4 0.019 25.1 0.549 -164.8 29.7

0.5 0.886 -161.5 23.4 14.80 96.3 -34.2 0.020 24.6 0.551 -168.2 28.7

0.6 0.896 -165.7 21.8 12.37 92.7 -34.2 0.020 24.1 0.556 -170.9 27.9

0.7 0.897 -169.5 20.6 10.74 90.5 -33.6 0.021 24.7 0.557 -173.5 27.1

0.8 0.898 -172.2 19.5 9.39 88.1 -33.5 0.021 24.4 0.559 -175.2 26.5

0.9 0.896 -174.9 18.6 8.47 85.9 -33.3 0.022 26.5 0.559 -176.9 25.9

10.896 -176.7 17.6 7.61 84.0 -32.9 0.023 26.3 0.560 -178.7 25.2

1.5 0.898 175.2 14.1 5.06 75.7 -32.1 0.025 29.9 0.558 176.0 23.1

20.887 168.0 11.8 3.91 68.1 -30.7 0.029 35.2 0.547 170.9 21.3

2.5 0.893 162.8 10.0 3.15 61.7 -29.5 0.034 35.8 0.545 166.9 18.9

30.886 156.9 8.4 2.63 55.1 -28.4 0.038 35.8 0.547 162.6 16.3

40.887 146.6 5.9 1.97 41.5 -26.7 0.046 33.2 0.554 154.3 13.6

50.894 136.8 3.9 1.57 29.4 -25.1 0.056 29.6 0.572 146.6 11.9

60.898 127.4 2.1 1.28 17.7 -23.9 0.064 25.5 0.590 139.0 10.3

70.896 119.7 0.7 1.09 6.3 -22.6 0.074 20.4 0.603 131.6 8.9

80.879 105.4 -0.9 0.90 -7.1 -21.1 0.088 12.4 0.594 122.7 6.6

90.888 95.0 -1.7 0.82 -19.3 -20.1 0.099 4.7 0.609 113.2 6.1

10 0.872 84.1 -2.9 0.72 -30.9 -19.2 0.110 -4.3 0.610 102.9 4.4

11 0.880 72.4 -3.8 0.65 -42.8 -18.6 0.118 -12.9 0.629 92.6 3.8

12 0.875 60.4 -4.8 0.58 -53.3 -18.0 0.126 -22.8 0.647 81.9 2.8

13 0.908 52.4 -6.2 0.49 -63.4 -17.7 0.130 -31.4 0.666 71.0 2.6

14 0.898 41.3 -7.1 0.44 -73.5 -17.2 0.138 -38.0 0.699 64.0 1.5

15 0.888 34.1 -8.2 0.39 -80.2 -16.8 0.144 -45.6 0.734 55.9 0.5

16 0.815 24.1 -8.9 0.36 -85.3 -16.2 0.156 -54.7 0.750 49.3 -1.7

17 0.725 11.3 -9.9 0.32 -90.9 -15.5 0.167 -66.0 0.809 43.5 -3.1

18 0.792 -9.8 -10.2 0.31 -95.1 -16.6 0.147 -84.8 0.652 39.7 -4.2

Notes:

1. Fmin values at 2 GHz and higher are based on measurements while the Fmins below 2 GHz have been extrapolated. The Fmin values are based on a set of

16 noise figure measurements made at 16 different impedances using an ATN NP5 test system. From these measurements a true Fmin is calculated.

Refer to the noise parameter application section for more information.

2. S and noise parameters are measured on a microstrip line made on 0.025 inch thick alumina carrier. The input reference plane is at the end of the gate

lead. The output reference plane is at the end of the drain lead.

ATF-521P8 Typical Scattering Parameters, VDS = 3V, IDS = 200 mA

Freq. S11 S21 S12 S22

MSG/MAG

GHz Mag. Ang. dB Mag. Ang. dB Mag. Ang. Mag. Ang. dB

0.1 0.867 -94.6 33.7 48.20 132.4 -36.8 0.014 45.1 0.482 -132.4 35.4

0.2 0.894 -132.9 29.4 29.66 113.2 -34.9 0.018 28.5 0.601 -154.2 32.2

0.3 0.899 -148.2 26.5 21.06 104.4 -34.1 0.020 23.2 0.636 -163.8 30.2

0.4 0.896 -157.2 24.1 16.00 99.1 -34.0 0.020 23.7 0.647 -169.2 29.0

0.5 0.892 -162.8 22.4 13.20 95.6 -33.6 0.021 24.5 0.650 -171.9 28.0

0.6 0.910 -167.4 20.8 11.00 92.3 -33.2 0.022 22.9 0.655 -174.4 27.0

0.7 0.906 -170.8 19.6 9.51 90.2 -33.2 0.022 23.9 0.657 -176.7 26.4

0.8 0.902 -173.6 18.4 8.35 87.8 -33.0 0.022 24.6 0.658 -178.2 25.8

0.9 0.907 -175.2 17.5 7.51 86.3 -32.9 0.023 27.0 0.660 -179.5 25.1

10.902 -177.7 16.6 6.76 84.2 -32.5 0.024 26.9 0.659 178.6 24.5

1.5 0.900 174.2 13.1 4.50 76.4 -31.5 0.027 32.7 0.656 173.4 22.2

20.896 168.1 10.8 3.49 69.1 -29.9 0.032 32.9 0.647 167.9 20.4

2.5 0.896 162.3 9.0 2.82 63.0 -29.0 0.036 34.3 0.642 163.7 18.6

30.887 156.7 7.4 2.35 56.9 -27.7 0.041 35.0 0.643 159.2 15.6

40.890 145.7 4.9 1.76 43.8 -26.1 0.050 32.2 0.645 150.4 12.9

50.898 136.3 3.0 1.41 32.1 -24.5 0.059 28.3 0.659 142.1 11.3

60.896 127.4 1.3 1.16 21.6 -23.4 0.068 23.5 0.671 134.3 9.5

70.904 119.4 -0.2 0.98 10.3 -22.1 0.078 17.7 0.677 126.6 8.5

80.877 104.9 -1.6 0.83 -2.3 -20.7 0.092 9.0 0.651 117.0 5.9

90.883 94.8 -2.4 0.76 -13.0 -19.8 0.102 1.3 0.661 107.2 5.3

10 0.877 83.1 -3.5 0.67 -26.0 -18.9 0.113 -7.3 0.657 96.8 4.0

11 0.875 71.7 -4.4 0.60 -36.3 -18.3 0.121 -16.6 0.670 86.7 3.1

12 0.863 60.6 -5.4 0.54 -47.4 -17.8 0.128 -25.1 0.680 76.2 1.9

13 0.910 51.6 -6.5 0.47 -57.9 -17.6 0.132 -33.6 0.694 65.9 2.3

14 0.868 40.9 -7.5 0.42 -62.8 -17.2 0.138 -40.4 0.721 59.3 0.2

15 0.863 33.4 -8.1 0.39 -74.7 -16.8 0.144 -47.6 0.748 51.3 -0.2

16 0.835 25.2 -9.6 0.33 -78.2 -16.3 0.154 -56.8 0.758 44.9 -2.1

17 0.720 11.2 -9.5 0.33 -90.8 -15.8 0.161 -67.6 0.818 39.4 -2.6

18 0.780 -7.7 -11.6 0.26 -92.8 -17.0 0.142 -85.1 0.655 37.1 -5.7

Freq Fmin Γopt Γopt RnGa

GHz dB Mag. Ang. dB

0.5 0.66 0.22 147.00 2.9 20.0

1.0 0.72 0.30 160.00 2.6 18.3

2.0 0.87 0.42 -179.94 1.9 16.0

3.0 1.00 0.59 -163.63 1.6 13.7

4.0 1.32 0.63 -153.81 3.7 11.3

5.0 1.49 0.72 -135.10 10.0 9.9

6.0 1.59 0.74 -128.97 15.0 8.5

7.0 1.79 0.78 -117.68 25.1 7.6

8.0 1.96 0.70 -110.04 29.2 5.6

Typical Noise Parameters, VDS = 3V, IDS = 200 mA

Figure 44. MSG/MAG and |S

vs.

Frequency at 3V, 200 mA.

MAG

FREQUENCY (GHz)

MSG/MAG and

(dB)

02010515

40.0

30.0

20.0

10.0

0.0

-10.0

-20.0

MSG

Notes:

1. Fmin values at 2 GHz and higher are based on measurements while the Fmins below 2 GHz have been extrapolated. The Fmin values are based on a set of

16 noise figure measurements made at 16 different impedances using an ATN NP5 test system. From these measurements a true Fmin is calculated.

Refer to the noise parameter application section for more information.

2. S and noise parameters are measured on a microstrip line made on 0.025 inch thick alumina carrier. The input reference plane is at the end of the gate

lead. The output reference plane is at the end of the drain lead.

ATF-521P8

Applications Information

Description

Agilent’s ATF-521P8 is an

enhancement mode PHEMT

designed for high linearity and

medium power applications.

With an OIP3 of 42 dBm and a

1dB compression point of

26 dBm, ATF-521P8 is well suited

as a base station transmit driver

or a first or second stage LNA in

a receive chain. Whether the

design is for a W-CDMA, CDMA,

or GSM basestation, this device

delivers good linearity in the

form of OIP3 or ACLR, which is

required for standards with high

peak to average ratios.

Application Guidelines

The ATF-521P8 device operates

as a normal FET requiring input

and output matching as well as

DC biasing. Unlike a depletion

mode transistor, this enhance-

ment mode device only requires a

single positive power supply,

which means a positive voltage is

placed on the drain and gate in

order for the transistor to turn

on. This application note walks

through the RF and DC design

employed in a single FET ampli-

fier. Included in this description

is an active feedback scheme to

accomplish this DC biasing.

RF Input & Output Matching

In order to achieve maximum

linearity, the appropriate input

(Γs) and output (ΓL) impedances

must be presented to the device.

Correctly matching from these

impedances to 50Ωs will result in

maximum linearity. Although

ATF-521P8 may be used in other

impedance systems, data col-

lected for this data sheet is all

referenced to a 50Ω system.

The input load pull parameter at

2 GHz is shown in Figure 1 along

with the optimum S11 conjugate

match.

16 dB

5 dB

9 dB

3 dB

S11

Return Loss

Figure 1. Input Match for ATF-521P8 at 2 GHz.

Thus, it should be obvious from

the illustration above that if this

device is matched for maximum

return loss i.e. S11*, then OIP3

will be sacrificed. Conversely, if

ATF-521P8 is matched for

maximum linearity, then return

loss will not be greater than

10 dB. For most applications, a

designer requires VSWR greater

than 2:1, hence limiting the input

match close to S11*. Normally,

the input return loss of a single

ended amplifier is not critical as

most basestation LNA and driver

amplifiers are in a balanced

configuration with 90° (quadra-

ture) couplers.

Proceeding from the same

premise, the output match of this

device becomes much simpler.

As background information, it is

important to note that OIP3 is

largely dependant on the output

match and that output return

loss is also required to be greater

than 10 dB. So, Figure 2 shows

how both good output return loss

and good linearity could be

achieved simultaneously with the

same impedance point.

Of course, these points are valid

only at 2 GHz, and other frequen-

cies will follow the same design

rules but will have different

locations. Also, the location of

these points is largely due to the

manufacturing process and

partly due to IC layout, but in

either case beyond the scope of

this application note.

S22*

ΓL

Figure 2. Output Match at 2 GHz.

Once a designer has chosen the

proper input and output imped-

ance points, the next step is to

choose the correct topology to

accomplish this match. For

example to perform the above

output impedance transforma-

tion from 50Ω to the given load

parameter of 0.53∠-176°, two

possible solutions exist. The first

potential match is a high pass

configuration accomplished by a

shunt inductor and a series

capacitor shown in Figure 3

along with its frequency response

in Figure 4.

C1RFin RFout

Figure 3. High Pass Circuit Topology.

Amp

Frequency

Figure 4. High Pass Frequency Response.

The second solution is a low pass

configuration with a shunt

capacitor and a series inductor

shown in Figure 5 and 6.

L1RF

Figure 5. Low Pass Circuit Topology.

Amp

Frequency

Figure 6. Low Pass Frequency Response.

The actual values of these

components may be calculated by

hand on a Smith Chart or more

accurately done on simulation

software such as ADS. There are

some advantages and disadvan-

tages of choosing a high pass

versus a low pass. For instance, a

high pass circuit cuts off low

frequency gain, which narrows

the usable bandwidth of the

amplifier, but consequently helps

avoid potential low frequency

instability problems. A low pass

match offers a much broader

frequency response, but it has

two major disadvantages. First it

has the potential for low fre-

quency instability, and second it

creates the need for an extra DC

blocking capacitor on the input

in order to isolate the device gate

from the preceding stages.

Figure 7 displays the input and

output matching selected for

ATF-521P8. In this example the

input and output match both

essentially function as high pass

filters, but the high frequency

gain of the device rolls off

precipitously giving a narrow

band frequency response, yet still

wide enough to accommodate a

CDMA or WCDMA transmit band.

For more information on RF

matching techniques refer to

MGA-53543 application note.

Passive Bias [1]

Once the RF matching has been

established, the next step is to

DC bias the device. A passive

biasing example is shown in

Figure 8. In this example the

voltage drop across resistor R3

sets the drain current (Id) and is

calculated by the following

equation:

R3 = Vdd – Vds (1)

Ids + Ibb

where,

Vdd is the power supply voltage;

Vds is the device drain to source

voltage;

Ids is the device drain to source

current;

Ibb for DC stability is 10X the

typical gate current;

A voltage divider network with

R1 and R2 establishes the typical

gate bias voltage (Vg).

R1 = Vg (2)

Ibb

R2 = (Vdd – Vg) x R1 (3)

Often the series resistor, R4, is

added to enhance the low fre-

quency stability. The complete

passive bias example may be

found in reference [1].

INPUT OUTPUT

C1 C4

Vdd

R1 R2

Figure 8. Passive Biasing.

++=

Input Match

Amp

Frequency

Amp

ATF-521P8

Frequency Frequency

Amp

Output Match

Total Response

Amp

Frequency

Zo 52

C1 C3

RFou

RFin

Figure 7. Input and Output Match for ATF-521P8 at 2 GHz.

Active Bias[2]

Due to very high DC power

dissipation and small package

constraints, it is recommended

that ATF-521P8 use active

biasing. The main advantage of

an active biasing scheme is the

ability to hold the drain to source

current constant over a wide

range of temperature variations.

A very inexpensive method of

accomplishing this is to use two

PNP bipolar transistors arranged

in a current mirror configuration

as shown in Figure 9. Due to

resistors R1 and R3, this circuit

is not acting as a true current

mirror, but if the voltage drop

across R1 and R3 is kept identi-

cal then it still displays some of

the more useful characteristics of

a current mirror. For example,

transistor Q1 is configured with

its base and collector tied

together. This acts as a simple PN

junction, which helps tempera-

ture compensate the Emitter-

Base junction of Q2.

To calculate the values of R1, R2,

R3, and R4 the following param-

eters must be know or chosen

first:

Ids is the device drain-to-source

current;

IR is the Reference current for

active bias;

Vdd is the power supply voltage

available;

Vds is the device drain-to-source

voltage;

Vg is the typical gate bias;

Vbe1 is the typical Base-Emitter

turn on voltage for Q1 & Q2;

Therefore, resistor R3, which sets

the desired device drain current,

is calculated as follows:

R3 = Vdd – Vds (4)

Ids + IC2

where,

IC2 is chosen for stability to be

10 times the typical gate current

and also equal to the reference

current IR.

The next three equations are

used to calculate the rest of the

biasing resistors for Figure 9.

Note that the voltage drop across

R1 must be set equal to the

voltage drop across R3, but with

a current of IR.

R1 = Vdd – Vds (5)

R2 sets the bias current through

Q1.

R2 = Vds – Vbe1 (6)

R4 sets the gate voltage for

ATF-521P8.

R4 = Vg (7)

IC2

Thus, by forcing the emitter

voltage (VE) of transistor Q1

equal to Vds, this circuit regulates

the drain current similar to a

current mirror. As long as Q2

operates in the forward active

mode, this holds true. In other

words, the Collector-Base junc-

tion of Q2 must be kept reversed

biased.

RFin RFou

L2 L3

R2 Q1 VE

VgVds

Vdd

ATF-521P8

2PL

Figure 9. Active Bias Circuit.

PCB Layout

A recommended PCB pad layout

for the Leadless Plastic Chip

Carrier (LPCC) package used by

the ATF-521P8 is shown in

Figure 10. This layout provides

plenty of plated through hole vias

for good thermal and RF ground-

ing. It also provides a good

transition from microstrip to the

device package. For more de-

tailed dimensions refer to

Section 9 of the data sheet.

Figure 10. Microstripline Layout.

RF Grounding

Unlike SOT packages, ATF-521P8

is housed in a leadless package

with the die mounted directly to

the lead frame or the belly of the

package shown in Figure 11.

Pin 8

Drain

Pin 6

Pin 5

Source

Gate

Pin 3

Source

Bottom View

Figure 11. LPCC Package for ATF-521P8.

This simplifies RF grounding by

reducing the amount of induc-

tance from the source to ground.

It is also recommended to ground

pins 1 and 4 since they are also

connected to the device source.

Pins 3, 5, 6, and 8 are not con-

nected, but may be used to

help dissipate heat from the

package or for better alignment

when soldering the device.

This three-layer board (Figure

12) contains a 10-mil layer and a

52-mil layer separated by a

ground plane. The first layer is

Getek RG200D material with

dielectric constant of 3.8. The

second layer is for mechanical

rigidity and consists of FR4 with

dielectric constant of 4.2.

High Linearity Tx Driver

The need for higher data rates

and increased voice capacity gave

rise to a new third generation

standard know as Wideband

CDMA or UMTS. This new

standard requires higher perfor-

mance from radio components

such as higher dynamic range

and better linearity. For example,

a WCDMA waveform has a very

high peak to average ratio which

forces amplifiers in a transmit

chain to have very good Adjacent

Channel Leakage power Ratio or

ACLR, or else operate in a

backed off mode. If the amplifier

is not backed off then the wave-

form is compressed and the

signal becomes very nonlinear.

This application example pre-

sents a highly linear transmit

drive for use in the 2.14GHz

frequency range. Using the RF

matching techniques described

earlier, ATF-521P8 is matched to

the following input and output

impedances:

Input

Match

Output

Match

2PL

50 Ohm

S11* = 0.89∠ -169 Γ

= 0.53∠ -176

50 Ohm

Figure 13. ATF-521P8 Matching.

Figure 12. ATF-521P8 demoboard.

J1 J2

BCV62B

C1 C8

short

As described previously the input

impedance must be matched to

S11* in order to guarantee return

loss greater than 10 dB. A high

pass network is chosen for this

match. The output is matched to

ΓL with another high pass

network. The next step is to

choose the proper DC biasing

conditions. From the data sheet,

ATF-521P8 produces good

linearity at a drain current of

200mA and a drain to source

voltage of 4.5V. Thus to construct

the active bias circuit described,

the following parameters are

given:

Ids = 200 mA

IR = 10 mA

Vdd = 5 V

Vds = 4.5V

Vg = 0.62 V

Vbe1 = 0.65V

Using equations 4, 5, 6, and 7, the

biasing resistor values are

calculated in column 2 of table 1,

and the actual values used are

listed in column 3.

Resistor Calculated Actual

R1 50Ω49.9Ω

R2 385Ω383Ω

R3 2.38Ω2.37Ω

R4 62Ω61.9Ω

Table 1. Resistors for Active Bias.

The entire circuit schematic for a

2.14 GHz Tx driver amplifier is

shown below in Figure 14.

Capacitors C4, C5, and C6 are

added as a low frequency bypass.

These terminate second order

harmonics and help improve

linearity. Resistors R5 and

R6 also help terminate low

frequencies, and can prevent

resonant frequencies between

the two bypass capacitors.

Performance of ATF-521P8 at

2140 MHz

ATF-521P8 delivers excellent

performance in the WCDMA

frequency band. With a drain-to-

source voltage of 4.5V and a

drain current of 200 mA, this

device has 16.5 dB of gain and

1.55 dB of noise figure as show in

Figure 15.

FREQUENCY (GHz)

GAIN and NF (dB)

1.6

2.61.8 2.2 2.42.0

Gain

Figure 15. Gain and Noise Figure vs. Frequency.

Input and output return loss are

both greater that 10 dB. Although

somewhat narrowband, the

response is adequate in the

frequency range of 2110 MHz to

2170 MHz for the WCDMA

downlink. If wider band response

is need, using a balanced configu-

ration improves return loss and

doubles OIP3.

FREQUENCY (GHz)

INPUT AND OUTPUT

RETURN LOSS (dB)

1.6

-5

-10

-15

2.61.8 2.2 2.42.0

S11

S22

Figure 16. Input and Output Return Loss vs.

Frequency.

Perhaps the most critical system

level specification for the

ATF-521P8 lies in its distortion-

less output power. Typically,

amplifiers are characterized for

linearity by measuring OIP3. This

is a two-tone harmonic measure-

ment using CW signals. But

because WCDMA is a modulated

waveform spread across

3.84 MHz, it is difficult to corre-

lated good OIP3 to good ACLR.

Thus, both are measured and

presented to avoid ambiguity.

Figure 14. 2140 MHz Schematic.

C1=1.2pF

RFin RFou

L4=3.9nH

L1=1.0nH

L2=12nH L3=39nH

R6=1.2Ω

R5=10Ω

R3=2.37Ω

R4=61.9Ω

C4=1µF

C3=4.7pF

C8=1.5pF

C7=150pF

C5=1µF

C6=.1µF

IC2

C2=1.5nH

R1=49.9Ω

R2=383Ω

be1+

+5V

ATF-521P8

2PL

FREQUENCY (MHz)

OIP3 (dBm)

2060

22002080 2120 2140

2100 2160 2180

Figure 17. OIP3 vs. Frequency in WCDMA Band

(Pout = 12 dBm).

Pout (dBm)

ACLR (dB)

-3

-30

-35

-40

-45

-50

-55

-60

-65

22212177

Figure 18. ACLR vs. Pout at 5 MHz Offset.

C1=1.2 pF Phycomp 0402CG129C9B200

C2,C8=1.5 pF Phycomp 0402CG159C9B200

C3=4.7 pF Phycomp 0402CG479C9B200

C4,C6=.1 µF Phycomp 06032F104M8B200

C5=1 µF AVX 0805ZC105KATZA

C7=150 pF Phycomp 0402CG151J9B200

L1=1.0 nH TOKO LL1005-FH1n0S

L2=12 nH TOKO LL1005-FS12N

L3=39 nH TOKO LL1005-FS39

L4=3.9 nH TOKO LL1005-FH3N9S

R1=49.9ΩRohmRK73H1J49R9F

R2=383ΩRohm RK73H1J3830F

R3=2.37ΩRohm RK73H1J2R37F

R4=61.9ΩRohm RK73H1J61R9F

R5=10ΩRohm RK73H1J10R0F

R6=1.2ΩRohm RK73H1J1R21F

Q1, Q2 Philips BCV62C

J1, J2 142-0701-851

Table 2. 2140 MHz Bill of Material.

Using the 3GPP standards

document Release 1999 version

2002-6, the following channel

configuration was used to test

ACLR. This table contains the

power levels of the main chan-

nels used for Test Model 1. Note

that the DPCH can be made up of

16, 32, or 64 separate channels

each at different power levels

and timing offsets. For a listing

of power levels, channelization

codes and timing offset see the

entire 3GPP TS 25.141 V3.10.0

(2002-06) standards document

at: http://www.3gpp.org/specs/

specs.htm

3GPP TS 25.141 V3.10.0 (2002-06)

Type Pwr (dB)

P-CCPCH+SCH -10

Primary CPICH -10

PICH -18

S-CCPCH containing PCH -18

(SF=256)

DPCH-64ch -1.1

(SF=128)

Table 3. ACLR Channel Power Configuration.

Thermal Design

When working with medium to

high power FET devices, thermal

dissipation should be a large part

of the design. This is done to

ensure that for a given ambient

temperature the transistor’s

channel does not exceed the

maximum rating, TCH, on the

data sheet. For example,

ATF-521P8 has a maximum

channel temperature of 150°C

and a channel to board thermal

resistance of 45°C/W, thus the

entire thermal design hinges

from these key data points. The

question that must be answered

is whether this device can

operate in a typical environment

with ambient temperature

fluctuations from -25°C to 85°C.

From Figure 19, a very useful

equation is derived to calculate

the temperature of the channel

for a given ambient temperature.

These calculations are all incor-

porated into Agilent Technolo-

gies AppCAD.

ch-b

Tch

(channel)

Tb (board

or belly

of the part)

(

ambient

)

Ts (sink)

Pdiss = Vds x Ids

b-s

s-a

Figure 19. Equivalent Circuit for Thermal

Resistance.

Hence very similar to Ohms Law,

the temperature of the channel is

calculated with equation 8 below.

TCH = Pdiss (θch–b + θb–s + θs–a)

+ Tamb (8)

If no heat sink is used or heat

sinking is incorporated into the

PCB board then equation 8 may

be reduced to:

TCH = Pdiss (θch–b + θb–a ) + Tamb

(9)

where,

θb–a is the board to ambient

thermal resistance;

θch–b is the channel to board

thermal resistance.

The board to ambient thermal

resistance thus becomes very

important for this is the

designer’s major source of heat

control. To demonstrate the

influence of θb-a, thermal resis-

tance is measured for two very

different scenarios using the

ATF-521P8 demoboard. The first

case is done with just the

demoboard by itself. The second

case is the ATF demoboard

mounted on a chassis or metal

casing, and the results are given

below:

ATF Demoboard θb-a

PCB 1/8" Chassis 10.4°C/W

PCB no HeatSink 32.9°C/W

Table 4. Thermal resistance measurements.

Therefore calculating the tem-

perature of the channel for these

two scenarios gives a good

indication of what type of heat

sinking is needed.

Case 1: Chassis Mounted @ 85°C

Tch = P x (θch-b + θb-a) + Ta

=.9W x (45+10.4)°C/W +85°C

Tch = 135°C

Case 2: No Heatsink @ 85°C

Tch = P x (θch-b + θb-a) + Ta

=.9W x (45+32.9)°C/W + 85°C

Tch = 155°C

In other words, if the board is

mounted to a chassis, the chan-

nel temperature is guaranteed to

be 135°C safely below the 150°C

maximum. But on the other

hand, if no heat sinking is used

and the θb-a is above 27°C/W

(32.9°C/W in this case), then the

power must be derated enough to

lower the temperature below

150°C. This can be better under-

stood with Figure 20 below. Note

power is derated at 13 mW/°C

for the board with no heat sink

and no derating is required for

the chassis mounted board until

an ambient temperature of

100°C.

Pdiss

(W)

0.9W

0 81 100 150 Tamb

(

°C

)

No Heatsink

(13 mW/°C)

Mounted on Chassis

(18 mW/°C)

Figure 20. Derating for ATF- 521P8.

Thus, for reliable operation of

ATF-521P8 and extended MTBF,

it is recommended to use some

form of thermal heatsinking. This

may include any or all of the

following suggestions:

•Maximize vias underneath and

around package;

•Maximize exposed surface

metal;

•Use 1 oz or greater copper clad;

•Minimize board thickness;

•Metal heat sinks or extrusions;

•Fans or forced air;

•Mount PCB to Chassis.

Summary

A high linearity Tx driver

amplifier for WCDMA has been

presented and designed using

Agilent’s ATF-521P8. This

includes RF, DC and good ther-

mal dissipation practices for

reliable lifetime operation. A

summary of the typical perfor-

mance for ATF-521P8 demoboard

at 2140 MHz is as follows:

Demo Board Results at 2140 MHz

Gain 16.5 dB

OIP3 41.2 dBm

ACLR -58 dBc

P1dB 24.8 dBm

NF 1.55 dB

References

[1] Ward, A. (2001) Agilent

ATF-54143 Low Noise Enhance-

ment Mode Pseudomorphic

HEMT in a Surface Mount

Plastic Package, 2001 [Internet],

Available from:

<http://www.agilent.com/view/rf>

[Accessed 22 August, 2002].

[2] Biasing Circuits and

Considerations for GaAs

MESFET Power Amplifiers, 2001

[Internet], Available from:

<http://www.rf-solutions.com/

pdf/AN-0002_ajp.pdf> [Accessed

22 August, 2002]

2x 2 LPCC (JEDEC DFP-N) Package Dimensions

Ordering Information

Part Number No. of Devices Container

ATF-521P8-TR1 3000 7” Reel

ATF-521P8-TR2 10000 13”Reel

ATF-521P8-BLK 100 antistatic bag

Device Models

Refer to Agilent’s Web Site

www.agilent.com/view/rf

pin1

DIMENSIONS ARE IN MILLIMETERS

DIMENSIONS

MIN.

0.70

0.225

1.9

0.65

1.9

1.45

NOM.

0.75

0.02

0.203 REF

0.25

2.0

0.80

2.0

1.6

0.50 BSC

MAX.

0.80

0.05

0.275

2.1

0.95

2.1

1.75

SYMBOL

pin1

2PX

Top View

End View

Bottom View

AA1

Device Orientation

PCB Land Pattern and Stencil Design

2.80 (110.24)

0.70 (27.56)

0.25 (9.84)

0.50 (19.68)

0.28 (10.83)

0.60 (23.62)

φ0.20 (7.87)

PIN 1

Solder

mask

transmission

line 0.80 (31.50)

0.15 (5.91)

0.55 (21.65)

1.60 (62.99)

2.72 (107.09)

0.63 (24.80)

0.22 (8.86)

0.32 (12.79)

0.50 (19.68)

0.25 (9.74)

0.63 (24.80)

Stencil Layout (top view)

PCB Land Pattern (top view)

0.72 (28.35)

PIN 1

1.54 (60.61)

USER

FEED

DIRECTION

COVER TAPE

CARRIER

TAPE

REEL

8 mm

4 mm

2PX2PX2PX2PX

Tape Dimensions

10° Max

DESCRIPTION SYMBOL SIZE (mm) SIZE (inches)

LENGTH

WIDTH

DEPTH

PITCH

BOTTOM HOLE DIAMETER

2.30 ± 0.05

1.00 ± 0.05

4.00 ± 0.10

1.00 + 0.25

0.091 ± 0.004

0.039 ± 0.002

0.157 ± 0.004

0.039 + 0.002

CAVITY

DIAMETER

PITCH

POSITION

1.50 ± 0.10

4.00 ± 0.10

1.75 ± 0.10

0.060 ± 0.004

0.157 ± 0.004

0.069 ± 0.004

PERFORATION

WIDTH

THICKNESS

8.00 + 0.30

0.254 ± 0.02

0.315 ± 0.012

8.00 – 0.10 0.315 ± 0.004

0.010 ± 0.0008

CARRIER TAPE

CAVITY TO PERFORATION

(WIDTH DIRECTION)

CAVITY TO PERFORATION

(LENGTH DIRECTION)

3.50 ± 0.05

2.00 ± 0.05

0.138 ± 0.002

0.079 ± 0.002

DISTANCE

WIDTH

TAPE THICKNESS

5.4 ± 0.10

0.062 ± 0.001

0.205 ± 0.004

0.0025 ± 0.0004

COVER TAPE

10° Max

www.agilent.com/semiconductors

For product information and a complete list of

distributors, please go to our web site.

For technical assistance call:

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Data subject to change.

Obsoletes 5988-8403

July 29, 2003

5988-9974EN