LT5528EUF_技术文档

LT5528

1.5GHz to 2.4GHz

High Linearity Direct

Quadrature Modulator

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DESCRIPTIO

FEATURES

■

Direct Conversion to 1.5GHz to 2.4GHz

The LT^®5528 is a direct I/Q modulator designed for high

performance wireless applications, including wireless

infrastructure. It allows direct modulation of an RF signal

using differential baseband I and Q signals. It supports

PHS, GSM, EDGE, TD-SCDMA, CDMA, CDMA2000,

W-CDMA and other systems. It may also be conﬁgured

as an image reject up-converting mixer, by applying

90° phase-shifted signals to the I and Q inputs. The I/Q

baseband inputs consist of voltage-to-current converters

that in turn drive double-balanced mixers. The outputs of

these mixers are summed and applied to an on-chip RF

transformer, which converts the differential mixer signals

to a 50Ω single-ended output. The four balanced I and Q

baseband input ports are intended for DC coupling from a

source with a common-mode voltage level of about 0.5V.

The LO path consists of an LO buffer with single-ended

input, and precision quadrature generators that produce

the LO drive for the mixers. The supply voltage range is

4.5V to 5.25V.

■

High OIP3: 21.8dBm at 2GHz

■

Low Output Noise Floor at 5MHz Offset:

No RF: –159.3dBm/Hz

P

= 4dBm: –151.8dBm/Hz

OUT

■

4-Ch W-CDMA ACPR: –66dBc at 2.14GHz

Integrated LO Buffer and LO Quadrature Phase

Generator

■

50Ω AC-Coupled Single-Ended LO and RF Ports

50Ω DC Interface to Baseband Inputs

Low Carrier Leakage: –42dBm at 2GHz

High Image Rejection: 45dB at 2GHz

16-Lead QFN 4mm × 4mm Package

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APPLICATIO S

■

Infrastructure Tx for DCS, PCS and UMTS Bands

■

Image Reject Up-Converters for PCS and UMTS

Bands

■

Low-Noise Variable Phase-Shifter for 1.5GHz to

, LTC and LT are registered trademarks of Linear Technology Corporation.

2.4GHz Local Oscillator Signals

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TYPICAL APPLICATIO

1.5GHz to 2.4GHz Direct Conversion Transmitter Application

with LO Feed-Through and Image Calibration Loop

W-CDMA ACPR, AltCPR and Noise vs RF Output

Power at 2140MHz for 1, 2 and 4 Channels

5V

V

CC 8, 13

–55

–60

–65

–70

–75

–80

–140

–145

–150

–155

–160

–165

DOWNLINK TEST MODEL 64 DPCH

LT5528

14

16

RF = 1.5GHz

TO 2.4GHz

I-DAC

V-I

I-CHANNEL

11

PA

0°

4-CH ACPR

2-CH ACPR

1

EN

90°

BALUN

2-CH AltCPR

1-CH AltCPR

4-CH NOISE

LO FEED-THROUGH CAL OUT

IMAGE CAL OUT

4-CH AltCPR

1-CH ACPR

Q-CHANNEL

V-I

7

5

Q-DAC

CAL

BASEBAND

DSP

3

VCO/SYNTHESIZER

2, 4, 6, 9, 10, 12, 15, 17

1-CH NOISE

–42 –38 –34 –30 –26 –22 –18 –14

RF OUTPUT POWER PER CARRIER (dBm)

ADC

5528 TA01a

5528 TA01b

5528f

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LT5528

W W U W

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W

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ABSOLUTE AXI U RATI GS

PACKAGE/ORDER I FOR ATIO

(Note 1)

TOP VIEW

ORDER PART

NUMBER

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

Common-Mode Level of BBPI, BBMI and

BBPQ, BBMQ .......................................................2.5V

Operating Ambient Temperature

16 15 14 13

EN

GND

LO

1

2

3

4

12 GND

11 RF

LT5528EUF

17

GND

10

9

(Note 2) ...............................................–40°C to 85°C

Storage Temperature Range.................. –65°C to 125°C

Voltage on Any Pin

GND

5

6

7

8

UF PART

MARKING

Not to Exceed......................–500mV to V + 500mV

CC

UF PACKAGE

16-LEAD (4mm × 4mm) PLASTIC QFN

= 125°C, θ = 37°C/W

5528A

T

JMAX

JA

EXPOSED PAD IS GROUND (PIN 17)

MUST BE SOLDERED TO PCB.

Consult LTC Marketing for parts speciﬁed with wider operating temperature ranges.

ELECTRICAL CHARACTERISTICS

V_CC= 5V, EN = High, T_A= 25°C, f_LO= 2GHz, f_RF= 2.002GHz, P_LO= 0dBm.

BBPI, BBMI, BBPQ, BBMQ inputs 0.525V_DC, Baseband Input Frequency = 2MHz, I&Q 90° shifted (upper sideband selection).

P_{RF, OUT}= –10dBm, unless otherwise noted. (Note 3)

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

RF Output (RF)

f

RF

RF Frequency Range

–3dB Bandwidth

–1dB Bandwidth

1.5 to 2.4

1.7 to 2.2

GHz

S

RF Output Return Loss

RF Output Noise Floor

EN = High (Note 6)

EN = Low (Note 6)

–15

–12

dB

22, ON

22, OFF

NFloor

No Input Signal (Note 8)

–159.3

–151.8

dBm/Hz

P

= 4dBm (Note 9)

= 4dBm (Note 10)

OUT

G

Conversion Power Gain

Conversion Voltage Gain

Absolute Output Power

3 • LO Conversion Gain Difference

Output 1dB Compression

Output 2nd Order Intercept

Output 3rd Order Intercept

Image Rejection

P

/P

OUT IN, I&Q

–6.5

–6

dB

P

20 • Log (V

/V

)

V

OUT, 50Ω IN, DIFF, I or Q

P

OUT

1V

CW Signal, I and Q

–2.1

–28

7.9

dBm

dB

P-P DIFF

G

(Note 17)

(Note 7)

3LO vs LO

OP1dB

OIP2

OIP3

IR

dBm

dBc

(Notes 13, 14)

(Notes 13, 15)

(Note 16)

49

21.8

–45

LOFT

Carrier Leakage

(LO Feed-Through)

EN = High, P = 0dBm (Note 16)

–42

–57.8

dBm

LO

EN = Low, P = 0dBm (Note 16)

LO

LO Input (LO)

f

LO Frequency Range

1.5 to 2.4

0

GHz

dBm

dB

LO

P

S

LO Input Power

–10

5

LO

LO Input Return Loss

EN = High (Note 6)

EN = Low (Note 6)

(Note 5) at 2GHz

–17

11, ON

11, OFF

LO Input Return Loss

–5.5

14.4

20.4

–10

dB

NF

LO Input Referred Noise Figure

LO to RF Small Signal Gain

LO Input 3rd Order Intercept

dB

LO

G

dB

LO

IIP3

dBm

LO

5528f

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LT5528

ELECTRICAL CHARACTERISTICS

V_CC= 5V, EN = High, T_A= 25°C, f_LO= 2GHz, f_RF= 2.002GHz, P_LO= 0dBm.

BBPI, BBMI, BBPQ, BBMQ inputs 0.525V_DC, Baseband Input Frequency = 2MHz, I&Q 90° shifted (upper sideband selection).

P_{RF, OUT}= –10dBm, unless otherwise noted. (Note 3)

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Baseband Inputs (BBPI, BBMI, BBPQ, BBMQ)

BW

Baseband Bandwidth

–3dB Bandwidth

(Note 4)

400

0.525

45

MHz

V

BB

V

DC Common Mode Voltage

Single-Ended Input Resistance

Carrier Feed-Through on BB

Input 1dB Compression Point

I/Q Absolute Gain Imbalance

I/Q Absolute Phase Imbalance

CMBB

R

IN, SE

(Note 4)

Ω

P

= 0 (Note 4)

OUT

–40

3.2

dBm

LO2BB

IP1dB

Differential Peak-to-Peak (Note 7)

V

P-P, DIFF

ΔG

0.05

0.5

dB

I/Q

Δϕ

Deg

Power Supply (V

)

CC

V

Supply Voltage

4.5

1.0

5

5.25

145

50

V

mA

µA

µs

CC

I

t

Supply Current

EN = High

125

0.05

0.25

1.3

CC, ON

CC, OFF

ON

Supply Current, Sleep Mode

Turn-On Time

EN = 0V

EN = Low to High (Note 11)

EN = High to Low (Note 12)

Turn-Off Time

µs

OFF

Enable (EN), Low = Off, High = On

Enable

Input High Voltage

Input High Current

EN = High

EN = 5V

V

µA

240

Sleep

Input Low Voltage

EN = Low

0.5

V

Note 1: Absolute Maximum Ratings are those values beyond which the life

of a device may be impaired.

Note 10: At 5MHz offset from the CW signal frequency.

Note 11: RF power is within 10% of ﬁnal value.

Note 2: Speciﬁcations over the –40°C to 85°C temperature range are

assured by design, characterization and correlation with statistical process

controls.

Note 3: Tests are performed as shown in the conﬁguration of Figure 7.

Note 4: On each of the four baseband inputs BBPI, BBMI, BBPQ and

Note 12: RF power is at least 30dB lower than in the ON state.

Note 13: Baseband is driven by 2MHz and 2.1MHz tones. Drive level is set

in such a way that the two resulting RF tones are –10dBm each.

Note 14: IM2 measured at LO frequency + 4.1MHz.

Note 15: IM3 measured at LO frequency + 1.9MHz and LO frequency +

2.2MHz.

Note 16: Amplitude average of the characterization data set without image

or LO feed-through nulling (unadjusted).

BBMQ.

Note 5: V(BBPI) – V(BBMI) = 1V , V(BBPQ) – V(BBMQ) = 1V

.

DC

Note 6: Maximum value within –1dB bandwidth.

Note 7: An external coupling capacitor is used in the RF output line.

Note 8: At 20MHz offset from the LO signal frequency.

Note 9: At 20MHz offset from the CW signal frequency.

Note 17: The difference in conversion gain between the spurious signal at

f = 3 • LO – BB versus the conversion gain at the desired signal at f = LO +

BB for BB = 2MHz and LO = 2GHz.

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LT5528

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V_CC= 5V, EN = High, T_A= 25°C, f_LO= 2.14GHz, P_LO

TYPICAL PERFOR A CE CHARACTERISTICS

= 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.525V_DC, Baseband Input Frequency f_BB= 2MHz, I&Q 90° shifted. f_RF= f_BB+ f_LO(upper

sideband selection). P_{RF, OUT}= –10dBm (–10dBm/tone for 2-tone measurements), unless otherwise noted. (Note 3)

Gain and Output 1dB

Gain and Output 1dB Compression

vs LO Frequency and Temperature

Compression vs LO Frequency

and Supply Voltage

Supply Current vs Supply Voltage

140

130

120

110

100

10

5

10

5

85°C

OP1dB

25°C

0

–5

–40°C

–10

–15

–20

–10

–15

–20

GAIN

–40°C

25°C

85°C

4.5V

5V

5.5V

4.5

5.0

5.5

1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7

SUPPLY VOLTAGE (V)

LO FREQUENCY (GHz)

5528 G01

5528 G02

5528 G03

Output IP3 and Noise Floor vs

LO Frequency and Temperature

LO Frequency and Supply Voltage

Output IP2 vs LO Frequency

26

24

22

20

18

16

14

12

10

8

–142

26

24

22

20

18

16

14

12

10

8

–142

65

60

55

50

45

40

35

–40°C

4.5V

25°C –144

85°C

5V –144

5.5V

–146

–148

–150

–152

–154

–156

–158

–160

–162

OIP3

= 2MHz

BB, 2

–148

–150

–152

–154

–156

–158

–160

–162

OIP3

= 2MHz

BB, 2

f

BB, 1

f

BB, 1

f

= 2.1MHz

f

= 2.1MHz

NOISE FLOOR

NO BASEBAND SIGNAL

20MHz OFFSET NOISE

NOISE FLOOR

NO BASEBAND SIGNAL

20MHz OFFSET NOISE

4.5V, 25°C

5V, –40°C

5V, 25°C

5V, 85°C

5.5V, 25°C

6

1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7

LO FREQUENCY (GHz)

5528 G04

5528 G05

f

= f

BB, 1

+ f

f

= 2.1MHz

IM2 BB,1 BB,2 LO

BB, 2

= 2MHz

5528 G06

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LT5528

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V_CC= 5V, EN = High, T_A= 25°C, f_LO= 2.14GHz, P_LO

= 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.525V_DC, Baseband Input Frequency f_BB= 2MHz, I&Q 90° shifted. f_RF= f_BB+ f_LO(upper

sideband selection). P_{RF, OUT}= –10dBm (–10dBm/tone for 2-tone measurements), unless otherwise noted. (Note 3)

TYPICAL PERFOR A CE CHARACTERISTICS

2 • LO Leakage to RF Output vs

2 • LO Frequency

3 • LO Leakage to RF Output vs

3 • LO Frequency

LO to RF Output Feed-Through vs

LO Frequency

–25

–30

–35

–40

–45

–50

–55

–30

–35

–40

–45

–50

–55

–60

–65

–70

–36

–38

–40

–42

–44

–46

–48

–50

–52

–54

4.5V, 25°C

5V, –40°C

5V, 25°C

5V, 85°C

5.5V, 25°C

4.5V, 25°C

5V, –40°C

5V, 25°C

5V, 85°C

5.5V, 25°C

4.5V, 25°C

5V, –40°C

5V, 25°C

5V, 85°C

5.5V, 25°C

2.6 3.0 3.4 3.8 4.2 4.6 5.0 5.4

3.9 4.5 5.1 5.7 6.3 6.9 7.5 8.1

1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7

2 • LO FREQUENCY (GHz)

3 • LO FREQUENCY (GHz)

LO FREQUENCY (GHz)

5528 G07

5528 G08

5528 G09

Absolute I/Q Gain Imbalance vs

LO Frequency

Absolute I/Q Phase Imbalance vs

LO Frequency

Image Rejection vs LO Frequency

–26

–28

–30

–32

–34

–36

–38

–40

–42

–44

–46

–48

0.3

0.2

0.1

0

5

4

3

2

1

0

4.5V, 25°C

5V, –40°C

5V, 25°C

5V, 85°C

5.5V, 25°C

4.5V, 25°C

5V, –40°C

5V, 25°C

5V, 85°C

5.5V, 25°C

4.5V, 25°C

5V, –40°C

5V, 25°C

5V, 85°C

5.5V, 25°C

1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7

LO FREQUENCY (GHz)

5528 G10

5528 G11

5528 G12

5528f

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LT5528

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V_CC= 5V, EN = High, T_A= 25°C, f_LO= 2.14GHz, P_LO

TYPICAL PERFOR A CE CHARACTERISTICS

= 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.525V_DC, Baseband Input Frequency f_BB= 2MHz, I&Q 90° shifted. f_RF= f_BB+ f_LO(upper

sideband selection). P_{RF, OUT}= –10dBm (–10dBm/tone for 2-tone measurements), unless otherwise noted. (Note 3)

RF Output Power, HD2 and HD3

at 2140MHz vs Baseband Voltage

and Temperature

Gain vs LO Power

Output IP3 vs LO Power

–4

–6

22

20

18

16

14

12

10

8

–10

–20

–30

–40

–50

–60

–70

10

RF

0

HD3

–8

–10

–20

–30

–40

–50

–10

–12

–14

–16

–18

–20

HD2

4.5V, 25°C

5V, –40°C

5V, 25°C

4.5V, 25°C

5V, –40°C

5V, 25°C

6

4

–40°C

25°C

85°C

5V, 85°C

2

5.5V, 25°C

0

–20 –16 –12 –8

–4

0

4

8

–20 –16 –12 –8

–4

0

4

8

0

1

2

3

4

5

LO POWER (dBm)

I AND Q BASEBAND VOLTAGE (V

)

P-P, DIFF

5528 G13

f

= 2MHz

= 2.1MHz

f

= 2MHz, 0°

BBQ

HD2 = MAX POWER AT f + 2 • f OR f – 2 • f

BB, 1

BB, 2

BBI

= 2MHz, 90°

5528 G14

LO BB LO

BB

HD3 = MAX POWER AT f + 3 • f OR f – 3 • f

LO

BB

LO

5528 G15

RF Output Power, HD2 and HD3

at 2140MHz vs Baseband Voltage

and Supply Voltage

LO Feed-Through and Image

Rejection at 2140MHz vs Baseband

Voltage and Temperature

–10

–20

–30

–40

–50

–60

–70

10

–25

–30

–35

–40

–45

–50

–40°C

25°C

RF

85°C

0

LOFT

HD3

–10

–20

–30

–40

–50

HD2

IR

4.5V

5V

5.5V

0

1

2

3

4

5

0

1

2

3

4

5

I AND Q BASEBAND VOLTAGE (V

)

I AND Q BASEBAND VOLTAGE (V

)

P-P, DIFF

f

= 2MHz, 0°

BBQ

HD2 = MAX POWER AT f + 2 • f OR f – 2 • f

f

= 2MHz, 0°

BBQ

BBI

= 2MHz, 90°

5528 G17

LO

BB

LO

BB

HD3 = MAX POWER AT f + 3 • f OR f – 3 • f

5528 G16

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LT5528

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V_CC= 5V, EN = High, T_A= 25°C, f_LO= 2.14GHz, P_LO

= 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.525V_DC, Baseband Input Frequency f_BB= 2MHz, I&Q 90° shifted. f_RF= f_BB+ f_LO(upper

sideband selection). P_{RF, OUT}= –10dBm (–10dBm/tone for 2-tone measurements), unless otherwise noted. (Note 3)

TYPICAL PERFOR A CE CHARACTERISTICS

LO Feed-Through and Image

Rejection at 2140MHz vs Baseband

Voltage and Supply Voltage

RF Output Power vs

LO and RF Port Return Loss vs

RF Frequency

RF Frequency at 1V_P-P

Differential Baseband Drive

–25

–30

–35

–40

–45

–50

0

–10

–20

–30

–40

–50

0

–2

4.5V

5V

LO PORT, EN = LOW

5.5V

LOFT

–4

–6

RF PORT,

LO PORT,

EN = HIGH

4.5V, 25°C

5V, –40°C

5V, 25°C

5V, 85°C

5.5V, 25°C

EN = HIGH,

P

= OFF

–8

LO

IR

RF PORT,

EN = HIGH,

= 0dBm

–10

–12

–14

RF PORT,

EN = LOW

P

LO

V

= 1V

P-P, DIFF

BBI

= 1V

BBQ

P-P, DIFF

0

1

2

3

4

5

1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7

I AND Q BASEBAND VOLTAGE (V

)

RF FREQUENCY (GHz)

P-P, DIFF

5528 G20

5528 G19

f

= 2MHz, 0°

BBQ

BBI

= 2MHz, 90°

5528 G18

U

PI FU CTIO S

EN(Pin1):EnableInput.WhentheENpinvoltageishigher BBPQ,BBMQ(Pins7,5):BasebandInputsfortheQ-chan-

than 1V, the IC is turned on. When the input voltage is less nel, each 45Ω input impedance. Internally biased at about

than 0.5V, the IC is turned off.

0.525V. Applied voltage must stay below 2.5V.

V (Pins 8, 13): Power Supply. Pins 8 and 13 are con-

CC

GND (Pins 2, 4, 6, 9, 10, 12, 15): Ground. Pins 6, 9, 15

and 17 (exposed pad) are connected to each other inter- nected to each other internally. It is recommended to use

nally. Pins 2 and 4 are connected to each other internally 0.1µF capacitors for decoupling to ground on each of

and function as the ground return for the LO signal. Pins these pins.

10 and 12 are connected to each other internally and

RF (Pin 11): RF Output. The RF output is an AC-coupled

function as the ground return for the on-chip RF balun.

single-ended output with approximately 50Ω output im-

For best RF performance, pins 2, 4, 6, 9, 10, 12, 15 and

pedance at RF frequencies. Externally applied DC voltage

the Exposed Pad 17 should be connected to the printed

should be within the range –0.5V to V + 0.5V in order

CC

circuit board ground plane.

to avoid turning on ESD protection diodes.

LO(Pin3):LOInput.TheLOinputisanAC-coupledsingle-

ended input with approximately 50Ω input impedance at

RF frequencies. Externally applied DC voltage should be

BBPI, BBMI (Pins 14, 16): Baseband Inputs for the

I-channel, each with 45Ω input impedance. These pins are

internally biased at about 0.525V. Applied voltage must

stay below 2.5V.

within the range –0.5V to V + 0.5V in order to avoid

CC

turning on ESD protection diodes.

Exposed Pad (Pin 17): Ground. This pin must be soldered

to the printed circuit board ground plane.

5528f

7

LT5528

W

BLOCK DIAGRA

V

CC

8

13

LT5528

BBPI 14

BBMI 16

V-I

11 RF

0°

90°

BALUN

BBPQ

BBMQ

7

5

1

EN

2

4

6

9

3

10

12

15

17

5528 BD

GND

LO

GND

U

W U U

APPLICATIO S I FOR ATIO

The LT5528 consists of I and Q input differential voltage-

to-current converters, I and Q up-conversion mixers, an

RF output balun, an LO quadrature phase generator and

LO buffers.

External I and Q baseband signals are applied to the dif-

ferential baseband input pins, BBPI, BBMI, and BBPQ,

BBMQ.Thesevoltagesignalsareconvertedtocurrentsand

translated to RF frequency by means of double-balanced

up-converting mixers. The mixer outputs are combined

in an RF output balun, which also transforms the output

impedance to 50Ω. The center frequency of the resulting

RF signal is equal to the LO signal frequency. The LO input

drives a phase shifter which splits the LO signal into in-

phaseandquadratureLOsignals.TheseLOsignalsarethen

applied to on-chip buffers which drive the up-conversion

mixers. Both the LO input and RF output are single-ended,

50Ω-matched and AC coupled.

LT5528

RF

= 5V

C

V

CC

BALUN

FROM

Q

LOMI

CM

LOPI

R1A

20Ω

R1B

23Ω

R2B

23Ω

R2A

20Ω

BBPI

R3

R4

12pF

Baseband Interface

V

REF

= 0.52V

BBMI

Thebasebandinputs(BBPI,BBMI),(BBPQ,BBMQ)present

a differential input impedance of about 90Ω. At each of the

fourbasebandinputs,aﬁrst-orderlow-passﬁlterusing20Ω

5528 F01

GND

Figure 1. Simpliﬁed Circuit Schematic of the LT5528

(Only I-Half is Drawn)

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LT5528

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APPLICATIO S I FOR ATIO

It is recommended that the part be driven differentially;

otherwise, the even-order distortion products will de-

grade the overall linearity severely. Typically, a DAC will

be the signal source for the LT5528. To prevent aliasing,

a ﬁlter should be placed between the DAC output and the

LT5528’sbasebandinputs.InFigure3,anexampleinterface

schematic shows a commonly used DAC output interface

and 12pF to ground is incorporated (see Figure 1), which

limits the baseband bandwidth to approximately 330MHz

(–1dB point). The common-mode voltage is about 0.52V

and is approximately constant over temperature.

Itisimportantthattheappliedcommon-modevoltagelevel

of the I and Q inputs is about 0.52V in order to properly

bias the LT5528. Some I/Q test generators allow setting

thecommon-modevoltageindependently.Inthiscase,the

common-mode voltage of those generators must be set

to 0.26V to match the LT5528 internal bias, because for

DC signals, there is no –6dB source-load voltage division

(see Figure 2).

th

followed by a passive 5 order ladder ﬁlter. The DAC in

this example sources a current from 0mA to 20mA. The

interface may be DC coupled. This allows adjustment of

the DAC’s differential output current to minimize the LO

feed-through. Optionally, transformer T1 can be inserted

to improve the current balance in the BBPI and BBMI pins.

Thiswillimprovethesecond-orderdistortionperformance

(OIP2).

50Ω

45Ω

0.26V

0.52V

DC

+

DC

0.52V

DC

The maximum single sideband CW RF output power at

2GHz using 20mA drive to both I and Q channels with the

conﬁguration shown in Figure 3 is about –2.5dBm. The

maximum CW output power can be increased by con-

necting resistors R5 and R6 to –5V instead of GND, and

changing their values to 550Ω. In that case, the maximum

singlesidebandCWRFoutputpowerat2GHzwillbeabout

2.3dBm. In addition, the ladder ﬁlter component values

require adjustment for a higher source impedance.

–

50Ω

GENERATOR

LT5528

5528 F02

Figure 2. DC Voltage Levels for a Generator Programmed at

0.26V_DCfor a 50Ω Load and the LT5528 as a Load

V

= 5V

CC

LT5528

LOPI

RF = –2.5dBm, MAX

BALUN

C

LOMI

CM

R1

R2

OPTIONAL

BBPI

0.5V

L1A

L2A

45Ω

T1

1:1

0mA TO 20mA

R5, 50Ω

C1

R6, 50Ω

R3

R4

DAC

C2

L1B

C3

L2B

V

REF

= 0.52V

GND

BBMI

0.5V

5528 F03

GND

Figure 3. LT5528 5^thOrder Filtered Baseband Interface with Common DAC (Only I-Channel is Shown)

5528f

9

LT5528

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APPLICATIO S I FOR ATIO

Table 1. LO Port Input Impedance vs Frequency for EN = High

LO Section

Frequency

MHz

Input Impedance

S

11

The internal LO input ampliﬁer performs single-ended to

differential conversion of the LO input signal. Figure 4

shows the equivalent circuit schematic of the LO input.

Ω

Mag

Angle

80

1000

1400

1600

1800

2000

2200

2400

2600

49.9 + j18.5

68.1 + j8.8

71.0 + j2.0

70.0 – j8.6

62.0 – j12.8

53.8 – j13.6

47.3 – j12.4

41.1 – j12.0

0.182

0.171

0.175

0.182

0.156

0.135

0.128

0.161

22

4.8

V

CC

–6.6

–40

–66

–95

–119

20pF

LO

INPUT

Z

IN

≈ 57Ω

5528 F04

If the part is in shut-down mode, the input impedance of

the LO port will be different. The LO input impedance for

EN = Low is given in Table 2.

Figure 4. Equivalent Circuit Schematic of the LO Input

The internal, differential LO signal is then split into in-

phase and quadrature (90° phase shifted) signals that

drive LO buffer sections. These buffers drive the double

balanced I and Q mixers. The phase relationship between

the LO input and the internal in-phase LO and quadrature

LO signals is ﬁxed, and is independent of start-up condi-

tions. The phase shifters are designed to deliver accurate

quadrature signals for an LO frequency near 2GHz. For

frequencies signiﬁcantly below 1.8GHz or above 2.4GHz,

the quadrature accuracy will diminish, causing the image

rejection to degrade. The LO pin input impedance is about

50Ω, and the recommended LO input power is 0dBm. For

lower LO input power, the gain, OIP2, OIP3 and dynamic-

Table 2. LO Port Input Impedance vs Frequency for EN = Low

Frequency

MHz

Input Impedance

S

11

Ω

Mag

Angle

67.8

1000

1400

1600

1800

2000

2200

2400

2600

46.6 + j47.6

136 + j44.5

157 – j24.5

114 – j70.6

70.7 – j72.1

45.3 – j59.0

31.2 – j45.2

22.8 – j34.2

0.443

0.507

0.526

0.533

0.528

0.527

0.543

13.8

–6.2

–24.6

–43.2

–62.8

–83.5

–103

RF Section

range will degrade, especially below –5dBm and at T =

A

85°C. For high LO input power (e.g. 5dBm), the LO feed-

through will increase with no improvement in linearity or

gain. Harmonics present on the LO signal can degrade the

imagerejectionbecausetheycanintroduceasmallexcess

phase shift in the internal phase splitter. For the second (at

4GHz) and third harmonics (at 6GHz) at –20dBc level, the

introduced signal at the image frequency is about –56dBc

or lower, corresponding to an excess phase shift much

below 1 degree. For the second and third harmonics at

–10dBc, the introduced signal at the image frequency is

about –47dBc. Higher harmonics than the third will have

less impact. The LO return loss typically will be better than

17dB over the 1.7GHz to 2.3GHz range. Table 1 shows the

LO port input impedance vs. frequency.

Afterup-conversion,theRFoutputsoftheIandQmixersare

combined. An on-chip balun performs internal differential

tosingle-endedoutputconversion,whiletransformingthe

output signal impedance to 50Ω. Table 3 shows the RF

port output impedance vs. frequency.

Table 3. RF Port Output Impedance vs Frequency for EN = High

and P_LO= 0dBm

Frequency

MHz

Output Impedance

S

22

Ω

Mag

Angle

158

113

87.6

63.2

127

174

163

155

1000

1400

1600

1800

2000

2200

2400

2600

23.1 + j7.9

34.4 + j20.7

45.8 + j22.3

54.5 + j12.4

48.7 + j1.7

39.1 + j1.0

32.9 + j4.4

29.7 + j7.4

0.382

0.298

0.231

0.125

0.022

0.123

0.213

0.269

5528f

10

LT5528

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APPLICATIO S I FOR ATIO

The RF output S with no LO power applied is given in coupling capacitor can be inserted in the RF output line.

22

Table 4.

This is strongly recommended during a 1dB compression

measurement.

Table 4. RF Port Output Impedance vs Frequency for EN = High

and No LO Power Applied

Enable Interface

Frequency

MHz

Output Impedance

S

22

Ω

Mag

Angle

157

112

93.6

123

159

154

147

142

Figure 6 shows a simpliﬁed schematic of the EN pin in-

terface. The voltage necessary to turn on the LT5528 is

1V. To disable (shut down) the chip, the Enable voltage

must be below 0.5V. If the EN pin is not connected, the

chip is disabled. This EN = Low condition is guaranteed

by the 75k on-chip pull-down resistor. It is important that

1000

1400

1600

1800

2000

2200

2400

2600

23.7 + j8.1

37.7 + j18.5

47.0 + j14.3

46.0 + j5.5

39.2 + j3.7

34.2 + j6.2

31.0 + j9.4

29.6 + j11.6

0.371

0.248

0.149

0.071

0.127

0.201

0.260

0.292

the voltage at the EN pin does not exceed V by more

CC

than 0.5V. If this should occur, the supply current could

be sourced through the EN pin ESD protection diodes,

which are not designed to carry the full supply current,

and damage may result.

For EN = Low the S is given in Table 5.

22

Table 5. RF Port Output Impedance vs Frequency for EN = Low

V

Frequency

MHz

Output Impedance

S

22

CC

Ω

Mag

Angle

158

1000

1400

1600

1800

2000

2200

2400

2600

22.8 + j7.7

32.4 + j20.8

42.4 + j25.1

54.6 + j20.1

55.3 + j6.0

44.7 + j0.0

36.0 + j1.9

31.3 + j4.8

0.386

0.321

0.274

0.193

0.076

0.056

0.164

0.237

EN

116

75k

25k

91.7

66.2

45.3

180

5528 F06

Figure 6. EN Pin Interface

171

162

Evaluation Board

Figure 7 shows the evaluation board schematic. A good

ground connection is required for the exposed pad. If this

is not done properly, the RF performance will degrade.

To improve S for lower frequencies, a shunt capacitor

22

can be added to the output. At higher frequencies, a shunt

inductorcanimprovetheS .Figure5showstheequivalent

22

circuit schematic of the RF output.

J1

J2

BBIM

BBIP

Note that an ESD diode is connected internally from

the RF output to ground. For strong output RF signal

levels (higher than 3dBm), this ESD diode can degrade

the linearity performance if the 50Ω termination imped-

ance is connected directly to ground. To prevent this, a

V

CC

C2

100nF

16

BBMI GND BBPI

EN

15

14

13

R1

100Ω

V

CC

1

2

3

4

12

GND

RF

V

CC

EN

J3

11

10

9

RF

OUT

GND

LO

J4

LO

IN

LT5528

GND

V

CC

17

BBMQ GND BBPQ

V

CC

20pF

5

6

7

8

RF

OUTPUT

C1

100nF

J5

3nH

21pF

52.5Ω

J6

BBQM

GND

BBQP

5528 F05

BOARD NUMBER: DC729A

5528 F07

Figure 5. Equivalent Circuit Schematic of the RF Output

Figure 7. Evaluation Circuit Schematic

5528f

11

LT5528

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APPLICATIO S I FOR ATIO

Additionally, theexposedpadprovidesheatsinkingforthe the results are described in an application note.

part and minimizes the possibility of the chip overheating.

R1 (optional) limits the Enable pin current in the event

IfimprovedLOandImagesuppressionarerequired, anLO

that the Enable pin is pulled high while the V inputs are

CC

feed-throughcalibrationandanImagesuppressioncalibra-

tion can be performed. The evaluation board schematic

of the calibration hardware, the calibration procedure and

low. In Figures 8, 9, 10 and 11, the silk screens and the

PCB board layout are shown.

Figure 8. Component Side Silk Screen of Evaluation Board

Figure 9. Component Side Layout of Evaluation Board

Figure 10. Bottom Side Silk Screen of Evaluation Board

Figure 11. Bottom Side Layout of Evaluation Board

5528f

12

LT5528

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APPLICATIO S I FOR ATIO

Application Measurements

Because of the LT5528’s very high dynamic-range, the

test equipment can limit the accuracy of the ACPR mea-

surement. Consult the factory for advice on the ACPR

measurement, if needed.

TheLT5528isrecommendedforbase-stationapplications

usingvariousmodulationformats. Figure12showsatypi-

cal application. The CAL box in Figure 12 allows for LO

feed-through and Image suppression calibration.

TheACPRperformanceissensitivetotheamplitudematch

of the BBIP and BBIM (or BBQP and BBQM) inputs. This

is because a difference in AC current amplitude will give

rise to a difference in amplitude between the even-order

harmonic products generated in the internal V-I converter.

As a result, they will not cancel out entirely. Therefore, it

is important to keep the currents in those pins exactly the

same (but of opposite sign). The current will enter the

LT5528’s common-base stage, and will ﬂow to the mixer

upper switches. This can be seen in Figure 1 where the

Figure13showstheACPRperformanceforW-CDMAusing

one,twoorfourchannelmodulation.Figures14,15and16

illustratethe1-, 2-and4-channelW-CDMAmeasurement.

To calculate ACPR, a correction is made for the spectrum

analyzer noise ﬂoor. If the output power is high, the ACPR

will be limited by the linearity performance of the part. If

the output power is low, the ACPR will be limited by the

noise performance of the part. In the middle, an optimum

ACPR is obtained.

5V

V

CC 8, 13

–55

–60

–65

–70

–75

–80

–140

–145

–150

–155

–160

–165

LT5528

14

16

RF = 1.5GHz

TO 2.4GHz

DOWNLINK TEST MODEL 64 DPCH

I-DAC

V-I

I-CHANNEL

11

PA

0°

1

EN

4-CH ACPR

2-CH ACPR

90°

BALUN

LO FEED-THROUGH CAL OUT

IMAGE CAL OUT

Q-CHANNEL

V-I

7

5

2-CH AltCPR

1-CH AltCPR

4-CH NOISE

4-CH AltCPR

1-CH ACPR

Q-DAC

CAL

BASEBAND

GENERATOR

3

VCO/SYNTHESIZER

2, 4, 6, 9, 10, 12, 15, 17

1-CH NOISE

–42 –38 –34 –30 –26 –22 –18 –14

RF OUTPUT POWER PER CARRIER (dBm)

ADC

5528 F12

5528 F13

Figure 12. 1.5GHz to 2.4GHz Direct Conversion Transmitter Application with

LO Feed-Through and Image Calibration Loop

Figure13:W-CDMAAPCR,AltCPRandNoise

vs RF Output Power at 2140MHz for 1, 2 and

4 Channels

–30

–40

–30

–40

DOWNLINK TEST

MODEL 64 DPCH

DOWNLINK TEST

MODEL 64

DPCH

DOWNLINK

TEST

–50

–60

MODEL 64

DPCH

–50

–60

–70

UNCOR-

CORRECTED

SPECTRUM

–70

–80

RECTED

UNCOR-

CORRECTED

SPECTRUM

CORRECTED

SPECTRUM

RECTED

UNCORRECTED

SPECTRUM

–80

–90

SPECTRUM

–90

–100

–110

–120

–130

–100

–110

–120

–100

–110

–120

SYSTEM

NOISE FLOOR

SYSTEM

NOISE FLOOR

SYSTEM

NOISE FLOOR

CORRECTED SPECTRUM

2125 2135 2145

RF FREQUENCY (MHz)

2127.5 2132.5 2137.5 2142.5 2147.5 2152.5

2125 2130 2135 2140 2145 2150 2155

2115

2155

2165

RF FREQUENCY (MHz)

5528 F14

5528 F15

5528 F16

Figure 14: 1-Channel W-CDMA Spectrum

Figure 15: 2-Channel W-CDMA Spectrum

Figure 16: 4-Channel W-CDMA Spectrum

5528f

13

LT5528

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APPLICATIO S I FOR ATIO

internal circuit of the LT5528 is drawn. For best results, secondary in combination with the required impedance

a high ohmic source is recommended; for example, the match.Thesecondarycentertapshouldnotbeconnected,

interface circuit drawn in Figure 3, modiﬁed by pulling which allows some voltage swing if there is a single-

resistors R5 and R6 to a –5V supply and adjusting their ended input impedance difference at the baseband pins.

values to 550Ω, with T1 omitted.

As a result, both currents will be equal. The disadvantage

is that there is no DC coupling, so the LO feed-through

calibration cannot be performed via the BB connections.

After calibration when the temperature changes, the LO

feed-through and the Image Rejection performance will

change.ThisisillustratedinFigure17.TheLOfeed-through

and Image Rejection can also change as a function of the

baseband drive level, as is depicted in Figure 18. The RF

output power, IM2 and IM3 vs a two-tone baseband drive

are given in Figure 19.

Another method to reduce current mismatch between

the currents ﬂowing in the BBIP and BBIM pins (or the

BBQP and BBQM pins) is to use a 1:1 transformer with

the two windings in the DC path (T1 in Figure 3). For DC,

the transformer forms a short, and for AC, the transformer

will reduce the common-mode current component, which

forcesthetwocurrentstobebettermatched. Alternatively,

atransformerwith1:2impedanceratiocanbeused, which

gives a convenient DC separation between primary and

–50

–20

–30

–40

–50

–60

–70

–80

–90

10

P

RF

–55

0

LO FEED-THROUGH

LOFT

IR

–60

–65

–10

–20

–30

–40

–50

–60

IMAGE REJECTION

–70

–75

–80

–40°C

25°C

85°C

CALIBRATED WITH P = –10dBm

RF

–85

–40

–20

0

20

40

60

80

0

1

2

3

4

5

TEMPERATURE (°C)

I AND Q BASEBAND VOLTAGE (V

)

P-P, DIFF

EN = HIGH

f

= 2.14GHz

EN = HIGH

f

= 2.14GHz

LO

V

= 5V

= f + f

RF BB LO

V

= 5V

f

= f + f

RF BB LO

CC

BBI

BBQ

CC

BBI

BBQ

f

= 2MHz, 0°

= 2MHz, 90°

P

= 0dBm

f

= 2MHz, 0°

= 2MHz, 90°

P

= 0dBm

LO

5528 F18

Figure 17: LO Feed-Through and Image Rejection vs Temperature

after Calibration at 25°C

Figure 18: LO Feed-Through and Image Rejection vs Baseband

Drive Voltage after Calibration at 25°C

10

0

P

RF

–10

–20

–30

–40

–50

–60

–70

–80

IM3

IM2

–40°C

25°C

85°C

–90

0.1

1

10

I AND Q BASEBAND VOLTAGE (V

EACH TONE)

P-P, DIFF

EN = HIGH

f

= 2.14GHz

LO

V

= 5V

= f + f

RF BB LO

CC

BBI

BBQ

f

= 2MHz, 2.1MHz, 0°

= 2MHz, 2.1MHz, 90°

P

= 0dBm

LO

IM2 = POWER AT f + 4.1MHz

LO

IM3 = MAX POWER AT f + 1.9MHz OR

LO

f

+ 2.2MHz

LO

5528 F19

Figure 19: RF Two-Tone Power, IM2 and IM3 at 2140MHz vs Baseband Voltage

5528f

14

LT5528

U

PACKAGE DESCRIPTIO

UF Package

16-Lead Plastic QFN (4mm × 4mm)

(Reference LTC DWG # 05-08-1692)

0.72 0.05

4.35 0.05

2.90 0.05

2.15 0.05

(4 SIDES)

PACKAGE OUTLINE

0.30 0.05

0.65 BSC

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

BOTTOM VIEW—EXPOSED PAD

0.75 0.05

R = 0.115

TYP

0.55 0.20

4.00 0.10

(4 SIDES)

15

16

PIN 1

TOP MARK

(NOTE 6)

1

2

2.15 0.10

(4-SIDES)

(UF) QFN 1103

0.30 0.05

0.65 BSC

0.200 REF

0.00 – 0.05

NOTE:

1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGGC)

2. DRAWING NOT TO SCALE

3. ALL DIMENSIONS ARE IN MILLIMETERS

4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE

5. EXPOSED PAD SHALL BE SOLDER PLATED

6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION

ON THE TOP AND BOTTOM OF PACKAGE

5528f

InformationfurnishedbyLinearTechnologyCorporationisbelievedtobeaccurateandreliable.However,

no responsibility is assumed for its use. Linear Technology Corporation makes no representation that

the interconnection of its circuits as described herein will not infringe on existing patent rights.

15

LT5528

RELATED PARTS

PART NUMBER

Infrastructure

LT5511

DESCRIPTION

COMMENTS

High Linearity Upconverting Mixer

RF Output to 3GHz, 17dBm IIP3, Integrated LO Buffer

DC to 3GHz, 17dBm IIP3, Integrated LO Buffer

LT5512

DC-3GHz High Signal Level Downconverting

Mixer

LT5514

LT5515

LT5516

Ultralow Distortion, IF Ampliﬁer/ADC Driver

with Digitally Controlled Gain

850MHz Bandwidth, 47dBm OIP3 at 100MHz, 10.5dB to 33dB Gain Control Range

1.5GHz to 2.5GHz Direct Conversion Quadrature 20dBm IIP3, Integrated LO Quadrature Generator

Demodulator

0.8GHz to 1.5GHz Direct Conversion Quadrature 21.5dBm IIP3, Integrated LO Quadrature Generator

Demodulator

LT5517

LT5519

40MHz to 900MHz Quadrature Demodulator

0.7GHz to 1.4GHz High Linearity Upconverting 17.1dBm IIP3 at 1GHz, Integrated RF Output Transformer with 50Ω Matching,

Mixer Single-Ended LO and RF Ports Operation

21dBm IIP3, Integrated LO Quadrature Generator

LT5520

LT5521

LT5522

LT5524

LT5526

1.3GHz to 2.3GHz High Linearity Upconverting 15.9dBm IIP3 at 1.9GHz, Integrated RF Output Transformer with 50Ω Matching,

Mixer

Single-Ended LO and RF Ports Operation

10MHz to 3700MHz High Linearity

Upconverting Mixer

24.2dBm IIP3 at 1.95GHz, NF = 12.5dB, 3.15V to 5.25V Supply, Single-Ended LO

Port Operation

600MHz to 2.7GHz High Signal Level

Downconverting Mixer

4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB, 50Ω Single-Ended RF

and LO Ports

Low Power, Low Distortion ADC Driver with

Digitally Programmable Gain

450MHz Bandwidth, 40dBm OIP3, 4.5dB to 27dB Gain Control

High Linearity, Low Power Downconverting

Mixer

3V to 5.3V Supply, 16.5dBm IIP3, 100kHz to 2GHz RF, NF = 11dB, I = 28mA,

S

–65dBm LO-RF Leakage

RF Power Detectors

LT5504

800MHz to 2.7GHz RF Measuring Receiver

80dB Dynamic Range, Temperature Compensated, 2.7V to 5.25V Supply

300MHz to 3GHz, Temperature Compensated, 2.7V to 6V Supply

LTC5505

RF Power Detectors with >40dB Dynamic

Range

LTC5507

LTC5508

LTC5509

LTC5530

LTC5531

LTC5532

LT5534

100kHz to 1000MHz RF Power Detector

300MHz to 7GHz RF Power Detector

300MHz to 3GHz RF Power Detector

100kHz to 1GHz, Temperature Compensated, 2.7V to 6V Supply

44dB Dynamic Range, Temperature Compensated, SC70 Package

36dB Dynamic Range, Low Power Consumption, SC70 Package

300MHz to 7GHz Precision RF Power Detector Precision V

Offset Control, Shutdown, Adjustable Gain

Offset Control, Shutdown, Adjustable Offset

Offset Control, Adjustable Gain and Offset

OUT

50MHz to 3GHz RF Power Detector with 60dB

Dynamic Range

1dB Output Variation over Temperature, 38ns Response Time

Low Voltage RF Building Blocks

LT5500

LT5502

LT5503

1.8GHz to 2.7GHz Receiver Front End

1.8V to 5.25V Supply, Dual-Gain LNA, Mixer, LO Buffer

400MHz Quadrature IF Demodulator with RSSI 1.8V to 5.25V Supply, 70MHz to 400MHz IF, 84dB Limiting Gain, 90dB RSSI Range

1.2GHz to 2.7GHz Direct IQ Modulator and

Upconverting Mixer

1.8V to 5.25V Supply, Four-Step RF Power Control, 120MHz Modulation Bandwidth

LT5506

LT5546

500MHz Quadrature Demodulator with VGA

1.8V to 5.25V Supply, 40MHz to 500MHz IF, –4dB to 57dB Linear Power Gain,

8.8MHz Baseband Bandwidth

500MHz Quadrature Demodulator with VGA and 17MHz Baseband Bandwidth, 40MHz to 500MHz IF, 1.8V to 5.25V Supply, –7dB to

17MHz Baseband Bandwidth

56dB Linear Power Gain

Wide Bandwidth ADCs

LTC1749

LTC1750

12-Bit, 80Msps

500MHz BW S/H, 71.8dB SNR

500MHz BW S/H, 75.5dB SNR

14-Bit, 80Msps

5528f

LT/TP 1104 1K • PRINTED IN USA

LinearTechnology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

16

●

(408) 432-1900 FAX: (408) 434-0507 www.linear.com


型号：	LT5528EUF
厂家：	Linear
描述：	1.5GHz to 2.4GHz High Linearity Direct Quadrature Modulator 1.5GHz至2.4GHz高线性度直接正交调制器射频微波
文件：	总16页 (文件大小：310K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LT5528EUF [Linear]

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