LT5572 1.5GHz to 2.5GHz High Linearity Direct Quadrature Modulator DESCRIPTIO U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Direct Conversion from Baseband to RF High Output: –2.5dB Conversion Gain High OIP3: +21.6dBm at 2GHz Low Output Noise Floor at 20MHz Offset: No RF: –158.6dBm/Hz POUT = 4dBm: –152.5dBm/Hz Low Carrier Leakage: –39.4dBm at 2GHz High Image Rejection: –41.2dBc at 2GHz 4-Channel W-CDMA ACPR: –67.7dBc at 2.14GHz Integrated LO Buffer and LO Quadrature Phase Generator 50Ω AC-Coupled Single-Ended LO and RF Ports High Impedance DC Interface to Baseband Inputs with 0.5V Common Mode Voltage 16-Lead QFN 4mm × 4mm Package U APPLICATIO S ■ ■ Infrastructure Tx for DCS, PCS and UMTS Bands Image Reject Up-Converters for DCS, PCS and UMTS Bands Low Noise Variable Phase Shifter for 1.5GHz to 2.5GHz Local Oscillator Signals , LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. U ■ The LT5572 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 high impedance 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. TYPICAL APPLICATIO W-CDMA ACPR, AltCPR and Noise vs RF Output Power at 2.14GHz for 1, 2 and 4 Channels Direct Conversion Transmitter Application V-I I-CH EN BASEBAND GENERATOR 0° 1 90° 7 Q-DAC 11 5 Q-CH BALUN V-I PA ACPR, AltCPR (dBc) 16 LT5572 DOWNLINK TEST MODEL 64 DPCH 4-CH ACPR 4-CH AltCPR –60 2-CH ACPR –135 –145 2-CH AltCPR –80 3 VCO/SYNTHESIZER 1-CH ACPR –70 –90 –30 1-CH AltCPR –155 2-CH NOISE 4-CH NOISE 5572 TA01a 2, 4, 6, 9, 10, 12, 15, 17 –125 1-CH NOISE –25 –15 –10 –5 –20 RF OUTPUT POWER PER CARRIER (dBm) NOISE FLOOR AT 30MHz OFFSET (dBm/Hz) VCC 14 I-DAC –50 5V 100nF ×2 RF = 1.5GHz TO 2.5GHz 8, 13 –165 5572 TA01b 5572f 1 LT5572 U W W W ABSOLUTE AXI U RATI GS U W U PACKAGE/ORDER I FOR ATIO (Note 1) Supply Voltage .........................................................5.5V Common Mode Level of BBPI, BBMI and BBPQ, BBMQ.....................................................0.6V Voltage on Any Pin Not to Exceed ........................–500mV to (VCC + 500mV) Operating Ambient Temperature Range (Note 2).................................................... –40°C to 85°C Storage Temperature Range................... –65°C to 125°C VCC BBPI GND BBMI TOP VIEW 16 15 14 13 EN 1 12 GND GND 2 11 RF 17 LO 3 10 GND GND 4 6 7 8 BBMQ GND BBPQ VCC 9 5 GND UF PACKAGE 16-LEAD (4mm × 4mm) PLASTIC QFN TJMAX = 125°C, θJA = 37°C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB ORDER PART NUMBER UF PART MARKING LT5572EUF 5572 Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS VCC = 5V, EN = High, TA = 25°C, fLO = 2GHz, fRF = 2002MHz, PLO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.5VDC, baseband input frequency = 2MHz, I and Q 90° shifted (upper sideband selection). PRF(OUT) = –10dBm, unless otherwise noted. (Note 3) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS RF Output (RF) fRF RF Frequency Range –3dB Bandwidth –1dB Bandwidth 1.5 to 2.5 1.7 to 2.15 GHz GHz S22(ON) RF Output Return Loss EN = High (Note 6) –13.5 dB S22(OFF) RF Output Return Loss EN = Low (Note 6) –12.5 dB NFloor RF Output Noise Floor No Input Signal (Note 8) POUT = 4dBm (Note 9) POUT = 4dBm (Note 10) –158.6 –152.5 –152.2 dBm/Hz dBm/Hz dBm/Hz GV Conversion Voltage Gain 20 • Log (VOUT(50Ω)/VIN(DIFF) I or Q) –2.5 dB POUT Output Power 1VPP(DIFF) CW Signal, I and Q 1.4 dBm G3LO VS LO 3 • LO Conversion Gain Difference (Note 17) –29.5 OP1dB Output 1dB Compression (Note 7) 9.3 dBm OIP2 Output 2nd Order Intercept (Notes 13, 14) 53.2 dBm OIP3 Output 3rd Order Intercept (Notes 13, 15) 21.6 dBm IR Image Rejection (Note 16) –41.2 dBc LOFT Carrier Leakage (LO Feedthrough) EN = High, PLO = 0dBm (Note 16) EN = Low, PLO = 0dBm (Note 16) –39.4 –58 dBm dBm dB 5572f 2 LT5572 ELECTRICAL CHARACTERISTICS VCC = 5V, EN = High, TA = 25°C, fLO = 2GHz, fRF = 2002MHz, PLO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.5VDC, baseband input frequency = 2MHz, I and Q 90° shifted (upper sideband selection). PRF(OUT) = –10dBm, unless otherwise noted. (Note 3) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS LO Input (LO) fLO LO Frequency Range 1.5 to 2.5 PLO LO Input Power S11(ON) LO Input Return Loss EN = High, PLO = 0dBm (Note 6) –15 dB S11(OFF) LO Input Return Loss EN = Low (Note 6) –5.3 dB NFLO LO Input Referred Noise Figure at 2GHz (Note 5) 14.5 dB GLO LO to RF Small-Signal Gain at 2GHz (Note 5) 25 dB IIP3LO LO Input 3rd Order Intercept at 2GHz (Note 5) –0.5 dBm MHz –10 0 GHz 5 dBm Baseband Inputs (BBPI, BBMI, BBPQ, BBMQ) BWBB Baseband Bandwidth –3dB Bandwidth 460 VCMBB DC Common Mode Voltage Externally Applied (Note 4) 0.5 RIN Differential Input Resistance IDC(IN) Baseband Static Input Current PLOBB 0.6 V 90 kΩ (Note 4) –20 µA Carrier Feedthrough to BB POUT = 0 (Note 4) –39 dBm IP1dB Input 1dB Compression Point Differential Peak-to-Peak (Notes 7, 18) 2.8 VP-P(DIFF) ΔGI/Q I/Q Absolute Gain Imbalance 0.07 dB ΔϕI/Q I/Q Absolute Phase Imbalance 0.9 Deg Power Supply (VCC) VCC Supply Voltage 4.5 5 5.25 V ICC(ON) Supply Current EN = High ICC(OFF) Supply Current, Sleep Mode EN = 0V 120 145 mA 50 µA tON Turn-On Time EN = Low to High (Note 11) 0.25 µs tOFF Turn-Off Time EN = High to Low (Note 12) 1.3 µs 230 µA Enable (EN), Low = Off, High = On Enable Sleep Input High Voltage EN = High Input High Current EN = 5V Input Low Voltage EN = Low Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. 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: At each of the four baseband inputs BBPI, BBMI, BBPQ and BBMQ. Note 5: VBBPI – VBBMI = 1VDC, VBBPQ – VBBMQ = 1VDC. 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 10: At 5MHz offset from the CW signal frequency. 1 V 0.5 V Note 11: RF power is within 10% of final value. 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 feedthrough nulling (unadjusted). Note 17: The difference in conversion gain between the spurious signal at f = 3 • LO – BB versus the conversion gain of the desired signal at f = LO + BB for BB = 2MHz and LO = 2GHz. Note 18: The input voltage corresponding to the output P1dB. 5572f 3 LT5572 U W TYPICAL PERFOR A CE CHARACTERISTICS VCC = 5V, EN = High, TA = 25°C, fLO = 2.14GHz, PLO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.5VDC, baseband input frequency fBB = 2MHz, I and Q 90° shifted, without image or LO feedthrough nulling. fRF = fBB + fLO (upper sideband selection). PRF(OUT) = –10dBm (–10dBm/tone for 2-tone measurements), unless otherwise noted. (Note 3) RF Output Power vs LO Frequency at 1VP-P Differential Baseband Drive Supply Current vs Supply Voltage RF OUTPUT POWER (dBm) SUPPLY CURRENT (mA) 85°C 130 25°C 120 –40°C 110 0 2 –2 0 –2 –4 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C –6 100 4.5 5 –8 1.3 5.5 1.5 SUPPLY VOLTAGE (V) 2.3 1.7 1.9 2.1 LO FREQUENCY (GHz) fBB1 = 2MHz fBB2 = 2.1MHz 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C 2.5 –12 1.3 2.7 1.5 2.3 1.7 1.9 2.1 LO FREQUENCY (GHz) 2.5 2.7 5572 G03 Output 1dB Compression vs LO Frequency 12 fIM2 = fBB1 + fBB2 + fLO fBB1 = 2MHz fBB2 = 2.1MHz 10 OIP2 (dBm) 18 16 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C 14 12 10 1.3 1.5 1.7 1.9 2.1 2.3 LO FREQUENCY (GHz) OP1dB (dBm) 60 20 OIP3 (dBm) –8 Output IP2 vs LO Frequency 65 22 55 2.5 45 2.7 1.3 1.5 1.7 1.9 2.1 2.3 LO FREQUENCY (GHz) 2.5 –50 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C 1.5 1.7 1.9 2.1 2.3 LO FREQUENCY (GHz) –30 –25 –35 –30 –40 –35 –40 –45 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C –55 2.7 5572 G07 2.3 1.7 1.9 2.1 LO FREQUENCY (GHz) 2.5 –60 2.6 3 3.4 3.8 4.2 4.6 2 • LO FREQUENCY (GHz) 2.7 5572 G06 –20 –50 2.5 1.5 3 • LO Leakage to RF Output vs 3 • LO Frequency P(3 • LO) (dBm) P(2 • LO) (dBm) –45 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C 5572 G05 –40 1.3 0 1.3 2.7 2 • LO Leakage to RF Output vs 2 • LO Frequency –35 –60 6 2 5572 G04 –55 8 4 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C 50 LO Feedthrough to RF Output vs LO Frequency LO FEEDTHROUGH (dBm) –6 5572 G02 Output IP3 vs LO Frequency 24 –4 –10 5572 G01 26 Voltage Gain vs LO Frequency 4 VOLTAGE GAIN (dB) 140 –45 –50 –55 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C –60 –65 5 5.4 5572 G08 –70 3.9 4.5 5.1 5.7 6.3 6.9 7.5 3 • LO FREQUENCY (GHz) 8.1 5572 G09 5572f 4 LT5572 U W TYPICAL PERFOR A CE CHARACTERISTICS VCC = 5V, EN = High, TA = 25°C, fLO = 2.14GHz, PLO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.5VDC, baseband input frequency fBB = 2MHz, I and Q 90° shifted, without image or LO feedthrough nulling. fRF = fBB + fLO (upper sideband selection). PRF(OUT) = –10dBm (–10dBm/tone for 2-tone measurements), unless otherwise noted. (Note 3) Noise Floor vs RF Frequency –156 LO PORT, EN = LOW –30 –160 –162 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C –164 –166 1.3 1.5 –35 –40 –45 –50 1.7 1.9 2.1 2.3 RF FREQUENCY (GHz) –55 1.3 2.7 2.5 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C 1.5 1.7 1.9 2.1 2.3 LO FREQUENCY (GHz) 2.5 1.3 2 4 –20 –16 –12 –8 –4 0 LO INPUT POWER (dBm) 4 1.5 1.7 1.9 2.1 2.3 LO FREQUENCY (GHz) 2.5 –18 –20 –16 2.7 5572 G16 –12 –4 0 –8 LO INPUT POWER (dBm) 4 Image Rejection vs LO Power –25 –35 –30 –40 –45 –50 –60 –20 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C –16 –4 0 –12 –8 LO INPUT POWER (dBm) 8 5572 G15 –30 –55 8 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C –16 IMAGE REJECTION (dBc) LO FEEDTHROUGH (dBm) 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C 6 –12 LO Feedthrough vs LO Power fBB1 = 2MHz fBB2 = 2.1MHz 8 –10 5572 G14 20 10 –8 –14 1 1.3 22 2.7 –6 3 Output IP3 vs LO Power 14 2.5 –4 5572 G13 16 1.7 1.8 2.1 2.3 RF FREQUENCY (GHz) Voltage Gain vs LO Power 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C 4 2.7 18 RF PORT, EN = HIGH, PLO = 0dBm –2 0 0 2.5 1.5 RF PORT, EN = LO 5572 G12 VOLTAGE GAIN (dB) ABSOLUTE I/Q PHASE IMBALANCE (DEG) ABSOLUTE I/Q GAIN IMBALANCE (dB) 0.1 12 RF PORT, EN = HIGH, NO LO Absolute I/Q Phase Imbalance vs LO Frequency 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C 1.7 1.9 2.1 2.3 LO FREQUENCY (GHz) –30 –50 2.7 5 1.5 LO PORT, EN = HIGH, PLO = –10dBm 5572 G11 Absolute I/Q Gain Imbalance vs LO Frequency 1.3 –20 –40 5572 G10 0.2 LO PORT, EN = HIGH, PLO = 0dBm –10 S11 (dB) IMAGE REJECTION (dBc) NOISE FLOOR (dBm/Hz) 0 –25 fLO = 2GHz (FIXED) –158 OIP3 (dBm) LO and RF Port Return Loss vs RF Frequency Image Rejection vs LO Frequency 4 –35 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C –40 –45 –50 8 5572 G17 –55 –20 –16 –4 0 –12 –8 LO INPUT POWER (dBm) 4 8 5572 G18 5572f 5 LT5572 U W TYPICAL PERFOR A CE CHARACTERISTICS VCC = 5V, EN = High, TA = 25°C, fLO = 2.14GHz, PLO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.5VDC, baseband input frequency fBB = 2MHz, I and Q 90° shifted, without image or LO feedthrough nulling. fRF = fBB + fLO (upper sideband selection). PRF(OUT) = –10dBm (–10dBm/tone for 2-tone measurements), unless otherwise noted. (Note 3) RF CW Output Power, HD2 and HD3 vs CW Baseband and Supply Voltage RF CW Output Power, HD2 and HD3 vs CW Baseband Voltage and Temperature RF –60 –70 –80 1 0 –20 25°C –30 85°C –40°C –40 HD2 = MAX POWER AT fLO + 2 • fBB OR fLO – 2 • fBB –50 HD3 = MAX POWER AT fLO + 3 • fBB OR fLO – 3 • fBB –60 2 3 5 4 –10 –30 HD2 –40 –50 –60 –70 –80 1 0 5572 G19 5572 G20 Image Rejection vs CW Baseband Voltage RF 2-Tone Power (Each Tone), IM2 and IM3 vs Baseband Voltage and Temperature –35 10 PLOAD (dBm) IM2, IM3 (dBc) –40 –45 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C –50 0 IM2 –50 1 3 4 5 2 I AND Q BASEBAND VOLTAGE (VP-P,DIFF) IM3 –20 IM2 = POWER AT fLO + 4.1MHz –30 IM3 = MAX POWER AT fLO + 1.9MHz –40 OR fLO + 2.2MHz IM2 –50 –70 0.1 1 10 I AND Q BASEBAND VOLTAGE (VP-P,DIFF, EACH TONE) RF 5V 5.5V 4.5V –10 –60 fBBI = 2MHz, 2.1MHz, 0° fBBQ = 2MHz, 2.1MHz, 90° fBBI = 2MHz, 2.1MHz, 0° fBBQ = 2MHz, 2.1MHz, 90° 1 10 0.1 I AND Q BASEBAND VOLTAGE (VP-P,DIFF, EACH TONE) 5572 G24 5572 G23 Noise Floor Distribution 40 fLO = 2GHz –40°C 25°C 85°C 30 fLO = 2GHz fNOISE = 2.02GHz 25 35 25 PERCENTAGE (%) PERCENTAGE (%) –40°C 25°C 85°C 0 5572 G21 IM3 Voltage Gain Distribution 30 –55 0 –20 IM2 = POWER AT fLO + 4.1MHz –30 IM3 = MAX POWER AT fLO + 1.9MHz –40 OR fLO + 2.2MHz –70 5V, –40°C 5V, 25°C 5V, 85°C 4.5V, 25°C 5.5V, 25°C 10 5572 G22 35 –45 RF 2-Tone Power (Each Tone), IM2 and IM3 vs Baseband and Supply Voltage –10 –60 1 3 4 5 2 I AND Q BASEBAND VOLTAGE (VP-P,DIFF) –40 –50 RF 25°C 85°C –40°C 0 IMAGE REJECTION (dBc) –30 5V 5.5V 4.5V –40 HD2 = MAX POWER AT fLO + 2 • fBB OR fLO – 2 • fBB –50 HD3 = MAX POWER AT fLO + 3 • fBB OR fLO – 3 • fBB –60 2 3 5 4 –35 I AND Q BASEBAND VOLTAGE (VP-P,DIFF) I AND Q BASEBAND VOLTAGE (VP-P,DIFF) –55 –20 PLOAD (dBm) IM2, IM3 (dBc) HD2, HD3 (dBc) HD2 –40 HD3 HD2, HD3 (dBc) –10 –30 0 –20 RF CW OUTPUT POWER (dBm) HD3 RF CW OUTPUT POWER (dBm) 0 –20 LO FEEDTHROUGH (dBm) RF –50 –30 10 –10 10 –10 LO Feedthrough to RF Output vs CW Baseband Voltage 20 15 10 20 15 10 5 5 0 0 –3.2 –2.8 –2.4 –2.0 –1.6 VOLTAGE GAIN (dB) –1.2 5572 G25 –159.4 –159 –158.6 –158.2 –157.8 5572 G26 NOISE FLOOR (dBm/Hz) 5572f 6 LT5572 U W TYPICAL PERFOR A CE CHARACTERISTICS VCC = 5V, EN = High, TA = 25°C, fLO = 2.14GHz, PLO = 0dBm. BBPI, BBMI, BBPQ, BBMQ inputs 0.5VDC, baseband input frequency fBB = 2MHz, I and Q 90° shifted, without image or LO feedthrough nulling. fRF = fBB + fLO (upper sideband selection). PRF(OUT) = –10dBm (–10dBm/tone for 2-tone measurements), unless otherwise noted. (Note 3) LO Leakage Distribution 45 –40°C 25°C 85°C 40 Image Rejection Distribution 35 fLO = 2GHz 30 –40°C 25°C 85°C fLO = 2GHz PERCENTAGE (%) PERCENTAGE (%) 35 30 25 20 15 25 20 15 10 10 5 5 0 <–45 –43 –41 –39 –37 LO LEAKAGE (dBm) –35 –33 5572 G27 0 <–52 –40 –36 –44 –48 IMAGE REJECTION (dBc) 5572 G28 U U U PI FU CTIO S EN (Pin 1): Enable Input. When the EN pin voltage is higher than 1V, the IC is turned on. When the input voltage is less than 0.5V, the IC is turned off. GND (Pins 2, 4, 6, 9, 10, 12, 15, 17): Ground. Pins 6, 9, 15 and the Exposed Pad, Pin 17, are connected to each other internally. Pins 2 and 4 are connected to each other internally and function as the ground return for the LO signal. Pins 10 and 12 are connected to each other internally and function as the ground return for the on-chip RF balun. For best RF performance, Pins 2, 4, 6, 9, 10, 12, 15 and the Exposed Pad, Pin 17, should be connected to the printed circuit board ground plane. LO (Pin 3): LO Input. The LO input is an AC-coupled singleended input with approximately 50Ω input impedance at RF frequencies. Externally applied DC voltage should be within the range –0.5V to (VCC + 0.5V) in order to avoid turning on ESD protection diodes. BBPQ, BBMQ (Pins 7, 5): Baseband Inputs for the Q channel with about 90kΩ differential input impedance. These pins should be externally biased at about 0.5V. Applied common mode voltage must stay below 0.6V. VCC (Pins 8, 13): Power Supply. Pins 8 and 13 are connected to each other internally. It is recommended to use 0.1µF capacitors for decoupling to ground on each of these pins. RF (Pin 11): RF Output. The RF output is an AC-coupled single-ended output with approximately 50Ω output impedance at RF frequencies. Externally applied DC voltage should be within the range –0.5V to (VCC + 0.5V) in order to avoid turning on ESD protection diodes. BBPI, BBMI (Pins 14, 16): Baseband Inputs for the I channel with about 90kΩ differential input impedance. These pins should be externally biased at about 0.5V. Applied common mode voltage must stay below 0.6V. 5572f 7 LT5572 W BLOCK DIAGRA VCC 8 13 BBPI 14 V-I BBMI 16 11 RF 0° 90° BALUN BBPQ 7 1 EN V-I BBMQ 5 2 4 6 9 GND 3 LO 10 12 15 GND 17 5572 BD U W U U APPLICATIO S I FOR ATIO The LT5572 consists of I and Q input differential voltageto-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 differential baseband input pins, BBPI, BBMI, and BBPQ, BBMQ. These voltage signals are converted to currents and 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-phase and quadrature LO signals. These LO signals are then applied to on-chip buffers which drive the upconversion mixers. Both the LO input and RF output are single-ended, 50Ω matched and AC coupled. Baseband Interface The baseband inputs (BBPI, BBMI) and (BBPQ, BBMQ) present a differential input impedance of about 90kΩ. At each of the four baseband inputs, a capacitor of 1.8pF to ground and a PNP emitter follower is incorporated (see Figure 1), which limits the baseband –1dB bandwidth to approximately 250MHz. The circuit is optimized for an externally applied common mode voltage of 0.5V. The baseband input pins should not be left floating because the internal PNP’s base current will pull the common mode voltage higher than the 0.6V limit. This may damage the part if continued indefinitely. The PNP’s base current is about 20µA in normal operation. On the LT5572 demo board, external 50Ω resistors to ground are included at each baseband input to prevent this condition and to serve as a termination resistance for the baseband connections. The I/Q input signals to the LT5572 should be DC coupled with an applied common mode voltage level of about 0.5V in order to bias the LT5572 at its optimum operating point. Some I/Q test generators allow setting the common mode voltage independently. In this case, the common mode voltage of those generators must be set to 0.5V (See Figure 2). The baseband inputs should be driven differentially; otherwise, the even-order distortion products will degrade the overall linearity severely. Typically, a DAC will be the signal source for the LT5572. Reconstruction filters should be placed between the DAC outputs and the LT5572’s baseband inputs. In Figure 3, a typical baseband interface is shown including a 5th-order lowpass ladder filter for reconstruction. For each baseband pin, a 0V to 1V swing is developed corresponding to a DAC output current of 0mA to 20mA. The maximum sinusoidal single sideband RF output power at 2.14GHz is about +6.2dBm for full 0V to 1V swing on each baseband 5572f 8 LT5572 U U W U APPLICATIO S I FOR ATIO C LT5572 RF VCC = 5V BALUN FROM Q-CHANNEL LOMI LOPI BBPI 1.8pF VCM = 0.5V 1.8pF BBMI 5572 F01 GND Figure 1. Simplified Circuit Schematic of the LT5572 (Only I Channel is Drawn) 50Ω 50Ω 0.5VDC + – 1VDC LT5572 0.5005VDC + – 50Ω 1VDC GENERATOR GENERATOR 50Ω EXTERNAL LOAD 20µADC 5572 F02 Figure 2. DC Voltage Levels for a Generator Programmed at 0.5VDC for a 50Ω Load Without and With the LT5572 as a Load C LT5572 MAX RF +6.2dBm VCC 5V BALUN FROM Q-CHANNEL LOMI L1A 0mA TO 20mA L2A 0.5VDC R1A 100Ω DAC BBPI R2A 100Ω C2 C1 R1B 100Ω LOPI L1B L2B 0mA TO 20mA C3 R2B 100Ω 1.8pF 1.8pF BBMI GND 5572 F03 GND Figure 3. LT5572 Baseband Interface with 5th Order Filter and 0.5VCM DAC (Only I Channel is Shown) 5572f 9 LT5572 U W U U APPLICATIO S I FOR ATIO Table 1. Typical Performance Characteristics vs VCM for fLO = 2GHz, PLO = 0dBm VCM (V) 0.1 0.2 0.3 0.4 0.5 0.6 ICC (mA) 77 89 101 113 126 138 GV (dB) –1.3 –2.7 –2.1 –2.0 –1.9 –1.9 OP1dB (dBm) 0.0 4.7 7.1 8.6 9.3 9.1 OIP2 (dBm) 47 45 49 51 52 52 input (2VP-P,DIFF). This maximum RF output level is limited by the 0.5VPEAK maximum baseband swing possible for a 0.5VDC common mode voltage level (assuming no extra negative supply voltage available). It is possible to bias the LT5572 to a common mode baseband voltage level other than 0.5V. Table 1 shows the typical performance for different common mode voltages. LO section 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. The internal, differential LO signal is 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 conditions. 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 VCC LO INPUT 20pF ZIN ≈ 56Ω 5572 F04 Figure 4. Equivalent Circuit Schematic of the LO Input OIP3 (dBm) 8.3 11.4 15.0 18.2 21.2 21.1 NFloor (dBm/Hz) –163.2 –162.2 –160.9 –160.2 –159.2 –158.6 LOFT (dBm) –45.6 –42.6 –42.0 –42.4 –42.4 –42.1 IR (dBc) –42.2 –36.2 –37.0 –39.3 –41.5 –44.4 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 range will degrade, especially below –5dBm and at TA = 85°C. For high LO input power (e.g., 5dBm), the LO feedthrough will increase, without improvement in linearity or gain. Harmonics present on the LO signal can degrade the image rejection, because they introduce a small excess 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 –57dBc or lower, corresponding to an excess phase shift much less than 1 degree. For the second and third harmonics at –10dBc, still 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 14dB over the 1.7GHz to 2.4GHz range. Table 2 shows the LO port input impedance vs frequency. Table 2. LO Port Input Impedance vs Frequency for EN = High and PLO = 0dBm FREQUENCY (MHz) INPUT IMPEDANCE (Ω) 1000 1400 1600 1800 2000 2200 2400 2600 45.9+j15.7 60.8+j2.1 63.2-j6.0 61.8-j14.2 56.4-j16.8 51.7-j14.7 47.3-j11.3 42.5-j8.6 S11 Mag 0.167 0.099 0.128 0.163 0.165 0.144 0.119 0.122 Angle 95 9.4 –22 –44 –61 –75 –97 –126 The input impedance of the LO port is different if the part is in shutdown mode. The LO input impedance for EN = Low is given in Table 3. 5572f 10 LT5572 U W U U APPLICATIO S I FOR ATIO Table 3. LO Port Input Impedance vs Frequency for EN = Low and PLO = 0dBm FREQUENCY (MHz) 1000 1400 1600 1800 2000 2200 2400 2600 INPUT IMPEDANCE (Ω) 51.2+j45.6 133-j11.8 97.8-j65.8 58.6-j67.8 39.0-j55.6 29.6-j43.2 23.7-j30.8 19.7-j20.5 S11 Mag 0.409 0.456 0.502 0.534 0.540 0.527 0.506 0.503 Angle 64 –4.5 –30 –51 –69 –87 –108 –130 RF Section After up-conversion, the RF outputs of the I and Q mixers are combined. An on-chip balun performs internal differential to single-ended output conversion, while transforming the output signal impedance to 50Ω. Table 4 shows the RF port output impedance vs frequency. Table 4. RF Port Output Impedance vs Frequency for EN = High and PLO = 0dBm FREQUENCY (MHz) OUTPUT IMPEDANCE (Ω) 1000 1400 1600 1800 2000 2200 2400 2600 20.7+j9.9 32.2+j20.3 44.9+j21.8 56.4+j12.2 52.6+j0.5 43.0+j0.5 36.8+j5.6 32.9+j11.0 S22 Mag 0.434 0.319 0.230 0.129 0.025 0.075 0.164 0.243 Angle 153 117 90 56 10 176 153 140 For EN = Low the S22 is given in Table 6. Table 6. RF Port Output Impedance vs Frequency for EN = Low FREQUENCY (MHz) OUTPUT IMPEDANCE (Ω) 1000 1400 1600 1800 2000 2200 2400 2600 20.3+j9.7 30.6+j20.2 41.8+j23.6 55.6+j18.5 58.3+j49.1 48.8-j0.1 40.4+j3.1 34.7+j8.3 FREQUENCY (MHz) OUTPUT IMPEDANCE (Ω) 1000 1400 1600 1800 2000 2200 2400 2600 21.2+j10.1 35.3+j18.4 46.1+j14.1 47.4+j5.0 42.0+j3.0 37.5+j6.8 34.8+j11.8 32.8+j16.1 S22 Mag 0.424 0.270 0.150 0.057 0.093 0.162 0.224 0.279 Angle 153 117 97 114 157 147 134 126 Angle 154 120 95 63 28 -172 160 146 To improve S22 for lower frequencies, a shunt capacitor can be added to the RF output. At higher frequencies, a shunt inductor can improve the S22. Figure 5 shows the equivalent circuit schematic of the RF output. 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 impedance is connected directly to ground. To prevent this, a coupling capacitor can be inserted in the RF output line. This is strongly recommended for 1dB compression measurements. VCC 20pF 52.59 The RF output S22 with no LO power applied is given in Table 5. Table 5. RF Port Output Impedance vs Frequency for EN = High and No LO Power Applied S22 Mag 0.440 0.338 0.264 0.181 0.089 0.012 0.112 0.205 2.1pF RF OUTPUT 3nH 5572 F05 Figure 5. Equivalent Circuit Schematic of the RF Output Enable Interface Figure 6 shows a simplified schematic of the EN pin interface. The voltage necessary to turn on the LT5572 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 the voltage at the EN pin does not exceed VCC by more than 0.5V. If this should occur, the full-chip supply 5572f 11 LT5572 U U W U APPLICATIO S I FOR ATIO event that the EN pin is pulled high while the VCC inputs are low. The application board PCB layouts are shown in Figures 8 and 9. VCC EN 75k 25k 5572 F06 Figure 6. EN Pin Interface current could be sourced through the EN pin ESD protection diodes, which are not designed for this purpose. Damage to the chip may result. 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. Additionally, the Exposed Pad provides heat sinking for the part and minimizes the possibility of the chip overheating. R1 (optional) limits the EN pin current in the J1 J2 BBIM Figure 8. Component Side of Evaluation Board BBIP R5 49.9Ω R2 49.9Ω 16 R1 100Ω VCC EN LO IN 15 14 C1 100nF 13 BBMI GND 1 2 J4 VCC 3 4 BBPI VCC 12 EN GND 11 GND RF 10 LT5572 LO GND 9 GND GND 17 GND BBMQ GND BBPQ VCC 5 6 7 R3 49.9Ω RF OUT 8 C2 100nF J5 BBQM J3 J6 BBQP R4 49.9Ω 5572 F07 BOARD NUMBER: DC945A Figure 7. Evaluation Circuit Schematic Figure 9. Bottom Side of Evaluation Board 5572f 12 LT5572 U U W U APPLICATIO S I FOR ATIO Application Measurements The LT5572 is recommended for basestation applications using various modulation formats. Figure 10 shows a typical application. Figure 11 shows the ACPR performance for W-CDMA using 1-, 2- or 4-channel modulation. Figures 12, 13 and 14 illustrate the 1-, 2- and 4-channel W-CDMA measurement. To calculate ACPR, a correction is made for the spectrum analyzer noise floor (Application Note 99). 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. –50 8, 13 I-DAC 16 V-I I-CH 11 0° 1 EN 90° 7 Q-DAC 5 100nF ×2 RF = 1.5GHz TO 2.5GHz LT5572 ACPR, AltCPR (dBc) VCC 14 PA BALUN Q-CH DOWNLINK TEST MODEL 64 DPCH 4-CH ACPR 4-CH AltCPR –60 2-CH ACPR 1-CH AltCPR –80 2, 4, 6, 9, 10, 12, 15, 17 –90 –30 3 VCO/SYNTHESIZER –135 –145 2-CH AltCPR –155 2-CH NOISE V-I 5572 TA01a 1-CH ACPR –70 4-CH NOISE BASEBAND GENERATOR –125 1-CH NOISE –25 –15 –10 –5 –20 RF OUTPUT POWER PER CARRIER (dBm) NOISE FLOOR AT 30MHz OFFSET (dBm/Hz) 5V –165 5572 TA01b Figure 10. 1.5GHz to 2.4GHz Direct Conversion Transmitter Application –40 –50 –60 –70 –80 –90 SPECTRUM ANALYSER NOISE FLOOR UNCORRECTED SPECTRUM CORRECTED SPECTRUM –100 –30 DOWNLINK TEST MODEL 64 DPCH –40 –50 –60 –70 –80 SPECTRUM ANALYSER NOISE FLOOR CORRECTED SPECTRUM –90 –100 –110 POWER IN 30kHz BW (dBm) POWER IN 30kHz BW (dBm) –40 –30 DOWNLINK TEST MODEL 64 DPCH POWER IN 30kHz BW (dBm) –30 Figure 11. W-CDMA ACPR, ALTCPR and Noise vs RF Output Power at 2140MHz for 1, 2 and 4 Channels DOWNLINK TEST MODEL 64 DPCH –50 –60 –70 –80 –90 SPECTRUM ANALYSER NOISE FLOOR –100 –110 –110 UNCORRECTED SPECTRUM –120 2.1275 2.1325 2.1375 2.1425 2.1475 2.1525 RF FREQUENCY (GHz) 5572 F12 Figure 12. 1-Channel W-CDMA Spectrum –120 2.125 CORRECTED SPECTRUM 2.13 2.135 2.14 2.145 RF FREQUENCY (GHz) UNCORRECTED SPECTRUM 2.15 2.155 5572 F13 Figure 13. 2-Channel W-CDMA Spectrum –120 2.115 2.125 2.145 2.155 2.135 RF FREQUENCY (GHz) 2.165 5572 F14 Figure 14. 4-Channel W-CDMA Spectrum 5572f 13 LT5572 U U W U APPLICATIO S I FOR ATIO Because of the LT5572’s very high dynamic range, the test equipment can limit the accuracy of the ACPR measurement. Consult the factory for advice on the ACPR measurement if needed. The ACPR performance is sensitive to the amplitude match of the BBIP and BBIM (or BBQP and BBQM) input voltage. This is because a difference in AC voltage amplitude will give rise to a difference in amplitude between the even-order harmonic products generated in the internal V-I converter. IMAGE REJECTION –60 –70 –90 –40 10 CALIBRATED WITH PRF = –10dBm –50 –80 When the temperature is changed after calibration, the LO feedthrough and the image rejection performance will change. This is illustrated in Figure 15. The LO feedthrough and image rejection can also change as a function of the baseband drive level as depicted in Figure 16. LO FEEDTHROUGH –20 VCC = 5V fBBI = 2MHz, 0° fBBQ = 2MHz, 90° fLO = 2GHz fRF = fBB + fLO EN = HIGH PLO = 0dB 0 20 40 TEMPERATURE (°C) 60 80 5572 F15 Figure 15. LO Feedthrough and Image Rejection vs Temperature After Calibration at 25°C PRF 0 PRF, LOFT (dBm), IR (dBc) LO FEEDTHROUGH (dBm), IR (dB) –40 As a result, they will not cancel out entirely. Therefore, it is important to keep the amplitudes at the BBIP and BBIM (or BBQP and BBQM) inputs as equal as possible. VCC = 5V fBBI = 2MHz, 0° fBBQ = 2MHz, 90° EN = HIGH –10 –20 fLO = 2GHz fRF = fBB + fLO EN = HIGH PLO = 0dB LO FT –30 –40 –50 –60 IR –70 25°C 85°C –40°C –80 0 5 4 1 3 2 I AND Q BASEBAND VOLTAGE (VP-P(DIFF)) 5572 F16 Figure 16. RF Output Power, Image Rejection and LO Feedthrough vs Baseband Drive Voltage After Calibration at 25°C 5572f 14 LT5572 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 2.15 ± 0.05 2.90 ± 0.05 (4 SIDES) PACKAGE OUTLINE 0.30 ±0.05 0.65 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS BOTTOM VIEW—EXPOSED PAD 4.00 ± 0.10 (4 SIDES) 0.75 ± 0.05 R = 0.115 TYP 15 PIN 1 NOTCH R = 0.20 TYP OR 0.35 × 45° CHAMFER 16 0.55 ± 0.20 PIN 1 TOP MARK (NOTE 6) 1 2.15 ± 0.10 (4-SIDES) 2 (UF16) QFN 10-04 0.200 REF 0.00 – 0.05 0.30 ± 0.05 0.65 BSC 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 5572f Information furnished by Linear Technology Corporation is believed to be accurate and reliable. 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 LT5572 RELATED PARTS PART NUMBER Infrastructure LT5511 LT5512 DESCRIPTION COMMENTS High Linearity Upconverting Mixer DC to 3GHz High Signal Level Downconverting Mixer RF Output to 3GHz, 17dBm IIP3, Integrated LO Buffer DC to 3GHz, 17dBm IIP3, Integrated LO Buffer LT5514 Ultralow Distortion, IF Amplifier/ADC Driver with Digitally Controlled Gain LT5515 1.5GHz to 2.5GHz Direct Conversion Quadrature Demodulator LT5516 0.8GHz to 1.5GHz Direct Conversion Quadrature Demodulator LT5517 40MHz to 900MHz Quadrature Demodulator LT5518 1.5GHz to 2.4GHz High Linearity Direct Quadrature Modulator LT5519 0.7GHz to 1.4GHz High Linearity Upconverting Mixer LT5520 1.3GHz to 2.3GHz High Linearity Upconverting Mixer LT5521 10MHz to 3700MHz High Linearity Upconverting Mixer LT5522 600MHz to 2.7GHz High Signal Level Downconverting Mixer LT5524 Low Power, Low Distortion ADC Driver with Digitally Programmable Gain LT5525 High Linearity, Low Power Downconverting Mixer LT5526 High Linearity, Low Power Downconverting Mixer LT5527 400MHz to 3.7GHz High Signal Level Downconverting Mixer LT5528 1.5GHz to 2.4GHz High Linearity Direct Quadrature Modulator RF Power Detectors LTC®5505 RF Power Detectors with >40dB Dynamic Range LTC5507 100kHz to 1000MHz RF Power Detector LTC5508 300MHz to 7GHz RF Power Detector LTC5509 300MHz to 3GHz RF Power Detector LTC5530 300MHz to 7GHz Precision RF Power Detector LTC5531 300MHz to 7GHz Precision RF Power Detector LTC5532 300MHz to 7GHz Precision RF Power Detector LT5534 50MHz to 3GHz Log RF Power Detector with 60dB Dynamic Range LTC5536 Precision 600MHz to 7GHz RF Power Detector with Fast Comparator Output LT5537 Wide Dynamic Range Log RF/IF Detector High Speed ADCs LTC2220-1 12-Bit, 185Msps ADC LTC2249 LTC2255 14-Bit, 80Msps ADC 14-Bit, 125Msps ADC 850MHz Bandwidth, 47dBm OIP3 at 100MHz, 10.5dB to 33dB Gain Control Range 20dBm IIP3, Integrated LO Quadrature Generator 21.5dBm IIP3, Integrated LO Quadrature Generator 21dBm IIP3, Integrated LO Quadrature Generator 22.8dBm OIP3 at 2GHz, –158.2dBm/Hz Noise Floor, 50Ω Single-Ended RF and LO Ports, 4-Channel W-CDMA ACPR = –64dBc at 2.14GHz 17.1dBm IIP3 at 1GHz, Integrated RF Output Transformer with 50Ω Matching, Single-Ended LO and RF Ports Operation 15.9dBm IIP3 at 1.9GHz, Integrated RF Output Transformer with 50Ω Matching, Single-Ended LO and RF Ports Operation 24.2dBm IIP3 at 1.95GHz, NF = 12.5dB, 3.15V to 5.25V Supply, Single-Ended LO Port Operation 4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB, 50Ω Single-Ended RF and LO Ports 450MHz Bandwidth, 40dBm OIP3, 4.5dB to 27dB Gain Control Single-Ended 50Ω RF and LO Ports, 17.6dBm IIP3 at 1900MHz, ICC = 28mA 3V to 5.3V Supply, 16.5dBm IIP3, 100kHz to 2GHz RF, NF = 11dB, ICC = 28mA, –65dBm LO-RF Leakage IIP3 = 23.5dBm and NF = 12.5dBm at 1900MHz, 4.5V to 5.25V Supply, ICC = 78mA 21.8dBm OIP3 at 2GHz, –159.3dBm/Hz Noise Floor, 50Ω, 0.5VDC Baseband Interface, 4-Channel W-CDMA ACPR = –66dBc at 2.14GHz 300MHz to 3GHz, Temperature Compensated, 2.7V to 6V Supply 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 Precision VOUT Offset Control, Shutdown, Adjustable Gain Precision VOUT Offset Control, Shutdown, Adjustable Offset Precision VOUT Offset Control, Adjustable Gain and Offset ±1dB Output Variation over Temperature, 38ns Response Time, Log Linear Response 25ns Response Time, Comparator Reference Input, Latch Enable Input, –26dBm to +12dBm Input Range Low Frequency to 1GHz, 83dB Dynamic Range, 2.7V to 5.25V Supply Single 3.3V Supply, 910mW Consumption, 67.5dB SNR, 80dB SFDR, 775MHz Full Power BW Single 3V Supply, 222mW Consumption, 73dB SNR, 90dB SFDR Single 3V Supply, 395mW Consumption, 72.4dB SNR, 88dB SFDR, 640MHz Full Power BW 5572f 16 Linear Technology Corporation LT 1205 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2005