LT5503EFE#TRPBF [Linear]
LT5503 - 1.2GHz to 2.7GHz Direct IQ Modulator and Mixer; Package: TSSOP; Pins: 20; Temperature Range: -40°C to 85°C;型号: | LT5503EFE#TRPBF |
厂家: | Linear |
描述: | LT5503 - 1.2GHz to 2.7GHz Direct IQ Modulator and Mixer; Package: TSSOP; Pins: 20; Temperature Range: -40°C to 85°C |
文件: | 总20页 (文件大小:212K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
Final Electrical Specifications
LT5503
1.2GHz to 2.7GHz Direct
IQ Modulator and Mixer
U
October 2001
DESCRIPTIO
FEATURES
TheLT®5503isafront-endtransmitterICdesignedforlow
voltageoperation, andiscompatiblewiththeLTCfamilyof
WLANproducts. TheICcontainsahighfrequencyquadra-
ture modulator with a variable gain amplifier (VGA) and a
balanced mixer. The modulator includes a precision 90°
phase shifter which allows direct modulation of an RF
signal by the baseband I and Q signals.
■
Single 1.8V to 5.25V Supply
■
Direct IQ Modulator with Integrated 90° Phase
Shifter*
■
Four Step RF Power Control
■
120MHz Modulation Bandwidth
■
Independent Double-Balanced Mixer
■
Modulation Accuracy Insensitive to Carrier Input
Power
In a superheterodyne system, the mixer can be used to
generatethehigh-frequencyRFinputforthemodulatorby
mixing the system’s 1st and 2nd local oscillators.
■
Modulator I/Q Inputs Internally Biased
U
APPLICATIO S
■
The LT5503 modulator output delivers –3dBm at 2.5GHz.
The VGA allows output power reduction in three steps up
to 13dB with digital control. The baseband inputs are
internally biased for maximum input voltage swing at low
supply voltage. If needed, they can be driven with external
bias voltages.
IEEE 802.11 DSSS and FHSS
■
High Speed Wireless LAN (WLAN)
■
Wireless Local Loop (WLL)
■
PCS Wireless Data
■
MMDS
, LTC and LT are registered trademarks of Linear Technology Corporation.
*Patent Pending
U
TYPICAL APPLICATIO
2.45GHz
BPF
2.45GHz Modulated Output
Power vs Supply Voltage
V
CC1
V
CC2
2V
2V
–2
–3
–4
–5
–6
+
–
BQ BQ
–
+
V
LO2 V LO1
MODIN
V
RF
V MOD
CC
MX
V
VGA
MX
CC CC
CC
CC
MIXER
MIXEN
ENABLE
MODULATOR
ENABLE
LO2IN
(750MHz)
MODEN
LO2
MODOUT
VGA
0°
÷2
P
P
= –12dBm
= –18dBm
LO1
LO2
90°
÷1
BASEBAND = 1V
P-P
T
= 27°C
A
CONTROL
LOGIC
1.8
2.4
3.0
3.6
4.2
4.8
5.4
SUPPLY VOLTAGE (V)
GC1
GND
GC2
DMODE
LO1
2.45GHz
MODULATED
RFOUT
5503 TA01b
5503 F01
+
–
LO1IN (2075MHz)
BI BI
Figure 1. 2.45GHz Transmitter Application, Carrier for Modulator Generated by Upmixer
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 represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
1
LT5503
W W
U W
U
W
U
ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
(Note 1)
ORDER PART
TOP VIEW
Supply Voltage ...................................................... 5.5V
Control Voltages .......................... –0.3V to (VCC + 0.3V)
Baseband Voltages (BI+ to BI– and BQ+ to BQ–) ...... ±2V
Baseband Common Mode Voltage.....1V to (VCC – 0.3V)
LO1 Input Power .................................................. 4dBm
LO2 Input Power .................................................. 4dBm
MODIN Input Power ............................................. 4dBm
Operating Temperature Range .................–40°C to 85°C
Storage Temperature Range ..................–65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
–
+
NUMBER
–
+
BQ
BQ
1
2
3
4
5
6
7
8
9
20 BI
19 BI
LT5503EFE
GC1
18 GC2
MODIN
17 MODOUT
V
MOD
16
15
14
13
12
11
V
V
VGA
LO2
CC
CC
V
RF
CC
CC
LO1
LO1
LO2
V
MODEN
MIXEN
CC
DMODE
+
–
MX 10
MX
21
FE PACKAGE
20-LEAD PLASTIC TSSOP
PIN 21 = GND (BACKSIDE)
TJMAX = 150°C, θJA = 38°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
2
LT5503
ELECTRICAL CHARACTERISTICS
(I/Q Modulator)
VCC1 = 3VDC, 2.4GHz matching, MODEN = High, GC1 = GC2 = Low, TA = 27ºC, MODRFIN = 2.45GHz at –16dBm, [I – IB] and [Q – QB] =
100kHz CW signal at 1VP-P differential, Q leads I by 90°, unless otherwise noted. (Test circuit shown in Figure 2.) (Note 3)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
GHz
RF Carrier Input (MODRFIN)
2
Frequency Range
1.2 to 2.7
1.3:1
Input VSWR
Input Power
Z = 50Ω
O
–20 to -10
dBm
MHz
+
–
+
–
Baseband Inputs (BI , BI , BQ , BQ )
Frequency Bandwidth (3dB)
Differential Input Voltage for 1dB Compressed Output
DC Common-Mode Voltage
Differential Input Resistance
Input Capacitance
120
1
V
P-P
Internally Biased
1.4
18
VDC
kΩ
pF
0.8
±0.2
±1
Gain Error
dB
Phase Error
DEG
Modulated RF Carrier Output (MODRFOUT)
Output Power, Max Gain
Output VSWR
–6
–3
1.5:1
–34
–32
–3
dBm
Z = 50Ω
O
Image Suppression
–26
–24
dBc
dBc
Carrier Suppression
Output 1dB Compression
Output 3rd Order Intercept
Output 2rd Order Intercept
Broadband Noise
dBm
f = 100kHz, f = 120kHz
I
2
dBm
Q
f = 100kHz, f = 120kHz
I
16
dBm
Q
20MHz Offset
–142
dBm/Hz
VGA Control Logic (GC2, GC1)
Switching Time
100
2
ns
µA
Input Current
Input Low Voltage
0.4
VDC
VDC
dB
Input High Voltage
1.7
Output Power Attenuation
Output Power Attenuation
Output Power Attenuation
Modulator Enable (MODEN) Low = Off, High = On
Turn ON/OFF Time
GC2 = Low, GC1 = High
GC2 = High, GC1 = Low
GC2 = High, GC1 = High
4.5
9
dB
13.5
dB
1
µs
µA
Input Current
105
Enable
V
– 0.4
VDC
VDC
CC
Disable
0.4
Modulator Power Supply Requirements
Supply Voltage
1.8
5.25
38
VDC
mA
µA
Modulator Supply Current
Modulator Shutdown Current
MODEN = High
MODEN = Low
29
25
3
LT5503
(Mixer)
ELECTRICAL CHARACTERISTICS
VCC2 = 3VDC, 2.4GHz matching, MIXEN = High, DMODE = Low (LO2 ÷ 2 mode), TA = 27ºC, LO2IN = 750MHz at –18dBm, LO1IN =
2075MHz at –12dBm. MIXRFOUT measured at 2450MHz, unless otherwise noted. (Test circuit shown in Figure 2.) (Note 3)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
MHz
dBm
MHz
dBm
MHz
Mixer 2nd LO Input (LO2IN)
Frequency Range
Input VSWR
50 to 1000
1.4:1
Z = 50Ω
O
Input Power
–20 to –12
Mixer 1st LO Input (LO1IN)
2
Frequency Range
1400 to 2400
1.5:1
Input VSWR
Z = 50Ω
O
Input 3rd Order Intercept
Mixer RF Output (MIXRFOUT)
–30dBm/Tone, ∆f = 200kHz
–12
2
Frequency Range
1700 to 2700
1.5:1
Output VSWR
Z = 50Ω
O
Small-Signal Conversion Gain
Output Power
P
= –30dBm
5
dB
dBm
LO1
–14.7
–22
–12.7
–29
LO1 Suppression
dBc
Output 1dB Compression
Broadband Noise
–15
dBm
20MHz Offset
–152
dBm/Hz
LO2 Divider Mode Control (DMODE) Low = f ÷ 2, High = f ÷ 1
LO2
LO2
Input Current
1
µA
VDC
VDC
Input Low Voltage (÷2)
Input High Voltage (÷1)
Mixer Enable (MIXEN) Low = Off, High = On
Turn ON/OFF Time
0.4
0.4
V
V
– 0.4
CC
CC
1
µs
µA
Input Current
130
Enable
– 0.4
VDC
VDC
Disable
Mixer Power Supply Requirements
Supply Voltage
1.8
5.25
15.5
VDC
mA
mA
µA
Supply Current (÷2 mode)
Supply Current (÷1 mode)
Shutdown Current
DMODE = Low, MIXEN = High
11.9
10.8
DMODE = High, MIXEN = High
MIXEN = Low
10
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: External component values on the final test circuit shown in
Note 3: Specifications over the –40°C to 85°C temperature range are
assured by design, characterization and correlation with statistical process
controls.
Figure 2 are optimized for operation in the 2.4GHz to 2.5GHz band.
4
LT5503
U W
(I/Q Modulator)
TYPICAL PERFOR A CE CHARACTERISTICS
VCC1 = 3VDC, 2.4GHz matching, MODEN = high, GC1 = GC2 = low (max gain), TA = 27°C, MODRFIN = 2.45GHz at –16dBm, (I–IB) and
(Q–QB) = 100kHz sine at 1VP-P differential, Q leads I by 90°, unless otherwise noted. (Test circuit shown in Figure 2.)
Modulator Supply Current vs
Supply Voltage
MODEN Current vs Enable
Voltage
Modulator Shutdown Current vs
Supply Voltage
38
36
34
32
30
28
26
24
22
20
100
10
1
220
200
180
160
140
120
100
80
MODEN = LOW
MODEN = V
CC1
T
A
= 85°C
T
A
= 85°C
T
A
= 85°C
T
A
= 27°C
T
= 27°C
A
T
A
= –40°C
T
A
= 27°C
T
= –40°C
A
60
T
= –40°C
A
0.1
40
1.8
4.6
5.3
2.5
V
3.2
3.9
1.8
4.6
5.3
2.5
V
3.2
3.9
1.8
5.3
2.5
3.2
3.9
4.6
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
MODEN VOLTAGE (V)
CC1
CC1
5503 G01
5503 G02
5503 G03
SSB Output Power vs
I, Q Amplitude
MODRFIN and MODRFOUT
Baseband Frequency Response
I/Q Amplitude = 1VP-P
Return Loss 2.4GHz Matching
0
–5
0
–5
0
–10
–20
–30
–40
3 VDC
1.8 VDC
5.25 VDC
DESIRED
SIDEBAND
MODRFOUT
–10
–15
–20
–25
–30
–35
–40
–45
–10
–15
–20
–25
–30
–35
–40
MODRFIN
CARRIER
IMAGE
2450
2650
2050
2850
0.01
0.1
10
2250
1
0.1
10
1
I, Q DIFFERENTIAL INPUT VOLTAGE (V
)
FREQUENCY (MHz)
P-P
I, Q INPUT FREQUENCY (MHz)
5503 G06
5503 G04
5503 G05
Typical SSB Spectrum
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
2450.0
FREQUENCY (MHz)
2449.6 2449.8
2450.2 2450.4 2450.6
5503 G07
5
LT5503
U W
(I/Q Modulator)
TYPICAL PERFOR A CE CHARACTERISTICS
2.4GHz matching, MODEN = high, GC1 = GC2 = low (max gain), MODRFIN = 2.45GHz, (I–IB) and (Q–QB) = 100kHz sine at 1VP-P
differential, Q leads I by 90°, unless otherwise noted. (Test circuit shown in Figure 2.)
Image Suppression vs Input
Power VCC1 = 1.8V
Carrier Suppression vs Input Power
VCC1 = 1.8V
SSB Output Power vs Input Power
VCC1 = 1.8V
–20
–30
–40
–50
–20
–30
–40
–50
–2
–4
T
= 27°C
A
–6
T
= –40°C
A
–8
T
= 27°C
A
T
= 27°C
A
T
= 85°C
A
–10
–12
–14
–16
–18
–20
T
= –40°C
A
T
= –40°C
A
T
= 85°C
A
T
= 85°C
A
–24 –22 –20 –18 –16 –14 –12 –10
MODRFIN INPUT POWER (dBm)
–24 –22 –20 –18 –16 –14 –12 –10
MODRFIN INPUT POWER (dBm)
–24 –22 –20 –18 –16 –14 –12 –10
MODRFIN INPUT POWER (dBm)
5503 G10
5503 G08
5503 G09
SSB Output Power vs Input Power
VCC1 = 3V
Carrier Suppression vs Input Power
VCC1 = 3V
Image Suppression vs Input Power
VCC1 = 3V
–20
–30
–40
–50
0
–2
–20
–30
–40
–50
T
= 27°C
A
–4
T
= –40°C
A
–6
T
A
= 27°C
T
= 27°C
A
–8
T
= –40°C
A
T
= –40°C
T
= 85°C
A
A
–10
–12
–14
–16
–18
T
= 85°C
A
T
A
= 85°C
–24 –22 –20 –18 –16 –14 –12 –10
MODRFIN INPUT POWER (dBm)
–24 –22 –20 –18 –16 –14 –12 –10
MODRFIN INPUT POWER (dBm)
–24 –22 –20 –18 –16 –14 –12 –10
MODRFIN INPUT POWER (dBm)
5503 G13
5503 G11
5503 G12
SSB Output Power vs Input Power
VCC1 = 5.25V
Carrier Suppression vs Input Power
VCC1 = 5.25V
Image Suppression vs Input Power
VCC1 = 5.25V
0
–2
–20
–20
T
= 27°C
A
T
= –40°C
A
–4
–6
–30
–40
–50
–30
–40
–50
T
= 27°C
A
T
= 27°C
A
T
= 85°C
A
–8
T
= –40°C
A
T
= –40°C
A
–10
–12
–14
–16
–18
T
= 85°C
A
T
= 85°C
A
–24 –22 –20 –18 –16 –14 –12 –10
MODRFIN INPUT POWER (dBm)
–24 –22 –20 –18 –16 –14 –12 –10
MODRFIN INPUT POWER (dBm)
–24 –22 –20 –18 –16 –14 –12 –10
MODRFIN INPUT POWER (dBm)
5503 G14
5503 G16
5503 G15
6
LT5503
U W
(I/Q Modulator)
TYPICAL PERFOR A CE CHARACTERISTICS
VCC1 = 3VDC, MODEN = high, TA = 27°C, PMODRFIN = –16dBm, (I–IB) and (Q–QB) = 100kHz sine at 1VP-P differential, Q leads I by 90°,
unless otherwise noted. (Test circuit shown in Figure 2.)
Output Power vs Frequency
1.2GHz Matching
Carrier Feedthrough vs Frequency
1.2GHz Matching
SSB Image vs Frequency
1.2GHz Matching
0
–2
–30
–40
–50
–60
–30
–40
–50
–60
GC2, GC1 = 00
GC2, GC1 = 00
01
–4
GC2, GC1 = 00
01
–6
01
–8
10
11
–10
–12
–14
–16
–18
–20
10
11
10
11
1000
1100
1200
1300
1400
1000
1100
1200
1300
1400
1000
1100
1200
1300
1400
MODRFIN FREQUENCY (MHz)
MODRFIN FREQUENCY (MHz)
MODRFIN FREQUENCY (MHz)
5503 G17
5503 G18
5503 G19
Output Power vs Frequency
1.9GHz Matching
Carrier Feedthrough vs Frequency
1.9GHz Matching
SSB Image vs Frequency
1.9GHz Matching
2
0
–30
–40
–50
–60
–30
–40
–50
–60
GC2, GC1 = 00
01
GC2, GC1 = 00
01
GC2, GC1 = 00
01
–2
–4
–6
10
11
–8
10
11
10
11
–10
–12
–14
–16
–18
1650
1750
1850
1950
2050
2150
1650
1750
1850
1950
2050
2150
1650
1750
1850
1950
2050
2150
MODRFIN FREQUENCY (MHz)
MODRFIN FREQUENCY (MHz)
MODRFIN FREQUENCY (MHz)
5503 G20
5503 G22
5503 G21
Output Power vs Frequency
2.4GHz Matching
Carrier Feedthrough vs Frequency
2.4GHz Matching
SSB Image vs Frequency
2.4GHz Matching
–30
–40
–50
–60
–30
–40
–50
–60
0
–2
GC2, GC1 = 00
GC2, GC1 = 00
GC2, GC1 = 00
01
–4
01
–6
10
11
01
–8
10
11
–10
–12
–14
–16
–18
10
11
2250
2350
2450
2550
2650
2250
2350
2450
2550
2650
2250
2350
2450
2550
2650
MODRFIN FREQUENCY (MHz)
MODRFIN FREQUENCY (MHz)
MODRFIN FREQUENCY (MHz)
5503 G25
5503 G23
5503 G24
7
LT5503
U W
(Mixer)
TYPICAL PERFOR A CE CHARACTERISTICS
2.4GHz matching, MIXEN = high, DMODE = low (LO2 ÷ 2 mode), LO2IN = 750MHz at –18dBm, LO1IN = 2075MHz. MIXRFOUT measured
at 2450MHz, unless otherwise noted. (Test circuit shown in Figure 2.)
Mixer Shutdown Current vs Supply
Voltage
Mixer Supply Current vs Supply
Mixer Supply Current vs Supply
Voltage (LO2 ÷ 2 Mode)
Voltage (LO2 ÷ 1 Mode)
14
13
12
11
10
9
100
10
1
14
13
12
11
10
9
DMODE = HIGH
MIXEN = LOW
T
= 85°C
A
T
= 27°C
T
= 85°C
A
A
T
A
= 27°C
T
A
= 85°C
T
= –40°C
A
T
= –40°C
A
T
= 27°C
A
T
= –40°C
A
8
0.1
8
1.8
2.5
V
3.2
3.9
4.6
5.3
1.8
2.5
V
3.2
3.9
4.6
5.3
1.8
2.5
V
3.2
3.9
4.6
5.3
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
CC2
SUPPLY VOLTAGE (V)
CC2
CC2
5503 G27
5503 G28
5503 G26
RF Output Power vs LO1 Input
Power (VCC2 = 5.25V)
RF Output Power vs LO1 Input
Power (VCC2 = 1.8V)
RF Output Power vs LO1 Input
Power (VCC2 = 3V)
–12
–14
–16
–18
–20
–22
–24
–26
–28
–12
–14
–16
–18
–20
–22
–24
–26
–28
–12
–14
–16
–18
–20
–22
–24
–26
–28
T
= –40°C
A
T
= –40°C
T
= –40°C
A
A
T
A
= 27°C
T
A
= 27°C
T
= 27°C
A
T
A
= 85°C
T
A
= 85°C
T
= 85°C
A
–21 –18
–21 –18
–30 –27 –24
–15 –12 –9 –6
–21 –18
–15 –12
–30 –27 –24
–15 –12 –9 –6
–30
–9 –6
–27 –24
LO1IN POWER (dBm)
LO1IN POWER (dBm)
LO1IN POWER (dBm)
1195 G30
1195 G29
1195 G31
LO1 Feedthrough vs LO1 Input
Power (VCC2 = 5.25V)
LO1 Feedthrough vs LO1 Input
Power (VCC2 = 1.8V)
LO1 Feedthrough vs LO1 Input
Power (VCC2 = 3V)
–20
–25
–30
–35
–40
–20
–25
–30
–35
–40
–20
–25
–30
–35
–40
T
= –40°C
A
T
A
= 85°C
T
= 85°C
T
= 27°C
A
T
= 85°C
A
A
T
= 27°C
A
T
= 27°C
A
T
= –40°C
A
T
= –40°C
A
–21 –18
–15 –12 –9 –6
–21 –18
–30 –27 –24
–30 –27 –24
–15 –12 –9 –6
–21 –18
–30 –27 –24
–15 –12 –9 –6
LO1IN POWER (dBm)
LO1IN POWER (dBm)
LO1IN POWER (dBm)
1195 G34
1195 G33
1195 G32
8
LT5503
U W
TYPICAL PERFOR A CE CHARACTERISTICS
(Mixer)
VCC2 = 3VDC, MIXEN = high, DMODE = low (LO2 ÷ 2mode), TA = 27°C, unless otherwise noted. (Test circuit shown in Figure 2.)
RF Output Power and LO1
Small-Signal Conversion Gain
and IIP3 1.9GHz Matching
LO1IN and MIXRFOUT Return Loss
1.9GHz Matching
Feedthrough 1.9GHz Matching
–12
–14
–16
–18
–20
–22
0
0
–5
6
4
–3
OUTPUT
POWER
–10
–20
–30
–40
–50
–6
SMALL-SIGNAL
CONVERSION
GAIN
–10
–15
–20
–25
–30
2
–9
MIXRFOUT
LO1IN
0
–12
–15
–18
LO1
FEEDTHROUGH
IIP3
–2
LO2IN = 480MHz AT –18dBm
LO2IN = 480MHz AT –18dBm
LO1IN = f –240MHz AT –12dBm
LO1IN = f –240MHz AT –30dBm/TONE
RF
RF
–4
1650
1750
1850
1950
2050
2150
1900
2300 2500
2100
1100 1300 1500 1700
1650
1750
1850
1950
2050
2150
RF OUTPUT FREQUENCY (MHz)
FREQUENCY (MHz)
RF OUTPUT FREQUENCY (MHz)
5503 G35
5503 G37
5503 G36
RF Output Power and LO1
Small-Signal Conversion Gain
and IIP3 2.4GHz Matching
LO1 and MIXRFOUT Return Loss
2.4GHz Matching
Feedthrough 2.4GHz Matching
–12
–14
–16
–18
–20
–22
0
0
–5
6
4
–3
OUTPUT
POWER
–10
–20
–30
–40
–50
SMALL-SIGNAL
CONVERSION
GAIN
–6
–10
–15
–20
–25
–30
2
–9
LO1
FEEDTHROUGH
MIXRFOUT
LO1
IIP3
0
–12
–15
–18
–2
LO2IN = 750MHz AT –18dBm
LO2IN = 750MHz AT –18dBm
LO1IN = f –375MHz AT –12dBm
LO1IN = f –375MHz AT –30dBm/TONE
RF
RF
–4
2250
2350
2450
2550
2650
2250
2650 2850
2450
1450 1650 1850 2050
2250
2350
2450
2550
2650
RF OUTPUT FREQUENCY (MHz)
FREQUENCY (MHz)
RF OUTPUT FREQUENCY (MHz)
5503 G38
5503 G40
5503 G39
MIXEN Input Current vs Enable
Voltage (MIXEN = VCC2
)
300
270
240
210
180
150
120
90
T
= 85°C
A
T
= –40°C
A
T
= 27°C
A
60
30
1.8
5.3
2.5
3.2
3.9
4.6
MIXEN VOLTAGE (V)
5503 G41
9
LT5503
U
U
U
PI FU CTIO S
BQ– (Pin1):NegativeBasebandInputPinoftheModulator
Q-Channel. This pin is internally biased to 1.4V, but can
alsobeoverdrivenwithanexternalDCvoltagegreaterthan
1.4V, but less than VCC – 0.4V.
MIXEN (Pin 12): Mixer Enable Pin. When the input voltage
is higher than VCC – 0.4V, the mixer circuits supplied
through pins 8, 10, 11 and 15 are enabled. When the input
voltage is less than 0.4V, these circuits are disabled.
BQ+ (Pin 2): Positive Baseband Input Pin of Modulator Q-
Channel. This pin is internally biased to 1.4V, but can also
be overdriven with an external DC voltage greater than
1.4V, but less than VCC – 0.4V.
MODEN (Pin 13): Modulator Enable Pin. When the input
voltage is higher than VCC – 0.4V, the modulator circuits
supplied through pins 5, 6, 16 and 17 are enabled. When
the input voltage is less than 0.4V, these circuits are
disabled.
GC1 (Pin 3): Gain Control Pin. This pin is the least
significant bit of the four-step modulator gain control.
LO2(Pin14): Mixer2ndLOInputPin. Thispinisinternally
biased and should be AC-coupled. An external matching
network is not required, but can be used for improved
matching to a 50Ω source.
MODIN (Pin 4): Modulator Carrier Input Pin. This pin is
internally biased and should be AC-coupled. An external
matching network is required for a 50Ω source.
VCCLO2 (Pin 15): Power Supply Pin for the Mixer LO2
Circuits. This pin should be externally connected to the
other VCC pins and decoupled with 1000pF and 0.1µF
capacitors.
VCCMOD (Pin 5): Power Supply Pin for the I/Q Modulator.
This pin should be externally connected to the other VCC
pins and decoupled with 1000pF and 0.1µF capacitors.
VCCRF (Pin 6): Power Supply Pin for the I/Q Modulator
Input RF Buffer and Phase Shifter. This pin should be
externally connected to the other VCC pins and decoupled
with 1000pF and 0.1µF capacitors.
VCCVGA (Pin 16): Power Supply Pin for the Modulator
Variable Gain Amplifier. This pin should be externally
connected to the other VCC pins through a 47Ω resistor
and decoupled with a good high frequency capacitor (2pF
typical) placed close to the pin.
LO1 (Pin 7): Mixer 1st LO Input Pin. This pin is internally
biased and should be AC-coupled. An external matching
network is required for a 50Ω source.
MODOUT (Pin 17): Modulator RF Output Pin. This pin
must be externally biased to VCC through a bias choke. An
external matching network is required to match to 50Ω.
VCCLO1 (Pin 8): Power Supply Pin for the Mixer LO1
Circuits. This pin should be externally connected to the
other VCC pins and decoupled with 1000pF and 0.1µF
capacitors.
GC2 (Pin 18): Gain Control Pin. This pin is the most
significant bit of the four-step modulator gain control.
BI+ (Pin19):PositiveBasebandInputPinoftheModulator
I-Channel.Thispinisinternallybiasedto1.4V,butcanalso
be overdriven with an external DC voltage greater than
1.4V, but less than VCC – 0.4V.
BI– (Pin 20): Negative Baseband Input Pin of the Modula-
tor I-Channel. This pin is internally biased to 1.4V, but can
alsobeoverdrivenwithanexternalDCvoltagegreaterthan
1.4V, but less than VCC – 0.4V.
DMODE (Pin 9): Mixer 2nd LO Divider Mode Control Pin.
Low = divide-by-2, High = divide-by-1.
MX+ (Pin 10): Mixer Positive RF Output Pin. This pin must
be connected to VCC through an external matching net-
work.
MX– (Pin11):MixerNegativeRFOutputPin.Thispinmust
be connected to VCC through an external matching net-
work.
GROUND (Backside Contact): Circuit Ground Return for
the Entire IC.
10
LT5503
W
BLOCK DIAGRA
+
–
–
+
BQ
2
BQ
1
BI
20
BI
19
V-I
V-I
V
MOD
5
CC
16
17
V
VGA
CC
VGA
MODOUT
V
RF
6
4
CC
18 GC2
CONTROL
LOCIC
90°
RF
BUFFER
0°
3
GC1
MODIN
MODULATOR BIAS CIRCUITS
MIXER BIAS CIRCUITS
13 MODEN
12 MIXEN
V
LO1
LO1
8
7
CC
LO1
BUFFER
15
14
V LO2
CC
÷2
LIM
LIM
LO2
÷1
21
10
11
–
9
5503 BD
+
GND
(BACKSIDE)
MX MX
DMODE
11
LT5503
TEST CIRCUIT
(BACKSIDE)
21
C17
1µF
C18
1µF
GND
1
2
20
19
18
17
16
15
14
13
12
11
–
+
–
Q
I
I
BQ
BQ
B
BI
BI
B
+
Q
C15
C16
1µF
1µF
3
GC1
GC2
GC1
GC2
C2
L2
C3
L3
MODRFOUT
4
MODRFIN
MODIN
MODOUT
L1
C23
R1
R2
47Ω
C10
C20
5
V
CC1
V
V
MOD
V
VGA
CC
CC
CC
C1
2.2pF
C19
0.01µF
V
C7
CC1
6
RF
V
LO2
CC
1000pF
C4
C22
1000pF
L4
7
LO1IN
LO1
LO2
C11
LO2IN
8
V
LO1
MODEN
MIXEN
MODEN
MIXEN
CC
C14
100pF
9
C43
8.2pF
DMODE
DMODE
10
+
–
MX
MX
C12
1000pF
L6
L5
C13
8.2pF
V
CC2
C21
0.01µF
C5
C6
4
2
3
5
1
T1
C9
NOTE: V
MODULATOR AND UPMIXER
SECTIONS RESPECTIVELY.
AND V
POWER THE
CC2
CC1
MIXRFOUT
5503 F02
Application Dependent Component Values
1.2GHz Matching
(Modulator Only) 1.9GHz Matching 2.4GHz Matching
L1
33nH
12nH
12nH
39pF
2.7pF
n/a
22nH
5.6nH
4.7nH
15pF
18nH
2.7nH
2.7nH
8.2pF
1.2pF
1.5pF
390Ω
8.2pF
2.2pF
2.7pF
1.2pF
4.7nH
2.2nH
L2
L3
C2, C3, C7
C10
C23
R1
1.8pF
1.5pF
390Ω
15pF
240Ω
n/a
C4
C5, C6
C9
n/a
1.8pF
15pF
n/a
C11
L4
n/a
2.2pF
6.8nH
5.6nH
n/a
L5,L6
T1
n/a
n/a
LDB15C101A1900 LDB15C500A2400
Figure 2. Test Schematic for 1.2GHz, 1.9GHz and 2.4GHz Applications
12
LT5503
W U U
APPLICATIO S I FOR ATIO
U
TheLT5503consistsofadirectquadraturemodulatorand bandpass filter loss. The balanced output from the modu-
a mixer. The mixer operates over the range of 1.7GHz to lator is applied to a variable gain amplifier (VGA) that
2.7GHz, and the modulator operates with an output range provides a single-ended output. Note that the modulator
of 1.2GHz to 2.7GHz. The LT5503 is designed specifically can also be used independently of the mixer, freeing the
for high accuracy digital modulation with supply voltages mixer to be used anywhere in the system. In this case,
aslowas1.8V.ItissuitableforIEEE802.11bwirelesslocal MODRFINwillbedrivenfromanexternalfrequencysource.
area network (WLAN), MMDS and wireless local loop
Modulator Baseband
(WLL) transmitters.
The baseband I and Q inputs (BI+/BI– and BQ+/BQ–) are
internally biased to 1.4V to maximize the input signal
rangeatlowsupplyvoltage.Thisbiasvoltageisstableover
temperature, and increases by approximately 50mV at the
maximum supply voltage. The modulator I and Q inputs
have very wide bandwidth (120MHz typical), making the
LT5503 suitable for even the most wideband modulation
applications. For best carrier suppression and lowest
distortion, differential input drive should be used. Single-
ended drive is possible too, with the unused inputs AC-
coupled to ground.
A dual-conversion RF system requires two local oscilla-
tors to convert signals between the baseband and RF
domains (see Figure 3). The LT5503’s double-balanced
mixer can be used to generate the LT5503 modulator’s
high frequency carrier input (MODRFIN) by mixing the
systems 1st and 2nd local oscillators (LO1 and LO2). In
this case, a bandpass filter is required to select the desired
mixer output for the modulator input. The mixer’s RF
differential output produces –12dBm typically at 2.45GHz
and the modulator MODIN pin requires ≥–16dBm, driven
single-ended. This allows approximately 4dB margin for
LT5502
I
A/D
90°
÷2
LNA
0°
Q
A/D
2ND LO
1ST LO
LT5503
÷2
90°
VGA
0°
÷1
I
D/A
D/A
Q
5503 F03
Figure 3. Example System Block Diagram for a Dual Conversion System
13
LT5503
W U U
U
APPLICATIO S I FOR ATIO
AC-Coupled Baseband. Figure 4 shows the simplified
circuit schematic of a high-pass AC-coupled baseband
interface.
Figure 5 shows a simplified circuit schematic for interfac-
ing the LT5503’s baseband inputs to the outputs of a D/A
converter. OIP and OIN are the positive and negative
baseband outputs, respectively, of the converter’s
I-channel. Similarly, OQP and OQN are the positive and
negativebasebandoutputs,respectively,oftheconverter’s
Q-channel.
C
C
C
C
+
CPL
CPL
CPL
CPL
LT5503
BI
I
0.8pF
0.8pF
0.8pF
0.8pF
18k
–
BI
I
B
+
LT5503
I
I
I
I
INPUT
INPUT
INPUT
BI
OIP
OIN
+
–
BQ
BQ
0.8pF
0.8pF
0.8pF
0.8pF
18k
Q
–
BI
18k
D/A
Q
B
+
–
BQ
OQP
OQN
5505 F04
18k
Figure 4. AC-Coupled Baseband Interface
INPUT BQ
With approximately 18k of differential input resistance,
the suggested minimum AC-coupling capacitor can be
determined using the following equation:
5505 F05
Figure 5. DC-Coupled Baseband Interface
Modulator RF Input (MODRFIN)
1
CCPL
=
The modulator RF input buffer is driven single-ended. An
internal active balun circuit produces balanced signals to
drive the integrated phase shifter. Limiters following the
phase shifter output accommodate a wide range of
MODRFIN power, resulting in minimal degradation of
modulation gain/phase accuracy performance or carrier
feedthrough. This pin is easily matched to a 50Ω source
with the simple lowpass network shown in Figure 2. This
pin is internally biased, therefore an AC-coupling capaci-
tor is required.
(18•103 • π • fC)
wherefC isthe3dBcut-offfrequencyofthebasebandinput
signal.
A larger capacitor may be used where the settling time of
charginganddischargingtheAC-couplingcapacitorisnot
critical.
DC-CoupledBaseband. Thebasebandinputs’internalbias
voltage can be overdriven with an external bias circuit.
This facilitates direct interfacing to a D/A converter for
faster transient response. In this case, the LT5503’s
baseband inputs are DC biased by the converter. The
optimal VBIAS is 1.4V, independent of VCC. In general, the
maximum VBIAS should be less than VCC – 0.4V. The DC
load on each converter output can be approximated using
the following equation where IINPUT is the current flowing
into a modulator input:
Modulator VGA (Variable Gain Amp)
The VGA has two digital selection lines to provide a
nominal 0dB, 4.5dB, 9dB and 13.5dB attenuation from the
maximummodulatoroutputpowersetting. Thelogictable
is shown below:
GC2
Attenuation
Low
0dB
High
9dB
V
BIAS − 1.4V
GC1
Low
High
I
=
INPUT
9kΩ
4.5dB
13.5dB
14
LT5503
W U U
APPLICATIO S I FOR ATIO
U
Pin 16 should be connected externally to VCC through a
low value series resistor (47Ω typical). To assure proper
output power control, a good, local high frequency AC
ground for Pin 16 is essential. The MODOUT port of the
VGA is an open collector configuration. An inductor with
high self resonance frequency is required to connect
Pin 17 to VCC as a DC return path, and as a part of the
output matching network. Additional matching compo-
nents are required to drive a 50Ω load as shown in
Figure 2.TheamplifierisdesignedtooperateinClassAfor
low distortion performance. The typical output 1dB com-
pression point (P1dB) is –3dBm at 2.45GHz. When the
Mixer LO2 Port
The mixer LO2 port is designed to operate in the 50MHz to
1000MHzrange. Thefirststageisalimitingamplifier. This
stage produces the correct output levels to drive the
internal divider circuit reliably, with LO2 input levels down
to –20dBm. The output of the divider then drives another
stage, which in turn switches the nonlinear inputs of the
double-balanced mixer. Note that the mixer output will
produce broadband noise if the LO2 signal level is too low.
The input amplifier is designed for a good match over the
entire frequency range. The only requirement (Figure 2) is
an external AC-coupling capacitor.
differentialbasebandinputvoltagesarehigherthan1VP-P
,
Mixer Output Ports (MX+/MX–)
the VGA operates in Class AB mode, and the distortion
performance of the modulator is degraded. The logic
controlinputsdonotdrawcurrentwhentheyarelow.They
draw about 2µA each when high.
The mixer output is a differential open collector configura-
tion. Bias current is supplied to these two pins through the
center tap of a balun as shown in Figure 2. Simple lowpass
matchingisusedtotransformeachlegofthemixeroutput
to 25Ω for the balun’s 50Ω input impedance.
Mixer LO1 Port
The mixer LO1 input port is the linear input to the mixer.
It consists of an active balun amplifier designed to operate
over the 1.4GHz to 2.4GHz frequency range. There is a
linear relationship between LO1 input power and
MIXRFOUTpowerforLO1inputlevelsuptoapproximately
–20dBm. After that, the mixer output begins to compress.
When operated in the recommended –14dBm to –8dBm
input power range, the mixer is well compressed, which in
turn creates a stable output level for the modulator input.
As shown in Figure 2, a simple lowpass matching network
is required to match this pin to 50Ω. This pin is internally
biased, therefore an AC-coupling capacitor is required.
The balun approach provides the highest output power
and best LO1 suppression, but is not absolutely neces-
sary. It is also possible to match each output to 50Ω and
couple power from one output. The unused output should
be terminated in the same characteristic impedance. In
this case, output power is approximately 2dB lower and
LO1 suppression degrades to approximately 15dBc. A
schematic for this approach is shown in Figure 6 where
inductors LB+ and LB– supply bias current to the mixer’s
differential outputs, and resistor RTERM terminates the
unused output.
+
–
10
11
1.9GHz
5.6nH
1.8pF
15pF
2.4GHz
2.7nH
0.68pF
8.2pF
MX
MX
L5,L6
C5, C6
C9
L6
L5
V
CC
+
–
LB
LB
R
TERM
C5
C6
51Ω
C9
C
BYPASS
MIXRFOUT
5503 F06
Figure 6. 50Ω Mixer Output Matching Without a Balun
15
LT5503
W U U
U
APPLICATIO S I FOR ATIO
EVALUATION BOARD
RF Layout Tips:
Figure 7 shows the circuit schematic of the evaluation
board. The MODRFIN, MODRFOUT and MIXRFOUT ports
are matched to 50Ω at 2.45GHz. The LO1IN port is
matched to 50Ω at 2.1GHz and the LO2IN port is internally
matched.
• Use 50Ω impedance transmission lines up to the
matching networks, use of a ground plane is a must.
• Keep the matching networks as close to the pins as
possible.
• Surface mount 0402 outline (or smaller) parts are
recommended to minimize parasitic inductances and
capacitances.
A 390Ω resistor is used to reduce the quality factor (Q) of
the modulator output and deliver an output power of
–3dBm typically. A lower value resistor may be used if the
desired output power is lower. For example, the output
power will be 3dB lower if a 200Ω resistor is used.
• Isolate the MODOUT pin from the LO2 input by putting
the LO2 transmission line on the bottom side of the
board.
Inductors with high self-resonance frequency should be
used for L1 to L6.
• Theonlygroundconnectionisthroughtheexposedpad
on the bottom of the package. This exposed pad must
be soldered to the board in such a way to get complete
RF contact.
Forsimplerevaluationinalabenvironment, theevaluation
board includes op amps to convert single-ended I and Q
input signals to differential . The op amp configuration has
a voltage gain of two; therefore the peak baseband input
voltage should be halved to maintain the same RF output
power. The op amp configuration shown will maintain
acceptable differential balance up to 10MHz typically. It is
also possible to bypass the op amps and drive the
modulator’s differential inputs directly by connecting to
the four oversized vias on the board (V1, V2, V3 and V4).
• Low impedance RF ground connections are essential
and can only be obtained by one or more vias tying
directly into the ground plane.
• VCC lines must be decoupled with low impedance,
broadband capacitors to prevent instability.
• Separate power supply lines should be used to isolate
the MODIN signal and other stray signals from the
MODOUT line. If possible, power planes should be
used.
Figure7alsoshowsatableofmatchingnetworkvaluesfor
designs centered at 1.9GHz and1.2GHz.
Figure 8 shows the evaluation board with connectors and
ICs. Figure 9 shows the test set-up with the upconverting
mixer and IQ modulator connected in a transmit configu-
ration. Refer to the demo boardDC365A Quick Start Guide
for detailed testing information.
• Avoid use of long traces whenever possible. Long RF
traces in particular can lead to signal radiation and
degraded isolation, as well as higher losses.
16
LT5503
W U U
APPLICATIO S I FOR ATIO
U
E4
V
CC4
V
CC4
C33
C34
C27
0.01µF
C29
0.01µF
C32
C28
4.7µF
4.7µF
J1
J4
4.7µF
4.7µF
5
5
8
8
I-IN
+
–
Q-IN
+
–
7
7
R14
U2-1
U3-1
R3
R13
510Ω
1%
R15
R16
510Ω
1%
R12
56Ω
1%
510Ω
LT1807
LT1807
56Ω
510Ω
1%
1%
1%
R18
R17
510Ω
4
4
6
6
510Ω
1%
1%
C16
1µF
C15
1µF
R28
49.9Ω
R25
49.9Ω
C35, 39pF
C36, 39pF
C38, 1pF
C37, 1pF
R20
R19
510Ω
1%
C41
1µF
OPT
C42
V
V
CC4
CC4
R22
10k
1%
510Ω
2
3
2
1µF
–
+
–
1%
R21
10k
1%
OPT
1
1
U2-2
LT1807
U3-2
LT1807
C18
C17
R26
49.9Ω
R27
49.9Ω
1µF
V3
V1
+
1µF
R23
10k
1%
LT5503
R24
10k
1%
3
C40
20
19
18
17
16
15
14
13
12
11
C39
1
2
3
4
5
6
7
8
9
–
+
–
+
BQ
BQ
BI
4.7µF
4.7µF
V2
V4
BI
*C2
J5
*L2
GC1
MODRFOUT
GC2
*C3
J2
*L3
*C23
*L1
*R1
MODRFIN
MODIN
MODOUT
R2
47Ω
*C10
E1
J3
V
V
V
MOD
V
VGA
CC1
CC
CC
CC
V
CC1
C20
RF
V
LO2
V
1000pF
CC
CC2
C14
100pF
*C4
J6
*L4
LO2IN
LO1IN
LO1
LO2
C1
2.2pF
C19
0.01µF
C22
1000pF
*C7
V
V
LO1
CC2
MODEN
MIXEN
CC
C43
8.2pF
*C11
E3
R29
10Ω
DMODE
C12
1000pF
V
CC3
C24
4.7µF
C45
0.1µF
10
+
–
MX
MX
GND
21
R5
20k
R4
2.7k
R6
20k
R7
20k
R8
2.7k
SW1
*L6
*L5
1
12
11
10
9
8
7
2
3
4
5
6
*Application Dependent Component Values
1.2GHz Matching
(Modulator Only) 1.9GHz Matching 2.4GHz Matching
*C5
*C6
E2
L1
L2
L3
33nH
12nH
12nH
39pF
2.7pF
n/a
240Ω
n/a
n/a
n/a
n/a
n/a
n/a
22nH
5.6nH
4.7nH
15pF
1.8pF
1.5pF
390Ω
15pF
1.8pF
15pF
2.2pF
6.8nH
5.6nH
18nH
2.7nH
2.7nH
8.2pF
1.2pF
1.5pF
390Ω
8.2pF
2.2pF
2.7pF
1.2pF
4.7nH
2.2nH
V
CC2
C21
C13
0.01µF
8.2pF
4
1
2
3
5
C2, C3, C7
C10
C23
R1
C4
C5, C6
C9
C11
L4
L5,L6
T1
J7
*C9
MIXER
OUT
T1
5503 F07
n/a
LDB15C101A1900 LDB15C500A2400
Figure 7. Evaluation Circuit Schematic for 1.2GHz, 1.9GHz and 2.4GHz Applications
17
LT5503
W U U
U
APPLICATIO S I FOR ATIO
QIN
IIN
V
CC4
GND
V
CC1
LT1807
V1
LT1807
V4
V3
V2
MODRFIN
MODRFOUT
LT5503
IC
LO1IN
LO2IN
1
2
3
4
5
6
GND
V
CC2
V
CC3
5503 F08
MIXRFOUT
Figure 8. LT5503 Evaluation Board Layout
18
LT5503
W U U
APPLICATIO S I FOR ATIO
U
+
–
POWER SUPPLY 4
DUAL SIGNAL
GENERATOR
0°
+
–
90°
POWER SUPPLY 1
QIN
IIN
V
CC4
GND
SPECTRUM
ANALYZER
LT1807
V1
LT1807
V4
MODRFIN
V3
V2
MODRFOUT
SIGNAL
GENERATOR 1
SIGNAL
GENERATOR 1
LT5503
IC
1
LO1IN
LO2IN
2
3
4
5
6
V
CC3
V
GND
CC2
+
–
POWER SUPPLY 3
+
–
MIXRFOUT
POWER SUPPLY 2
EXTERNAL 3dB
ATTENUATOR PAD,
OR 2.45GHz BPF
5503 F09
Figure 9. Test Set-Up for Upconverting Mixer and
I/Q Modulator Transmit Chain Measurements.
19
LT5503
U
PACKAGE DESCRIPTIO
FE Package
20-Lead Plastic TSSOP (4.4mm)
(Reference LTC DWG # 05-08-1663)
6.40 – 6.60*
(.252 – .260)
5.2
(.205)
20 1918 17 16 15 14 1312 11
3.0
(.118)
6.25 – 6.50
(.246 – .256)
5
7
8
1
2
3
4
6
9 10
1.15
(.0453)
MAX
4.30 – 4.48**
(.169 – .176)
0° – 8°
.65
(.0256)
BSC
.50 – .70
.105 – .180
.05 – .15
(.020 – .028)
(.0041 – .0071)
(.002 – .006)
.18 – .26
(.0071 – .0102)
FE20 TSSOP 0501
NOTE:
1. CONTROLLING DIMENSION: MILLIMETERS
MILLIMETERS
2. DIMENSIONS ARE IN
(INCHES)
3. DRAWING NOT TO SCALE
*DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED .152mm (.006") PER SIDE
**DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED .254mm (.010") PER SIDE
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT5502
400MHz Quadrature IF Demodulator with RSSI
5503i LT/TP 1001 1.5K • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 2001
20 LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
●
●
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
相关型号:
LT5506EUF#TR
LT5506 - 40MHz to 500MHz Quadrature Demodulator with VGA; Package: QFN; Pins: 16; Temperature Range: -40°C to 85°C
Linear
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