TRF3762
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INTEGER-N PLL WITH INTEGRATED VCO
REF
To Microcontroller
AVDD_REF
AVDD_CP
35 34
33
32 31
30
GND
AVDD
GND
36
CPOUT
REF_IN
37
MUX_OUT
DVDD2
C2
39 38
GND
29
AVDD_BIAS
CLOCK
3
28
RBIAS1
27
GND
26
VCTRL_IN
25
AVDD_VCO
R3
2.37 kΩ
DATA
4
STROBE
5
DGND
6
DGND
7
24
AVDD_BUF
DVDD1
8
23
AVDD_CAPARRAY
AVDD_PRES
9
22
GND
R5
120 Ω
18
RSVD
C7
1000 pF
R6
120 Ω
AVDD
GND
16 17
21
19 20
RBIAS2
15
AVDD_VCOBUF
14
GND
12 13
AVDD_OUTBUF
10
11
VCO_OUTM
GND
TRF3762
(TOP VIEW)
VCO_OUTP
Wireless Infrastructure
– WCDMA, CDMA, GSM
– Wideband Transceivers
– Wireless Local Loop
– RFID Transceivers
– Clock generation
– IF LO generation
C3
R1
2
APPLICATIONS
•
C1
C4
1000 pF
(See Note A)
CHIP_EN
GND
•
•
•
•
•
•
40
1
PD_OUTBUF
R2
GND
•
•
•
Fully Integrated VCO
Low Phase Noise: –137dBc/Hz
at 600kHz, fVCO of 1.9GHz
Low Noise Floor: –158dBc/Hz at 10MHz Offset
Integer-N PLL
Input Reference Frequency range:
10MHz to 104MHz
VCO Frequency Divided by 2-4 Output
Output Buffer Enable Pin
Programmable Charge Pump Current
Hardware and Software Power Down
3-Wire Serial Interface
Single Supply: 4.5V to 5.25V Operation
To Microcontroller
•
•
GND
FEATURES
1
R4
4.75 kΩ
VDD
VDD
C5
10 pF
C6
10 pF
LOAD
A.
See the Application Information section for
Loop Filter Design procedures.
AVAILABLE DEVICE OPTIONS
PART NUMBER
TRF3762-E
Div by 1
Div by 2
Div by 4
Fstart
Fstop
Fstart
Fstop
Fstart
Fstop
1805
1936
902.5
968
451.25
484
DESCRIPTION
TRF3762-E is a high performance, highly integrated frequency synthesizer, optimized for high performance
applications. The device includes a low-noise, voltage-controlled oscillator (VCO) and an integer-N PLL.
TRF3762-E integrates divide-by 1, 2, or 4 options for a more flexible output frequency range. The device is
controlled through a 3-wire serial-programming-interface (SPI) interface. For power sensitive applications, the
device can be powered down by the SPI interface or externally via CHIP_EN (pin 2).
The TRF3762-E offers the ability to reduce lock time when compared to the TRF3761-E device. The TRF3762-E
was designed so that the external loop filter is the determining factor in the setting of lock time. Typical lock times
for the TRF3762-E are less than 350µs (depending on the loop filter circuit). All other features of the TRF3762-E
are identical to the TRF3761-E including superior phase noise and spurious output as well as the programming
model and register mapping. The TRF3762-E is pin-to-pin compatible to the TRF3761-E.
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2008, Texas Instruments Incorporated
TRF3762
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This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
PACKAGE/ORDERING INFORMATION (1)
(1)
(2)
PRODUCT
PACKAGE
LEAD
PACKAGE
DESIGNATOR (2)
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
MARKINGS
TRF3762-E
QFN-40
RHA
–40°C to 85°C
TRF3762-E
ORDERING
NUMBER
TRANSPORT MEDIA,
QUANTITY
TRF3762-EIRHAR
Tape and Reel, 2500
TRF3762-EIRHAT
Tape and Reel, 250
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
website at www.ti.com.
Thermal pad size: 177 × 177 mils.
39
3
Lock
Det
STROBE
DATA
CLOCK
MUX_OUT
Functional Block Diagram
4
5
Serial
Interface
38
R Div
REF_IN
PFD
Charge
Pump
34
CPOUT
N−Divider
B−
counter
A−
counter
26
Prescaler
div p/p+1
2
SPI
From
SPI
From
13
VCO_OUTP
Power
Down
RSVD
18
2
VCO_OUTM
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1
PD_OUTBUF
CHIP_EN
SPI
From
14
Div1/2/4
VCTRL_IN
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35 34
33
32 31
30
GND
AVDD
36
CPOUT
37
GND
AVDD_CP
39 38
GND
40
1
AVDD_REF
PD_OUTBUF
REF_IN
DVDD2
MUX_OUT
RHA PACKAGE
(TOP VIEW)
GND
CHIP_EN
2
29
AVDD_BIAS
CLOCK
3
28
RBIAS1
DATA
4
27
GND
STROBE
5
26
VCTRL_IN
DGND
6
25
AVDD_VCO
9
22
GND
15
16 17
18
AVDD
GND
14
AVDD_VCOBUF
12 13
21
19 20
VCO_OUTP
GND
GND
10
11
RBIAS2
AVDD_PRES
RSVD
AVDD_CAPARRAY
GND
AVDD_BUF
23
AVDD_OUTBUF
24
8
VCO_OUTM
7
GND
DGND
DVDD1
TERMINAL FUNCTIONS
TERMINAL (1)
NAME
NO.
I/O
DESCRIPTION
PD_OUTBUF
1
I
Once configured in register 1, this pin will control the output buffer. Logic level 0
turns on the buffer and logic level 1 turns off the buffer.
CHIP_EN
2
I
This pin requires 4.5 to 5.25V applied for normal operation. Grounding this pin will
disable the chip.
CLOCK
3
I
Serial-programming-interface clock
DATA
4
I/O
5
I
STROBE
Serial-programming-interface data, used for programming the frequency and other
features.
Serial-programming-interface strobe required to write the data to the chip
DGND
6, 7
DVDD1
8
Digital power supply, requires 4.5 to 5.25V, Suggested decoupling, 0.1µF and
10pF capacitors in parallel.
AVDD_PRES
9
Power supply for prescaler circuit, requires 4.5 to 5.25V, Suggested decoupling,
0.1µF and 10pF capacitors in parallel.
VCO_OUTP
13
O
VCO output, can be used single ended matched to 50Ω or in conjuction with
VCO_OUTM (pin 14) with a balun.
VCO_OUTM
14
O
VCO output, can be used single ended matched to 50Ω or in conjunction with
VCO_OUTP (pin 13) with a balun.
AVDD_OUTBUF
15
Power supply for output buffers, requires 4.5 to 5.25V, Suggested decoupling,
0.1µF and 10pF capacitors in parallel.
AVDD_VCOBUF
17
Power supply for VCO buffers, requires 4.5 to 5.25V, Suggested decoupling, 0.1µF
and 10pF capacitors in parallel.
RSVD
18
I
Reserved for internal use, requires a 1000pF capacitor to ground for opperation.
RBIAS2
19
I/O
External bias resistor for setting the internal reference current requires a 4.75KΩ
resister to ground.
(1)
Digital ground
Power Supply = VCC = DVDD1, AVDD1, AVDD_PRES, AVDD_VCOBUF, AVDD, AVDD_CAPARRAY, AVDD_BUF, AVDD_VCO,
AVDD_BIAS, AVDD_CP, AVDD_REF, DVDD2
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TERMINAL FUNCTIONS (continued)
TERMINAL (1)
I/O
DESCRIPTION
NAME
NO.
AVDD
21
Analog power supply, requires 4.5 to 5.25 V, Suggested decoupling, 0.1µF and
10pF capacitors in parallel.
AVDD_CAPARRAY
23
Power supply for VCO core and buffer, requires 4.5 to 5.25V, Suggested
decoupling, 0.1µF and 10pF capacitors in parallel.
AVDD_BUF
24
Power supply for VCO core and buffer, requires 4.5 to 5.25V, Suggested
decoupling, 0.1µF and 10pF capacitors in parallel.
AVDD_VCO
25
Power supply for VCO core and buffer, requires 4.5 to 5.25V, Suggested
decoupling, 0.1µF and 10pF capacitors in parallel.
VCTRL_IN
26
I
RBIAS1
28
I/O
AVDD_BIAS
29
VCO control voltage, the output of the loop filter is applied to this pin.
External bias resistor for setting charge pump reference current, requires 2.37KΩ
resistor to ground.
Power supply for band gap current bias, requires 4.5 to 5.25V, Suggested
decoupling, 0.1µF and 10pF capacitors in parallel.
GND
10, 11, 12, 16, 20, 22,
27, 30, 31, 33, 37
AVDD
32
CPOUT
34
AVDD_CP
35
Analog power supply for charge pump, requires 4.5 to 5.25V, Suggested
decoupling, 0.1µF and 10pF capacitors in parallel
AVDD_REF
36
Power supply for REF_IN circuitry, requires 4.5 to 5.25V, Suggested decoupling,
0.1µF and 10pF capacitors in parallel.
REF_IN
38
I
Reference signal input, reference oscillator input of 10MHz to 104MHz.
MUX_OUT
39
O
Generally used for digital lock detect, can be used to verify locked condition by
microcontroller, high = locked, low = unlocked.
DVDD2
40
Analog ground
Power supply for FUSE cell, requires 4.5 to 5.25V. Suggested decoupling, 0.1µF,
1nF and 1pF capacitors in parallel.
O
Charge pump output, connected to the input of loop filter.
Power supply for the digital regulator, requires 4.5 to 5.25V, Suggested decoupling,
0.1µF and 10pF capacitors in parallel.
THERMAL CHARACTERISTICS
over operating free-air temperature range (unless otherwise noted)
PARAMETER (1)
TEST CONDITIONS
MIN
θJA
(1)
Thermal derating, junction-to-ambient
TYP
MAX
UNIT
26
°C/W
Soldered slug, 200-LFM airflow
20.1
°C/W
Soldered slug, 400-LFM airflow
17.4
°C/W
Soldered slug, no airflow
Determined using JEDEC standard JESD-51 with High K board.
ABSOLUTE MAXIMUM RATINGS
Over operating free-air temperature range (unless otherwise noted) (1)
Supply voltage range
(2)
Digital I/O voltage range
VALUE
UNIT
–0.3 to 5.5
V
–0.3 to VCC +0.3
V
TJ
Operating virtual junction temperature range
–40 to 150
°C
Tstg
Storage temperature range
–65 to 150
°C
(1)
(2)
4
Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute maximum rated conditions for extended periods may affect device reliability.
All voltage values are with respect to network ground terminal.
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RECOMMENDED OPERATING CONDITIONS
Over operating free-air temperature range (unless otherwise noted)
VCC
Power supply voltage
MIN
NOM
MAX
4.5
5
5.25
V
500
µVpp
Power supply voltage ripple
UNIT
TA
Operating free air temperature range
–40
85
°C
TJ
Operating virtual junction temperature range
–40
150
°C
ELECTRICAL CHARACTERISTICS
Supply voltage = VCC = 4.5V to 5.25V, TA = –40 to 85 °C (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
DC Parameters
ICC
Total supply current
TA = 25°C
Divide by 1 output
130
mA
Divide by 2 output
140
mA
Divide by 4 output
150
mA
Reference Oscillator Parameters
fref
Reference frequency
10
104
MHz
Reference input sensitivity (REF_IN)
0.5
2
VPP
Reference input impedance (REF_IN)
Parallel capacitance
Parallel resistance
2
pF
3000
Ω
PFD Charge Pump
PFD frequency
Charge pump current (ICP_OUT )
30
SPI programmable
5.6
MHz
mA
Digital Interface (PD_OUTBUF, CHIP_EN, CLOCK, DATA, STROBE)
VIH
High-level input voltage
2.5
VCC
V
VIL
Low-level input voltage
0
0.8
V
VOH
High-level output voltage
VOL
Low-level output voltage
0.8VCC
V
0.2VCC
V
Output Power
Single ended
0
dBm
Differential
3
dBm
TIMING REQUIREMENTS
Supply voltage = VCC = 4.5V to 5.25V, TA = –40 to 85 °C
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
t(CLK)
Clock period
50
ns
tsu1
Setup time, data
10
ns
th
Hold time, data
10
ns
tw
Pulse width, STROBE
20
ns
tsu2
Setup time, STROBE
10
ns
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tsu1
th
1” Clock Pike
t(CLK)
CLOCK
DATA
DB0 (LSB)
Address bit 1
DB1
Address bit 2
DB2
Address bit 3
DB29
Cmd bit 30
DB30
Cmd bit 31
DB31 (MSB)
Cmd bit 32
tsu2
tw
STROBE
A.
The first 4 bits, DB(3-0), of data are Address bits. The 28 remaining bits, DB(31-4), are part of the command. The
command is little endian or lower bits first.
Figure 1. Serial Programming Timing Diagram
6
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TRF3762-E ELECTRICAL CHARACTERISTICS
Supply voltage = VCC = 5V, TA = –40 to 85 °C (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
NOISE CHARACTERISTICS
VCO phase noise,
Free running VCO direct output
fVCO = 1869MHz,
fO = 1869MHz
VCO phase noise,
Free running VCO divide-by-2 output
fVCO = 1869MHz,
fO = 934.5MHz
VCO phase noise,
Free running VCO divide-by-4 output
fVCO = 1869MHz,
fO = 467.25MHz
100kHz offset
-119.3
600kHz offset
-137.3
1MHz offset
-141.4
6MHz offset
-154.1
10MHz offset
-156
100kHz offset
-124.4
600kHz offset
-143
1MHz offset
-146.7
6MHz offset
-156.5
10MHz offset
-156.7
100kHz offset
-131
600kHz offset
-149
1MHz offset
-151
6MHz offset
-155.8
10MHz offset
-156.1
1kHz offset
VCO phase noise,
Closed loop phase noise direct output (1) (2) (3)
fVCO = 1869MHz,
fO = 1869MHz
100Hz to 10MHz
VCO phase noise,
Closed loop phase noise divide-by-2 output (1) (2) (3)
fVCO = 1869MHz,
fO = 934.5MHz
-136.7
1MHz offset
-141.6
600kHz offset
1MHz offset
10MHz offset
100Hz to 10MHz
RMS phase error
Closed loop phase noise divide-by-4 output (3)
100Hz to 10MHz
VCO gain, Kv
VCO free running
Reference spur and multiples
(1)
(2)
(3)
fVCO = 1869MHz,
fO = 467.25MHz
dBc/Hz
-156
-87.8
-142.6
-147
dBc/Hz
-1567.6
0.521°
1kHz offset
VCO phase noise,
Closed loop phase noise divide-by-4 output (1) (2) (3)
dBc/Hz
1.02°
1kHz offset
RMS phase error
Closed loop phase noise divide-by-2 output (3)
dBc/Hz
-82.5
600kHz offset
10MHz offset
RMS phase error
Closed loop phase noise direct output (3)
dBc/Hz
-92.9
600kHz offset
-148.1
1MHz offset
-151.4
10MHz offset
-155.2
(2)
dBc/Hz
0.251°
24
MHz/V
-80
dBc
See Application Circuit Figure 15.
PFD = 200kHz, Loop Filter BW = 15kHz, Output frequency step = 200kHz.
Reference oscillator RMS phase error = 0.008250°, RMS jitter = 881.764 fs.
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TRF3762-E TYPICAL CHARACTERISTICS
Closed Loop VCO Phase Noise
Open Loop VCO Phase Noise
−70
−70
CL = 1869 MHz
−90
−100
−110
−120
−130
−140
−150
−160
1k
−90
−100
−110
−120
−130
−140
−150
10k
100k
−160
1k
10M
1M
Figure 3.
Open Loop VCO Phase Noise
CL = 934.5 MHz
OL = 934.5 MHz
−80
−90
Phase Noise − dBc/Hz
Phase Noise − dBc/Hz
10M
−70
−100
−110
−120
−130
−140
−150
−90
−100
−110
−120
−130
−140
−150
10k
100k
−160
1k
10M
1M
10k
100k
1M
f − Frequency − Hz
f − Frequency − Hz
Figure 4.
Figure 5.
Closed Loop VCO Phase Noise
10M
Open Loop VCO Phase Noise
−70
−70
CL = 467.25 MHz
−80
OL = 467.25 MHz
−80
−90
Phase Noise − dBc/Hz
Phase Noise − dBc/Hz
1M
f − Frequency − Hz
−80
−100
−110
−120
−130
−140
−150
8
100k
Figure 2.
Closed Loop VCO Phase Noise
−160
1k
10k
f − Frequency − Hz
−70
−160
1k
OL = 1869 MHz
−80
Phase Noise − dBc/Hz
Phase Noise − dBc/Hz
−80
−90
−100
−110
−120
−130
−140
−150
10k
100k
1M
10M
−160
1k
10k
100k
f − Frequency − Hz
f − Frequency − Hz
Figure 6.
Figure 7.
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1M
10M
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TRF3762-E TYPICAL CHARACTERISTICS (continued)
Direct Output: PFD Frequency Spurs
Figure 8.
Direct-By-2 Output: PFD Frequency Spurs
Figure 9.
Direct-By-4 Output: PFD Frequency Spurs
Figure 10.
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SERIAL INTERFACE PROGRAMMING REGISTERS DEFINITION
The TRF3762 features a 3-wire serial programming interface that controls an internal, 32-bit shift register. There
are a total of 3 signals that need to be applied: the CLOCK (pin 3), the serial DATA (pin 4) and the STROBE (pin
5). The DATA (DB0-DB31) is loaded LSB first and is read on the rising edge of the CLOCK. The STROBE is
asynchronous to the CLOCK and at its rising edge the data in the shift register gets loaded onto the selected
internal register. The first four bits (DB0-DB3) is the address to select the available internal registers.
tsu1
th
t(CLK)
1” Clock Pike
CLOCK
DATA
DB0 (LSB)
Address bit 1
DB1
Address bit 2
DB2
Address bit 3
DB29
Cmd bit 30
DB30
Cmd bit 31
DB31 (MSB)
Cmd bit 32
tsu2
tw
STROBE
A.
The first 4 bits, DB(3-0), of data are Address bits. The 28 remaining bits, DB(31-4), are part of the command. The
command is little endian or lower bits first.
Figure 11. Serial Programming Timing Diagram
Register Address
DB0
DB1
DB2
REST
DB3
DB4
Charge Pump Current
Select
DB5
DB6
DB7
Output Mode
DB8
DB9
Reference Clock Divider (RDiv)
DB16
DB17
DB18
DB19
DB20
DB21
DB22
OUTBUF
EN_SEL
PD
BUFOUT
DB10
DB11
Anti Backlash
DB23
DB24
DB25
DB26
DB27
Reference Clock Divider (RDiv)
DB12
DB13
DB14
DB15
PFD_P
OL
TRIS_C
P
CP_TE
ST
Full Cal
Req
DB28
DB29
DB30
DB31
Figure 12. Register 1
10
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Table 1. Register 1: Device Setup
REGISTER 1 MAPPING
Data Field
Address
Bits
DB31
FULL_CAL_REQ
This is a read only bit, that indicates if a
power-up cal is required
0 power-up cal is not required
1 power-up cal is required
DB30
CP_TEST
TI internal use only
1 test enabled
DB29
TRIS_CP
High-impedance state charge pump
output
1 CP high-impedance state
0 for normal operation
DB28
PFD_POL
Selects Polarity of PFD, should match
polarity of VCO gain. If using external
VCO with Negative gain then set to 0
and vise versa. The internal VCO has
positive gain so set to positive(1)
0 negative
1 positive
DB27
ABPW1
ABPW: anti-backlash pulse width
00
01
10
11
DB26
ABPW0
DB25
RDIV_13
14-bit reference clock divider
DB24
RDIV_12
RDIV:00...01: divide by 1
RDIV:00...10: divide by 2
RDIV:00...11: divide by 3
DB23
RDIV_11
DB22
RDIV_10
DB21
RDIV_9
DB20
RDIV_8
DB19
RDIV_7
DB18
RDIV_6
DB17
RDIV_5
DB16
RDIV_4
DB15
RDIV_3
DB14
RDIV_2
DB13
RDIV_1
DB12
RDIV_0
DB11
PD_BUFOUT
If DB10 = 0 then it controls power down
of output buffer
:
00 default; output buffer on
01 output buffer off
1x output buffer on/off controlled by
OUTBUF_EN pin
DB10
OUTBUF_EN_SEL
Select Output Buffer enable control:
0 internal
1 through OUTBUF_EN pin
DB9
OUT_MODE_1
DB8
OUT_MODE_0
OUTBUFMODE: Selection of RF
output buffer division ratio
00 divide by 1
01 divide by 2
10 divide by 4
DB7
ICP2
DB6
ICP1
DB5
ICP0
DB4
RESET
DB3
1.5ns
0.9ns
3.8ns
2.7ns
delay
delay
delay
delay
ICP: select charge pump current
(1 mA step). From 1.4mA to 11.2mA
with Rbias set to 2.37KΩ.
Registers reset
1 high
0 low for normal operation
Address Bits =0000 for register 1
DB2
DB1
DB0
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OUT_MODE: TRF3762 has an optional divide by 2 or 4 output, which is selectable by programming bits
of register 1 (see Table 1).
CP_TEST: By setting bit DB30 to 1 it is possible to test the PFD up or down pulses. Internal TI use only.
TRIS_CP: If bit DB29 is set to 1, the charge pump output goes in tri-state. For normal operation, DB29 must be
set to 0.
ABPW: Bits are used to program the width of the anti-backlash pulses of the PFD. The user
selects one of the following values: 0.9ns, 1.5ns, 2.7ns and 3.8ns. Backlash can occur when Fpfd becomes
phase aligned with Fout of the VCO. This will cause a high impedance state on the phase detector and allow the
output frequency to drift until the phase difference is enough to cause the phase detector to start sending signals
to the charge pump to correct the difference. This slight variation will show up as a sub harmonic of the pfd
signal in the passband of the loop filter which would result in a significant spur in the output of the VCO. It is
recommended that the anti-backlash pulse be set to the 1.5ns which gives the best spur reduction for the
TRF3762.
PFD_POL: Bit DB28 of register 1 sets the polarity of the PFD. A Low (0) selects a negative polarity, and a High
(1) selects a positive polarity. By choosing the correct polarity, the TRF3762 will works with an external VCO
having both positive and negative gain (Kv). For example if an external VCO has a Kv = -23MHz/V then the PFD
polarity would need to be negative, so DB28 would be set to a Low (0). When using the internal VCO with a Kv
of 23MHz/V, the PDF_POL should be set to 1.
RDiv: A 14-bit word programs the RDiv for the reference signal, DB25 is the MSB and DB12 is the LSB. RDiv
value is determined by dividing the reference frequency by the channel step size. For example if the reference
frequency is 10MHz and the channel step size is 200KHz then RDiv would be 50. This sets up the Fpfd for the
phase detector, in other words the reference frequency will be divided down by a factor of RDiv which in this
example is 50.
ICP: Bits set the charge pump current.
1.2 V
22.168
ICP =
× (N + 1) ×
Rbias1
8
(1)
which reduces to:
ICP =
3.3252 × (N + 1)
Rbias1
(2)
where N = decimal value of [Reg1 DB]. The range is set by N and Rbias2. It is recommended that Icp be
set to 7mA or =101.
OUTBUF_EN_SEL: Output buffer on/off state is controlled through serial interface or an external pin. If bit DB10
is a 0 (default state) the output buffers state is elected through bit DB11. If DB10 is a 1, the buffers on/off are
directly controlled by the OUTBU_EN pin.
RESET: Setting bit DB4 to 1, all registers are reset to default values.
Refer to Register 1 under the Application Information section.
Register Address
DB0
DB1
DB2
Reference Frequency (Integer Part)
DB3
DB4
DB5
DB6
Reference
Frequency
Continued
DB16
DB17
DB7
DB8
Reference Frequency (Fractional Part)
DB9
DB10
DB11
DB12
DB13
DB14
VCO Frequency in MHz
DB18
DB19
DB20
DB21
DB22
DB23
DB24
DB25
DB15
START
_CAL
DB26
DB27
DB28
DB29
DB30
DB31
Figure 13. Register 2
12
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Table 2. Register 2: VCO Calibration
REGISTER 2 MAPPING
Data Field
Address
Bits
DB31
START_CAL
DB30
FOUT12
DB29
FOUT11
DB28
FOUT10
DB27
FOUT9
DB26
FOUT8
DB25
FOUT7
DB24
FOUT6
DB23
FOUT5
DB22
FOUT4
DB21
FOUT3
DB20
FOUT2
DB19
FOUT1
DB18
FOUT0
DB17
REF_FRAC6
DB16
REF_FRAC5
DB15
REF_FRAC4
DB14
REF_FRAC3
DB13
REF_FRAC2
DB12
REF_FRAC1
DB11
REF_FRAC0
DB10
REF6
DB9
REF5
DB8
REF4
DB7
REF3
DB6
REF2
DB5
REF1
DB4
REF0
DB3
0
DB2
0
DB1
0
DB0
1
1 start calibration
VCO frequency in MHz start calibration
Reference frequency in MHz (fractional
part)
Reference frequency in MHz (integer
part)
0000000
0000001
0000010
.....
1100011
= 0.00MHz
= 0.01MHz
= 0.02MHz
= 0.99MHz
0001010 = 10MHz
0001011 = 11MHz
.....
1101000 = 104MHz
Address Bits =0001 for register 2
Reference Frequency: The 14 bits are used to specify the input reference frequency as multiples
of 10kHz. Bits specify the integer part of the reference frequency expressed in MHz. Bits
set the fraction part. Those values are then used during the calibration of the internal VCO. For
example if using a 20MHz reference oscillator then bits would be 0010100 and bits
would be 0000000. If the reference oscillator is 13.1MHz then bits would be 0001101 and
bits would be 0001010.
Start Calibration: A 1 in DB31 starts the internal VCO calibration. When the calibration is complete, DB31 bit is
internally reset to 0.
FOUT: This 13-bit word specifies the VCO output frequency in MHz. If output frequency is
not a integer multiple of MHz, this value must be approximated to the closest integer in MHz.
Refer to Register 2 under the Application Information section.
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Register Address
DB0
DB1
DB2
Dual-Modulus
Prescalar Mode
DB3
DB4
DB5
A-Counter
DB6
DB7
DB8
DB9
B-Counter
DB10
B-Counter
DB16
DB17
DB18
DB19
DB20
DB11
DB12
Test MUX
DB21
DB22
DB23
DB24
DB25
DB26
DB27
DB28
DB13
DB14
DB15
Lock
PLL
RSRV
RSRV
DB29
DB30
DB31
Figure 14. Register 3
Table 3. Register 3: A and B Counters
REGISTER 3 MAPPING
Data Field
Address
Bits
14
DB31
Rsrv
Reserved
DB30
Rsrv
Reserved
DB29
START_LK
Lock PLL to frequency
1 active
DB28
TEST_MUX_3
0001 = LOCK_DETECT enabled
DB27
TEST_MUX_2
See Table 4 for descriptions and
settings.
DB26
TEST_MUX_1
DB25
TEST_MUX_0
DB24
B_12
DB23
B_11
DB22
B_10
DB21
B_9
DB20
B_8
DB19
B_7
DB18
B_6
DB17
B_5
DB16
B_4
DB15
B_3
DB14
B_2
DB13
B_1
DB12
B_0
DB11
A_5
DB10
A_4
DB9
A_3
DB8
A_2
DB7
A_1
DB6
A_0
DB5
PRESC_MOD1
DB4
PRESC_MOD0
DB3
0
DB2
0
DB1
1
DB0
0
13-bit B counter
6-bit A counter
Dual-modulus prescaler mode
:00
:01
:10
:11
Address Bits
=0010 for register 3
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for
for
for
for
8/9
16/17
32/33
64/65
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B: This 13-bit word controls the value of the B counter of the N divider. The valid range is
from 3 to 8191.
A: These 6 bits control the value of the A counter. The valid range is from 0 to 63.
PRESC_MOD: These bits define the mode of the dual-modulus prescaler according to
Table 3.
START_LK: TRF3762 does not load the serial interface registers values into the dividers registers until bit DB29
of register 3 is set to 1. After TRF3762 is locked to the new frequency, bit DB29 is internally reset to 0.
Refer to Register 3 under the Application Information section.
FUNCTIONAL DESCRIPTION
VCO
The TRF3762 integrates a high-performance, LC tank, voltage-controlled oscillator (VCO). For each of the
devices of the TRF3762 family, the inductance and capacitance of the tank are optimized to yield the best
phase-noise performance. The VCO output is fed externally and to the prescaler through a series of very low
noise buffers, that greatly reduce the effect of load pulling onto the VCO.
Divide by 2, by 4, and Output Buffer
To extend the frequency coverage, the TRF3762 integrates a divide by 2 and by 4 with very low noise floor. The
VCO signal is fed externally through a final open-collector differential-output buffer. This buffer is able to provide
up to 3dBm (typical) of power into a 200Ω differential resistive load. The open-collector structure gives the
flexibility to choose different load configurations to meet different requirements.
N-Divider
Prescaler Stage
This stage divides down the VCO frequency before the A and B counters. This is a dual-modulus prescaler
and the user can select any of the following settings: 8/9, 16/17, 32/33, and 64/65. Prescaling is used due to
the fact that the internal devices are limited in frequency operations of 200MHz. To determine the proper
prescaler value, Fout which is the frequency out of the VCO is divided by the numerator of the prescaler if
the answer is less than 200MHz then that is the prescalar to use, see Equation 3. If the value is higher than
200MHz then repeat this procedure with the next prescalar numerator until a value of 200MHz or less is
achieved. Refer to Synthesizing a Selected Frequency in the Section 7 Register 3.
FOUT
Prescalarnum
£ 200MHz
(3)
A and B Counter Stage
The TRF3762 includes a 6-bit A counter and a 13-bit B counter that operate on the output of the prescaler.
The A counter can take values from 0 to 63, while the B counter can take values from 3 to 8191. Also, the
value for the B counter must be greater than or equal to the value for the A counter. The A and B counter
with the prescaler stage create the VCO N-divider, see Equation 4 and Equation 5. Refer to Synthesizing a
Selected Frequency in the Section 7 Register 3.
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N=
FOUT
= (A COUNTER + Prescalarnum × B COUNTER )
FPFD
(4)
N
= xinteger ´ y decimal , Þ
Prescalarnum
BCOUNTER = xinteger and A COUNTER = Prescalarnum × y decimal
(5)
Reference Divider
TRF3762 includes a 14-bit RDiv, also known as RDiv, that allows the input reference frequency to be divided
down to produce the reference clock to the phase frequency detector (PFD) this clock is also known as FPFD
which is also the channel step size. Division ratios from 1 to 16,383 are allowed. To determine RDIV use
Equation 6.
RDIV =
FREF_IN
FPFD
(6)
The output frequency (FOUT) is determined using Equation 7.
FOUT = FPFD × N =
FREF_IN
RDIV
× (A COUNTER + Prescalarnum × B COUNTER )
(7)
Phase Frequency Detector (PFD) and Charge Pump Stage
The outputs of the RDiv and the N counter are fed into the PFD stage, where the two signals are compared in
frequency and phase. The TRF3762 features an anti-backlash pulse, whose width is controllable by the user
through the serial programming interface. The PFD feeds the charge pump, whose output current pulses are fed
into an external loop filter, which eventually produces the tuning voltage needed to control the integrated VCO to
the desired frequency.
Mux Out
MUX_OUT pin (39) provides a communication port to the microcontroller circuit. See Table 4 in the Application
Information section.
Div 1/2/4
Div 1/2/4 is the frequency divider for the TRF3762. This circuit can be programmed thru the serial programming
interface (SPI) to divide the output frequency of the VCO by 1, 2 or 4. This feature allows for the same loop filter
design to be used for any of the 3 divide by modes, 1, 2 and 4. For example, if the VCO is running at 1499MHz
to 1608MHz band then with the same exact circuit, run the output in the divide by 2 mode 749.5MHz to 804MHz
band or in the divide by 4 mode 374.75MHz to 402MHz.
Serial interface
The programming interface pins (3, 4, 5) to the chip are the serial programming interface (SPI). The interface
requires a Clock, Data, and Strobe signal to operate. See timing diagram Figure 11.
CHIP ENABLE
This feature provides a way to shut down the chip when not needed in order to conserve power. CHIP_EN Pin
(2) needs to be High for normal operation.
Buffer Power Down
PD_OUTBUFF pin (1), when enabled in software can provide a -40dB reduction in the output power while the
VCO is locked and running. This feature is to help with isolation between RX and TX.
16
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APPLICATION INFORMATION
Initial Calibration and Frequency Setup at Power Up
The integrated high performance VCO requires an internal frequency calibration at power up. To perform such
calibration the following procedure is recommended:
• Apply 5V power supply to IC.
• Apply an input reference frequency to pin (38) and ensure the signal is stable.
• Turn on the TRF3762 using the chip enable pin (CHIP_EN, pin 2), by applying 5V.
Register 1
• Setup the device through Register 1 referencing Table 1.
a. The first 4 bits of the 32-bit code sent to the chip are set DB to 0000; which is the address of
register 1.
b. Bit 5, DB4, sets the soft reset for the chip. Soft reset allows for the registers to be reset without powering
down the chip. If a soft reset is used then write to register 1 twice: once with DB4 set high and once with
DB4 set low. Typically, this bit is only used when the chip has been powered up and registers 1, 2, and 3
have already been written to, so on power-up reset is not required, so DB4 is, by default, set low.
c. DB sets the charge pump current based on the resistor value on pin 28 of the TRF3762 and the
decimal value of Register 1, DB used in Equation 1. This equation reduces to Equation 2, where
N = decimal value of [Reg1 DB].
d. DB sets the mode of the chip. The mode is how the device will or will not divide down the VCO’s
frequency. There are 3 choices for the mode setting, divide by 1, 2 or 4 per Table 1. For example if
525MHz is required from the TRF3762 which has a main frequency of 1575MHz then the divide-by-4
mode is chosen by setting DB to 10.
e. DB controls the output buffer. Both of these are set to 00 by default, so the buffer is controlled
internally. See Table 1 for more information.
f. DB sets the RDiv value. Once the calculations under the Synthesizing a Selected Frequency
section have been completed the value is known, based on the external reference oscillator. The value
for R is entered into the DB . For example, if the reference oscillator is at a frequency (FREF_IN) of
61.44MHz and a channel step size of 120kHz is required, which is also the frequency (FPFD) the phase
frequency detector will use to compare against the VCO's output frequency (FOUT), then FREF_IN /FPFD =
512, which is entered as follows: MSB: LSB 0001000000000.
g. By default, DB are set to 00 for a 1.5ns delay on the anti-backlash pulse width. See Table 1 for
more information.
h. DB 28 is set to 1 for positive by default. See Table 1 for more information.
i. DB 29 is set to 0 for normal operation. See Table 1 for more information.
j. DB 30 is set to 0 by default. See Table 1 for more information.
k. DB 31 is set to 0 by default. See Table 1 for more information.
Register 2
• Initiate calibration procedure by programming register 2 as follows: Reference Table 2
a. The first 4 bits of the 32-bit code sent to the chip are set DB to 0001; which is the address of
register 2.
b. Use bits DB of register 2 to specify the input reference frequency in MHz. The value is split into
an integer and a fraction part. For example: to insert a fREF of 30.72MHz, set:
– DB (integer part) equal to 0011110 (30) and
– DB (fraction part) equal to 1001000 (72).
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•
c. Set DB of register 2 to the desired frequency. For example: 2200MHz would be 0100010011000
(2200).
d. Set DB31of register 2 to 1 to start the calibration. The VCO calibration runs for 5ms. During the cal
procedure it will not be possible to program register 2 and 3. At the end of the calibration, bit DB31 of
register 2 resets to 0.
e. Subsequent frequency programming requires DB31 to be set to 0.
Register 3
Completion of the frequency set up, on initial calibration, cannot proceed until 5ms has elapsed, due to full
calibration, then it will require that the A and B values, the prescalar ratio, be known. See Synthesizing a
Selected Frequency section below for calculation. Reference Table 3.
a. The first 4 bits of the 32-bit code sent to the chip are set DB to 0010; which is the address of
register 3.
b. DB sets the prescalar ratio, 8/9, 16/17, 32/33, 64/65. For example: if 16/17 are required, set the
register bits DB to 01.
c. DB sets the A value for the N counter. For example: if A is 4, set DB as follows: 000100 (4).
d. DB sets the B value for the N counter. For example: if B is 1156, set DB as follows:
0010010000100 (4).
e. DB sets the TEST_MUX. This allows the user to check via the microcontroller the state of the
TRF3762 by programming it to one of 6 states. The most common state to use is the Digital lock Detect
which places the pin in a logic high state with indicates the VCO is locked.
Table 4. MUX-Out Settings
STATE
DB
STATE
DB
3-state o/p ( High impedance state on Pin 39)
0000
RDiv o/p (Shows R-value on Pin 39)
0100
Digital lock Detect (High when locked on Pin 39)
0001
Analog lock detect (High when locked on Pin 39)
0101
N-Divider o/p (Shows N-value on Pin 39)
0010
Read back ( read back register settings)
0110
DVDD (internal TI use)
0011
DGND (internal TI use)
0111
f. DB29 sets the START LOCK, which is set to 0, on the initial frequency setup and then set to 1 on
additional frequency changes.
Once all registers are written, the TRF3762 will lock to the desired frequency. In order to change the frequency
once the initial calibration is complete, only registers 2 and 3 need to be reprogrammed. No calibration is
required.
Re-Calibration After Power Up
Assuming the TRF3762 is powered up and operational, a VCO calibration is also possible without powering
down the IC. To perform such calibration the following procedure is recommended:
• Set bit DB4 (RESET) of register 1 to 1. This performs a software reset and clears all registers of VCO
calibration data. Once the reset command is issued then DB4 of register 1 will need to be set to 0.
• Repeat the Initial Calibration and Frequency setup at Power up section, skipping the power up section and
performing the register programming sequence.
18
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Synthesizing a Selected Frequency
The TRF3762 is an integer-N PLL synthesizer, and because of its flexibility (14-bit RDiv, 6-bit A counter, 13-bit B
counter, and dual modulus prescaler), is ideal for synthesizing virtually any desired frequency. If synthesizing a
900MHz local oscillator, with spacing capability (minimum frequency increment) of 200kHz, as in a typical GSM
application, the choice of the external reference oscillator is beyond the scope of this section. However, if a
10MHz reference is selected, the settings are calculated to yield the desired output frequency and channel
spacing. There is more than one solution to a specific set of conditions, so below is one way of achieving the
desired result. First, select the appropriate RDiv counter value. Since a channel spacing of 200kHz is desired,
the FPFD is set to 200kHz. Calculate the RDiv value through:
RDiv = FREFIN/FPFD = 10MHz/ 200kHz = 50.
Assume a prescaler value of 16/17 is selected. This is a valid choice, since the prescaler output is well within the
200MHz limit (1805MHz / 16 = 112.8MHz). Select the appropriate A and B counter values.
RFOUT = FPFD × N = (FREFIN / RDiv) × (A counter + Prescalar numerator × B counter).
Therefore, the following equation must be solved:
1805MHz = 200kHz x (A + 8 × B).
There are many solutions to this single equation with two unknowns; there are some basic constraints on the
solution, since 3 ≤ B ≤ 8191, and also B ≥ A. So, if A = 1, solving the equation yields B = 564. One complete
solution would be to choose:
RDiv = 50, A counter = 1, Bcounter = 564 and Prescalar = 16/17
resulting in the desired N counter value = 9025. This is how the A counter, B counter and prescalar make up the
N counter.
When this procedure is complete the values for the N counter , R, and the prescalar ratio should be known.
Registers 2 and 3 need to be set up for operation of the chip. See Table 2 and Table 3 for this procedure.
Register 2 bits 12:0 set the output frequency of the device along with register 3. See the N-Divider
section under the Functional Description.
Application Schematic
Figure 15 shows a typical application schematic for the TRF3762. In this example, the output signal is taken
differential using the 2 resistive pull-up resistors of the final output buffer. A single-ended and tuned load
configuration is also available.
The loop filter components:
C1 = 680pF, R1 = 7.5kΩ, C2 = 10,000pF, R2 = 6.34kΩ, C3 = 330pF
are typical ones used for the plots shown above. Those values can be optimized differently according to the
requirements of the different applications.
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REF
C1
C4
1000 pF
AVDD_REF
AVDD_CP
CPOUT
GND
AVDD
37
36
35 34
33
32 31
30
GND
GND
C2
39 38
MUX_OUT
(See Note A)
C3
R1
REF_IN
40
1
PD_OUTBUF
R2
GND
R3
2.37 kΩ
CHIP_EN
2
29
AVDD_BIAS
CLOCK
3
28
RBIAS1
DATA
4
27
GND
STROBE
5
26
VCTRL_IN
DGND
6
25
AVDD_VCO
DGND
7
24
AVDD_BUF
DVDD1
8
23
AVDD_CAPARRAY
AVDD_PRES
9
22
GND
R5
120 Ω
RSVD
21
19 20
C7
1000 pF
R6
120 Ω
AVDD
GND
18
RBIAS2
16 17
AVDD_VCOBUF
15
GND
14
AVDD_OUTBUF
12 13
VCO_OUTM
GND
10
11
VCO_OUTP
GND
TRF3762
(TOP VIEW)
GND
To Microcontroller
DVDD2
To Microcontroller
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R4
4.75 kΩ
VDD
VDD
C5
10 pF
C6
10 pF
LOAD
A.
Refer to the Application Information section Loop Filter Design.
Figure 15. TRF3762 Application Schematic
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Loop Filter Design
Numerous methodologies and design techniques exist for designing optimized loop filters for particular
applications. The loop filter design can affect the stability of the loop, the lock time, the bandwidth, the extra
attenuation on the reference spurs, etc. The role of the loop filter is to integrate and lowpass the pulses of the
charge pump and eventually yield an output tuning voltage that drives the VCO. Several filter topologies can be
implemented, including both passive and active. In this section, a third-order passive filter is used. For this
example, assume these several design parameters. The internal VCO has a value of 23MHz/V, meaning that in
the linear region, changing the tuning voltage of the VCO by 1V induces a change of the output frequency of
about 23MHz. It is known that N = 4500 and Fpfd = 200kHz from our previous example. It is assumed that
current setting in register 1 is set to 100 and sets a maximum current of 5.6mA. TI recommends an
Icp of 5.6mA, which give the best spur performance, but can be changed for different application. In addition, the
bandwidth of the loop filter must be determined. This is a critical consideration as it affects the lock time of the
system. Assuming an approximate bandwidth of around 20kHz is required and that for stability a phase margin of
about 45 degrees is desired, the following values for the components of the loop filter can be derived. There is
almost an infinite number of solutions to the problem of designing the loop filter and the designer is called to
make tradeoff decisions for each application. Texas Instruments has provided a loopfilter program in the product
folder for the TRF3762.
Some terms are interchangeable and are described and equated here:
• Fcom = FPDF which identify the comparing frequency or phase detector frequency which is also equal to the
system channel step size. FOUT must be a multiple of Fcom.
• Fmin is the lower frequency of the design band.
• Fmax is the upper frequency of the design band.
• Fref is the reference frequency for the PLL. Fref must be a multiple of Fcom.
• Kvco = Kv expressed in MHz per Volt (MHz/V) which is the gain of the VCO. The TRF3762 internal VCO has a
Kv = 23MHz/V.
• Icp is the charge pump current. The TRF3762 is typically set to 5.6mA.
• Fc is the loop filter bandwidth which should be no more than 1/10 Fcom.
• φ is phase margin in degrees. Values should be between 30 and 70. The higher the phase margin the better
the stability of the PLL but the slower the lock time. 45 degrees is a good tradeoff.
• T3/T1 in percent is the percentage of the poles in the loop filter. Usually set to 45%. The higher the value
(closer to 100%) the more the spurs are attenuated, but peaking occurs in the pass band of the loop filter.
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FOUT = FminFmax
(8)
FOUT
F com
vc = 2πFc
(10)
æ 1 ö
ç
÷ - tanf
cosf ø
è
T1 =
T3 ö
æ
vc ç 1 +
T1 ÷ø
è
(11)
æ T3 ö
T3 = ç
÷ T1
è T1 ø
(12)
N=
T2 =
(9)
1
vc2 (T1+T3 )
é
K
Kf ê
T1
C1 =
× VCO
x ê
ê
T2
vc2N
ê
ë
(13)
1
ù2
2
ú
1 + (vc T2 )
ú
ú
2
2
2
2
1 + vc T1
1 + vc T3 ú
û
(
)(
)
(14)
C1
æ T2
ö
C2 = C1ç
- 1÷ , C3 =
T1
10
è
ø
(15)
T2
T3
R1 =
, R2 =
C2
C3
(16)
Loop filter components:
C1 = 303pF
R1 = 8.87kW
R2 = 3.4kW
C2 = 1650pF
C3 = 330pF
Frequency jump from
1046MHz to 1085MHz:
Locktime freq ~ 250mS
Figure 16. Phase Locktime
22
Figure 17. Frequency Locktime
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TRF3762
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Loop Filter Design Example
Given these parameters which were used for the lock time plot Figure 17:
• Fmin = 1805 MHz
• Fmax = 1936 MHz
• Fcom = 200 KHz
• Icp = 7mA
• Kvco = 23 MHz
• Fc = 40 KHz
• Phase Margin = 35 degrees
• T3/T1 = 35%
Calculate FOUT of design
FOUT = FminFmax = 1870MHz (rounded up)
(17)
Next calculate N
N=
FOUT
= 9350
F com
(18)
Then calculate ωc
vc = 2πFc = 251.3 x 103
(19)
Now calculate T1-T3 to give the RC time constants.
æ 1 ö
ç
÷ - tanf
cosf ø
T1 = è
= 1.5 x 10-6
T3 ö
æ
vc ç 1 +
T1 ÷ø
è
(20)
Use T1 to find T3
æT
ö
T3 = ç 3 ÷ T1 = 537 x 10 -9
T1 ø
è
(21)
Then use T1 and T3 to find T2
T2 =
1
= 7.6 x 10 -6
2
v (T1 + T3 )
C
(22)
Now C1, C2, C3, R1, and R2 are calculated using T1, T2, and T3.
1
é
ù2
2
ê
ú
1 + (vc T2 )
K
Kf
T
ú = 110pF
C1 = 1 × VCO
× ê
2
ê
ú
T2
2
2
2
2
vc N
1 + vc T ú
ê 1 + vc T1
3
ë
û
(
)(
)
(23)
æT
ö
C2 = C1ç 2 - 1÷ = 436pF
è T1
ø
C1
C3 =
= 11pF
10
(24)
(25)
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TRF3762
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Now using C2 and T2, find R2. Use C3 and T3 to find R3
T
R2 = 2 = 17kΩ
C2
T
R3 = 3 = 49kΩ
C3
(26)
(27)
R3 x C3 can be scaled using T3, so if C3 = 110pF, then R3 = 41 kΩ => 4.9 kΩ in the loop filter. R2 and C2 can
be adjusted to improve the lock time. The actual values used in the lock time plot were optimized for lock time as
well as using real valued components.
Layout/PCB Considerations
This section of the design of the complete PLL is of paramount importance in achieving the desired performance.
Wherever possible, a multi-layer PCB board should be used, with at least one dedicated ground plane. A
dedicated power plane (split between the supplies if necessary) is also recommended. The impedance of all RF
traces (the VCO output and feedback into the PLL) should be controlled to 50Ω. All small value (10pF and 0.1µF)
decoupling capacitors should be placed as close to the device pins as possible. It is also recommended that both
top and bottom layers of the circuit board be flooded with ground, with plenty of ground vias dispersed as
appropriate. Because the digital lines are not in use during normal operation of the device and are only used to
program the device on start up and during frequency changes the analog grounds (GND) and digital grounds
(DGND) are tied to the same ground plain. The most sensitive part of any PLL is the section between the charge
pump output and the input to the VCO. This includes the loop filter components, and the corresponding traces.
The charge pump is a precision element of the PLL and any extra leakage on its path can adversely affect
performance. Extra care should be given to ensure that parasitics are minimized in the charge pump output, and
that the trace runs are short and optimized. Similarly, it is also recommend that extra care is taken in ensuring
that any flux residue is thoroughly cleaned and moisture baked out of the PCB. From an EMI perspective, and
since the synthesizer is typically a small portion of a bigger, complex circuit board, shielding is recommended to
minimize EMI effects.
24
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MUX_OUT
Via to bottom ground
BOTTOM
GND
TOP
GND
De-coupling
Capacitor’s
on back side
of board
RSVD
De-coupling
Capacitor’s
on top side
of board
BOTTOM
GND
A.
See the Application Information section for Loop Filter Design procedures.
Figure 18. TRF3762 Layout
Application Example for a High Performance RF Transmit Signal Chain
Much in the same way as described above, the TRF3762 is an ideal synthesizer to use in implementing a
complete high performance RF transmitter chain such as the TSW3000 and TSW3003 Demonstration kits. Using
a complete suite of high performance Texas Instruments components, a state-of-the-art transmitter can be
implemented featuring excellent performance. Texas Instruments offers ideal solutions for the digital-to-analog
conversion portion of transmitter as well as the analog and RF components needed to complete the transmitter.
The baseband digital data is converted to I and Q signals through the dual DAC5687, which features a 16-bit
interpolating dual digital-to-analog converter (DAC). The device incorporates a digital modulator, independent
differential offset control, and I/Q amplitude control. The device is typically used in baseband mode or in low IF
mode in conjunction with an analog quadrature modulator. The DAC5687, after filtering, feeds a TRF3703, which
is a direct, upconversion IQ modulator. This device accepts a differential input voltage quadrature signal at
baseband or low IF frequencies and outputs a modulated RF signal based on the LO drive frequency. The LO
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25
TRF3762
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drive input of the IQ modulator is generated by the TRF3762. The TRF3762 is a family of high performance,
highly integrated frequency synthesizers, optimized for wireless infrastructure applications. The TRF3762
includes an integrated VCO and integer-N PLL. Different members of the TRF3762 family can be chosen for
application specific VCO frequency ranges. In addition, the CDC7005 clocking solution can be used to clock the
DAC and other portions of the transmitter. A block diagram of the proposed architecture is shown in Figure 19.
For more details, contact Texas Instruments directly.
Digital-to-RF Up Converter
Gain and Power Amplifier
DAC
TX
LPA
ANT
0°
90°
I/Q
Modulator
Diplexer
I/Q
Demod
A/D
RX
LNA
LO-to-Digital Conveter
Low Noise Amplifier and
RF-to-LO Down Converter
Figure 19. Transmit Chain Block Diagram
26
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PACKAGE OPTION ADDENDUM
www.ti.com
29-Aug-2015
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
TRF3762-EIRHAR
ACTIVE
VQFN
RHA
40
TBD
Call TI
Call TI
-40 to 85
TRF3762
-E
TRF3762-EIRHAT
ACTIVE
VQFN
RHA
40
TBD
Call TI
Call TI
-40 to 85
TRF3762
-E
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
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information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
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29-Aug-2015
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
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