April 28, 2009
LMX3305
Triple Phase Locked Loop for RF Personal
Communications
General Description
Features
The LMX3305 contains three Phase Locked Loops (PLL) on
a single chip. It has a RF PLL, an IF Rx PLL and an IF Tx PLL
for CDMA applications. The RF fractional-N PLL uses a
16/17/20/21 quadruple modulus prescaler for PCS application and a 8/9/12/13 quadruple modulus prescaler for cellular
application. Both quadruple modulus prescalers offer modulo
1 through 16 fractional compensation circuitry. The RF fractional-N PLL can be programmed to operate from 800 MHz to
1400MHz in cellular band and 1200MHz to 2300 MHz in PCS
band. The IF Rx PLL and the IF Tx PLL are integer-N frequency synthesizers that operate from 45 MHz to 600 MHz
with 8/9 dual modulus prescalers. Serial data is transferred
into the LMX3305 via a microwire interface (Clock, Data, &
LE).
The RF PLL provides a fastlock feature allowing the loop
bandwidth to be increased by 3X during initial lock-on.
The supply voltage of the LMX3305 ranges from 2.7V to 3.6V.
It typically consumes 9 mA of supply current and is packaged
in a 24-pin CSP package.
■ Three PLLs integrated on a single chip
■ RF PLL fractional-N counter
■ 16/17/20/21 RF quadruple modulus prescaler for PCS
application
■ 8/9/12/13 RF quadruple modulus prescaler for cellular
application
■ 2.7V to 3.6V operation
■ Low current consumption: ICC = 9 mA (typ) at 3.0V
■ Programmable or logical power down mode: ICC = 10 µA
■
■
■
■
(typ) at 3.0V
RF PLL Fastlock feature with timeout counter
Digital lock detect
Microwire Interface with data preset
24-pin CSP package
Applications
■ CDMA Cellular telephone systems
Block Diagram
10136101
TRI-STATE® is a registered trademark of National Semiconductor Corporation.
© 2009 National Semiconductor Corporation
101361
101361 Version 3 Revision 5
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Print Date/Time: 2009/04/28 20:23:25
LMX3305 Triple Phase Locked Loop for RF Personal Communications
OBSOLETE
LMX3305
Functional Block Diagram
10136102
Connection Diagram
10136103
Top View
Order Number LMX3305SLBX
See NS Package Number SLB24A
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101361 Version 3 Revision 5
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LMX3305
Pin Descriptions
Pin No.
I/O
Description
1
RF_CPo
Pin Name
O
Charge pump output for RF PLL. For connection to a loop filter for driving the input of an external
VCO.
2
RF_GND
PWR
3
RF_FIN
I
4
RF_VCC
PWR
RF PLL power supply voltage. Input may range from 2.7V to 3.6V. Bypass capacitors should be
placed as close as possible to this pin and be connected directly to the ground plane. Tx VCC =
Rx VCC = RF VCC.
5
Lock_Det
O
Multiplexed output of the RF, Rx, and Tx PLL's analog or digital lock detects. The outputs from
the R, N and Fastlock counters can also be selected for test purposes. Refer to Section 2.3.4
for more detail.
6
N/C
7
RF_En
I
RF PLL enable pin. A LOW on RF En powers down the RF PLL and TRI-STATE®s the RF PLL
charge pump.
8
Rx_En
I
Rx PLL enable pin. A LOW on Rx En powers down the Rx PLL and TRI-STATEs the Rx PLL
charge pump.
9
Tx_En
I
Tx PLL enable pin. A LOW on Tx En powers down the Tx PLL and TRI-STATEs the Tx PLL
charge pump.
10
Clock
I
High impedance CMOS clock input. Data for the various counters is clocked on the rising edge
into the CMOS input.
11
Data
I
Binary serial data input. Data entered MSB first.
12
LE
I
High impedance CMOS input. When LE goes LOW, data is transferred into the shift registers.
When LE goes HIGH, data is transferred from the internal registers into the appropriate latches.
13
Tx_FIN
I
Tx prescaler input. Small signal input from the Tx VCO.
14
Tx_CPo
O
Charge pump output for Tx PLL. For connection to a loop filter for driving the input of an external
VCO.
15
Tx_GND
16
Tx_VCC
PWR
Tx PLL power supply voltage input. Input may range from 2.7V to 3.6V. Bypass capacitors should
be placed as close as possible to this pin and be connected directly to the ground plane. Tx
VCC = Rx VCC = RF VCC.
17
OSCIN
I
PLL reference input which has a VCC/2 input threshold and can be driven from an external CMOS
or TLL logic gate. The R counter is clocked on the falling edge of the OSCIN signal.
18
Rx_VCC
PWR
Rx PLL power supply voltage. Input ranges from 2.7V to 3.6V. Bypass capacitors should be
placed as close as possible to this pin and be connected directly to the ground plane. Tx VCC =
Rx VCC = RF VCC.
19
Rx_GND
PWR
Rx PLL ground.
20
Rx_CPo
O
Charge pump output for Rx PLL. For connection to a loop filter for driving the input of an external
VCO.
21
Rx_FIN
I
Rx prescaler input. Small signal input from the Rx VCO.
22
RF_Sw1
O
An open drain NMOS output which can be use for bandswitching or Fastlocking the RF PLL.
(During Fastlock mode a second loop filter damping resistor can be switched in parallel with the
first to ground.) Refer to Section 2.5.3 for more detail.
23
RF_Sw2
O
An open drain NMOS output which can be use for bandswitching or Fastlocking the RF PLL.
(During Fastlock mode a second loop filter damping resistor can be switched in parallel with the
first to ground.) Refer to Section 2.5.3 for more detail.
24
VP
O
RF PLL charge pump power supply. An internal voltage doubler can be enabled in 3V
applications to allow the RF charge pump to operate over a wider tuning range.
RF PLL ground.
RF prescaler input. Small signal input from the RF Cellular or PCS VCO.
No Connect.
Tx PLL ground.
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LMX3305
Lead Temp. (solder, 4 sec.) (TL)
ESD - Whole Body Model (Note 2)
Absolute Maximum Ratings (Notes 1, 2)
Power Supply Voltage (PLL VCC)
(Note 3)
Supply Voltage (VP)
Voltage on any Pin with
GND = 0V (VI)
Storage Temperature Range (TS)
+240°C
2 kV
Recommended Operating
Conditions (Note 1)
−0.3V to +6.5V
−0.3V to +6.5V
Power Supply Voltage (PLL VCC)
(Note 3)
Supply Voltage (VP) (Note 3)
Operating Temperature (TA)
−0.3V to VCC +0.3V
−65°C to +150°C
2.7V to 3.6V
PLL VCC to 5.5V
−30°C to +85°C
Electrical Characteristics
(VCC = VP = 3V, −30°C < TA < 85°C except as specified)
Symbol
Parameter
Conditions
Value
Min
Unit
Typ
Max
9.0
15
mA
10
75
µA
GENERAL
ICC
Power Supply Current
RF = On, Rx = On, Tx = On
ICC-PWDN
Power Down Current
fIN
PCS Operating Frequency
1200
2300
Cellular Operating Frequency
800
1400
IF Operating Frequency (Rx, Tx)
45
600
2.7V ≤ VCC ≤ 3.6V
fOSC
Oscillator Frequency
fφ
Phase Detector Frequency
PfIN
PCS/Cellular/IF Input Sensitivity
PfOSC
Oscillator Sensitivity
RF PN
RF Phase Noise
IF PN
IF Phase Noise
19.68
2.7V ≤ VCC ≤ 3.6V
−15
0.5
FOUT = 1 GHz
MHz
10
MHz
+0
dBm
VCC
VPP
dBc/Hz
−70
Fractional Spur @ 10 kHz
Tsw
25
−70
1 kHz Loop Filter (Note 4)
−50
Fractional Spur Harmonic
Switching Speed
Attenuate 6 dB/OCT
after 10 kHz
1 kHz Loop Filter, 60 MHz Jump to
Within 1 kHz
MHz
dBc
dBc
4.0
ms
CHARGE PUMP
RF IDo
Source
RF Charge Pump Source Current
VDo = VP/2 (Note 5)
−22
INOM
22
%
RF IDo Sink
RF Charge Pump Sink Current
VDo = VP/2 (Note 5)
−22
INOM
22
%
IF IDo
Source
IF Charge Pump Source Current
VDo = VCC/2 (Note 5)
80
100
120
µA
IF IDo Sink
IF Charge Pump Sink Current
VDo = VCC/2 (Note 5)
−80
−100
−120
µA
IDo-TRI
Charge Pump TRI-STATE Current
(Note 6)
1000
pA
IDo Sink vs
IDo Source
Charge Pump Sink vs Source Mismatch TA = 25°C (Note 7)
3
10
%
IDo vs VDo
Charge Pump Current vs Voltage
8
15
%
IDo vs TA
Charge Pump Current vs Temperature (Note 7)
5
10
%
TA = 25°C (Note 6)
DIGITAL INPUTS AND OUTPUTS
VIH
High-Level Input Voltage
VCC = 2.7V to 3.6V
VIL
Low-Level Input Voltage
VCC = 2.7V to 3.6V
VOL
Low-Level Output Voltage
IOL = 2 mA
IIH
High-Level Input Current
VIH = VCC = 3.6V
−1.0
IIL
Low-Level Input Current
VIL = 0V, VCC = 3.6V
−1.0
IIH
OSCIN High-Level Input Current
VIH = VCC = 3.6V
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0.8 VCC
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101361 Version 3 Revision 5
V
0.2 VCC
Print Date/Time: 2009/04/28 20:23:25
V
0.4
V
1.0
µA
1.0
µA
100
µA
Parameter
Conditions
VIL = 0V, VCC = 3.6V
Value
Min
Typ
Max
Unit
IIL
OSCIN Low-Level Input Current
−100
µA
tCS
Data to Clock Setup Time
50
ns
tCH
Data to Clock Hold Time
10
ns
tCWH
Clock Pulse Width High
50
ns
TCWL
Clock Pulse Width Low
50
ns
tENSL
Clock to Load_En Setup Time
50
ns
tENW
Load_En Pulse Width
50
ns
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Recommended Operating Conditions indicate conditions for
which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical
Characteristics.
Note 2: This device is a high performance RF integrated circuit and is ESD sensitive. Handling and assembly of this device should be done on ESD protected
workstations.
Note 3: PLL VCC represents RF VCC, Tx VCC and Rx VCC collectively.
Note 4: Guaranteed by design. Not tested in production.
Note 5: INOM = 100 µA, 400 µA, 700 µA or 900 µA for RF charge pump.
Note 6: For RF charge pump, 0.5 ≤ VDo ≤ VP - 0.5; for IF charge pump, 0.5 ≤ VDo ≤ VCC - 0.5.
Note 7: For RF charge pump, VDo = VP/2, for IF charge pump, VDo = VCC/2.
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101361 Version 3 Revision 5
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LMX3305
Symbol
LMX3305
Charge Pump Current Specification
Definitions
10136104
I1 = CP sink current at VDo = VP − ΔV
I2 = CP sink current at VDo = VP/2
I3 = CP sink current at VDo = ΔV
I4 = CP source current at VDo = VP − ΔV
I5 = CP source current at VDo = VP/2
I6 = CP source current at VDo = ΔV
ΔV = Voltage offset from positive and negative rails. Dependent on VCO tuning range relative to VCC and ground. Typical values are between 0.5V and 1.0V.
1. IDo vs VDo = Charge Pump Output Current magnitude variation vs Voltage =
[½ * {|I1| − |I3|}] / [½ * {|I1| + |I3|}] * 100% and [½ * {|I4| − |I6|}] / [½ * {|I4| + |I6|}] * 100%
2. IDo-sink vs IDo-source = Charge Pump Output Current Sink vs Source Mismatch =
[|I2| − |I5|] / [½ * {|I2| + |I5|}] * 100%
3. IDo vs TA = Charge Pump Output Current magnitude variation vs Temperature =
[|I2 @ temp| − |I2 @ 25°C|] / |I2 @ 25°C| * 100% and [|I5 @ temp| − |I5 @ 25°C|] / |I5 @ 25°C| * 100%
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101361 Version 3 Revision 5
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The LMX3305 phase-lock-loop (PLL) system configuration
consists of a high-stability crystal reference oscillator, three
frequency synthesizers, three voltage controlled oscillators
(VCO), and three passive loop filters. Each of the frequency
synthesizers includes a phase detector, a current mode
charge pump, as well as programmable reference [R] and
feedback [N] frequency dividers. The VCO frequency is established by dividing the crystal reference signal down via the
R-counter to obtain a comparison reference frequency. This
reference signal (fR) is then presented to the input of a phase/
frequency detector and compared with the feedback signal
(fN), which is obtained by dividing the VCO frequency down
by way of the N-counter, and fractional circuitry. The phase/
frequency detector's current source output pumps charge into
the loop filter, which then converts the charge into the VCO's
control voltage. The function of phase/frequency comparator
is to adjust the voltage presented to the VCO until the feedback signal frequency and phase match that of the reference
signal. When the RF PLL is in a “Phase-Locked” condition,
the RF VCO frequency will be (N + F) times that of the comparison frequency, where N is the integer divide ratio, and F
is the fractional component. The fractional synthesis allows
the phase detector frequency to be increased while maintaining the same frequency step size for channel selection. The
divider ratio N is thereby reduced giving a lower phase noise
referred to the phase detector input, and the comparison frequency is increased allowing faster switching time.
1.5 FRACTIONAL COMPENSATION
The fractional compensation circuitry of the LMX3305 RF divider allows the user to adjust the VCO tuning resolution in
1/2 through 1/16th increments of the phase detector comparison frequency. A 4-bit denominator register (FRAC_D) selects the fractional modulo base. The integer averaging is
accomplished by using a 4-bit accumulator. A variable phase
delay stage compensates for the accumulated integer phase
error, minimizes the charge pump duty cycle and reduces the
spurious levels. This technique eliminates the need for compensation current injection into the loop filter. An overflow
signal generated by the accumulator is equivalent to one full
RF VCO cycle, and results in a pulse swallow.
1.6 PHASE/FREQUENCY DETECTORS
The RF and IF phase/frequency detectors are driven from
their respective N- and R-counter outputs. The maximum frequency at the phase detector inputs is 10 MHz unless limited
by the minimum continuous divide ratio of the multi-modulus
prescaler. The phase detector output controls the charge
pump. The polarity of the pump-up or pump-down control is
programmed using RF_PD_POL, Rx_PD_POL, or
Tx_PD_POL depending on whether RF or IF VCO characteristics are positive or negative. The phase detector also
receives a feedback signal from the charge pump in order to
eliminate dead zones.
1.1 REFERENCE OSCILLATOR INPUTS
The reference oscillator frequency for the RF and IF PLLs are
provided from the external references through the OSCIN pin.
OSCIN input can operate up to 25 MHz with input sensitivity
of 0.5 VPP minimum and it drives RF, Rx and Tx R-counters.
OSCIN input has a VCC/2 input threshold that can be driven
from an external CMOS or TTL logic gate. Typically, the
OSCIN is connected to the output of a crystal oscillator.
1.7 CHARGE PUMPS
The phase detector's current source output pumps charge into an external loop filter, which then converts it into the VCO's
control voltage. The charge pump steers the charge pump
output CPo to VCC (pump-up) or Ground (pump-down). When
locked, CPo is primarily in a TRI-STATE mode with small corrections. The IF charge pump output current magnitudes are
nominally 100 µA. The RF charge pump output currents can
be programmed by the RF_Icpo bits at 100 µA, 400 µA, 700
µA, or 900 µA.
1.2 REFERENCE DIVIDERS (R-COUNTERS)
The RF, Rx and Tx R-counters are clocked through the oscillator block. The maximum frequency is 25 MHz. All RF, Rx
and Tx R-counters are CMOS design. The RF R-counter is 8bit in length with programmable divider ratio from 2 to 255.
The Rx and Tx R-counters are 10-bit in length with programmable divider ratio from 2 to 1023.
1.8 VOLTAGE DOUBLER (VP)
The VP pin is normally driven from an external power supply
over a range of VCC to 5.5V to provide current for the RF
charge pump circuit. An internal voltage doubler circuit connected between the VCC and VP supply pins alternately allows
VCC = 3V (±10%) users to run the RF charge pump circuit at
close to twice the VCC power supply voltage. The voltage
doubler mode is enabled by setting the V2X bit to a HIGH
level. The voltage doubler's charge pump driver originates
from the oscillator input. The device will not totally powerdown
until the V2X bit is programmed LOW. The average delivery
current of the doubler is less than the instantaneous current
demand of the RF charge pump when active and is thus not
capable of sustaining a continuous out of lock condition. A
large external capacitor connected to VP (=0.1 µF) is needed
to control power supply droop when changing frequencies.
1.3 PRESCALERS
The LMX3305 has a 16/17/20/21 quadruple modulus
prescaler for the PCS application and a 8/9/12/13 quadruple
modulus prescaler for the cellular application. The Rx and Tx
prescalers are dual modulus with 8/9 modulus ratio. Both RF/
IF prescalers' outputs drive the subsequent CMOS flip-flop
chain comprising the programmable N feedback counters.
1.4 FEEDBACK DIVIDERS (N-COUNTERS)
The RF, Rx and Tx N-counters are clocked by the output of
RF, Rx and Tx prescalers respectively. The RF N-counter is
composed of two parts: the 15 MSB bits comprise the integer
portion and the 4 LSB bits comprise the fractional portion. The
RF fractional N divider is fully programmable from 80 to 32767
over the frequency range from 1200 MHz-2300 MHz for PCS
application and 40 to 16383 over the frequency range from
800 MHz-1400 MHz for cellular application. The 4-bit fractional portion of the RF counter represents the fraction's
numerator. The fraction's denominator base is determined by
the four FRAC_D register bits.
1.9 MICROWIRE INTERFACE
The programmable register set is accessed through the microwire serial interface. The interface is comprised of three
signal pins: Clock, Data, and LE. After the LE goes LOW, serial data is clocked into the 32-bit shift register upon the rising
edge of Clock MSB first. The last three data bits shifted into
the shift register select one of five addresses. When LE goes
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101361 Version 3 Revision 5
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LMX3305
The Rx and Tx N-counters are each a 13-bit integer divisor,
fully programmable from 56 to 8,191 over the frequency range
from 45 MHz–600 MHz. The Rx and Tx N-counters do not
include fractional compensation.
1.0 Functional Description
LMX3305
HIGH, data is transferred from the shift registers into one of
the four register bank latches. Selecting the address <000>
presets the data in the four register banks. The synthesizer
can be programmed even in the power down (or not enabled)
state.
1.10 LOCK DETECT OUTPUTS
The open-drain Lock Detect is available in the LMX3305 to
provide a digital or analog lock detect indication for the sum
of the active PLLs. In the digital lock detect mode, an internal
digital filter produces a logic level HIGH at the lock detect
output when the error between the phase detector inputs is
less than 15 ns for five consecutive comparison cycles. The
lock detect output is LOW when the error between the phase
detector inputs is more than 30 ns for one comparison cycle.
In the analog lock detect mode, the lock detect pin becomes
active low whenever any of the active PLLs are charge pumping. The Lock_Det pin can also be programmed to provide
the outputs of the R, N or fastlock timeout counters.
1.11 POWER CONTROL
Each PLL is individually power controlled by the microwire
power down bits Rx_PWDN, Tx_PWDN and RF_PWDN. Alternatively, the PLLs can also be power controlled by the
Tx_En, Rx_En, and RF_En pins. The enable pins override
the power down bits except for the V2X bit. When the respective PLL's enable pin is high, the power down bits determine
the state of power control. Activation of any PLL power down
modes result in the disabling of the respective N counter and
de-biasing of its respective fIN input (to a high impedance
state). The R counter functionality also becomes disabled
when the power down bit is activated. The reference oscillator
block powers down and the OSCIN pin reverts to a high
impedance state when all of the enable pins are LOW or all
of the power down bits are programmed HIGH, unless V2X
bit is HIGH. Power down forces the respective charge pump
and phase comparator logic to a TRI-STATE condition. A
power down counter reset function resets both N and R counters of the respective PLL. Upon powering up the N counter
resumes counting in “close” alignment with the R counter (the
maximum error is one prescaler cycle). The microwire control
register remains active and capable of loading and latching in
data during all of the power down modes.
2.0 Programming Description
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101361 Version 3 Revision 5
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IF_R27
IF_N27
IF_R28
IF_N28
25
Tx_R_CNTR [9:0]
26
Tx_NB_CNTR [9:0]
RF_R26
RF_N26
RF_R27
RF_N27
RF_R28
RF_N28
Note: X denotes don't care bits.
RF_R25
RF_N25
IF_R
27
RF_R24
RF_N24
RF_R_CNTR [7:0]
IF_R26
IF_N26
28
IF_R25
IF_N25
29
IF_R24
IF_N24
RF_R23
RF_N23
IF_N
IF_R23
IF_N23
30
24
23
RF_N_CNTR [14:0]
RF_N22
31
RF_N21
RF_R
RF_N
IF_R22
IF_N22
RF_R22
22
IF_R21
RF_R21
IF_N21
21
19
17
Data Field
18
16
15
Tx_NA_
CNTR [2:0]
FSTL_CNTR [6:0]
LD [3:0]
All Register bits Preset
(Upon LE latching address <000>)
20
RF_R19
RF_N19
IF_R20
RF_R18
RF_N18
IF_N20
RF_R20
IF_R18 Tx_PD_POL
IF_N18
RF_R17
RF_N17
IF_R19
Tx_RST
IF_R17
IF_N17
RF_R16
RF_N16
IF_N19
RF_N20
IF_R16
IF_N16
IF_R15
RF_R15
RF_N15
14
13
11
FRAC_N [3:0]
10
9
Rx_R_CNTR [9:0]
12
Rx_NB_CNTR [9:0]
IF_R14
IF_N14
RF_R14
RF_N14
IF_R13
IF_N13
FSTM2
RF_R13
RF_N13
IF_R12
IF_N12
FSTM1
RF_R11
RF_N11
Tx_PWDN
IF_R11
IF_N11
FSTSW2
RF_R10
IF_N15
IF_R10
IF_N10
RF_R12
IF_R9
RF_N10
8
FRAC_CAL [4:0]
IF_R7
IF_N7
7
FRAC_D [3:0]
6
5
Rx_NA_CNTR
[2:0]
RF_R6
RF_N6
IF_N9
RF_R9
RF_N9
IF_R6
IF_N6
Fbps RF_R5
RF_N5
FSTSW1
RF_N12
IF_R8
IF_N8
RF_R8
RF_N8
IF_R4
IF_N4
PCS RF_R4
RF_N4
RF_Icpo
IF_R5
RF_R7
IF_R3
IF_N3
RF_N3 RF_PWDN RF_R3
4
Rx_RST
IF_N1 Rx_PWDN IF_R1
P
X
3
X
Test [2:0]
1
0
0
1
1
0
1
0
0
0
0
0
0
1
0
1
0
Address
Field
2
2.1 MICROWIRE SERIAL BUS INTERFACE
The LMX3305 uses Clock, Data, and LE signals to accomplish all data transactions. Data is latched into the 32-bit shift register on the rising edge of Clock, MSB first. The last three bits
loaded are the address bits that determine which of the four Data register banks the shift register data will be transferred to when LE goes HIGH.
Most Significant Bit
SHIFT REGISTER BIT LOCATION
Least Significant Bit
RF_N2
IF_N5
RF_N7
IF_R2 Rx_PD_POL
RF_R2 RF_PD_POL IF_N2
IF_R0
IF_N0
V2X
RF_R0
RF_RST
RF_R1
RF_N1
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RF_N0
101361 Version 3 Revision 5
LMX3305
9
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0
1
0
0
0
1
0
0
13
12
11
0
0
0
1
10
9
0
1
0
6
0
7
0
8
1
0
1
1
0
1
1
1
0
0
0
0
1
1
0
0
1
1
1
RF_N19
0
RF_N20
1
RF_N21
1
RF_N22
1
RF_N23
1
RF_N24
1
RF_N25
0
RF_N26
0
RF_N27
0
RF_N28
LMX3305
0
1
0
0
0
0
0
Test [2:0]
1
0
1
0
0
0
0
0
1
1
0
0
0
1
0
1
0
Address Field
2
Nmod = 1423
phase detect freq = 120 kHz
Fvco = 170.76 MHz
Tx
Nmod = 2014 6 / 16
phase detect freq = 480 kHz
Fvco = 966.90 MHz
1
RF_N18
These preset bit states provide the following local oscillator conditions for an OSCIN frequency of 19.68 MHz:
Rx PLL: Rmod = 164
PLL: Rmod = 16
Nmod = 212
phase detect freq = 1.23 MHz
Fvco = 260.76 MHz
RF PLL: Rmod = 41, T.O count = 480
0
0
0
0
0
0
0
0
1
1
0
0
1
1
0
RF_N17
FRAC_D [3:0]
0
RF_N16
FRAC_N [3:0]
0
0
0
RF_N15
RF_N_CNTR [14:0]
0
FRAC_CAL [4:0]
1
X
0
RF_N14
RF_R28
RF_N13
RF_R27
RF_N12
RF_R26
RF_N11
RF_R25
RF_N10
RF_R24
RF_N9
RF_R23
0
RF_R22
1
RF_R21
0
RF_R20
1
RF_R18
0
RF_R17
0
RF_R19
FSTL_CNTR [6:0]
RF_R16
RF_R_CNTR [7:0]
RF_R15
3
1
1
1
1
0
0
0
1
1
0
1
0
0
0
0
0
1
0
1
0
1
1
0
0
0
0
0
IF_N28
RF_R14
4
X
IF_N27
RF_R13
5
Rx_NA_CNTR
[2:0]
IF_N26
Rx_NB_CNTR [9:0]
0
Rx_R_CNTR [9:0]
(Upon LE latching address <000>)
14
IF_N25
Tx_NA_
CNTR [2:0]
0
15
Data Field
16
IF_N24
Tx_NB_CNTR [9:0]
0
0
LD [3:0]
All Register bits Preset
17
IF_N23
RF_R12
RF_N8
IF_R
18
IF_N22
RF_R11
RF_N7
IF_N
19
IF_N21
IF_R28
IF_N20
IF_R27
IF_N19
IF_R26
0
IF_R25
0
IF_R24
0
IF_R23
IF_N18
IF_R20
IF_N17
IF_R19
Tx_PD_
POL
IF_N16
IF_R18
Tx_RST
IF_R17
0
IF_R22
20
IF_R16
Tx_R_CNTR [9:0]
IF_R21
21
IF_R15
IF_N15
IF_R14
IF_N14
IF_R13
IF_N13
RF_R10
FSTM2
RF_R9
FSTM1
IF_N12
RF_R8
FSTSW2
IF_N11
RF_R7
FSTSW1
IF_N10
IF_R12
22
IF_R11
23
IF_R10
31 30 29 28 27 26 25 24
IF_R9
IF_N9
RF_R6
RF_N6
P
2.2 P REGISTER
P register has the special function of programming all of the registers to a preset known set state shown below. Note that this does not prevent the other four address registers from being
programmed after this.
Most Significant Bit
SHIFT REGISTER BIT LOCATION
Least Significant Bit
IF_R8
IF_N8
IF_R7
IF_N7
IF_R6
IF_N6
IF_R5
IF_N5
RF_R5
Fbps
RF_N5
RF_R
RF_N
IF_R4
IF_N4
RF_Icpo
RF_R4
PCS
RF_N4
RF_R3
RF_PD_POL IF_N2
RF_R2
IF_N3
RF_PWDN
RF_N3
Print Date/Time: 2009/04/28 20:23:25
RF_N2
RF_R1
Tx_PWDN
IF_R3
Rx_PD_
POL
IF_R2
Rx_RST
IF_R1
Rx_PWDN
RF_RST IF_N1
IF_R0
V2X IF_N0
RF_R0
101361 Version 3 Revision 5
RF_N1
10
RF_N0
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20
Tx_RST
IF_R17
21
IF_R18 Tx_PD_POL
22
IF_R19
IF_R21
IF_R20
Tx_R_CNTR [9:0]
19
IF_R16
31 30 29 28 27 2 25 2 23
6
4
IF_R25
IF_R26
IF_R27
IF_R28
IF_R
Note: X denotes don't care bit.
LD [3:0]
Data Field
13
IF_R10
14
IF_R12
IF_R13
IF_R14
IF_R15
IF_R22
IF_R23
IF_R24
11
10
9
Rx_R_CNTR [9:0]
12
IF_R9
15
IF_R8
16
IF_R7
17
IF_R6
18
X
4
Rx_RST
IF_R1
5
IF_R2 Rx_PD_POL
6
IF_R3
7
IF_R4
8
3
IF_R0
IF_R5
IF_R11
1
0
0
0
1
Address Field
2
2.3 IF_R REGISTER
If the ADDRESS [2:0] field is set to 001, data is transferred from the 32-bit shift register into the IF_R register when LE signal goes high. The IF_R register sets the Rx PLL's 10-bit R
counter divide ratio, the Tx PLL's 10-bit R counter divide ratio and various programmable bits. The divide ratio for both Rx and Tx R counters are from 2 to 1023.
Most Significant Bit
SHIFT REGISTER BIT LOCATION
Least Significant Bit
LMX3305
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LMX3305
2.3.1 10-Bit IF Programming Reference Divider Ratio (Tx
R Counter, Rx R Counter)
Divide Ratio
Tx_R_CNTR [9:0] or Rx_R_CNTR [9:0]
2
0
0
0
0
0
0
0
0
1
0
3
0
0
0
0
0
0
0
0
1
1
•
•
•
•
•
•
•
•
•
•
•
1023
1
1
1
1
1
1
1
1
1
1
Note: Divide ratio for both Tx and Rx R counters are from 2 to 1023.
2.3.2 Tx_PD_POL (IF_R[18])
This bit sets the polarity of the Tx phase detector. It is set to
one when Tx VCO characteristics are positive. When Tx VCO
frequency decreases with increasing control voltage,
Tx_PD_POL should be set to zero.
2.3.4 LD (IF_R[16]-[13])
The LD pin is a multiplexed output. When in lock detect mode,
LD does ANDing function on the active PLLs. The RF fractional test mode is only intended for factory testing.
2.3.3 Tx_RST (IF_R[17])
This bit will reset the Tx R and N counters when it is set to
one. For normal operation, Tx_RST should be set to zero.
Lock Detect Output Truth Table
LD [3:0]
LD Pin Function
Output Format
0
0
0
0
Digital Lock Detect
Open Drain
0
0
0
1
Analog Lock Detect
Open Drain
1
0
0
0
Rx R Counter
CMOS
1
0
0
1
Rx N Counter
CMOS
1
0
1
0
Tx R Counter
CMOS
1
0
1
1
Tx N Counter
CMOS
1
1
0
0
RF R Counter
CMOS
1
1
0
1
RF N Counter
CMOS
1
1
1
0
RF Fastlock Timeout Counter
CMOS
1
1
1
1
RF Fractional Test Mode
Analog
Once in lock (Lock Det = HIGH), the RC delay is changed to
approximately 30 ns. To exit the locked state (Lock Det =
LOW), the phase error must become greater than the 30 ns
RC delay. When the PLL is in the powerdown mode, Lock Det
is forced HIGH. A flow chart of the digital filter is shown below.
Lock Detect Digital Filter
The Lock Detect Digital Filter compares the difference between the phase of the inputs of the phase detector to a RC
generated delay of approximately 15 ns. To enter the locked
state (Lock Det = HIGH) the phase error must be less than
the 15 ns RC delay for five consecutive reference cycles.
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12
101361 Version 3 Revision 5
Print Date/Time: 2009/04/28 20:23:25
LMX3305
10136105
13
101361 Version 3 Revision 5
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LMX3305
Typical Lock Detect Timing
10136106
2.3.5 Rx_PD_POL (IF_R[2])
This bit sets the polarity of the Rx phase detector. It is set to
one when Rx VCO characteristics are positive. When Rx VCO
frequency decreases with increasing control voltage,
Rx_PD_POL should set to zero.
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2.3.6 Rx_RST (IF_R[1])
This bit will reset the Rx R and N counters when it is set to
one. For normal operation, Rx_RST should be set to zero.
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101361 Version 3 Revision 5
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30
23
IF_N17
IF_N18
Tx_NA_
CNTR [2:0]
IF_N16
IF_N22
IF_N23
IF_N24
IF_N
17
15
IF_N12
16
IF_N13
IF_N14
IF_N15 Tx_PWDN
Data Field
18
13
12
8
9
IF_N6
10
IF_N7
11
IF_N8
Rx_NB_CNTR [9:0]
14
IF_N11
19
IF_N10
20
IF_N9
21
6
5
Rx_NA_
CNTR [2:0]
7
IF_N4
Tx_NB_CNTR [9:0]
22
IF_N19
IF_N20
24
IF_N3
25
IF_N2
26
4
Rx_PWDN
IF_N1
27
X
3
IF_N0
28
IF_N25
IF_N27
IF_N28
Note: X denotes don't care bit.
29
IF_N26
31
IF_N5
IF_N21
1
0
0
1
0
Address Field
2
2.4 IF_N REGISTER
If the ADDRESS [2:0] field is set to 010, data is transferred from the 32-bit shift register into the IF_N register when LE signal goes high. The IF_N register sets the Rx PLL's 13-bit N
counter divide ratio, the Tx PLL's 13-bit N counter divide ratio and various programmable bits. Both N counters consist of the 3-bit swallow counter (A counter) and the 10-bit programmable
counter (B counter). N divider continuous integer divide ratio is from 56 to 8191.
Most Significant Bit
SHIFT REGISTER BIT LOCATION
Least Significant Bit
LMX3305
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101361 Version 3 Revision 5
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LMX3305
2.4.1 3-Bit IF Swallow Counter Divide Ratio (Tx A Counter,
Rx A Counter)
Divide Ratio
Tx_NA_CNTR [2:0] or Rx_NA_CNTR [2:0]
0
0
0
0
1
0
0
1
•
•
•
•
7
1
1
1
Divide ratio is from 0 to 7
Tx_NB_CNTR ≥ Tx_NA_CNTR and Rx_NB_CNTR ≥ Rx_NA_CNTR
2.4.2 10-Bit IF Programmable Counter Divide Ratio (Tx B
Counter, Rx B Counter)
Divide
Ratio
Tx_NB_CNTR [9:0] or Rx_NB_CNTR [9:0]
3
0
0
0
0
0
0
0
0
1
1
4
0
0
0
0
0
0
0
1
0
0
•
•
•
•
•
•
•
•
•
•
•
1023
1
1
1
1
1
1
1
1
1
1
Divide ratio is from 3 to 1023 (Divide ratios less than 3 are prohibited)
Tx_NB_CNTR ≥ Tx_NA_CNTR and Rx_NB_CNTR ≥ Rx_NA_CNTR
N = PB + A
B = N div P
A = N mod P
2.4.3 Tx_PWDN (IF_N[15])
This bit will asynchronously powerdown the Tx PLL when set
to one. For normal operation, it should be set to zero.
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2.4.4 Rx_PWDN (IF_N[1])
This bit will asynchronously powerdown the Rx PLL when set
to one. For normal operation, it should be set to zero.
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101361 Version 3 Revision 5
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30
RF_R27
31
23
RF_R20
24
RF_R17
RF_R18
RF_R23
RF_R24
RF_R25
RF_R26
RF_R
FSTL_CNTR [6:0]
RF_R16
17
13
FSTSW1
RF_R10
14
FSTSW2
RF_R11
15
FSTM1
RF_R12
16
FSTM2
RF_R13
RF_R14
RF_R15
Data Field
12
RF_R9
18
10
9
FRAC_CAL [4:0]
11
RF_R8
19
RF_R7
20
8
RF_R5
21
RF_R6
RF_R_CNTR [7:0]
22
RF_R19
RF_R21
25
6
7
RF_R4
RF_Icpo
26
5
RF_PD_POL
RF_R2
27
4
3
RF_RST
RF_R1
28
V2X
RF_R0
29
RF_R3
RF_R22
RF_R28
1
0
0
1
1
Address Field
2
2.5 RF_R REGISTER
If the ADDRESS [2:0] field is set to 011, data is transferred from the 32-bit shift register into the RF_R register when LE signal goes high. The RF_R register sets the RF PLL's 8-bit R
counter divide ratio and various programmable bits. The divide ratio for RF R counter is from 2 to 255.
Most Significant Bit
SHIFT REGISTER BIT LOCATION
Least Significant Bit
LMX3305
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LMX3305
2.5.1 8-Bit RF Programming Reference Divider Ratio (RF
R Counter)
Divide Ratio
RF_R_CNTR [7:0]
2
0
0
0
0
0
0
1
0
3
0
0
0
0
0
0
1
1
•
•
•
•
•
•
•
•
•
255
1
1
1
1
1
1
1
1
Divide ratio for RF R counter is from 2 to 255.
detector cycles the fastlock mode remains in HIGH gain is the
binary FSTL_CNTR value loaded multiplied by eight.)
2.5.2 FSTL_CNTR (RF_R[20]-[14])
The Fastlock Timeout Counter is a 10 bit counter wherein only
the seven MSB bits are programmable. (The number of phase
Phase Detect
Cycles
FSTL_CNTR [6:0]
24
0
0
0
0
0
1
1
32
0
0
0
0
1
0
0
•
•
•
•
•
•
•
•
1008
1
1
1
1
1
1
0
1016
1
1
1
1
1
1
1
When bit FSTM2 and/or FSTM1 is set HIGH, the RF fastlock
is enabled. As a new frequency is loaded, RF_Sw2 pin and/
or RF_Sw1 pin goes to a LOW state to switch in the damping
resistors, the RF CPo is set to a higher gain, and fastlock
timeout counter starts counting. Once the timeout counter finishes counting, the PLL returns to its normal operation (the
Icpo gain is forced to 100 µA irrespective of RF_Icpo bits).
When bit FSTM2 and/or FSTM1 is set LOW, pins RF_Sw2
and/or RF_Sw1 can be toggled HIGH or LOW to drive other
devices. RF_Sw2 and/or RF_Sw1 can also be set LOW to
switch in different damping resistors to change the loop filter
performance. FSTSW bits control the output states of the
RF_Sw2 and RF_Sw1 pins.
2.5.3 FSTM (RF_R[13]-[12]) and FSTSW (RF_R[11]-[10])
Fastlock enables the designer to achieve both fast frequency
transitions and good phase noise performance by dynamically changing the PLL loop bandwidth. The Fastlock modes
allow wide band PLL fast locking with seamless transition to
a low phase noise narrow band PLL. Consistent gain and
phase margins are maintained by simultaneously changing
charge pump current magnitude and loop filter damping resistor. In the LMX3305, the RF fastlock can achieve substantial improvement in lock time by increasing the charge pump
current by 4X, 7X or 9X, which causes a 2X, 2.6X or 3X increase in the loop bandwidth respectively. The damping resistors are connected to FSTSW pins.
RF_R[12] FSTM1
RF_R[10] FSTSW1
RF_Sw1 Output Function
0
0
RF_Sw1 pin reflects RF_SwBit “0” logic state
0
1
RF_Sw1 pin reflects RF_SwBit “1” logic state
1
x
RF_Sw1 pin LOW while T.O. counter is active
RF_R[13] FSTM2
RF_R[11] FSTSW2
0
0
RF_Sw2 pin reflects RF_SwBit “0” logic state
0
1
RF_Sw2 pin reflects RF_SwBit “1” logic state
1
x
RF_Sw2 pin LOW while T.O. counter is active
RF_Sw2 Output Function
tional spur. Improvements can be made by selecting the bits
to be one greater or less than the denominator value. For example, in the 1/16 fractional mode, these four bits can be
programmed to 15 or 17. In normal operation, these bits
should be set to zero.
2.5.4 FRAC_CAL (RF_R[9]-[5])
These five bits allow the users to optimize the fractional circuitry, therefore reducing the fractional reference spurs. The
MSB bit, RF_R[9], activates the other four calibration bits
RF_R[8]-[5]. These four bits can be adjusted to improve frac-
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LMX3305
2.5.5 RF_Icpo (RF_R[4]-[3])
These two bits set the charge pump gain of the RF PLL. The
user is able to set the charge pump gain during the acquisition
phase of the fastlock mode to 4X, 7X or 9X.
Charge Pump Gain
RF_R[4]
RF_R[3]
100 µA
0
0
400 µA
0
1
700 µA
1
0
900 µA
1
1
2.5.6 RF_PD_POL (RF_R[2])
This bit sets the polarity of the RF phase detector. It is set to
one when RF VCO characteristics are positive. When RF
VCO frequency decreases with increasing control voltage,
RF_PD_POL should be set to zero.
2.5.8 V2X (RF_R[0])
V2X when set high enables the voltage doubler for the RF
charge pump supply.
2.5.7 RF_RST (RF_R[1])
This bit will reset the RF R and N counters when it is set to
one. For normal operation, RF_RST should be set to zero.
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20
101361 Version 3 Revision 5
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26
RF_N23
27
RF_N24
28
RF_N25
29
RF_N26
30
RF_N27
31
20
RF_N17
21
RF_N20
RF_N21
RF_N22
RF_N
17
16
RF_N13
RF_N14
RF_N15
14
13
RF_N10
11
10
FRAC_D [3:0]
12
RF_N9
FRAC_N [3:0]
15
RF_N12
Data Field
RF_N11
18
RF_N8
RF_N18
RF_N19
RF_N_CNTR [14:0]
19
RF_N16
22
RF_N7
23
9
RF_N6
24
PCS
RF_N4
Fbps
RF_N5
4
Test [2:0]
5
6
RF_N3 RF_PWDN
7
8
RF_N1
25
RF_N2
RF_N28
LMX3305
3
1
0
1
0
0
Address Field
2
2.6 RF_N REGISTER
If the ADDRESS [2:0] field is set to 100, data is transferred from the 32-bit shift register into the RF_N register when LE signal goes high. The RF_N register set the RF PLL's 23-bit
fractional N counter and various programmable bits. The fractional N counter consists of 15 bits integer portion and 8 bits fractional portion. The integer portion consists of a 2-bit swallow
counter (A word), a 2-bit programmable counter (B word) and a 11-bit programmable counter (C word). The fractional portion consists of a 4-bit numerator and a 4-bit denominator.
Most Significant Bit
SHIFT REGISTER BIT LOCATION
Least Significant Bit
RF_N0
LMX3305
N = PC + 4B + A
C ≥ max {A,B} + 2
The A, B, and C values can be determined as follows:
C = N div P
B = (N - CP) div 4
A = (N - CP) mod 4
2.6.1 RF_N_CNTR (RF_N[28]-[14])
The RF N counter value is determined by three counter values
that work in conjunction with four prescalers. This quadruple
modulus prescaler architecture allows lower minimum continuous divide ratios than are possible with a dual modulus
prescaler architecture. For the determination of the A, B, and
C counter values, the fundamental relationships are shown
below.
N REGISTER FOR THE CELLULAR (8/9/12/13) PRESCALER OPERATING IN FRACTIONAL MODE
Divide
RF_N_CNTR [14:0]
Ratio
C Word
B Word
A Word
Divide Ratios Less than 24 are impossible since it is required that C ≥ 3
1-23
24-39
Some of these N values are Legal Divide Ratios, some are not
40
0
0
0
0
0
0
0
0
1
0
1
0
0
0
0
41
0
0
0
0
0
0
0
0
1
0
1
0
0
0
1
…
.
.
.
.
.
.
.
.
.
.
.
0
.
.
.
16383
1
1
1
1
1
1
1
1
1
1
1
0
1
1
1
N REGISTER FOR THE PCS (16/17/20/21) PRESCALER OPERATING IN FRACTIONAL MODE
Divide
RF_N_CNTR [14:0]
Ratio
C Word
B Word
1-47
Divide Ratios Less than 48 are impossible since it is required that C ≥ 3
48-79
Some of these N values are Legal Divide Ratios, some are not
A Word
80
0
0
0
0
0
0
0
0
1
0
1
0
0
0
0
81
0
0
0
0
0
0
0
0
1
0
1
0
0
0
1
…
.
.
.
.
.
.
.
.
.
.
.
0
.
.
.
32767
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2.6.2 FRAC_N (RF_N[13]-[10])
These four bits, the fractional accumulator modulus numerator, set the fractional numerator values in the fraction.
Modulus Numerator
FRAC_N [3:0]
0
0
0
0
0
1
0
0
0
1
2
0
0
1
0
•
•
•
•
•
14
1
1
1
0
15
1
1
1
1
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LMX3305
2.6.3 FRAC_D (RF_N[9]-[6])
These four bits, the fractional accumulator modulus denominator, set the fractional denominator from 1/2 to 1/16 resolution.
Modulus Denominator
FRAC_D [3:0]
1-8
9
Not Allowed
1
0
0
1
10-14
•
•
•
•
15
1
1
1
1
16
0
0
0
0
MODULUS NUMERATOR (FRAC_N) AND DENOMINATOR (FRAC_D) PROGRAMMING
Fractional
Numerator
(FRAC_N)
1
2
3
4
5
RF_N[13]- 0001 0010 0011 0100 0101
[10]
0=0000
1=0001
2=0010
3=0011
4=0100
5=0101
6=0110
7=0111
8=1000
Fractional Denominator, (FRAC_D)
RF_N[9]-[6]
6
0110
7
0111
8
9
10
11
12
13
14
15
1000 1001 1010 1011 1100 1101 1110 1111
16
0000
Functions like an integer-N PLL as fractional component is set to 0.
*
*
*
*
(8/16) (5/15) (4/16) (3/15)
*
*
*
(10/1 (8/16) (6/15)
5)
*
*
(12/1 (9/15)
6)
*
(12/1
5)
*
*
*
(2/12) (2/14) (2/16)
*
*
*
(4/12) (4/14) (4/16)
1/9
1/10
1/11
1/12
1/13
1/14
1/15
1/16
2/9
2/10
2/11
2/12
2/13
2/14
2/15
2/16
*
*
*
(6/12) (6/14) (6/16)
3/9
3/10
3/11
3/12
3/13
3/14
3/15
3/16
*
*
*
(8/12) (8/14) (8/16)
4/9
4/10
4/11
4/12
4/13
4/14
4/15
4/16
*
(10/1
2)
5/9
5/10
5/11
5/12
5/13
5/14
5/15
5/16
6/9
6/10
6/11
6/12
6/13
6/14
6/15
6/16
7/9
7/10
7/11
7/12
7/13
7/14
7/15
7/16
8/9
8/10
8/11
8/12
8/13
8/14
8/15
8/16
9/10
9/11
9/12
9/13
9/14
9/15
9/16
10/1
1
10/1
2
10/1
3
10/1
4
10/1
5
10/16
11/1
2
11/1
3
11/1
4
11/1
5
11/16
12/1
3
12/1
4
12/1
5
12/16
13/1
4
13/1
5
13/16
14/1
5
14/16
*
*
(10/1 (10/1
4)
6)
*
*
(12/1 (12/1
4)
6)
*
(14/1
6)
FRAC_D values between 1 to 8 are not allowed.
9=1001
10=1010
11=1011
12=1100
13=1101
14=1110
15=1111
15/16
Remark: The *(FRAC_N / FRAC_D) denotes that the fraction number can be represented by (FRAC_N / FRAC_D) as indicated in the parenthesis. For example,
1/2 can be represented by 8/16.
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22
101361 Version 3 Revision 5
Print Date/Time: 2009/04/28 20:23:25
bit is set to one, the RF PLL will operate in the PCS mode and
when it is set to zero, the cellular mode.
2.6.5 PCS (RF_N[4])
This bit will determine whether the RF PLL should operate in
PCS frequency range or cellular frequency range. When the
2.6.7 Test (RF_N[2]-[0])
These bits are the internal factory testing only. They should
be set to zero for normal operation.
2.6.6 RF_PWDN (RF_N[3])
This bit will asynchronously powerdown the RF PLL when set
to one. For normal operation, it should be set to zero.
23
101361 Version 3 Revision 5
Print Date/Time: 2009/04/28 20:23:25
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LMX3305
2.6.4 FBPS (RF_N[5])
This bit when set to one will bypass the delay line calculation
used in the fractional circuitry. This will improve the phase
noise while sacrificing performance on reference spurs.
When the bit is set to zero, the delay line circuit is in effect to
reduce reference spur.
LMX3305
SERIAL DATA INPUT TIMING
10136107
Notes: Parenthesis data indicates programmable reference
divider data.
Data shifted into register on clock rising edge.
Data is shifted in MSB first.
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Test Conditions: The Serial Data Input Timing is tested using a symmetrical waveform around VCC/2. The test waveform
has an edge rate of 0.6 V/ns with amplitudes of 1.84V @
VCC = 2.3V and 4.4V @ VCC = 5.5V.
24
101361 Version 3 Revision 5
Print Date/Time: 2009/04/28 20:23:25
LMX3305
Physical Dimensions inches (millimeters) unless otherwise noted
LMX3305 Package Drawing
Order Number LMX3305SLBX
NS Package Number SLB24A
25
101361 Version 3 Revision 5
Print Date/Time: 2009/04/28 20:23:25
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LMX3305 Triple Phase Locked Loop for RF Personal Communications
Notes
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