LMX2315/LMX2320/LMX2325
PLLatinum
TM
Frequency Synthesizer for RF Personal
Communications
LMX2325 2.5 GHz
LMX2320 2.0 GHz
LMX2315 1.2 GHz
General Description
The LMX2315/2320/2325's are high performance frequency
synthesizers with integrated prescalers designed for RF op-
eration up to 2.5 GHz. They are fabricated using National's
ABiC IV BiCMOS process.
A 64/65 or a 128/129 divide ratio can be selected for the
LMX2315 and LMX2320 RF synthesizer at input frequencies
of up to 1.2 GHz and 2.0 GHz, while 32/33 and 64/65 divide
ratios are available in the 2.5 GHz LMX2325. Using a pro-
prietary digital phase locked loop technique, the LMX2315/
2320/2325's linear phase detector characteristics can gen-
erate very stable, low noise signals for controlling a local
oscillator.
Serial data is transferred into the LMX2320 and the
LMX2325 via a three line MICROWIRE
TM
interface (Data,
Enable, Clock). Supply voltage can range from 2.7V to 5.5V.
The LMX2315, LMX2320 and the LMX2325 feature very low
current consumption, typically 6 mA, 10 mA and 11 mA
respectively.
The LMX2315, LMX2320 and the LMX2325 are available in
a TSSOP 20-pin surface mount plastic package.
Features
n
RF operation up to 2.5 GHz
n
2.7V to 5.5V operation
n
Low current consumption
n
Dual modulus prescaler:
LMX2325:
32/33 or 64/65
LMX2320/LMX2315:
64/65 or 128/129
n
Internal balanced, low leakage charge pump
n
Power down feature for sleep mode: I
CC
= 30 A (typ)
at V
CC
= 3V
n
Small-outline, plastic, surface mount TSSOP, 0.173"
wide
Applications
n
Cellular telephone systems
(GSM, IS-54, IS-95, (RCR-27)
n
Portable wireless communications (DECT, PHS)
n
CATV
n
Other wireless communication systems
Block Diagram
TRI-STATE
is a registered trademark of National Semiconductor Corporation.
MICROWIRE
TM
and PLLatinum
TM
are trademarks of National Semiconductor Corporation.
DS012339-1
February 2002
LMX2315/LMX2320/LMX2325
PLLatinum
Frequency
Synthesizer
for
RF
Personal
Communications
LMX2325
2.5
GHz
LMX2320
2.0
GHz
LMX2315
1.2
GHz
2002 National Semiconductor Corporation
DS012339
www.national.com
Connection Diagram
Pin Descriptions
Pin No.
Pin
Name
I/O
Description
1
OSC
IN
I
Oscillator input. A CMOS inverting gate input intended for connection to a crystal resonator for
operation as an oscillator. The input has a V
CC
/2 input threshold and can be driven from an
external CMOS or TTL logic gate. May also be used as a buffer for an externally provided
reference oscillator.
3
OSC
OUT
O
Oscillator output.
4
V
P
Power supply for charge pump. Must be
V
CC
.
5
V
CC
Power supply voltage input. Input may range from 2.7V to 5.5V. Bypass capacitors should be
placed as close as possible to this pin and be connected directly to the ground plane.
6
D
o
O
Internal charge pump output. For connection to a loop filter for driving the input of an external VCO.
7
GND
Ground.
8
LD
O
Lock detect. Output provided to indicate when the VCO frequency is in "lock". When the loop is
locked, the pin's output is HIGH with narrow low pulses.
10
f
IN
I
Prescaler input. Small signal input from the VCO.
11
CLOCK
I
High impedance CMOS Clock input. Data is clocked in on the rising edge, into the various counters
and registers.
13
DATA
I
Binary serial data input. Data entered MSB first. LSB is control bit. High impedance CMOS input.
14
LE
I
Load enable input (with internal pull-up resistor). When LE transitions HIGH, data stored in the shift
registers is loaded into the appropriate latch (control bit dependent). Clock must be low when LE
toggles high or low. See Serial Data Input Timing Diagram.
15
FC
I
Phase control select (with internal pull-up resistor). When FC is LOW, the polarity of the phase
comparator and charge pump combination is reversed.
16
BISW
O
Analog switch output. When LE is HIGH, the analog switch is ON, routing the internal charge pump
output through BISW (as well as through D
o
).
17
f
OUT
O
Monitor pin of phase comparator input. CMOS output.
18
p
O
Output for external charge pump.
p
is an open drain N-channel transistor and requires a pull-up
resistor.
19
PWDN
I
Power Down (with internal pull-up resistor).
PWDN = HIGH for normal operation.
PWDN = LOW for power saving.
Power down function is gated by the return of the charge pump to a TRI-STATE
condition.
20
r
O
Output for external charge pump.
r
is a CMOS logic output.
2,9,12
NC
No connect.
LMX2315/LMX2320/LMX2325
DS012339-2
20-Lead (0.173" Wide) Thin Shrink Small Outline Package (TM)
Order Number LMX2315TM, LMX2315TMX, LMX2325TM, LMX2325TMX, LMX2320TM or LMX2320TMX
See NS Package Number MTC20
LMX2315/LMX2320/LMX2325
www.national.com
2
Functional Block Diagram
Note 1: The prescalar for the LMX2315 and LMX2320 is either 64/65 or 128/129, while the prescalar for the LMX2325 is 32/33 or 64/65.
Note 2: The power down function is gated by the charge pump to prevent unwanted frequency jumps. Once the power down pin is brought low the part will go into
power down mode when the charge pump reaches a TRI-STATE condition.
DS012339-3
LMX2315/LMX2320/LMX2325
www.national.com
3
Absolute Maximum Ratings
(Notes 4, 3)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Power Supply Voltage
V
CC
-0.3V to +6.5V
V
P
-0.3V to +6.5V
Voltage on Any Pin
with GND = 0V (V
I
)
-0.3V to +6.5V
Storage Temperature Range (T
S
)
-65C to +150C
Lead Temperature (T
L
) (solder, 4 sec.)
+260C
Recommended Operating
Conditions
Power Supply Voltage
V
CC
2.7V to 5.5V
V
P
V
CC
to +5.5V
Operating Temperature (T
A
)
-40C to +85C
Note 3: Absolute Maximum Ratings indicate limits beyond which damage to
the device may occur. Operating Ratings indicate conditions for which the
device is intended to be functional, but do not guarantee specific perfor-
mance limits. For guaranteed specifications and test conditions, see the
Electrical Characteristics. The guaranteed specifications apply only for the
test conditions listed.
Note 4: This device is a high performance RF integrated circuit with an ESD
rating
<
2 kV and is ESD sensitive. Handling and assembly of this device
should be done at ESD workstations.
Electrical Characteristics
LMX2325 and LMX2320 V
CC
= V
P
= 3.0V; LMX2315 V
CC
= V
P
= 5.0V; -40C
<
T
A
<
85C, except as specified
Symbol
Parameter
Conditions
Min
Typ
Max
Units
I
CC
Power Supply Current
LMX2315
V
CC
= 3.0V
6.0
8.0
mA
V
CC
= 5.0V
6.5
8.5
mA
LMX2320
V
CC
= 3.0V
10
13.5
mA
LMX2325
V
CC
= 3.0V
11
15
mA
I
CC-PWDN
Power Down Current
V
CC
= 3.0V
30
180
A
V
CC
= 5.0V
60
350
A
f
IN
Maximum Operating Frequency
LMX2315
1.2
LMX2320
2.0
GHz
LMX2325
1.2
2.5
f
OSC
Oscillator Frequency
5
20
MHz
No Load on OSC
out
5
40
MHz
f
Phase Detector Frequency
10
MHz
Pf
IN
Input Sensitivity
V
CC
= 2.7V to 3.3V
-15
+6
dBm
V
CC
= 3.3V to 5.5V
-10
+6
V
OSC
Oscillator Sensitivity
OSC
IN
0.5
V
PP
V
IH
High-Level Input Voltage
(Note 5)
0.7
V
CC
V
V
IL
Low-Level Input Voltage
(Note 5)
0.3
V
CC
V
I
IH
High-Level Input Current (Clock, Data)
V
IH
= V
CC
= 5.5V
-1.0
1.0
A
I
IL
Low-Level Input Current (Clock, Data)
V
IL
= 0V, V
CC
= 5.5V
-1.0
1.0
A
I
IH
Oscillator Input Current
V
IH
= V
CC
= 5.5V
100
A
I
IL
V
IL
= 0V, V
CC
= 5.5V
-100
A
I
IH
High-Level Input Current (LE, FC)
V
IH
= V
CC
= 5.5V
-1.0
1.0
A
I
IL
Low-Level Input Current (LE, FC)
V
IL
= 0V, V
CC
= 5.5V
-100
1.0
A
I
Do-source
Charge Pump Output Current
V
CC
= V
P
= 3.0V, V
Do
= V
P
/2
-2.5
mA
I
Do-sink
V
CC
= V
P
= 3.0V, V
Do
= V
P
/2
2.5
mA
I
Do-source
Charge Pump Output Current
V
CC
= V
P
= 5.0V, V
Do
= V
P
/2
-5.0
mA
I
Do-sink
V
CC
= V
P
= 5.0V, V
Do
= V
P
/2
5.0
mA
I
Do-Tri
Charge Pump TRI-STATE Current
0.5V
V
Do
V
P
- 0.5V
-2.5
2.5
nA
T = 85C
I
Do
vs
V
Do
Charge Pump Output Current
0.5V
V
Do
V
P
- 0.5V
Magnitude Variation vs Voltage
T = 25C
15
%
(Note 7)
LMX2315/LMX2320/LMX2325
www.national.com
4
Electrical Characteristics
(Continued)
LMX2325 and LMX2320 V
CC
= V
P
= 3.0V; LMX2315 V
CC
= V
P
= 5.0V; -40C
<
T
A
<
85C, except as specified
Symbol
Parameter
Conditions
Min
Typ
Max
Units
I
Do-sink
vs
Charge Pump Output Current
V
Do
= V
P
/2
I
Do-source
Sink vs Source Mismatch
T = 25C
10
%
(Note 7)
I
Do
vs T
Charge Pump Output Current
-40C
<
T
<
85C
Magnitude Variation vs Temperature
V
Do
= V
P
/2
10
%
(Note 7)
V
OH
High-Level Output Voltage
I
OH
= -1.0 mA (Note 6)
V
CC
- 0.8
V
V
OL
Low-Level Output Voltage
I
OL
= 1.0 mA (Note 6)
0.4
V
V
OH
High-Level Output Voltage (OSC
OUT
)
I
OH
= -200 A
V
CC
- 0.8
V
V
OL
Low-Level Output Voltage (OSC
OUT
)
I
OL
= 200 A
0.4
V
I
OL
Open Drain Output Current (
p
)
V
CC
= 5.0V, V
OL
= 0.4V
1.0
mA
I
OH
Open Drain Output Current (
p
)
V
OH
= 5.5V
100
A
R
ON
Analog Switch ON Resistance (2315)
100
t
CS
Data to Clock Set Up Time
See Data Input Timing
50
ns
t
CH
Data to Clock Hold Time
See Data Input Timing
10
ns
t
CWH
Clock Pulse Width High
See Data Input Timing
50
ns
t
CWL
Clock Pulse Width Low
See Data Input Timing
50
ns
t
ES
Clock to Enable Set Up Time
See Data Input Timing
50
ns
t
EW
Enable Pulse Width
See Data Input Timing
50
ns
Note 5: Except f
IN
and OSC
IN
Note 6: Except OSC
OUT
Note 7: See related equations in Charge Pump Current Specification Definitions
Typical Performance Characteristics
I
CC
vs V
CC
LMX2320/25
DS012339-4
I
CC
vs V
CC
LMX2315
DS012339-51
LMX2315/LMX2320/LMX2325
www.national.com
5
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