NJ88C33
Frequency Synthesiser (I
2
C BUS Programmable)
Advance Information
DS2429 - 3.2 September 1994
The NJ88C33 is a synthesiser circuit fabricated on Zarlink
Semiconductor's 1.4 micron CMOS process, assuring very
high performance. It is I
2
C compatible and can also be
programmed at up to 5MHz. It contains a 16-bit R counter, a
12-bit N counter and a 7-bit A counter.
A digital phase comparator gives improved loop stability
with current source outputs to reduce loop components. A
voltage doubler is provided for the loop driver to improve
control voltage range to the VCO when operating at low supply
voltages.
DP14
FEATURES
s
s
s
s
s
s
s
s
s
Easy to Use
Low Power Consumption (15mW)
Single Supply 2.5V to 5.5V
Digital Phase Comparator with Current Source
Outputs
Serial (I
2
C Compatible) Programming, 5MHz max
Channel Loading in 8µs
150MHz Input Frequency Without Prescaler at 4.5V
(52MHz at 2.7V)
Standby Modes
Use of Two-Modulus Prescaler is Possible
MP14
Fig.1 Pin connections (not to scale) - top views
ABSOLUTE MAXIMUM RATINGS
Supply voltage, V
DD
Input voltage, V
IM1
Output voltage on pin 13, V
IM2
Storage temperature, T
stg
-0.3V to 7V
-0.3 to V
DD
+0.3V
-V
DD
to 0V
-55°C to +125°C
APPLICATIONS
s
s
s
s
s
Cordless Telephones (CT2, DECT)
Cellular Telephones (GSM, PCN, ETACS)
Hand Held Marine Radios
Sonarbuoys
Video Clock generators
ORDERING INFORMATION
NJ88C33 MA DP
(Industrial - Plastic DIL package)
NJ88C33 MA MP
(Industrial - Miniature Plastic DIL package)
Fig.2 Simplified block diagram of NJ88C33
NJ88C33
PIN DESIGNATIONS
Pin
No.
1
2
3
4
5
6
7
Pin
Name
V
DD
RI
S/D
SDA
SCL
PORT
MOD
Supply voltage (normally 5V or 3V).
Reference frequency input from an accurate source, normally a crystal oscillator. The input is normally
an AC coupled sinewave but may be a DC coupled square wave.
Single/dual modulus operating mode selection input. Single modulus operation is selected by driving
the pin low. 'High' selects dual modulus mode.
I
2
C bus data input pin. It is also an open-drain output for generating I
2
C bus acknowledge pulses.
I
2
C bus clock input. It can be clocked at up to 5MHz.
Output control pin, which can be programmed via the I
2
C bus. It can be connected to the S/D pin to
select single or dual modulus mode under bus control.
Modulus control pin. It is high in single modulus mode but switches in dual modulus operation. In dual
modulus mode, MOD remains low during operation of the A counter until A=0; MOD then remains high
until N=0, when both counters are reloaded. It can be programmed via the I
2
C bus as an open-drain
or push-pull output.
Frequency input from a VCO or prescaler. The input is normally an AC coupled sinewave but may be
a DC coupled square wave.
Dedicated ground for the FI input buffer. It should be connected to the VCO ground or the prescaler
ground, if used. Any noise on this pin will affect the performance of the VCO loop.
Open-drain output from the N counter.
Ground supply pin (global).
Tristate current output from the phase detector. The polarity of the output can be programmed via the
I
2
C bus.
Voltage doubler output. The operation of the doubler can be controlled via the I2C bus. In applications
where the voltage doubler is switched off, this pin should be connected to GND1; a reservior capacitor
should be connected from this pin to GND1 for applications where it is switched on.
Open-drain lock detect output - requires integration if used.
Description
8
9
10
11
12
13
FI
GND2
FVN
GND1
PD
C
14
LD
OPERATING RANGE
Test conditions (unless otherwise stated):
PLL locked, RI = 10MHz
Characteristic
Supply voltage
Ambient temperature
Supply current
Single modulus
Symbol
V
DD
T
amb
I
DD
I
DD
2.5
-40
Value
Min. Typ. Max.
5
5.5
+85
3.0
V
°C
mA
FI = 50MHz, V
FI
= 150mVrms, N,R > 1000 without
voltage doubler, V
DD
= 5V, T
amb
= 25°C
FI = 10MHz, V
FI
= 500mVrms, N,R > 1000 without
voltage doubler, V
DD
= 5V, T
amb
= 25°C
Unit
Conditions
2.1
Dual modulus
2
3.0
mA
Standby mode
I
DD
I
DD
1
µA
FI = 50MHz, V
FI
= 150mVrms, preamp off, divider off,
V
DD
= 5V, T
amb
= 25°C
FI = 50MHz, V
FI
= 150mVrms, preamp on, divider off,
V
DD
= 5V, T
amb
= 25°C
Standby mode
1.0
1.5
mA
2
NJ88C33
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following conditions (unless otherwise stated):
V
DD
= 4.5V to 5.5V, T
amb
= -40°C to +85°C
INPUT SIGNALS
Characteristic
Input Signals SDA,
SCL, S/D
Input voltage high
Input voltage low
Input capacitance
Input current
Input signal RI
Input frequency
Input voltage
Input capacitance
Input current
Input signal FI
Input frequency
Input voltage
Input capacitance
Input current
Input signal FI
Input frequency
Input voltage
Input capacitance
Input current
Symbol
Min.
Value
Typ.
Max.
Unit
Conditions
V
IH
V
IL
C
I
I
IN
f
max
V
Irms
C
I
I
IN
f
max
V
Irms
C
I
I
IN
f
max
V
Irms
V
Irms
V
Irms
C
I
I
IN
0.7V
DD
0
V
DD
0.3V
DD
10
10
52
V
V
pF
µA
MHz
mV
pF
µA
MHz
mV
pF
µA
MHz
mV
mV
mV
pF
µA
V
IN
= V
DD
= 5.5V
Sinewave input
Note 1, 2
V
IN
= V
DD
= 5.5V
Dual modulus operation
Sinewave input
Note 1, 2
V
IN
= V
DD
= 5.5V
Single modulus operation
Sinewave input
FI = 0-70MHz Note 1, 2
FI = 70-120MHz Note 1, 2
FI = 120-150MHz Note 1, 2
V
IN
= V
DD
= 5.5V
100
10
10
52
50
10
10
150
30
100
200
10
10
Note.1Lowest noise floor achieved at 10dB above this level with I
2
C bus operating. The source impedance should be less
than 2kΩ.
Note.2DC coupled input amplitude V
IRMS
> 0.8V
DD
.
OUTPUT SIGNALS
Characteristic
Output Signals SDA, LD
Output voltage low
Output Signal PD
High current mode (see Fig.4)
Low current mode
Tristate
Output Signal FVN
Output voltage low
Output low pulse width
Output Signals MOD, PORT
Output voltage high
Output voltage low
Output Signal LD
Output voltage low
Output low pulse width
Symbol
Min.
V
OL
I
HU
I
HD
I
LU
I
LD
I
Z
V
OL
t
WL
V
OH
V
OL
V
OL
t
WL
V
DD
-0.4
Value
Typ.
Max.
0.4
2.5
1.9
3.1
-2.5
-1.9
-3.1
0.475 0.625 0.775
-0.475 -0.625 -0.775
50
0.4
1/FI
V
mA
mA
mA
mA
nA
V
Unit
Conditions
Open drain, I
OL
= 3mA
C
L
= 400pF, tristate output
0 < V
PD
< 4.5, V
DD
= 5V, T = 25°C Note 1
0.4 < V
PD
< 5, V
DD
= 5V, T = 25°C Note 1
0 < V
PD
< 4.6, V
DD
= 5V, T = 25°C Note 1
0.4 < V
PD
< 5, V
DD
= 5V, T = 25°C Note 1
T
amb
= -25°C to +60°C
Open drain output
I
OL
= 1mA
C
L
= 30pF
Push-pull output
IOH = 0.5mA
I
OL
= 0.5mA
Open drain output
I
OL
= 3mA, C
L
= 30pF
Loop locked
Loop not locked
FVN = FI/N
f
C
= RI/R
0.4
0.4
1/FVN
1/f
C
V
V
V
ns
10
Note.1Temperature coefficient for current is typically -0.7%/°C
4
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