RF INPUT
V
RATIO SELECT
OUTPUT
2100MHz Very Low Current Multi-Modulus Divider
The SP8714 is a switchable divide by 32/33, 64/65
programmable divider which is guaranteed to operate up to
2100MHz. It will operate from a supply of 2.7V to 5.25V and
requires typically 6.8mA (including the output current). It also
features a power down facility for battery economy.
The RF inputs are internally biased and should be capacitively
coupled to the signal source. The output is designed to interface
with CMOS synthesisers.
FEATURES
■ Operation to 2100MHz
■ Very Low Power
■ Single Supply Operation 2.7V to 5.25V
■ Power Down Facility for Battery Economy
■ Latched Modulus Control Input
■ Push Pull Output Drive
■ ESD Protection on All Pins
APPLICATIONS
■ Cellular Telephones
■ Cordless Telephones
†
SP8714
SP8714
DS3562 - 5.1 April 1999
CC
1 8
2 7
SP8714
3 6
4 5
RF INPUT
POWER DOWN
MODULUS CONTROL
V
EE
MP8
Fig. 1 Pin connections - top view
ORDERING INFORMATION
SP8714 IG MPAS Industrial Temperature Range
SP8714 IG MPAC As above supplied on Tape and Reel
Miniature Plastic SOIC Package
†
ESD precautions must be observed
RF
INPUT
(CLOCK)
6
M
3
R
1
8
D
V
D TYPE
V
EE
V
K
CONTROL
LOGIC
DIVIDE BY
4 / 5
DIVIDE BY
8 / 16
2
BIAS
250K
NOMINAL
7
P
DOWN
5
4
V
EE
UTPUT
WER
Fig. 2 Block diagram
1
SP8714
ABSOLUTE MAXIMUM RATINGS
Supply voltage (VEE=0V) (note 1) -0.5V to 7V
Control and RF inputs,
RF output (V
RF input current (note 1) 10mA
Operating temperature -40°C to +85°C
Storage temperature range -55°C to +150°C
Maximum junction temperature +150°C
NOTE 1. Duration <2 minutes.
ELECTRICAL CHARACTERISTICS
Guaranteed over the following conditions (unless otherwise stated):
VCC=+2.7V to +5.25V (with respect to VEE), Output load (pin 4) = 10pF, T
=0V) (note 1) -0.5V to VCC+0.5V
EE
= -40°C to +85°C (note 2)
amb
Characteristic Units Conditions
Value
Min. Typ. Max.
Supply current (note 3) 6.8 8.5 mA Power down input low
Supply current (note 3) 8 50 µA Power down input high
Power down high VCC-0.5 V
CC
V
Power down low 0 VCC-2.0 V
Modulus control high (note 4) 0.6V
CC
Modulus control low (note 4) 0 0.4V
Ratio select high (note 4, 9) 0.6V
CC
Ratio select low (note 4, 9) 0 0.4V
V
CC
CC
V
CC
CC
V Divide by 32 or 64
V Divide by 33 or 65
V Divide by 32 or 33
V Divide by 64 or 65
Max. sinewave input frequency 2100 MHz See Figure 5
Min. sinewave input frequency 200 MHz See Figure 5
Min. RF input voltage 50 mV RMS RF input 200MHz to
2100MHz. See Figure 5
Max. RF input voltage 200 mV RMS RF input 200MHz to
2100MHz. See Figure 5
Output level (pin 4) 500 600 mV p-p
Modulus set-up time, t
Modulus hold time, t
Power down time, t
h
pd
(notes 5,6,8) 10 ns RF input = 1GHz
s
(notes 6,8) 1 ns RF input = 1GHz
(notes 7,8) 10 µs See Figure 9
Power down recovery time, tpu(notes 7,8) 8 µs See Figure 9
NOTES
2. All electrical testing is performed at +85°C.
3. Typical values are measured at +25°C and VCC = +5V.
4. Modulus Control and Ratio Select are high impedance inputs which can be driven directly by standard CMOS outputs.
5. Modulus control is latched at the end of the previous cycle.
6. See Figure 4.
7. See Figure 8.
8. These parameters are not tested but are guaranteed by design.
9. The ratio select pin is not intended to be switched dynamically.
2
SP8714
OPERATING NOTES
The RF inputs are biased internally and are normally coupled to the signal source with suitable capaitors.
The output stage has a novel design and is intended to drive a CMOS synthesiser input. External pull-down resistors or
circuits are not required. The SP8714 is
The device will operate down to DC frequencies for non-sinusoidal signals provided that the input slew rate is better than
100V/µs.
POWER DOWN (pin 7) is connected internally to a pull-up resistor. If the battery economy facility is not used, pin 7 should
be connected to V
EE
.
not suitable for driving TTL or similar devices.
1000
RF INPUT
CLOCK
M
DULU
CONTROL
INPUTS
Ratio Modulus Division
Select Control Ratio
(Pin 3) (Pin 6)
LL65
LH64
HL33
HH32
Table 1 Truth table
800
TYPICAL
600
400
RF INPUT VOLTAGE (mV RMS)
200
0
500 1000 1500 2000 2500 3000
GUARANTEED*
OPERATING WINDOW
OVERLOAD
TYPICAL
SENSITIVITY
FREQUENCY (MHz)
* Tested as specified in table of Electrical Characteristics
Fig. 3 Typical input characteristics
DON'T CAREDON'T CARE
UTPUT
32 (16
t
s
t
h
32 (16) or 33 (17
Fig. 4 Modulus control timing diagram
3