www.maxim-ic.com
DS4000
Digitally Controlled (DC)-TCXO
PIN ASSIGNMENT (Top View)
AB
SCL
SDA
A0
GND
OSC
N.C.
GND
6
5
4
3
2
1
BGA
C D
F
2
V
CC
F
1
V
OSC
GND
GND
www.maxim-ic.com
FEATURES
§
§
§
Aging
≤1.0ppm
per year
Frequency stability ±1.0ppm from -40°C to
+85°C
Frequency versus supply stability of ±1.0ppm
per volt
-
Base frequency is digitally tunable by
±6.0ppm
-
One fixed-frequency output and one
(n + 1) or 2(n + 1) division of the base
frequency output.
Temperature measurements from -40C° to
+85°C with 10-bit/+0.25°C resolution and
±3°C accuracy
2-wire serial interface
Reference Oscillators in PLL Circuits
Global Positioning Systems
SATCOM
Telecom
Wireless Base Stations
PIN-
PACKAGE
12 BGA
12 BGA
12 BGA
12 BGA
12 BGA
12 BGA
12 BGA
12 BGA
§
§
§
§
§
§
§
PIN DESCRIPTION
V
CC
GND
V
OSC
GND
OSC
SDA
SCL
A
0
F
2
, F
1
N.C.
- Power Supply
- Ground
- Oscillator Power Supply
- Oscillator Ground
- 2-Wire Serial-Data Input/Output
- 2-Wire Serial Clock
- 2-Wire Serial-Address Input
- DC-TCXO Outputs
- No Connection (do not connect)
APPLICATIONS
ORDERING INFORMATION
PART
DS4000A0/BGA
DS4000CW/BGA
DS4000D0BGA
DS4000EC/BGA
DS4000G0/BGA
DS4000GF/BGA
DS4000GW/BGA
DS4000KI/BGA
TOP MARK
DS4000A0
DS4000CW
DS4000D0
DS4000EC
DS4000G0
DS4000GF
DS4000GW
DS4000KI
FREQUENCY
DESIGNATOR (MHz)
10.00000
12.80000
13.00000
14.31818
16.00000
16.38400
16.80000
19.44000
DESCRIPTION
The DS4000 digitally controlled temperature-compensated crystal oscillator (DC-TCXO) features a
digital temperature sensor, one fixed-frequency temperature-compensated square-wave output (F
1
), one
programmable temperature-compensated square-wave output (F
2
), and digital communication for
frequency tuning (SDA, SCL).
Note:
Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here:
http://www.maxim-ic.com/errata.
1 of 14
072402
DS4000
SIGNAL DESCRIPTIONS
V
CC
, GND
– DC power is provided to the device on these pins.
V
OSC
, GND
OSC
– DC power is provided to the oscillator on these pins.
SDA (Serial-Data Input/Output)
– SDA is the input/output pin for the 2-wire serial interface. The SDA
pin is open drain and requires an external pullup resistor.
SCL (Serial-Clock Input)
– SCL is used to synchronize data movement on the serial interface. The SCL
pin is open drain and requires an external pullup resistor.
A
0
– 2-wire slave address input. This pin is used to configure the slave address.
F
2
, F
1
– DC-TCXO frequency outputs.
N.C.
– Do not connect.
Figure 1. BLOCK DIAGRAM
V
CC
V
OSC
TEMPERATURE-
COMPENSATED
CRYSTAL
OSCILLATOR
SDA
SCL
A0
2-WIRE
SERIAL
INTERFACE
DIGITAL
TEMPERATURE
SENSOR
F
2
F
1
DS4000
GND
GND
OSC
2 of 14
DS4000
TEMPERATURE-COMPENSATED CRYSTAL OSCILLATOR
The DS4000 can either function as a standalone TCXO or as a digitally controlled TCXO. When used as
a standalone TCXO, the only requirements needed to function properly are power, ground, and an output.
However, the 2-wire interface must be used to tune (push and pull) the crystal.
The DS4000 is capable of supplying two different outputs, F
1
and F
2
.
1) F
1
is the base frequency of the crystal unit inside of the device. The output type is a CMOS square
wave.
2) F
2
is a programmable frequency output. The frequency select register can program this output to an
integer division of the base (F
1
) frequency. The duty cycle (DC) bit determines if the output is an
n + 1 or a 2(n + 1) division of F
1
.
F
2
FREQUENCY SELECT REGISTER (FSR) (5Dh)
BIT 7
D7
BIT 6
D6
BIT 5
D5
BIT 4
D4
BIT 3
D3
BIT 2
D2
BIT 1
D1
BIT 0
D0
F
2
= F
1
/ (FSR value + 1); with DC = 0
F
2
= F
1
/ [2 x (FSR value + 1)]; with DC = 1
TCXO CONTROL REGISTER (60h)
BIT 7
X
BIT 6
X
BIT 5
X
BIT 4
X
BIT 3
F
2
OE
BIT 2
F
1
OE
BIT 1
F
T
BIT 0
DC
DC
–
Duty Cycle Bit.
If 50% duty cycle is desired, then this bit must be set to logic 1. The default
condition at power-up is logic 0.
F
T
– This bit must be programmed by the user to a 0.
F
1
OE
–
F
1
Output Enable Bit.
This bit allows the user to disable/enable the F
1
output.
F
2
OE
–
F
2
Output Enable Bit.
This bit allows the user to disable/enable the F
2
output.
3 of 14
DS4000
Digital Tuning the Base Crystal Frequency
When using the 2-wire interface for tuning the base frequency, the frequency tuning register is used. The
frequency tuning register contains two’s complement data. The data is used to add or subtract an offset
from the crystal loading register. When the tuning register is programmed with a value, the next
temperature-update cycle sums the programmed value with the factory-compensated value. This allows
the user/system to digitally control the base frequency by a microcontroller using the 2-wire protocol.
FREQUENCY TUNING REGISTER (66h)
BIT 7
BIT 6
BIT 5
BIT 4
SIGN
FO6
FO5
FO4
BIT 3
FO3
BIT 2
FO2
BIT 1
FO1
BIT 0
FO0
FOS[6:0]
–
Frequency Offset.
These bits are used to tune the base crystal frequency. Each bit represents
approximately 0.05ppm and, therefore, for a value of 07FH, pushes or pulls the base frequency by
approximately 6.35ppm.
SIGN
–
Sign Bit.
This bit is used to determine whether to add or subtract the frequency offset from the
crystal loading.
Table 1. FREQUENCY TUNING RELATIONSHIP
CALCULATED
FREQUENCY OFFSET
(ppm)
+6.35
+5.0
+3.3
+1.2
+0.05
0.0
-0.05
-1.2
-3.3
-5.0
-6.35
DIGITAL DATA
(Binary)
0111 1111
0110 0100
0100 0010
0001 0111
0000 0001
0000 0000
1111 1111
1110 1000
1011 0011
1001 1100
1000 0000
DIGITAL DATA
(hex)
7Fh
64h
42h
17h
01h
00h
FFh
E8h
B3h
9Ch
80h
4 of 14
DS4000
DIGITAL TEMPERATURE SENSOR
The digital temperature sensor provides 10-bit temperature readings that indicate the temperature of the
device. Temperature readings are communicated from the DS4000 over a 2-wire serial interface. No
additional components are required. The DS4000 has an external address bit that allows a user to choose
the slave address from two possible values.
Overview
The factory-calibrated temperature sensor requires no external components. Upon power-up, the DS4000
starts performing temperature conversions with a resolution of 10 bits (+0.25°C resolution). Following an
8-bit command protocol, temperature data can be read over the 2-wire interface. The host can periodically
read the value in the temperature register, which contains the last completed conversion. As conversions
are performed in the background, reading the temperature register does not affect the conversion in
progress.
Reading Temperature
The DS4000 measures temperature through the use of an on-chip temperature-measurement technique
with an operation range from -40°C to +85°C. The device performs continuous conversions with the most
recent result being stored in the temperature register. The digital temperature is retrieved from the
temperature register using the READ TEMPERATURE command, as described in detail in the following
paragraphs.
Table 2 describes the exact relationship of output data to measured temperature. The data is transmitted
serially over the 2-wire serial interface, MSB first. The MSB of the temperature register contains the
“sign” (S) bit, denoting whether the temperature is positive or negative. For Fahrenheit usage, a lookup
table or conversion routine must be used.
TEMPERATURE/DATA RELATIONSHIP (UNIT =
°C)
MSB (64h)
BIT 7
BIT 6
S
2
6
LSB (65h)
BIT 7
BIT 6
2
-1
2
-2
BIT 5
2
5
BIT 5
0
BIT 4
2
4
BIT 4
0
BIT 3
2
3
BIT 3
0
BIT 2
2
2
BIT 2
0
BIT 1
2
1
BIT 1
0
BIT 0
2
0
BIT 0
0
Table 2. TEMPERATURE/DATA RELATIONSHIP
TEMPERATURE
(°C)
+85
+75
+0.5
0
-0.5
-20
-40
DIGITAL OUTPUT
(Binary)
0101 0101 0000 0000
0100 1011 0000 0000
0000 0000 1000 0000
0000 0000 0000 0000
1111 1111 1000 0000
1110 1100 0000 0000
1101 1000 0000 0000
DIGITALOUTPUT
(hex)
5500h
4B00h
0080h
0000h
FF80h
EC00h
D800h
Note:
Internal power dissipation raises the temperature above the ambient. The delta between ambient and the die temperature depends on
power consumption, PC board layout, and airflow.
5 of 14
