Dallas DS32KHZ-N/DIP 32.768khz temperature-compensated crystal oscillator Datasheet

DS32kHz
32.768kHz Temperature-Compensated
Crystal Oscillator
www.maxim-ic.com
GENERAL DESCRIPTION
FEATURES
The DS32kHz is a temperature-compensated crystal
oscillator (TCXO) with an output frequency of
32.768kHz. This device addresses applications
requiring better timekeeping accuracy and can be
used to drive the X1 input of most Dallas
Semiconductor real-time clocks (RTCs), chipsets, and
other ICs containing RTCs. This device is available in
commercial (DS32kHz) and industrial (DS32kHz-N)
temperature versions.
§
§
§
§
APPLICATIONS
GPS Receivers
Telematics
Network Timing and Synchronization in Servers,
Routers, Hubs, and Switches
Automatic Power Meters
Accurate to ±4 Min/Yr (-40°C to +85°C)
Accurate to ±1 Min/Yr (0°C to +40°C)
Battery Backup for Continuous Timekeeping
VBAT Operating Voltage: 2.7V to 5.5V with VCC
Grounded
VCC Operating Voltage: 4.5V to 5.5V
Operating Temperature Range:
0°C to +70°C (Commercial)
-40°C to +85°C (Industrial)
No Calibration Required
Low-Power Consumption
Surface Mountable Using BGA Package
UL Recognized
§
§
§
§
§
§
ORDERING INFORMATION
PART
DS32kHz/DIP
DS32kHz-N/DIP
DS32kHz/WBGA
DS32kHz-N/WBGA
TEMP RANGE
0ºC to +70ºC
-40ºC to +85ºC
0ºC to +70ºC
-40ºC to +85ºC
PIN-PACKAGE
14 DIP
14 DIP
36 BGA
36 BGA
PIN CONFIGURATIONS
TOP VIEW
N.C.
N.C.
14
2
13
VCC
3
12
32KHZ OUT
11
TPIN
10
TPIN
DS32kHz
1
GND
4
VBAT
5
N.C.
6
9
N.C.
N.C.
7
8
N.C.
DIP
BGA
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: www.maxim-ic.com/errata.
1 of 10
REV: 041603
DS32kHz
ABSOLUTE MAXIMUM RATINGS
Voltage Range on Any Pin Relative to Ground
Operating Temperature Range
Commercial
Industrial
Storage Temperature Range
Soldering Temperature (BGA)
Soldering Temperature, Leads (DIP)
-3.0V to +7.0V
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
See IPC/JEDEC J-STD-020A (2x max) (Note 1)
260°C for 10 seconds (Notes 1, 2)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is
not implied. Exposure to the absolute maximum rating conditions for extended periods may affect device.
RECOMMENDED DC OPERATING CONDITIONS
(TA = -40°C to +85°C)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Power-Supply Voltage
VCC
4.5
5.0
5.5
V
Battery Voltage (Note 3)
VBAT
2.7
3.0
3.3, 5.5
V
MIN
TYP
MAX
UNITS
150
180
µA
1
4
µA
DC ELECTRICAL CHARACTERISTICS
(Over the operating range, unless otherwise specified.)
PARAMETER
SYMBOL
CONDITIONS
Active Supply Current
ICC
(Notes 4, 5)
Active Battery Current
IBAT
VCC = 0V, VBAT = 3.3V
(Notes 4, 5, 6, 7)
High Output Voltage (VCC)
VOH
IOH = -1.0mA
Low Output Voltage
VOL
IOL = 2.1mA
Battery Switch Voltage
VSW
High Output Voltage (VBAT)
VOH
2.4
V
0.4
VBAT
IOH = -0.1mA
2.4
V
V
V
Note 1: Post-solder cleaning with water-washing techniques is acceptable, provided that ultrasonic vibration is not used. Such cleaning can
damage the crystal.
Note 2: Encapsulated DIP modules can be successfully processed through conventional wave-soldering techniques, as long as the temperature
of the crystal contained inside does not exceed +150°C.
Note 3: VBAT must be no greater than 3.3V when the device is used in the dual-supply operating modes.
Note 4: Typical values are at +25°C and 5.0V VCC, 3.0 VBAT, unless otherwise indicated.
Note 5: These parameters are measured under no load conditions.
Note 6: This current is the active mode current sourced from the backup supply/battery.
Note 7: Battery current increases to 450µA (typ) for 122ms (typ) for every 64 seconds.
2 of 10
DS32kHz
AC TIMING CHARACTERISTICS
(Over the operating range, unless otherwise specified.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
32.768
UNITS
Output Frequency
fOUT
Frequency Stability vs.
Temperature
∆f/fO
Duty Cycle
tW/t
Cycle Time
tCYC
(Note 8)
30.518
µs
High/Low Time
tH/tL
(Note 8)
15.06
µs
Rise Time
tR
(Note 8)
200
ns
Fall Time
tF
(Note 8)
60
ns
1
s
±2.5
ppm/V
±1.0
ppm/yr
0°C to +40°C
-40°C to +85°C or
0°C to +70°C
-2.0
+2.0
-7.5
+7.5
45
Oscillator Startup Time
tOSC
Frequency Stability vs.
Operating Voltage
∆f/V
(Note 8)
VCC = 5.0V or
VBAT = 3.0V, VCC = 0V
(Notes 4, 9)
Crystal Aging
∆f/fO
(Notes 4, 10)
Note 8: These parameters are measured using a 15pF load.
Note 9: Error is measured from the nominal supply voltage of whichever supply is powering the device.
Note 10: After reflow.
3 of 10
kHz
50
55
ppm
%
DS32kHz
TYPICAL OPERATING CHARACTERISTICS
(VCC = 3.3V, TA = +25°∞ C, unless otherwise noted.)
ICC vs. VCC
2.5
100
75
50
2.0
1.5
3.5
4.0
4.5
5.0
5.5
10.0
7.50
22pF
6.00
10pF
0pF
0
2.5
3.0
VBAT (V)
3.5
4.0
4.5
5.0
5.5
2.5
3.0
3.5
VCC (V)
FREQUENCY ERROR vs. VCC
FREQUENCY ERROR vs. VBAT
2.0
DS32kHZ toc04
8
7
6
4.0
VBAT
DS32kHZ toc05
3.0
47pF
2.50
25
1.5
5
ERROR (ppm)
2.5
12.5
SUPPLY CURRENT (mA)
125
SUPPLY CURRENT (mA)
3.0
15.0
DS32kHZ toc02
DS32kHZ toc01
3.5
ERROR (ppm)
SUPPLY CURRENT (mA)
4.0
IBAT vs. OUTPUT LOAD vs. VCC
150
4
3
1.0
0.5
0
2
1
-0.5
0
-1.0
-1
2.5
3.0
3.5
4.0
4.5
5.0
DS32kHZ toc03
IBAT vs. VBAT
4.5
4.5
5.5
5.0
VCC (V)
VBAT (V)
4 of 11
5.5
4.5
5.0
5.5
DS32kHz
PIN DESCRIPTIONS
PIN
NAME
FUNCTION
BGA
DIP
A4, A5, B4, B5
5
VBAT
+3V Batttery Supply
A7, A8, B7, B8,
C7, C8, D7, D8
10, 11
TPIN
Test Pin (must be grounded)
C2, C3, D2, D3
13
VCC
C4, C5, D4, D5
12
32KHZ OUT
—
1, 6–9, 14
N.C.
No Connection
All remaining balls
4
GND
Ground
Primary Power Supply
32.768kHz Output
Figure 1. Delta Time and Frequency vs. Temperature
0.00
-10.00
-30.00
-40.00
-50.00
-60.00
TYPICAL CRYSTAL
UNCOMPENSATED
DS32kHz
OUTPUT
DELTA TIME (MIN/YR)
-20.00
-70.00
-80.00
-90.00
-100.00
FUNCTIONAL DESCRIPTION
The DS32kHz requires four pins for operation: VCC, GND, VBAT, and 32KHZ OUT. (See Figure 3 for connection
schemes.) Power is applied through VCC and GND, while VBAT is used to maintain the 32kHz output in the absence
of power. The output is accurate to ±7.5ppm (±4 min/yr) from –40°C to +85°C and ±2ppm (±1 min/yr) from 0°C to
+40°C.
The DS32kHz is packaged in a small 36-pin SMD using ball grid array (BGA)
with dimensions 0.400" wide, 0.450" long, and 0.124" high. It also is available in a 14-pin DIP module.
technology
The additional board space required is negligible in most applications and, therefore, the recommended land
pattern layout should be implemented on all new designs and future board revisions to satisfy applications requiring
better timekeeping accuracy.
5 of 10
DS32kHz
Figure 2. Block Diagram
OPERATION
The DS32kHz module contains a crystal and an IC. While powered, the DS32kHz peridocially measures the
temperature and adjusts the crystal load to compensate.
The DS32kHz is designed to operate in two modes. In the dual-supply mode, a comparator circuit, powered by VCC,
monitors the relationship between the VCC and VBAT input levels. When VCC drops below a certain level compared to
VBAT, the device switches over to VBAT (Figure 3A). This mode uses VCC to conserve the battery connected to VBAT
while VCC is applied.
In the single-supply mode, VCC is grounded and the unit is powered by VBAT. Current consumption is less than that
of VCC, because the comparator circuit is unpowered (Figure 3B).
Figure 3A shows how the DS32kHz should be connected when using two power supplies. VCC should be between
4.5V and 5.5V and VBAT should be between 2.7V and 3.3V. Figure 3B shows how the DS32kHz can be used when
only a single-supply system is available. VCC should be grounded and VBAT should then be held between 2.7V and
5.5V. The VBAT pin should be connected directly to a battery. Figure 3C shows a single supply mode where VCC is
held at +5V. See the frequency stability versus operating voltage for information about frequency error versus
supply voltage.
Figure 3. Power-Supply Connections
6 of 10
DS32kHz
Figure 4 illustrates how a standard 32.768kHz crystal and the DS32kHz should be connected to address the
interchangeable option. Using this connection scheme and the recommended layout provides a solution, which
requires no hardware modifications. Only one device should be used at a time, and both layouts should be located
very close together if the recommended layout is not used.
The DS32kHz ICC and IBAT currents are specified with no output loads. Many RTC oscillator circuits use a quartz
crystal or resonator. Driving the oscillator circuit with the rail-to-rail output of the DS32kHz can increase the ICC and
IBAT currents significantly and increase the current consumption of the RTC as well. Figure 5 shows one circuit that
can be used to reduce the current consumption of a DS32kHz and an RTC. The values of R1 and C1 may vary
depending on the RTC used. However, values of 1.0MW and 100pF are recommended as a starting point. R2 is
used to shift the input waveform to the proper level. The recommended value for R2 is 33kW.
Figure 4. DS32kHz Connections
THE STANDARD 32.768kHz CRYSTAL AND THE DS32kHz SHOULD BE CONNECTED TO ADDRESS THE
INTERCHANGEABLE OPTION.
Figure 5. DS32kHz and RTC Connections
THIS SHOWS A CIRCUIT THAT CAN BE USED TO REDUCE
THE CURRENT CONSUMPTION OF A DS32kHz AND AN RTC.
7 of 10
DS32kHz
Figure 6. DS32kHz Output Waveform
RELATED APPLICATION NOTES
Application Note 58: Crystal Considerations with Dallas Real-Time Clocks
Application Note 701: Using the DS32kHz with Dallas RTCs
PACKAGE INFORMATION
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package information, go to
www.maxim-ic.com/DallasPackInfo.)
G
H
D
C
PKG
F
E
A
B
8 of 10
DIM
A IN
B IN
C IN
D IN
E IN
F IN
G IN
H IN
36-PIN BGA
MIN
0.395
0.445
0.022
0.047
0.047
0.347
0.118
0.020
MAX
0.405
0.455
0.028
0.053
0.053
0.353
0.130
0.030
DS32kHz
PACKAGE INFORMATION (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package information, go to
www.maxim-ic.com/DallasPackInfo.)
9 of 10
DS32kHz
PACKAGE INFORMATION (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package information, go to
www.maxim-ic.com/DallasPackInfo.)
Note: Pins 2, 3 are missing by design.
PKG
DIM
A IN
B IN
C IN
D IN
E IN
F IN
G IN
H IN
J IN
K IN
14-PIN DIP
MIN
MAX
0.825
0.840
0.420
0.440
0.235
0.260
0.100
0.130
0.015
0.030
0.110
0.140
0.090
0.110
0.290
0.330
0.008
0.012
0.015
0.021
10 of 10
Similar pages