DS32kHz
32.768kHz Temperature-Compensated
Crystal Oscillator
www.maxim-ic.com
GENERAL DESCRIPTION
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.
FEATURES
§
§
§
§
§
§
§
§
§
§
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
V
BAT
Operating Voltage: 2.7V to 5.5V with V
CC
Grounded
V
CC
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
APPLICATIONS
GPS Receivers
Telematics
Network Timing and Synchronization in Servers,
Routers, Hubs, and Switches
Automatic Power Meters
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.
1
2
3
DS32kHz
14
13
12
11
10
9
8
N.C.
V
CC
32KHZ OUT
TPIN
TPIN
N.C.
N.C.
GND
V
BAT
N.C.
N.C.
4
5
6
7
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.
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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
(T
A
= -40°C to +85°C)
PARAMETER
Power-Supply Voltage
Battery Voltage (Note 3)
SYMBOL
V
CC
V
BAT
CONDITIONS
MIN
4.5
2.7
TYP
5.0
3.0
MAX
5.5
3.3, 5.5
UNITS
V
V
DC ELECTRICAL CHARACTERISTICS
(Over the operating range, unless otherwise specified.)
PARAMETER
Active Supply Current
Active Battery Current
High Output Voltage (V
CC
)
Low Output Voltage
Battery Switch Voltage
High Output Voltage (V
BAT
)
SYMBOL
I
CC
I
BAT
V
OH
V
OL
V
SW
V
OH
I
OH
= -0.1mA
2.4
CONDITIONS
(Notes 4, 5)
V
CC
= 0V, V
BAT
= 3.3V
(Notes 4, 5, 6, 7)
I
OH
= -1.0mA
I
OL
= 2.1mA
V
BAT
2.4
0.4
MIN
TYP
150
1
MAX
180
4
UNITS
µA
µA
V
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:
V
BAT
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 V
CC
, 3.0 V
BAT
, 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.
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DS32kHz
AC TIMING CHARACTERISTICS
(Over the operating range, unless otherwise specified.)
PARAMETER
Output Frequency
Frequency Stability vs.
Temperature
Duty Cycle
Cycle Time
High/Low Time
Rise Time
Fall Time
Oscillator Startup Time
Frequency Stability vs.
Operating Voltage
Crystal Aging
SYMBOL
f
OUT
∆f/f
O
t
W
/t
t
CYC
t
H
/t
L
t
R
t
F
t
OSC
∆f/
V
∆f/f
O
(Note 8)
(Note 8)
(Note 8)
(Note 8)
(Note 8)
V
CC
= 5.0V or
V
BAT
= 3.0V, V
CC
= 0V
(Notes 4, 9)
(Notes 4, 10)
0°C to +40°C
-40°C to +85°C or
0°C to +70°C
-2.0
-7.5
45
50
30.518
15.06
200
60
1
±2.5
±1.0
CONDITIONS
MIN
TYP
32.768
+2.0
+7.5
55
ppm
%
µs
µs
ns
ns
s
ppm/
V
ppm/yr
MAX
UNITS
kHz
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.
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DS32kHz
TYPICAL OPERATING CHARACTERISTICS
(V
CC
= 3.3V, T
A
= +25°C, unless otherwise noted.)
∞
I
BAT
vs. V
BAT
DS32kHZ toc01
I
CC
vs. V
CC
DS32kHZ toc02
I
BAT
vs. OUTPUT LOAD vs. V
CC
DS32kHZ toc03
4.5
4.0
SUPPLY CURRENT (mA)
3.5
3.0
2.5
2.0
1.5
2.5
3.0
3.5
4.0
V
BAT
(V)
4.5
5.0
150
125
SUPPLY CURRENT (mA)
100
75
50
25
15.0
12.5
SUPPLY CURRENT (mA)
10.0
7.50
6.00
2.50
0
22pF
10pF
0pF
47pF
5.5
2.5
3.0
3.5
4.0
V
CC
(V)
4.5
5.0
5.5
2.5
3.0
3.5
4.0
V
BAT
4.5
5.0
5.5
FREQUENCY ERROR vs. V
BAT
7
6
ERROR (ppm)
5
4
3
2
1
0
-1
2.5
3.0
3.5
4.0
VBAT (V)
4.5
5.0
5.5
DS32kHZ toc04
FREQUENCY ERROR vs. V
CC
DS32kHZ toc05
8
2.0
1.5
1.0
0.5
0
-0.5
-1.0
4.5
5.0
V
CC
(V)
ERROR (ppm)
5.5
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DS32kHz
PIN DESCRIPTIONS
PIN
BGA
A4, A5, B4, B5
A7, A8, B7, B8,
C7, C8, D7, D8
C2, C3, D2, D3
C4, C5, D4, D5
—
All remaining balls
DIP
5
10, 11
13
12
1, 6–9, 14
4
NAME
V
BAT
TPIN
V
CC
32KHZ OUT
N.C.
GND
FUNCTION
+3V Batttery Supply
Test Pin (must be grounded)
Primary Power Supply
32.768kHz Output
No Connection
Ground
Figure 1. Delta Time and Frequency vs. Temperature
0.00
-10.00
-20.00
-30.00
-40.00
-50.00
TYPICAL CRYSTAL
UNCOMPENSATED
-60.00
DS32kHz
OUTPUT
-70.00
-80.00
-90.00
-100.00
DELTA TIME (MIN/YR)
FUNCTIONAL DESCRIPTION
The DS32kHz requires four pins for operation: V
CC
, GND, V
BAT
, and 32KHZ OUT. (See Figure 3 for connection
schemes.) Power is applied through V
CC
and GND, while V
BAT
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.
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