AVAILAB
LE
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 Minutes/Year (-40°C to +85°C)
Accurate to ±1 Minute/Year (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
DS32KHZN/DIP
DS32KHZS
DS32KHZS#
DS32KHZSN
DS32KHZSN#
DS32KHZ/WBGA
DS32KHZN/WBGA
TEMP
RANGE
0ºC to +70ºC
-40ºC to +85ºC
0ºC to +70ºC
0ºC to +70ºC
-40ºC to +85ºC
-40ºC to +85ºC
0ºC to +70ºC
-40ºC to +85ºC
14 DIP
14 DIP
16 SO (0.300”)
16 SO (0.300”)
16 SO (0.300”)
16 SO (0.300”)
36 BGA
36 BGA
PIN-
PACKAGE
TOP MARK*
DS32KHZ
DS32KHZ-N
DS32KHZS
DS32KHZS
DS32KHZSN
DS32KHZSN
DS32KHZ
DS32KHZ-N
Functional Diagrams
#Denotes
a RoHS-compliant device that may include lead that is exempt
under the RoHS requirements. The lead finish is JESD97 category e3, and
is compatible with both lead-based and lead-free soldering processes.
*A
“#” anywhere on the top mark denotes a RoHS-compliant device. An “N”
denotes an industrial device.
PIN CONFIGURATIONS
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
REV: 080607
DS32kHz
ABSOLUTE MAXIMUM RATINGS
Voltage Range on Any Pin Relative to Ground………………………………………………………………-3.0V to +7.0V
Operating Temperature Range (Noncondensing)
Commercial:…………………………………………………………………………………………………..0°C to +70°C
Industrial:……………………………………………………………………………………………………-40°C to +85°C
Storage Temperature Range………………………………………………………………………………….-40°C to +85°C
Soldering Temperature (BGA, SO)……………………….See the
Handling, PC Board Layout, and Assembly
section.
Soldering Temperature, Leads (DIP)……………………………………………………..+260°C for 10 seconds (Note
1)
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 reliability.
RECOMMENDED DC OPERATING CONDITIONS
(T
A
= -40°C to +85°C) (Note 1)
PARAMETER
Power-Supply Voltage
Battery Voltage
SYMBOL
V
CC
V
BAT
CONDITIONS
(Note 2)
(Notes 2, 3)
MIN
4.5
2.7
TYP
5.0
3.0
MAX
5.5
3.5,
5.5
UNITS
V
V
DC ELECTRICAL CHARACTERISTICS
(Over the operating range, unless otherwise specified.) (Note 1)
PARAMETER
Active Supply Current
Battery Input-Leakage Current
High Output Voltage (V
CC
)
Low Output Voltage
High Output Voltage (V
BAT
)
Battery Switch Voltage
SYMBOL
I
CC
I
BATLKG
V
OH
V
OL
V
OH
V
SW
CONDITIONS
V
BAT
= 0V or
2.7V
≤
V
BAT
≤
3.5V
(Notes 3, 4)
V
CC
MIN
≤
V
CC
≤
V
CC
MAX
I
OH
= -1.0mA (Note 2)
I
OL
= 2.1mA (Note 2)
I
OH
= -0.1mA (Note 2)
(Note 2)
2.4
V
BAT
-50
2.4
0.4
MIN
TYP
150
MAX
220
+50
UNITS
μA
nA
V
V
V
V
(V
CC
= 0V, T
A
= -40°C to +85°C.) (Note 1)
PARAMETER
Active Battery Current
Battery Current During
Temperature Measurement
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
SYMBOL
I
BAT
I
BATCNV
CONDITIONS
V
BAT
= 3.3V (Notes 4, 5, 6)
V
BAT
= 3.3V (Notes 4, 5, 7)
MIN
TYP
1
450
MAX
4
UNITS
μA
μA
Limits at -40°C are guaranteed by design and are not production tested.
All voltages are referenced to ground.
V
BAT
must be no greater than 3.5V when the device is used in the dual-supply operating modes.
Typical values are at +25°C and 5.0V V
CC
, 3.0 V
BAT
, unless otherwise indicated.
These parameters are measured under no output load conditions.
This current is the active-mode current sourced from the backup supply/battery.
A temperature conversion lasts 122ms (typ) and occurs on power-up and then once every 64 seconds.
2 of 8
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 (First Year)
Note 8:
Note 9:
Note 10:
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
CONDITIONS
0°C to +40°C
-40°C to +85°C or
0°C to +70°C
(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)
MIN
-2.0
-7.5
45
TYP
32.768
MAX
+2.0
+7.5
UNITS
kHz
ppm
%
μs
μs
ns
ns
seconds
ppm/
V
ppm
50
30.518
15.06
200
60
1
+2.5
±1.0
55
These parameters are measured using a 15pF load.
Error is measured from the nominal supply voltage of whichever supply is powering the device.
After reflow.
Figure 1. DS32kHz Output Waveform
3 of 8
DS32kHz
TYPICAL OPERATING CHARACTERISTICS
(V
CC
= 3.3V, T
A
= +25°C, unless otherwise noted.)
I
BAT
versus V
BAT
4.5
4
SUPPLY CURRENT (uA)
SUPPLY CURRENT (uA)
3.5
3
2.5
2
1.5
2.7
3.2
3.7
4.2
V
BAT
(V)
4.7
5.2
145
135
125
115
105
95
85
75
4.50
4.75
5.00
V
CC
(V)
5.25
5.50
I
CC
versus V
CC
15.0
I
BAT
vs. V
BAT
vs. output load
Frequency Deviation Versus Supply Voltage
7
6
47pF
12.5
5
SUPPLY CURRENT (uA)
10.0
Deviation in ppm
4
3
2
V
BAT
7.5
22pF
5.0
10pF
V
CC
1
2.5
0pF
0
-1
0.0
2.7
3.2
3.7
4.2
V
BAT
4.7
5.2
2.7
3.2
3.7
4.2
4.7
Supply Voltage (V)
5.2
4 of 8
DS32kHz
PIN DESCRIPTION
PIN
SO
1
2
3–12, 15, 16
13
14
BGA
C4, C5, D4, D5
C2, C3, D2, D3
A7, A8, B7, B8,
C7, C8, D7, D8
All remaining
balls
A4, A5, B4, B5
DIP
12
13
1, 6–11, 14
4
5
NAME
32kHz
V
CC
N.C.
GND
V
BAT
FUNCTION
32.768kHz Push-Pull Output
Primary Power Supply
No Connection (Must be grounded)
Ground
+3V Nominal Supply Input. Used to operate the
device when V
CC
is absent.
Figure 2. Delta Time and Frequency vs. Temperature
20
0
Crystal +20ppm
0
Typical Crystal,
Uncompensated
-20
Delta Frequency (ppm)
-40
-60
-80
-100
-120
-140
-160
-180
-200
-40
-30
-20
-10
0
Crystal -20ppm
-40
-60
-80
-100
10
20
30
40
50
60
70
80
Temperature (°C)
FUNCTIONAL DESCRIPTION
The DS32kHz is a temperature-compensated crystal oscillator (TCXO) that outputs a 32,768Hz square wave.
While the DS32kHz is powered by either supply input, the device measures the temperature every 64 seconds and
adjusts the output frequency. The device requires four pins for operation: V
CC
, GND, V
BAT
, and 32kHz. (See
Figure 4
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. Once every 64 seconds, the DS32kHz measures the temperature and
adjusts the output frequency. The output is accurate to ±2ppm (±1 min/yr) from 0°C to +40°C and to ±7.5ppm
(±4 min/year) from -40°C to 0°C and from +40°C to +85°C.
5 of 8
Delta Time (Min/Year)
DS32kHz
Accuracy
Band
-20
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