Datasheet DS32KHZ-WBGA, DS32KHZ-DIP, DS32KHZ-N-WBGA, DS32KHZ-N-DIP Datasheet (Dallas Semiconductor)

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32.768kHz Temperature-Compensated

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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.

APPLICATIONS

GPS Receivers
Telematics
Network Timing and Synchronization in Servers,

Routers, Hubs, and Switches

Automatic Power Meters

PIN CONFIGURATIONS

TOP VIEW

DS32kHz

Crystal Oscillato

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

§ V

Operating Voltage: 2.7V to 5.5V with VCC

BAT

Grounded

Operating Voltage: 4.5V to 5.5V

CC

§ 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 TEMP RANGE PIN-PACKAGE

DS32kHz/DIP 0ºC to +70ºC 14 DIP
DS32kHz-N/DIP -40ºC to +85ºC 14 DIP
DS32kHz/WBGA 0ºC to +70ºC 36 BGA
DS32kHz-N/WBGA -40ºC to +85ºC 36 BGA

9

8

N.C.

V

CC

32KHZ OUT

TPIN

TPIN

N.C.

N.C.

N.C.

GND

V

BAT

N.C.

N.C.

14

1

13

2

DS32kHz

12

3

11

4

10

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 -3.0V to +7.0V
Operating Temperature Range
Commercial 0°C to +70°C
Industrial -40°C to +85°C
Storage Temperature Range -40°C to +85°C
Soldering Temperature (BGA) See IPC/JEDEC J-STD-020A (2x max) (Note 1)
Soldering Temperature, Leads (DIP) 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

Battery Voltage (Note 3) V

BAT

4.5 5.0 5.5 V

2.7 3.0 3.3, 5.5 V

DC ELECTRICAL CHARACTERISTICS

(Over the operating range, unless otherwise specified.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Active Supply Current ICC (Notes 4, 5) 150 180 µA

Active Battery Current I

BAT

= 0V, V

V

CC

(Notes 4, 5, 6, 7)

= 3.3V

BAT

1 4 µA

High Output Voltage (VCC) VOH IOH = -1.0mA 2.4 V

Low Output Voltage VOL IOL = 2.1mA 0.4 V

Battery Switch Voltage VSW V

High Output Voltage (V

Note 1: Post-solder cleaning with water-washing techniques is acceptable, provided that ultrasonic vibration is not used. Such cleaning can

Note 2: Encapsulated DIP modules can be successfully processed through conventional wave-soldering techniques, as long as the temperature

Note 3: V
Note 4: Typical values are at +25°C and 5.0V VCC, 3.0 V
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:

damage the crystal.

of the crystal contained inside does not exceed +150°C.

must be no greater than 3.3V when the device is used in the dual-supply operating modes.

BAT

Battery current increases to 450µA (typ) for 122ms (typ) for every 64 seconds.

) VOH IOH = -0.1mA 2.4 V

BAT

, unless otherwise indicated.

BAT

V

BAT

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AC TIMING CHARACTERISTICS

(Over the operating range, unless otherwise specified.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DS32kHz

Output Frequency f

Frequency Stability vs.
Temperature

32.768 kHz

OUT

0°C to +40°C -2.0 +2.0

∆f/f

O

-40°C to +85°C or
0°C to +70°C

-7.5 +7.5

ppm

Duty Cycle tW/t 45 50 55 %

Cycle Time t

(Note 8) 30.518 µs

CYC

High/Low Time tH/tL (Note 8) 15.06 µs

Rise Time tR (Note 8) 200 ns

Fall Time tF (Note 8) 60 ns

Oscillator Startup Time t

Frequency Stability vs.
Operating Voltage

(Note 8) 1 s

OSC

= 5.0V or

V

CC

V

= 3.0V, VCC = 0V

BAT

(Notes 4, 9)

±2.5 ppm/V

∆f/

V

Crystal Aging ∆f/fO (Notes 4, 10) ±1.0 ppm/yr

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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TYPICAL OPERATING CHARACTERISTICS

(VCC = 3.3V, T

4.5

+25°∞ C, unless otherwise noted.)

A =

I

vs. V

BAT

BAT

150

ICC vs. V

DS32kHz

I

vs. OUTPUT LOAD vs. V

CC

15.0

BAT

CC

4.0

3.5

3.0

2.5

SUPPLY CURRENT (mA)

2.0

1.5

2.5 5.5
V

(V)

BAT

FREQUENCY ERROR vs. V

8
7
6
5
4
3

ERROR (ppm)

2
1
0

-1

2.5 5.5

5.04.54.03.53.0

VBAT (V)

DS32kHZ toc01

125

100

75

SUPPLY CURRENT (mA)

50

25

2.5 5.5
VCC (V)

BAT

DS32kHZ toc04

5.04.54.03.53.0

12.5

DS32kHZ toc02

10.0

7.50

6.00

SUPPLY CURRENT (mA)

2.50

0

5.04.54.03.53.0

2.5 5.5

FREQUENCY ERROR vs. V

2.0

1.5

1.0

0.5

ERROR (ppm)

0

-0.5

-1.0

4.5 5.5

5.0

VCC (V)

47pF

22pF
10pF
0pF

V

BAT

CC

DS32kHZ toc05

DS32kHZ toc03

5.04.54.03.53.0

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PIN DESCRIPTIONS

DS32kHz

PIN

NAME FUNCTION

BGA DIP

A4, A5, B4, B5 5 V

A7, A8, B7, B8,
C7, C8, D7, D8

10, 11 TPIN Test Pin (must be grounded)

+3V Batttery Supply

BAT

C2, C3, D2, D3 13 VCC Primary Power Supply

C4, C5, D4, D5 12 32KHZ OUT 32.768kHz Output

— 1, 6–9, 14 N.C. No Connection

All remaining balls 4 GND Ground

Figure 1. Delta Time and Frequency vs. Temperature

TYPICAL CRYSTAL
UNCOMPENSATED

DS32kHz
OUTPUT

0.00

-10.00

-20.00

-30.00

-40.00

-50.00

-60.00

-70.00

-80.00

-90.00

-100.00

DELTA TIME (MIN/YR)

FUNCTIONAL DESCRIPTION

The DS32kHz requires four pins for operation: VCC, GND, V
schemes.) Power is applied through V

and GND, while V

CC

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) technology
with dimensions 0.400" wide, 0.450" long, and 0.124" high. It also is available in a 14-pin DIP module.

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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, and 32KHZ OUT. (See Figure 3 for connection

BAT

is used to maintain the 32kHz output in the absence

BAT

Figure 2. Block Diagram

DS32kHz

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 V
monitors the relationship between the VCC and V
V

, the device switches over to V

BAT

while V

is applied.

CC

(Figure 3A). This mode uses VCC to conserve the battery connected to V

BAT

input levels. When VCC drops below a certain level compared to

BAT

In the single-supply mode, V
of V

, because the comparator circuit is unpowered (Figure 3B).

CC

is grounded and the unit is powered by V

CC

. Current consumption is less than that

BAT

Figure 3A shows how the DS32kHz should be connected when using two power supplies. V

4.5V and 5.5V and V
only a single-supply system is available. V

5.5V. The V

pin should be connected directly to a battery. Figure 3C shows a single supply mode where VCC is

BAT

should be between 2.7V and 3.3V. Figure 3B shows how the DS32kHz can be used when

BAT

should be grounded and V

CC

should then be held between 2.7V and

BAT

should be between

CC

held at +5V. See the frequency stability versus operating voltage for information about frequency error versus
supply voltage.

Figure 3. Power-Supply Connections

CC,

BAT

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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 I
crystal or resonator. Driving the oscillator circuit with the rail-to-rail output of the DS32kHz can increase the I
I

currents significantly and increase the current consumption of the RTC as well. Figure 5 shows one circuit that

BAT

and I

CC

currents are specified with no output loads. Many RTC oscillator circuits use a quartz

BAT

CC

and

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.

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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

.)

DS32kHz

G

G

G

E

E

B

B

B

E

H

H

H

F

F

F

C

C

C

D

D

A

A

A

PKG 36-PIN BGA

DIM MIN MAX

A IN 0.395 0.405

B IN 0.445 0.455
C IN 0.022 0.028
D IN 0.047 0.053

E IN 0.047 0.053

F IN 0.347 0.353
G IN 0.118 0.130
H IN 0.020 0.030

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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

.)

DS32kHz

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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.

DS32kHz

PKG 14-PIN DIP

DIM MIN MAX

A IN 0.825 0.840

B IN 0.420 0.440
C IN 0.235 0.260
D IN 0.100 0.130
E IN 0.015 0.030
F IN 0.110 0.140

G IN 0.090 0.110

H IN 0.290 0.330

J IN 0.008 0.012
K IN 0.015 0.021

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