LINEAR TECHNOLOGY LTC6903, LTC6904 Technical data

FEATURES

■

1kHz to 68MHz Square Wave Output

■

0.5% (Typ) Initial Frequency Accuracy

■

Frequency Error <1.1% Over All Settings

■

10ppm/°C Typical Frequency Drift Over
Temperature

■

0.1% Resolution

■

1.7mA Typical Supply Current (f < 1MHz, VS = 2.7V)

■

2.7V to 5.5V Single Supply Operation

■

Jitter <0.4% Typical 1kHz to 8MHz

■

Easy to Use SPI (LTC6903) or I2C (LTC6904) Serial
Interface

■

Output Enable Pin

■

–40°C to 125°C Operation

■

MS8 Package

U

APPLICATIO S

■

Precision Digitally Controlled Oscillator

■

Power Management

■

Direct Digital Frequency Synthesis (DDS)
Replacement

■

Replacement for DAC and VCO

■

Switched Capacitor Filter Clock

LTC6903/LTC6904

1kHz - 68MHz Serial

Port Programmable Oscillator

U

DESCRIPTIO

The LTC®6903/LTC6904 are low power self contained
digital frequency sources providing a precision frequency
from 1kHz to 68MHz, set through a serial port. The
LTC6903/LTC6904 require
than a power supply bypass capacitor, and they operate
over a single wide supply range of 2.7V to 5.5V.

The LTC6903/LTC6904 feature a proprietary feedback
loop that linearizes the relationship between digital control
setting and frequency, resulting in a very simple frequency
setting equation:

OCT

f

=

2078

⎛

2

⎜
⎝

–

DAC

1024

Where OCT is a 4-bit digital code and DAC is a 10-bit digital
code.

The LTC6903 is controlled by a convenient SPI compatible
serial interface. The LTC6904 uses an industry standard
I2C compatible interface.

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents
including 6342817 and 6614313.

no external components

Hz

()

kHz f MHz

<<2

168•

;

⎞
⎟

⎠

other

TYPICAL APPLICATIO

A Microcontroller Controlling Its Clock

MICROCONTROLLER

OSC1/CLKIN

10k

5V

0.1μF

OSC2/CLKOUT
MCLR/V

P–P

RC3/SCK/SCL

V

DD

V

SS

V

SS

PIC16F73

RC5/SDO

RC2/CCP1

U

GND

SDI

LTC6903

SCK

SEN

POWER-UP CLOCK
FREQUENCY IS 1039Hz

CLK

CLK

LTC6903 Frequency Error

Distribution

40

VS = 3V

= 25°C

T

30

20

UNITS

10

f = 1039Hz
443
UNITS
TESTED

0

–1.0

A

–0.5

FREQUENCY ERROR (%)

0 0.5 1.0

6903 TA01b

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5V

+

V

OE

10Ω

1μF

0.01μF

6903 TA01

1

LTC6903/LTC6904

WW

W

ABSOLUTE AXI U RATI GS

U

UUW

PACKAGE/ORDER I FOR ATIO

(Note 1)

Total Supply Voltage (V+ to GND) .............................. 6V

Maximum Voltage on any Pin

........................... (GND – 0.3V) ≤ VPIN ≤ (V+ + 0.3V)

Output Short Circuit Duration (Note 2) ............ Indefinite

Operating Temperature Range (Note 3)

LTC6903CMS8/LTC6904CMS8 ........... –40°C to 85°C

LTC6903IMS8/LTC6904IMS8 ............. –40°C to 85°C

LTC6903HMS8/LTC6904HMS8 ......... –40°C to 125°C

Specified Temperature Range (Note 4)

LTC6903CMS8/LTC6904CMS8 ........... –40°C to 85°C

LTC6903IMS8/LTC6904IMS8 ............. –40°C to 85°C

LTC6903HMS8/LTC6904HMS8 ......... –40°C to 125°C

Storage Temperature Range ..................–65°C to 150°C

Lead Temperature (Soldering, 10sec)................... 300°C

ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating

TOP VIEW

GND

1

SDI

2

SCK

SEN/ADR*

*SEN (LTC6903)

ADR (LTC6904)

*The temperature grade
Consult LTC Marketing for parts specified with wider operating temperature ranges.

3
4

MS8 PACKAGE

8-LEAD PLASTIC MSOP

T

= 150°C, θJA = 200°C/W

JMAX

+

8

V

7

OE

6

CLK

5

CLK

is identified by a label on the shipping container.

ORDER PART

NUMBER

LTC6903CMS8
LTC6903IMS8
LTC6903HMS8
LTC6904CMS8
LTC6904IMS8
LTC6904HMS8

MS8 PART MARKING*

LTABN
LTAES

temperature range, otherwise specifications are at TA = 25°C. V+ = 2.7V to 5.5V, GND = 0V, unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

Δfi Initial Frequency Accuracy f = 1.039kHz, V+ = 3V, C
Δf Total Frequency Accuracy (Note 7) Single Output Active:

Over All Settings, V+ = 2.7V, C
Over All Settings, V
LTC6903CMS8, LTC6904CMS8:
Over All Settings, V
Over All Settings, V
LTC6903HMS8, LTC6903IMS8,
LTC6904HMS8, LTC6904IMS8:
Over All Settings, V
Over All Settings, V

f

MAX

f

MIN

Δf/ΔT Frequency Drift Over Temperature 10 ppm/°C
Δf/ΔV Frequency Drift Over Supply 0.05 %/V

R

OUT

V

OH

V

OL

Maximum Operating Frequency 68 MHz
Minimum Operating Frequency 1.039 kHz

Long Term Frequency Stability 300 ppm/√kHr
Timing Jitter 1.039kHz to 8.5MHz 0.4 %

(See Graph) 1.039kHz to 68MHz 1 %
Duty Cycle 1.039kHz to 1MHz ● 49 50 51 %

1.039kHz to 68MHz 50 %
Output Resistance CLK, CLK Pins, V+ = 2.7V 45 Ω
High Level Output Voltage V+ = 5.5V, 4mA Load ● 4.8 5.3 V

Low Level Output Voltage V+ = 5.5V, 4mA Load ● 0.15 0.3 V

+

= 2.7V, 4mA Load ● 2 2.3 V

V
V+ = 5.5V, 1mA Load ● 5.2 5.45 V

+

= 2.7V, 1mA Load ● 2.3 2.55 V

V

+

= 2.7V, 4mA Load ● 0.25 0.45 V

V
V+ = 5.5V, 1mA Load ● 0.05 0.15 V

+

= 2.7V, 1mA Load ● 0.05 0.2 V

V

+

+
+

+
+

= 5pF ±0.75 %

LOAD

= 5pF 0.5 1.1 %

= 5.5V, C

= 2.7V, C
= 5.5V, C

= 2.7V, C
= 5.5V, C

LOAD

= 5pF 0.5 1.6 %

LOAD

= 5pF ● 0.5 1.65 %

LOAD

= 5pF ● 0.5 2 %

LOAD

= 5pF ● 0.5 1.9 %

LOAD

= 5pF ● 0.5 2.2 %

LOAD

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2

LTC6903/LTC6904

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at T

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

t

r

t

f

Output Rise Time (10% - 90%) V+ = 5.5V, R

Output Fall Time (10% - 90%) V+ = 5.5V, R

The ● denotes the specifications which apply over the full operating

= 25°C. V+ = 2.7V to 5.5V, GND = 0V, unless otherwise noted.

A

+

V

= 2.7V, R

+

= 2.7V, R

V

LOAD
LOAD

LOAD
LOAD

= ∞, C
= ∞, C

= ∞, C
= ∞, C

= 5pF 1 ns

LOAD

= 5pF 1 ns

LOAD

= 5pF 1 ns

LOAD

= 5pF 1 ns

LOAD

WU

POWER REQUIRE E TS

range, otherwise specifications are at T

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

S

IS, SHDN V+ Supply Current, Shutdown VS = 2.7V ● 0.25 0.6 mA

IS, DC V+ Supply Current, Single Output f = 68MHz, 5pF Load, V+ = 2.7V ● 3.6 7 mA

Supply Voltage Applied Between V+ and GND ● 2.7 5.5 V

Enabled f < 1MHz, V

= 25°C. V+ = 2.7V to 5.5V, GND = 0V, unless otherwise noted.

A

SERIAL PORT ELECTRICAL CHARACTERISTICS

the full operating temperature range, otherwise specifications are at TA = 25°C. V+ = 2.7V to 5.5V, GND = 0V, unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

IH

V

IL

I

IN

Min High Level Input Voltage ● 0.67 V
SEN, SCK, SDI Pins

Max Low Level Input Voltage ● 0.33 V
SEN, SCK, SDI Pins

Digital Input Leakage ● 10 μA
SEN, SCK, SDI Pins

The ● denotes the specifications which apply over the full operating temperature

= 5.5V ● 0.6 2.2 mA

V

S

+

= 2.7V ● 1.7 3.1 mA
f = 68MHz, 5pF Load, V
f < 1MHz, V

+

= 5.5V ● 1.9 4.5 mA

+

= 5.5V ● 715 mA

The ● denotes the specifications which apply over

+

+

V

V

UW

TI I G CHARACTERISTICS

range, otherwise specifications are at TA = 25°C. V+ = 2.7V to 5.5V, GND = 0V, unless otherwise noted.

SYMBOL PARAMETER MIN TYP MAX UNITS
LTC6903 (Notes 5, 6)

f

SCK

t

CKHI

t

CKLO

t

su

t

hLD

t

LCH

t

FCK

LTC6904 (Notes 5, 6)

f

SMB

t

BUF

t

HD, STA

t

SU, STA

t

SU, STO

Serial Port Clock Frequency ● 20 MHz
Min Clock High Time ● 25 ns
Min Clock Low Time ● 25 ns
Min Setup Time - SDI to SCK ● 10 ns
Min Hold Time - SCK to SDI ● 10 ns
Min Latch Time - SEN to SEN ● 400 ns
Min First Clock - SEN to SCK ● 20 ns

SMBus Operating Frequency ● 10 100 kHz
Bus Free Time Between Stop and Start Condition ● 4.7 μs
Hold Time After (Repeated) Start Condition ● 4.0 μs
Repeated Start Condition Setup Time ● 4.7 μs
Stop Condition Setup Time ● 4.0 μs

The ● denotes specifications which apply over the full operating temperature

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3

LTC6903/LTC6904

TEMPERATURE (°C)

–40 –20 0 20 40 60 80 120100

FREQUENCY (%)

6903 G03

0.10

0.06

0.02

0.08

0.04

0

–0.02

–0.04

–0.06

–0.08

–0.10

UW

TI I G CHARACTERISTICS

range, otherwise specifications are at T

SYMBOL PARAMETER MIN TYP MAX UNITS
LTC6904 (Notes 5, 6)

t

HD, DAT

t

SU, DAT

t

LOW

t

HIGH

t

f

t

r

Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.

Note 2: A heatsink may be required to keep the junction temperature
below the absolute maximum when the output is shorted indefinitely.

Note 3: The LTC6903CMS8, LTC6904CMS8, LTC6903IMS8, and
LTC6904IMS8 are guaranteed functional over the operating temperature
range of –40°C to 85°C. The LTC6903HMS8 and LTC6904HMS8 are
guaranteed functional over the extended operating temperature range of
–40°C to 125°C.

Note 4: The LTC6903CMS8 and LTC6904CMS8 are guaranteed to meet

Data Hold Time ● 300 ns
Data Setup Time ● 250 ns
Clock Low Period ● 4.7 μs
Clock High Period ● 4.0 50 μs
Clock, Data Fall Time ● 300 ns
Clock, Data Rise Time ● 1000 ns

= 25°C. V+ = 2.7V to 5.5V, GND = 0V, unless otherwise noted.

A

The ● denotes specifications which apply over the full operating temperature

the specified performance limits over the 0°C to 70°C temperature range
and are designed, characterized and expected to meet the specified
performance from –40°C to 85°C but are not tested or QA sampled at
these temperatures. The LTC6903IMS8 and LTC6904IMS8 are guaranteed
to meet the specified performance limits over the –40°C to 85°C
temperature range. The LTC6903HMS8 and LTC6904HMS8 are
guaranteed to meet the specified performance limits over the –40°C to
125°C temperature range.

Note 5: All values are referenced to V
Note 6: Guaranteed by design and not subject to test.
Note 7: Parts with tighter frequency accuracy are available. Consult LTC

Marketing for details.

and VIL levels.

IH

TYPICAL PERFOR A CE CHARACTERISTICS

Integral Nonlinearity

1.0

0.8

0.6

0.4

0.2

0

–0.2

–0.4

–0.6

INTEGRAL NONLINEARITY (LSB)

–0.8

–1.0

0 200 400 600 800 1000

4

DAC SETTING

UW

6903 G01

Differential Nonlinearity

1.0

0.8

0.6

0.4

0.2

0

–0.2

–0.4

–0.6

DIFFERENTIAL NONLINEARITY (LSB)

–0.8

–1.0

0 200 400 600 800 1000

DAC SETTING

Frequency vs Temperature

6903 G01

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