LMK01000ISQE - National Semiconductor

March 6, 2008

LMK01000/LMK01010/LMK01020

1.6 GHz High Performance Clock Buffer, Divider, and

Distributor

General Description

The LMK01000/LMK01010/LMK01020 family provides an

easy way to divide and distribute high performance clock sig-

nals throughout the system. These devices provide best-in-

class noise performance and are designed to be pin-to-pin

and footprint compatible with LMK03000/LMK02000 family of

precision clock conditioners.

The LMK01000/LMK01010/LMK01020 family features two

programmable clock inputs (CLKin0 and CLKin1) that allow

the user to dynamically switch between different clock do-

mains.

Each device features 8 clock outputs with independently pro-

grammable dividers and delay adjustments. The outputs of

the device can be easily synchronized by an external pin

(SYNC*).

Target Applications

■High performance Clock Distribution

■Wireless Infrastructure

■Medical Imaging

■Wired Communications

■Test and Measurement

■Military / Aerospace

Features

■30 fs additive jitter (100 Hz to 20 MHz)

■Dual clock inputs

■Programmable output channels (0 to 1600 MHz)

—LMK01000: 3 LVDS outputs (CLKout0 - CLKout2) + 5

LVPECL outputs (CLKout3 - CLKout7)

—LMK01010: 8 LVDS outputs

—LMK01020: 8 LVPECL outputs

—Channel divider values of 1, 2 to 510 (even divides)

—Programmable output skew control

■External synchronization

■Pin compatible family of clocking devices

■3.15 to 3.45 V operation

■Package: 48 pin LLP (7.0 x 7.0 x 0.8 mm)

System Diagram

30042806

TRI-STATE® is a registered trademark of National Semiconductor Corporation.

LMK01000/LMK01010/LMK01020 1.6 GHz High Performance Clock Buffer, Divider, and

Distributor

Functional Block Diagram

30042801

Connection Diagram

48-Pin LLP Package

30042802

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LMK01000/LMK01010/LMK01020

Pin Descriptions

Pin # Pin Name I/O Description

1, 25 GND - Ground

2, 7, 9,10, 32 NC - No Connect. Pin is not connected to the die.

3, 8, 13, 16, 19, 22, 26,

30, 31, 33, 37, 40, 43, 46

Vcc1, Vcc2, Vcc3, Vcc4, Vcc5, Vcc6, Vcc7,

Vcc8, Vcc9, Vcc10, Vcc11, Vcc12, Vcc13, Vcc14 - Power Supply

4 CLKuWire I MICROWIRE Clock Input

5 DATAuWire I MICROWIRE Data Input

6 LEuWire I MICROWIRE Latch Enable Input

11 GOE I Global Output Enable

12 Test O

This is an output pin used strictly for test purposes

and should be not connected for normal operation.

However, any load of an impedance of more than 1

kΩ is acceptable.

14, 15 CLKout0, CLKout0* O Clock Output 0

17, 18 CLKout1, CLKout1* O Clock Output 1

20, 21 CLKout2, CLKout2* O Clock Output 2

23, 24 CLKout3, CLKout3* O Clock Output 3

27 SYNC* I Global Clock Output Synchronization

28, 29 CLKin0,CLKin0* I CLKin 0 Input; Must be AC coupled

34, 35 CLKin1, CLKin1* I CLKin 1 Input; Must be AC coupled

36 Bias I Bias Bypass

38, 39 CLKout4, CLKout4* O Clock Output 4

41, 42 CLKout5, CLKout5* O Clock Output 5

44, 45 CLKout6, CLKout6* O Clock Output 6

47, 48 CLKout7, CLKout7* O Clock Output 7

DAP DAP - Die Attach Pad should be connected to ground.

The LMK01000 family is footprint compatible with the LMK03000/02000 family of devices. All CLKout pins are pin-to-pin compatible,

and CLKin0 and CLKin1 are equivalent to OSCin and Fin, respectively .

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LMK01000/LMK01010/LMK01020

Absolute Maximum Ratings (Notes 1, 2)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors

for availability and specifications.

Parameter Symbol Ratings Units

Power Supply Voltage VCC -0.3 to 3.6 V

Input Voltage VIN -0.3 to (VCC + 0.3) V

Storage Temperature Range TSTG -65 to 150 °C

Lead Temperature (solder 4 s) TL+260 °C

Junction Temperature TJ125 °C

Recommended Operating Conditions

Parameter Symbol Min Typ Max Units

Ambient Temperature TA-40 25 85 °C

Power Supply Voltage VCC 3.15 3.3 3.45 V

Note 1: "Absolute Maximum Ratings" indicate limits beyond which damage to the device may occur, including inoperability and degradation of device reliability

and/or performance. Functional operation of the device and/or non-degradation at the Absolute Maximum Ratings or other conditions beyond those indicated in

the Recommended Operating Conditions is not implied. The Recommended Operating Conditions indicate conditions at which the device is functional and the

device should not be operated beyond such conditions.

Note 2: This device is a high performance integrated circuit with ESD handling precautions. Handling of this device should only be done at ESD protected work

stations. The device is rated to a HBM-ESD of > 2 kV, a MM-ESD of > 200 V, and a CDM-ESD of > 1.2 kV.

Package Thermal Resistance

Package θJA θJ-PAD (Thermal Pad)

48-Lead LLP (Note 3) 27.4° C/W 5.8° C/W

Note 3: Specification assumes 16 thermal vias connect the die attach pad to the embedded copper plane on the 4-layer JEDEC board. These vias play a key

role in improving the thermal performance of the LLP. It is recommended that the maximum number of vias be used in the board layout.

Electrical Characteristics (Note 4)

(3.15 V ≤ Vcc ≤ 3.45 V, -40 °C ≤ TA ≤ 85 °C, Differential Inputs/Outputs; except as specified. Typical values represent most likely

parametric norms at Vcc = 3.3 V, TA = 25 °C, and at the Recommended Operation Conditions at the time of product characterization

and are not guaranteed).

Symbol Parameter Conditions Min Typ Max Units

Current Consumption

ICC

Power Supply Current

(Note 5)

All outputs

enabled, no

divide or delay

( CLKoutX_MUX

= Bypassed )

LMK01000 271

LMK01010 160

LMK01020 338

Per channel, no

divide or delay

(CLKoutX_MUX

= Bypassed )

LVDS 17.8

LVPECL

(Includes Emitter

Resistors)

ICCPD Power Down Current POWERDOWN = 1 1

CLKin0, CLKin0*, CLKin1, CLKin1*

fCLKin CLKin Frequency Range 1 1600 MHz

SLEWCLKin CLKin Frequency Input Slew Rate (Notes 6, 8) 0.5 V/ns

DUTYCLKin CLKin Frequency Input Duty Cycle fCLKin ≤ 800 MHz 30 70 %

fCLKin > 800 MHz 40 60

PCLKin

Input Power Range for CLKin or

CLKin* AC coupled -13 5 dBm

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LMK01000/LMK01010/LMK01020

Symbol Parameter Conditions Min Typ Max Units

Clock Distribution Section--Delays

DelayCLKout Maximum Allowable Delay(Note 8)

fCLKoutX ≤ 1 GHz

(Delay is limited to maximum

programmable value)

2250

fCLKoutX > 1 GHz

(Delay is limited to 1/2 of a period) 0.5/

fCLKoutX

Clock Distribution Section - Divides

DivideCLKoutX

Allowable divide range. (Note that 1 is

the only allowable odd divide value)

fCLKinX ≤ 1300 MHz 1 510 n/a

1300 MHz < fCLKinX ≤ 1600 MHz 1 2

Clock Distribution Section - LVDS Clock Outputs

JitterADD Additive RMS Jitter (Note 7)

RL = 100 Ω

Bandwidth =

100 Hz to 20 MHz

Vboost = 1

fCLKoutX = 200 MHz 80

fCLKoutX = 800 MHz 30

fCLKoutX = 1600 MHz 25

Noise Floor Divider Noise Floor(Note 7) RL = 100

Vboost = 1

fCLKoutX = 200 MHz -156

dBc/Hz

fCLKoutX = 800 MHz -153

fCLKoutX = 1600 MHz -148

tSKEW CLKoutX to CLKoutY (Note 8)

Equal loading and identical clock

configuration

RL = 100 Ω

-30 ±4 30 ps

VOD Differential Output Voltage (Note 9) Vboost=0 250 350 450 mV

Vboost=1 390

ΔVOD

Change in magnitude of VOD for

complementary output states RL = 100 Ω -50 50 mV

VOS Output Offset Voltage RL = 100 Ω 1.070 1.25 1.370 V

ΔVOS

Change in magnitude of VOS for

complementary output states RL = 100 Ω -35 35 mV

ISA

ISB

Clock Output Short Circuit Current

single ended Single ended outputs shorted to GND -24 24 mA

ISAB

Clock Output Short Circuit Current

differential Complementary outputs tied together -12 12 mA

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LMK01000/LMK01010/LMK01020

Symbol Parameter Conditions Min Typ Max Units

Clock Distribution Section - LVPECL Clock Outputs

JitterADD Additive RMS Jitter(Note 7)

RL = 100 Ω

Bandwidth =

100 Hz to 20 MHz

Vboost = 1

fCLKoutX = 200 MHz 65

fCLKoutX = 800 MHz 25

fCLKoutX = 1600 MHz 25

Noise Floor Divider Noise Floor(Note 7) RL = 100

Vboost = 1

fCLKoutX = 200 MHz -158

dBc/Hz

fCLKoutX = 800 MHz -154

fCLKoutX = 1600 MHz -148

tSKEW CLKoutX to CLKoutY (Note 8)

Equal loading and identical clock

configuration

Termination = 50 Ω to Vcc - 2 V

-30 ±3 30 ps

VOH Output High Voltage

Termination = 50 Ω to Vcc - 2 V

Vcc -

0.98 V

VOL Output Low Voltage Vcc -

1.8 V

VOD Differential Output Voltage (Note 9) Vboost = 0 660 810 965 mV

Vboost = 1 865

Digital LVTTL Interfaces (Note 10)

VIH High-Level Input Voltage 2.0 Vcc V

VIL Low-Level Input Voltage 0.8 V

IIH High-Level Input Current VIH = Vcc -5.0 5.0 µA

IIL Low-Level Input Current VIL = 0 -40.0 5.0 µA

VOH High-Level Output Voltage IOH = +500 µA Vcc -

0.4 V

VOL Low-Level Output Voltage IOL = -500 µA 0.4 V

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LMK01000/LMK01010/LMK01020

Symbol Parameter Conditions Min Typ Max Units

Digital MICROWIRE Interfaces (Note 11)

VIH High-Level Input Voltage 1.6 Vcc V

VIL Low-Level Input Voltage 0.4 V

IIH High-Level Input Current VIH = Vcc -5.0 5.0 µA

IIL Low-Level Input Current VIL = 0 -5.0 5.0 µA

MICROWIRE Timing

tCS Data to Clock Set Up Time See Data Input Timing 25 ns

tCH Data to Clock Hold Time See Data Input Timing 8 ns

tCWH Clock Pulse Width High See Data Input Timing 25 ns

tCWL Clock Pulse Width Low See Data Input Timing 25 ns

tES Clock to Enable Set Up Time See Data Input Timing 25 ns

tCES Enable to Clock Set Up Time See Data Input Timing 25 ns

tEWH Enable Pulse Width High See Data Input Timing 25 ns

Note 4: The Electrical Characteristics tables list guaranteed specifications under the listed Recommended Operating Conditions except as otherwise modified

or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and are not guaranteed.

Note 5: See section 3.2 for more current consumption / power dissipation calculation information.

Note 6: For all frequencies the slew rate, SLEWCLKin1, is measured between 20% and 80%.

Note 7: The noise floor of the divider is measured as the far out phase noise of the divider. Typically this offset is 40 MHz, but for lower frequencies this

measurement offset can be as low as 5 MHz due to measurement equipment limitations. If the delay is used, then use section 1.3.

Note 8: Specification is guaranteed by characterization and is not tested in production.

Note 9: See characterization plots to see how this parameter varies over frequency.

Note 10: Applies to GOE, LD, and SYNC*.

Note 11: Applies to CLKuWire, DATAuWire, and LEuWire.

Serial Data Timing Diagram

30042803

Data bits set on the DATAuWire signal are clocked into a shift register, MSB first, on each rising edge of the CLKuWire signal. On

the rising edge of the LEuWire signal, the data is sent from the shift register to the addressed register determined by the LSB bits.

After the programming is complete the CLKuWire, DATAuWire, and LEuWire signals should be returned to a low state. The slew

rate of CLKuWire, DatauWire, and LEuWire should be at least 30 V/µs.

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LMK01000/LMK01010/LMK01020

Typical Performance Characteristics

LVDS Single-Ended Peak to Peak Voltage

30042807

LVPECL Single-Ended Peak to Peak Voltage

30042808

LVDS Output Noise Floor

30042809

LVPECL Output Noise Floor

30042810

Delay Noise Floor (Adds to Output Noise Floor)

30042811

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LMK01000/LMK01010/LMK01020

1.0 Functional Description

The LMK010X0 family of clock distribution devices include a

programmable divider, a phase synchronization circuit, a pro-

grammable delay, a clock output mux, and an LVDS or

LVPECL output buffer in each channel. This allows multiple

integer-related and phase-adjusted copies of the reference to

be distributed to up to eight system components.

This family of devices comes in a 48-pin LLP package that is

pin-to-pin and footprint compatible with other LMK02000/

LMK03000 family of clocking devices.

1.1 BIAS PIN

To properly use the device, bypass Bias (pin 36) with a low

leakage 1 µF capacitor connected to Vcc. This is important

for low noise performance.

1.2 CLKin0/CLKin0* and CLKin1/CLKin1 INPUT PORTS

The device can be driven either by the CLKin0/CLKin0* or the

CLKin1/CLKin1* pins. The choice of which one to use is soft-

ware selectable. These input ports must be AC coupled. To

drive these inputs in a single ended fashion, AC ground the

complementary input with a 0.1 µF capacitor.

1.3 CLKout DELAYS

Each individual clock output includes a delay adjustment.

Clock output delay registers (CLKoutX_DLY) support a 150

ps step size and range from 0 to 2250 ps of total delay. When

the delay is enabled it adds to the output noise floor; the total

additive noise is 10(log( 10^(Output Noise Floor/10) + 10^

(Delay Noise Floor/10) ). Refer to the Typical Performance

Characteristics plots for the Delay Noise Floor information.

1.4 LVDS/LVPECL OUTPUTS

Each LVDS or LVPECL output may be disabled individually

by programming the CLKoutX_EN bits. All the outputs may

be disabled simultaneously by pulling the GOE pin low or

programming EN_CLKout_Global to 0.

1.5 GLOBAL CLOCK OUTPUT SYNCHRONIZATION

The SYNC* pin synchronizes the clock outputs. When the

SYNC* pin is held in a logic low state, the divided outputs are

also held in a logic low state. When the SYNC* pin goes high,

the divided clock outputs are activated and will transition to a

high state simultaneously. Clocks in the Bypassed state are

not affected by SYNC* and are always synchronized with the

divided outputs.

The SYNC* pin must be held low for greater than one clock

cycle of the Frequency Input port, also known as the distribu-

tion path. Once this low event has been registered, the out-

puts will not reflect the low state for four more cycles. When

the SYNC* pin becomes high, the outputs will not simultane-

ously transition high until four more distribution path clock

cycles have passed. See the SYNC* timing diagram for fur-

ther detail. In the timing diagram below the clocks are pro-

grammed as CLKout0_MUX = Bypassed, CLKout1_MUX =

Divided, CLKout1_DIV = 2, CLKout2_MUX = Divided, and

CLKout2_DIV = 4.

SYNC* Timing Diagram

30042804

The SYNC* pin provides an internal pull-up resistor as shown

on the functional block diagram. If the SYNC* pin is not ter-

minated externally the clock outputs will operate normally. If

the SYNC* function is not used, clock output synchronization

is not guaranteed.

1.6 CONNECTION TO LVDS OUTPUTS

LMK01000/10 LVDS outputs can be connected in AC or DC

coupling configurations; however, in DC coupling configura-

tion, proper conditions must be presented by the LVDS re-

ceiver. To ensure such conditions, we recommend the usage

of LVDS receivers without fail-safe or internal input bias such

as DS90LV110T. LMK01000/10 LVDS drivers will provide the

adequate DC bias for the LVDS receiver. We recommend AC

coupling when using LVDS receivers with fail-safe or internal

input bias.

1.7 CLKout OUTPUT STATES

Each clock output may be individually enabled with the

CLKoutX_EN bits. Each individual output enable control bit is

gated with the Global Output Enable input pin (GOE) and the

Global Output Enable bit (EN_CLKout_Global).

All clock outputs can be disabled simultaneously if the GOE

pin is pulled low by an external signal or EN_CLKout_Global

is set to 0.

CLKoutX

_EN bit

EN_CLKout

_Global bit

GOE pin Clock X

Output State

1 1 Low Low

Don't care 0 Don't care Off

0 Don't care Don't care Off

1 1 High / No

Connect Enabled

When an LVDS output is in the Off state, the outputs are at a

voltage of approximately 1.5 volts. When an LVPECL output

is in the Off state, the outputs are at a voltage of approximately

1 volt.

1.8 GLOBAL OUTPUT ENABLE

The GOE pin provides an internal pull-up resistor. If it is not

terminated externally, the clock output states are determined

by the Clock Output Enable bits (CLKoutX_EN) and the

EN_CLKout_Global bit.

1.9 POWER-ON-RESET

When supply voltage to the device increases monotonically

from ground to Vcc, the power-on-reset circuit sets all regis-

ters to their default values, which are specified in the General

Programming Information section. Voltage should be applied

to all Vcc pins simultaneously.

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LMK01000/LMK01010/LMK01020

2.0 General Programming

Information

The LMK01000/LMK01010/LMK01020 device is pro-

grammed using several 32-bit registers which control the

device's operation. The registers consist of a data field and

an address field. The last 4 register bits, ADDR[3:0] form the

address field. The remaining 28 bits form the data field DATA

[27:0].

During programming, LEuWire is low and serial data is

clocked in on the rising edge of clock (MSB first). When

LEuWire goes high, data is transferred to the register bank

selected by the address field. Only registers R0 to R7 and R14

need to be programmed for proper device operation.

It is required to program register R14.

2.1 RECOMMENDED PROGRAMMING SEQUENCE

The recommended programming sequence involves pro-

gramming R0 with the reset bit set (RESET = 1) to ensure the

device is in a default state. It is not necessary to program R0

again, but if R0 is programmed again, the reset bit is pro-

grammed clear (RESET = 0). An example programming se-

quence is shown below.

•Program R0 with the reset bit set (RESET = 1). This

ensures the device is in a default state. When the reset bit

is set in R0, the other R0 bits are ignored.

—If R0 is programmed again, the reset bit is programmed

clear (RESET = 0).

•Program R0 to R7 as necessary with desired clocks with

appropriate enable, mux, divider, and delay settings.

•Program R14 with global clock output bit, power down

setting.

—R14 must be programmed in accordance with the

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LMK01000/LMK01010/LMK01020

2.2 LMK01000/LMK01010/LMK01020 REGISTER MAP

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Data [27:0] A3 A2 A1 A0

RESET

000000000000

CLKout0

_MUX

[1:0]

CLKout0

_EN

CLKout0_DIV

[7:0]

CLKout0_DLY

[3:0] 0 0 0 0

R10000000000000

CLKout1

_MUX

[1:0]

CLKout1

_EN

CLKout1_DIV

[7:0]

CLKout1_DLY

[3:0] 0 0 0 1

R20000000000000

CLKout2

_MUX

[1:0]

CLKout2

_EN

CLKout2_DIV

[7:0]

CLKout2_DLY

[3:0] 0 0 1 0

R30000000000000

CLKout3

_MUX

[1:0]

CLKout3

_EN

CLKout3_DIV

[7:0]

CLKout3_DLY

[3:0] 0 0 1 1

R40000000000000

CLKout4

_MUX

[1:0]

CLKout4

_EN

CLKout4_DIV

[7:0]

CLKout4_DLY

[3:0] 0 1 0 0

R50000000000000

CLKout5

_MUX

[1:0]

CLKout5

_EN

CLKout5_DIV

[7:0]

CLKout5_DLY

[3:0] 0 1 0 1

R60000000000000

CLKout6

_MUX

[1:0]

CLKout6

_EN

CLKout6_DIV

[7:0]

CLKout6_DLY

[3:0] 0 1 1 0

R70000000000000

CLKout7

_MUX

[1:0]

CLKout7

_EN

CLKout7_DIV

[7:0]

CLKout7_DLY

[3:0] 0 1 1 1

R9101000000000001Vbo

ost 0010101000001001

R14 0 0 0

CLKin

_SELECT

EN_CLKout

_Global

POWERDOWN

00000000000000000000001110

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LMK01000/LMK01010/LMK01020

2.3 REGISTER R0 to R7

Registers R0 through R7 control the eight clock outputs. Reg-

ister R0 controls CLKout0, Register R1 controls CLKout1, and

so on. There is one additional bit in register R0 called RESET.

Aside from this, the functions of these bits are identical. The

X in CLKoutX_MUX, CLKoutX_DIV, CLKoutX_DLY, and

CLKoutX_EN denote the actual clock output which may be

from 0 to 7.

Default Register Settings after Power-on-Reset

Bit Name Default

Bit Value Bit State Bit Description Register Bit

Location

RESET 0 No reset, normal operation Reset to power on defaults R0 31

CLKoutX_MUX 0 Bypassed CLKoutX mux mode

R0 to R7

18:17

CLKoutX_EN 0 Disabled CLKoutX enable 16

CLKoutX_DIV 1 Divide by 2 CLKoutX clock divide 15:8

CLKoutX_DLY 0 0 ps CLKoutX clock delay 7:4

CLKin_SELECT 0 CLKin1 Select CLKin0 or CLKin1

R14

EN_CLKout_Global 1 Normal - CLKouts normal Global clock output enable 27

POWERDOWN 0 Normal - Device active Device power down 26

2.3.1 RESET Bit -- R0 only

This bit is only in register R0. The use of this bit is optional

and it should be set to '0' if not used. Setting this bit to a '1'

forces all registers to their power-on-reset condition and

therefore automatically clears this bit. If this bit is set, all other

R0 bits are ignored and R0 needs to be programmed again if

used with its proper values and RESET = 0.

2.3.2 CLKoutX_MUX[1:0] -- Clock Output Multiplexers

These bits control the Clock Output Multiplexer for each clock

output. Changing between the different modes changes the

blocks in the signal path and therefore incurs a delay relative

to the Bypassed mode. The different MUX modes and asso-

ciated delays are listed below.

CLKoutX_MUX

[1:0]

Mode Added Delay

Relative to

Bypassed Mode

0 Bypassed (default) 0 ps

1 Divided 100 ps

2 Delayed

400 ps

(In addition to the

programmed

delay)

3Divided and

Delayed

500 ps

(In addition to the

programmed

delay)

2.3.3 CLKoutX_DIV[7:0] -- Clock Output Dividers

These bits control the clock output divider value. In order for

these dividers to be active, the respective CLKoutX_MUX

(See 2.3.2) bit must be set to either "Divided" or "Divided and

Delayed" mode. After all the dividers are programed, the

SYNC* pin must be used to ensure that all edges of the clock

outputs are aligned (See 1.7). By adding the divider block to

the output path a fixed delay of approximately 100 ps is in-

curred.

The actual Clock Output Divide value is twice the binary value

programmed as listed in the table below.

CLKoutX_DIV[7:0] Clock Output

Divider value

0 0 0 0 0 0 0 0 Invalid

0 0 0 0 0 0 0 1 2 (default)

CLKoutX_DIV[7:0] Clock Output

Divider value

0 0 0 0 0 0 1 0 4

0 0 0 0 0 0 1 1 6

0 0 0 0 0 1 0 0 8

0 0 0 0 0 1 0 1 10

. . . . . . . . ...

1 1 1 1 1 1 1 1 510

2.3.4 CLKoutX_DLY[3:0] -- Clock Output Delays

These bits control the delay stages for each clock output. In

order for these delays to be active, the respective

CLKoutX_MUX (See 2.3.2) bit must be set to either "Delayed"

or "Divided and Delayed" mode. By adding the delay block to

the output path a fixed delay of approximately 400 ps is in-

curred in addition to the delay shown in the table below.

CLKoutX_DLY[3:0] Delay (ps)

0 0 (default)

1 150

2 300

3 450

4 600

5 750

6 900

7 1050

8 1200

9 1350

10 1500

11 1650

12 1800

13 1950

14 2100

15 2250

2.3.5 CLKoutX_EN bit -- Clock Output Enables

These bits control whether an individual clock output is en-

abled or not. If the EN_CLKout_Global bit is set to zero or if

GOE pin is held low, all CLKoutX_EN bit states will be ignored

and all clock outputs will be disabled.

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LMK01000/LMK01010/LMK01020

CLKoutX_EN bit Conditions CLKoutX State

0 EN_CLKout_Global

bit = 1

GOE pin = High / No

Connect 1

Disabled (default)

1 Enabled

2.4 REGISTER R9 and R14

The LMK01000 family requires register R14 to be pro-

grammed as shown in the register map (see 2.2). R9 only

needs to be programmed if Vboost is set to 1.

2.4.1 Vboost - Voltage Boost Bit

Enabling this bit sets all clock outputs in voltage boost mode

which increases the voltage at these outputs. This can im-

prove the noise floor performance of the output, but also

increases current consumption, and can cause the outputs to

be too high to meet the LVPECL/LVDS specifications.

Vboost

bit

fCLKoutX < 1300

MHz

1300 MHz ≤

fCLKoutX <

1500 MHz

1500 MHz ≤

fCLKoutX ≤

1600 MHz

0 Recommended to

hit voltage level

specifications for

LVPECL/LVDS

Insufficient voltage level for

LVDS/LVPECL

specifications, but saves

current

1 Voltage May

overdrive LVPECL/

LVDS

specifications, but

noise floor is about

2-4 dB better and

current

consumption is

increased

Voltage is

sufficient for

LVDS/

LEVPECL

specifications

. Current

consumption

is increased,

but noise floor

is about the

same.

Insufficient

voltage for

LVDS/

LVPECL

specifications

, but still

higher than

when

Vboost=0.

Increased

current

consumption.

2.4.2 POWERDOWN Bit -- Device Power Down

This bit can power down the device. Enabling this bit powers

down the entire device and all blocks, regardless of the state

of any of the other bits or pins.

POWERDOWN bit Mode

0 Normal Operation (default)

1 Entire Device Powered Down

2.4.3 INPUT_MUX Bit -- Device CLKin Select

This bit determines which CLKin pin is used.

CLKin bit Mode

0 CLKin1 (default)

1 CLKin0

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LMK01000/LMK01010/LMK01020

3.0 Application Information

3.1 SYSTEM LEVEL DIAGRAM

The following shows the LMK01000LMK01010/LMK01020 in

a typical application. In this setup the clock may be divided,

skewed, and redistributed.

30042870

FIGURE 1. Typical Application

www.national.com 14

LMK01000/LMK01010/LMK01020

3.2 CURRENT CONSUMPTION / POWER DISSIPATION

CALCULATIONS ( Vcc = 3.3 V, TA = 25° C )

Block Condition

Current

Consumptio

n at 3.3 V

(mA)

Power

Dissipated

in device

(mW)

Power

Dissipated in

LVPECL emitter

resistors (mW)

Core Current All outputs disabled. Includes input buffer currents. 19 62.7 -

Low clock buffer

(internal)

The low clock buffer is enabled anytime one of CLKout0

through CLKout3 are enabled 9 29.7 -

High clock

buffer (internal)

The high clock buffer is enabled anytime one of the CLKout4

through CLKout7 are enabled 9 29.7 -

Output buffers

LVDS output, Bypassed mode 17.8 58.7 -

LVPECL output, Bypassed mode

(includes 120 Ω emitter resistors) 40 72 60

LVPECL output, disabled mode

(includes 120 Ω emitter resistors) 17.4 38.3 19.1

LVPECL output, disabled mode.

No emitter resistors placed; open outputs 0 0 -

Vboost Additional current per channel due

to setting Vboost from 0 to 1.

LVPECL Output 0.5 1.65 -

LVDS Output 1.5 5.0

Divide circuitry

per output

Divide enabled, divide = 2 5.3 17.5 -

Divide enabled, divide > 2 8.5 28.0 -

Delay circuitry

per output

Delay enabled, delay < 8 5.8 19.1 -

Delay enabled, delay > 7 9.9 32.7 -

Entire device

CLKout0 &

CLKout4

enabled in

Bypassed mode

LMK01000 85.8 223.1 60

LMK01010 63.6 209.9 -

LMK01020 108 236.4 120

Entire device

all outputs

enabled with no

delay and divide

value of 2

LMK01000 323.8 768.5 300

LMK01010 212.8 702.3 -

LMK01020 390.4 808.3 480

From the above table, the current can be calculated in any

configuration. For example, the current for the entire device

with 1 LVDS (CLKout0) & 1 LVPECL (CLKout4) output in By-

passed mode can be calculated by adding up the following

blocks: core current, low clock buffer, high clock buffer, one

LVDS output buffer current, and one LVPECL output buffer

current. There will also be one LVPECL output drawing emit-

ter current, but some of the power from the current draw is

dissipated in the external 120 Ω resistors which doesn't add

to the power dissipation budget for the device. If delays or

divides are switched in, then the additional current for these

stages needs to be added as well.

For power dissipated by the device, the total current entering

the device is multiplied by the voltage at the device minus the

power dissipated in any emitter resistors connected to any of

the LVPECL outputs. If no emitter resistors are connected to

the LVPECL outputs, this power will be 0 watts. For example,

in the case of 1 LVDS (CLKout0) & 1 LVPECL (CLKout4) op-

erating at 3.3 volts for LMK01000, we calculate 3.3 V × (10 +

9 + 9 + 17.8 + 40) mA = 3.3 V × 85.8 mA = 283.1 mW. Because

the LVPECL output (CLKout4) has the emitter resistors

hooked up and the power dissipated by these resistors is 60

mW, the total power dissipation is 283.1 mW - 60 mW = 223.1

mW. When the LVPECL output is active, ~1.9 V is the average

voltage on each output as calculated from the LVPECL Voh

& Vol typical specification. Therefore the power dissipated in

each emitter resistor is approximately (1.9 V)2 / 120 Ω = 30

mW. When the LVPECL output is disabled, the emitter resis-

tor voltage is ~1.07 V. Therefore the power dissipated in each

emitter resistor is approximately (1.07 V)2 / 120 Ω = 9.5 mW.

15 www.national.com

LMK01000/LMK01010/LMK01020

3.3 THERMAL MANAGEMENT

Power consumption of the LMK01000/LMK01010/LMK01020

can be high enough to require attention to thermal manage-

ment. For reliability and performance reasons the die tem-

perature should be limited to a maximum of 125 °C. That is,

as an estimate, TA (ambient temperature) plus device power

consumption times θJA should not exceed 125 °C.

The package of the device has an exposed pad that provides

the primary heat removal path as well as excellent electrical

grounding to the printed circuit board. To maximize the re-

moval of heat from the package a thermal land pattern in-

cluding multiple vias to a ground plane must be incorporated

on the PCB within the footprint of the package. The exposed

pad must be soldered down to ensure adequate heat con-

duction out of the package. A recommended land and via

pattern is shown in Figure 2. More information on soldering

LLP packages can be obtained at www.national.com.

30042873

FIGURE 2.

To minimize junction temperature it is recommended that a

simple heat sink be built into the PCB (if the ground plane

layer is not exposed). This is done by including a copper area

of about 2 square inches on the opposite side of the PCB from

the device. This copper area may be plated or solder coated

to prevent corrosion but should not have conformal coating (if

possible), which could provide thermal insulation. The vias

shown in Figure 2 should connect these top and bottom cop-

per layers and to the ground layer. These vias act as “heat

pipes” to carry the thermal energy away from the device side

of the board to where it can be more effectively dissipated.

www.national.com 16

LMK01000/LMK01010/LMK01020

Physical Dimensions inches (millimeters) unless otherwise noted

Leadless Leadframe Package (Bottom View)

48 Pin LLP (SQA48A) Package

Order Number Package Marking Packing LVDS Outputs LVPECL

Outputs

LMK01000ISQ K01000 I 250 Unit Tape and Reel 3 5

LMK01000ISQX K01000 I 2500 Unit Tape and Reel 3 5

LMK01010ISQ K01010 I 250 Unit Tape and Reel 8 -

LMK01010ISQX K01010 I 2500 Unit Tape and Reel 8 -

LMK01020ISQ K01020 I 250 Unit Tape and Reel - 8

LMK01020ISQX K01020 I 2500 Unit Tape and Reel - 8

17 www.national.com

LMK01000/LMK01010/LMK01020

Notes

LMK01000/LMK01010/LMK01020 1.6 GHz High Performance Clock Buffer, Divider, and

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