Silicon Labs UG298 User Manual

UG298: Si5xxUC-EVB

Universal Oscillator Evaluation Board

This document describes operation of the Silicon Laboratories Si5xxUC-EVB evaluation board designed to evaluate any of Silicon Labs’ pin-controlled or I2C configurable Si5xx

XOs or VCXOs. Three device sites are available to support one of either 5mm x 7mm,

3.2mm x 5mm, or 2.5mm x 3.2mm devices in either 4, 6, or 8 pin configurations. Selector switches make it easy to configure device control pins (pins 1, 2, 7, or 8) for proper operation without the use of jumpers. Similarly, XO device VDD voltage (3.3V, 2.5V,

1.8V) can be selected via switches based on either external +5V (for stand-alone operation) or micro USB sourced +5V USB operation. The EVB also features flexible output termination circuits and PCB layout optimized for superior signal integrity.

Ext +5V

micro

USB

+VDD

GND

SDA

Vc_In

Power Select Switch

Silicon Labs

MCU

Pin 1

Signal

Selector

Switch

I2C Bus

Pin 1

SDA

SCL

Pin 1

Pin 2

Pin 7 Pin 8

Power Supply

+VDD

Location 1

(5mm x 7mm)

KEY FEATURES

• Evaluation of any Silicon Labs XO or VCXO (Si51x, Si53x, Si54x, Si55x, Si56x, Si57x, Si59x)

• AC coupled differential/single-ended output clocks.

• Voltage control (Vc) port for VCXO evalution.

• Switch selectable settings. No jumpers.

• External power or USB powered.

• Use stand-alone or with our Pro-

grammable Oscillator Calculator SW tool

Voltage

Selector

Switches

Output

Termination

CLK1_P

CLK1_N

+VDD

GND

SCL

+VDD

GND

SDA

+VDD

GND

SCL

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Pin 2

Signal

Selector

Switch

Pin 7

Signal

Selector

Switch

Pin 8

Signal

Selector

Switch

Pin 2

Pin 7

Pin 8

Pin 1

Pin 2

Pin 7 Pin 8

Pin 1

Pin 2

Pin 7 Pin 8

Location 2

(3.2mm x 5mm)

Location 3

(2.5mm x 3.2mm)

Output

Termination

Output

Termination

CLK2_P

CLK2_N

CLK3_P

CLK3_N

Table of Contents

1. Quick Start - Board Configuration Check List ...................3

2. Functional Description............................4

3. General Operational Restrictions ........................5

3.1 Evaluate Only a Single Device at a Time .....................5

4. Power Supply and I2C Bus Control .......................6

5. Control Signal Switch Settings.........................7

5.1 Oscillator Pin 1 Control DIP Switch (Pin_1_Ctrl) ...................8

5.2 Oscillator Pin 2 Control DIP Switch (Pin_2_Ctrl) ...................9

5.3 Oscillator Pin 7 Control DIP Switch (Pin_7_Ctrl) ...................10

5.4 Oscillator Pin 8 Control DIP Switch (Pin_8_Ctrl) ...................11

6. Supported Devices - Stand-Alone Mode ....................12

7. Supported Devices - Software Controlled Mode - I2C ...............15

8. USB Port and External Powering .......................16

9. Output Clock Terminations .........................17

10. EVB Test Points and LEDs .........................18

10.1 Test Points ...............................18

10.2 LEDs .................................18

11. VCXO Voltage Control Input Circuit .....................19

12. Programmable Oscillator Calculator Tool ...................20

13. Layout of Board .............................21

13.1 Si56x XO and VCXO 2.5x3.2mm Footprint Recommendation ..............22

14. Si5xxUC-EVB Schematic .........................23

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UG298: Si5xxUC-EVB

Quick Start - Board Configuration Check List

1. Quick Start - Board Configuration Check List

Mount your oscillator device on the board at appropriate oscillator site location (U1, U2, or U3, but on only one location) if a device is not yet mounted.

1. Start with EVB board powered down/off.

2. Set DIP switches (described in Section 5. Control Signal Switch Settings) for your specific device:

a. Look up your device as appropriate in the tables of Sections 6. Supported Devices - Stand-Alone Mode or 7. Supported Devi-

ces - Software Controlled Mode - I2C.

b. Make DIP switch settings per table entry for pins 1,2,7,8 as appropriate. See Sections 6. Supported Devices - Stand-Alone

Mode or 7. Supported Devices - Software Controlled Mode - I2C .

3. Verify output termination is appropriate for your device (see Section 9. Output Clock Terminations for more info).

4. Set +5V Select switch (SW5) based on how you will power the EVB, either via USB or via external +5V supply.

5. Connect power, either via USB port or external +5V power supply as chosen in previous step.

6. Output Clocks:

• For pin controlled oscillators, clock output should be available on output SMAs of DUT site in use.

• For I2C oscillators, run appropriate configuration software (e.g., Programmable Oscillator Software tool) and perform device configuration to get desired output clock.

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UG298: Si5xxUC-EVB

Functional Description

2. Functional Description

The Si5xxUC-EVB is an evaluation board designed to support any Silicon Labs XO/VCXO device. The Si5xxUC-EVB is designed to operate in one of two general operational modes:

• Stand-alone mode: The stand-alone mode is for evaluation of fixed output frequency or pin-controlled XO/VCXO devices where I2C support is NOT required to operate or evaluate the device. Control of device pins, such as OE or FS, is done via on-board

switches. In Stand-alone mode the on-board switches must be set according to the requirements of the device installed on the board. For example, if the installed device is a dual frequency part with output enable, the appropriate switches must be set to assert output enable (OE) and the frequency select pin (FS) to give the desired output frequency. Device VDD voltage can be set via on-

board switches as well. Switch setting details for Stand-alone mode are shown in Section 4. Power Supply and I2C Bus Control (for power supply) and Section 5. Control Signal Switch Settings (for device pins).

• Software controlled mode: The software controlled mode is for use with PC-based software tools (such as our Programmable Os-

cillator Calculator Tool) to control/configure the device being evaluated via the device I2C bus. The software controlled mode is pri-

marily intended for I2C controlled XO/VCXO devices. When using software controlled mode, some of the on-board switches must be placed in specific default settings to allow the on-board MCU to perform I2C control. Other switches must still be used on certain

device signals, like output enable (OE). Switch setting details for software controlled mode are shown in Section 4. Power Supply

and I2C Bus Control (for power supply & I2C) and Section 5. Control Signal Switch Settings (for device pins).

For each of the 3 device locations on the Si5XXUC-EVB, separate sets of SMA outputs and terminations are provided per XO “Device Under Test” (DUT) location even though only one device may be populated and used at a time (see Section 3. General Operational

Restrictions below). Separate outputs and terminations per device site provides the best possible clock signal integrity for each DUT

location.

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UG298: Si5xxUC-EVB

General Operational Restrictions

3. General Operational Restrictions

3.1 Evaluate Only a Single Device at a Time

Note: It is strongly recommended to populate only one device on the Si5xxUC-EVB board at a time. Carefully read the next paragraph

for important information.

The Si5xxUC-EVB supports evaluation of a single device in one of three different DUT locations. Device sizes supported are 5mm x 7mm, 3.2mm x 5mm, or 2.5mm x 3.2mm. All device locations can support 4, 6, or 8 pin configurations, but only one device at a time should be installed in any one of the three locations on the Si5xxUC-EVB. This restriction is made to ensure no problems will occur due to potential signal crosstalk, power supply over-loading/coupling, or signal contention/loading between multiple devices. Do not simply remove power from a mounted device in an attempt to place it in an “unused”, but still mounted, state. Board control signals are wired in parallel to all 3 locations and a non-powered device may load control signals to a powered device under test. Please follow this “one device at a time” recommendation and only populate one device at a time.

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UG298: Si5xxUC-EVB

Power Supply and I2C Bus Control

4. Power Supply and I2C Bus Control

The power supply uses a linear voltage regulator to drop the +5 V input supply voltage to one of the supported nominal VDD voltages of +3.3 V, +2.5 V, or +1.8 V. A switch is provided on the EVB (SW5) to select the +5 V source for the voltage regulator as either the USB port +5V or an external +5 V source. The EVB power supply supports operation in one of 2 general modes that correspond to the two operational EVB use cases.

• Stand-alone mode: Power can be sourced from either external supply or USB port, but software is not required and no EVB software tool should be actively connected to Si5XXUC-EVB when being used in Stand-alone mode. In Stand-alone mode the oscillator device VDD voltage is set via the “VDD_DUT_SEL” switch according to the voltage select table shown below. By default this switch is

set to 1.8 V and will need to be changed if evaluating a non-I2C oscillator with 2.5 V or 3.3 V VDD.

• Software controlled mode: Power can be sourced from either external power supply or USB port, but the Programmable Oscillator Software tool can be used to set the VDD voltage to the oscillator. In software controlled mode, “VDD_DUT_SEL” switches should remain set to 1.8 V setting regardless of the desired VDD voltage.

The I2C Disable switch is typically set to the “Off” setting (to enable the on-board MCU to drive the I2C bus) unless the user is attempting to connect an external I2C master to communicate with the oscillator device. The I2C Disable control allows for disabling the onboard I2C buffer to disconnect the oscillator from the on-board MCU. This disconnection is useful if the user wishes to connect an external I2C bus master to communicate with the DUT.

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UG298: Si5xxUC-EVB

Control Signal Switch Settings

5. Control Signal Switch Settings

Four of the 5 on-board DIP switches (SW1, 2, 3, 4) are used for configuration of the EVB oscillator locations to match any standard oscillator pin-out. Using this DIP switch arrangement, the Si5xxUC-EVB can be configured to support all Silicon Labs oscillator devices. The oscillator device pins that can vary in function, depending on the device variant, are pins 1, 2, 7, and 8 as shown in the Device Pinout Mapping table below. Pins 3, 4, 5, and 6 are typically fixed function pins that do not change with device variant.

Note: All device locations on the Si5xxUC-EVB can support up to 8 pin variant devices. Devices with fewer pins (4, 6 pin) can be installed in the same location and will fit within the 8 pin footprint.

Device Pin-out Mapping

4 pin

Device

6 pin

Device

8 pin

Device

DIP Switch

Function

Options

1 1 1 Pin_1_Ctrl (SW1) FS/OE/SDA/Vc

- 2 2 Pin_2_Ctrl (SW2) FS/OE/SCL

2 3 3 - GND

3 4 4 - Output

- 5 5 - Output

4 6 6 - VDD

- - 7 Pin_7_Ctrl (SW3) FS/SDA

- - 8 Pin_8_Ctrl (SW4) FS/SCL

Note:

1. Fixed function pins

Configuration details of each of the 4 variable pin function DIP switches is described in following sections. For devices that may not utilize all 4 of the variable pin function switches, the corresponding unused DIP switch can be set to the NC setting (all Off position). Make sure to make the following switch settings with the Si5xxUC-EVB powered down. Once all are set appropriately, the board may be powered on.

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UG298: Si5xxUC-EVB

Control Signal Switch Settings

5.1 Oscillator Pin 1 Control DIP Switch (Pin_1_Ctrl)

The pin 1 control DIP switch allows oscillator pin 1 to be driven from any of these 4 sources.

1. High (VDD) level

2. Low (GND) level

3. I2C bus SDA signal

4. External control voltage Vc (for VCXO applications)

Note: The 4 signal sources listed above are connected on separate pins on left side of the switch and all pins on right side are tied together (common) and then connect to pin 1 of the oscillator. This means that only one (1) of the switches in this DIP switch bank can be in the ON position at a time. Switching more than 1 switch to the on position at a time may cause undesired behavior. All switches can be set to OFF position to effectively isolate pin 1 from any signal source and is the No Connect (NC) state.

To determine the required Pin 1 switch settings for your specific device, please refer to the Supported Device Tables in Chapter

6. Supported Devices - Stand-Alone Mode and Chapter 7. Supported Devices - Software Controlled Mode - I2C.

Pin 1 DIP Switch (4, 6, or 8 pin DUT)

1 2 3 4 Pin 1 Signal

Off Off Off Off NC

On Off Off Off FS/OE high

Off On Off Off FS/OE low

Off Off On Off SDA

Off Off Off On Vc

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UG298: Si5xxUC-EVB

Control Signal Switch Settings

5.2 Oscillator Pin 2 Control DIP Switch (Pin_2_Ctrl)

This DIP switch allows oscillator pin 2 to be driven from 1 of 3 sources.

1. High (VDD) level

2. Low (GND) level

3. I2C bus SCL signal

Note: The 3 signal sources listed above are located on separate pins on the left side of the switch and all pins on the right side are tied together (common) and then connect to pin 2 of the oscillator. This means that only one (1) of the switches in this DIP switch bank can be in the ON position at a time. Switching more than 1 switch to the ON position at a time may cause undesired behavior. All switches set to OFF position effectively isolates pin 2 from any signal source and is the No Connect (NC) state.

To determine the required Pin 2 switch settings for your specific device, please refer to the Supported Device Tables in Chapter

6. Supported Devices - Stand-Alone Mode and Chapter 7. Supported Devices - Software Controlled Mode - I2C.

Pin 2 DIP Switch (6 or 8 pin DUT)

1 2 3 Pin 2 Signal

Off Off Off NC

On Off Off FS/OE high

Off On Off FS/OE low

Off Off On SCL

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UG298: Si5xxUC-EVB

Control Signal Switch Settings

5.3 Oscillator Pin 7 Control DIP Switch (Pin_7_Ctrl)

This DIP switch allows oscillator pin 7 to be driven from 1 of 3 sources.

1. High (VDD) level

2. Low (GND) level

3. I2C bus SDA signal

Note: The 3 signal sources listed above are located on separate pins on the left side of the switch and all pins on the right side are tied together (common) and then connect to pin 7 of the oscillator. This means that only one (1) of the switches in this DIP switch bank can be in the ON position at a time. Switching more than 1 switch to the ON position at a time may cause undesired behavior. All switches set to OFF position effectively isolates pin 7 from any signal source and is the No Connect (NC) state.

To determine the required Pin 7 switch settings for your specific device, please refer to the Supported Device Tables in Chapter

6. Supported Devices - Stand-Alone Mode and Chapter 7. Supported Devices - Software Controlled Mode - I2C.

Pin 7 DIP Switch (8 pin DUT)

1 2 3 Pin 7 Signal

Off Off Off NC

On Off Off FS high

Off On Off FS low

Off Off On SDA

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UG298: Si5xxUC-EVB

Control Signal Switch Settings

5.4 Oscillator Pin 8 Control DIP Switch (Pin_8_Ctrl)

This DIP switch allows oscillator pin 8 to be driven from 1 of 3 sources.

1. High (VDD) level

2. Low (GND) level

3. I2C bus SCL signal

Note: The 3 signal sources listed above are located on separate pins on the left side of the switch and all pins on the right side are tied together (common) and then connect to pin 8 of the oscillator. This means that only one (1) of the switches in this DIP switch bank can be in the ON position at a time. Switching more than 1 switch to the ON position at a time may cause undesired behavior. All switches set to OFF position effectively isolates pin 8 from any signal source and is the No Connect (NC) state.

To determine the required Pin 8 switch settings for your specific device, please refer to the Supported Device Tables in Chapter

6. Supported Devices - Stand-Alone Mode and Chapter 7. Supported Devices - Software Controlled Mode - I2C.

Pin 8 DIP Switch (8 pin DUT)

1 2 3 Pin 8 Signal

Off Off Off NC

On Off Off FS high

Off On Off FS low

Off Off On SCL

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UG298: Si5xxUC-EVB

Supported Devices - Stand-Alone Mode

6. Supported Devices - Stand-Alone Mode

If using the Si5XXUC-EVB with a device that is either fixed frequency or has pin-controlled output frequency, this “Stand-alone mode” section should be used to configure the EVB.

If you have a device installed that utilizes the I2C bus for making frequency or other changes to the device, please refer to Section

7. Supported Devices - Software Controlled Mode - I2C.

The tables below show pin controlled XO and VCXO devices supported by the Si5xxUC-EVB along with possible package sizes and control pin mapping. The control pin mapping can be used to determine the corresponding switch settings on the Si5xxUC-EVB.

Table 6.1. Pin Controlled XOs

SiLabs Device

Si510 XO Single

Si510 XO Single (Diff) 6 5x7, 3.2x5,

Type # Freqs # Pins Pkg Sizes

(mm x mm)

4 5x7, 3.2x5,

(CMOS)

2.5x3.2

Pin 1 Control

OE - - -

Pin 2 Control

Pin 7 Control

Pin 8 Control

Pin 4 Output

CLK

Pin 5 Output

NC OE - - CLK+ CLK-

2.5x3.2

Si511 XO Single 6 5x7, 3.2x5,

OE NC - - CLK+ CLK-

2.5x3.2

Si512 XO Dual

(CMOS)

Si512 XO Dual (Diff) 6 5x7, 3.2x5,

6 5x7, 3.2x5,

2.5x3.2

FS OE - - CLK NC

FS OE - - CLK+ CLK-

2.5x3.2

Si513 XO Dual

(CMOS)

Si513 XO Dual (Diff) 6 5x7, 3.2x5,

6 5x7, 3.2x5,

2.5x3.2

OE FS - - CLK NC

OE FS - - CLK+ CLK-

2.5x3.2

Si530 XO Single (Diff) 6 5x7 NC OE - - CLK+ CLK-

Si530 XO Single

6 5x7 OE NC - - CLK NC

(CMOS)

Si531 XO Single 6 5x7 OE NC - - CLK+ CLK-

Si532 XO Dual (Diff) 6 5x7 FS OE - - CLK+ CLK-

Si532 XO Dual

6 5x7 FS OE - - CLK NC

(CMOS)

Si533 XO Dual (Diff) 6 5x7 OE FS - - CLK+ CLK-

Si533 XO Dual

6 5x7 OE FS - - CLK NC

(CMOS)

Si534 XO Quad (Diff) 8 5x7 NC OE FS1 FS0 CLK+ CLK-

Si534 XO Quad

8 5x7 NC OE FS1 FS0 CLK NC

(CMOS)

Si535 XO Single 6 5x7 NC OE - - CLK+ CLK-

Si536 XO Single 6 5x7 OE NC - - CLK+ CLK-

Si540 XO Single 6 5x7, 3.2x5,

OE/NC NC/OE - - CLK+ CLK-

2.5x3.2

Si541 XO Dual 6 5x7, 3.2x5,

OE/FS FS/OE - - CLK+ CLK-

2.5x3.2

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UG298: Si5xxUC-EVB

Supported Devices - Stand-Alone Mode

SiLabs Device

Type # Freqs # Pins Pkg Sizes

(mm x mm)

Si542 XO Quad 8 5x7, 3.2x5,

2.5x3.2

Si544 XO Single/Dual/

Quad (or

8 5x7, 3.2x5,

2.5x3.2

I2C)

Si545 XO Single 6 5x7, 3.2x5,

2.5x3.2

Si546 XO Dual 6 5x7, 3.2x5,

2.5x3.2

Si547 XO Quad 8 5x7, 3.2x5,

2.5x3.2

Si549 XO Single/Dual/

Quad (or

8 5x7, 3.2x5,

2.5x3.2

I2C)

Si560 XO Single 6 5x7, 3.2x5,

2.5x3.2

Si561 XO Dual 6 5x7, 3.2x5,

2.5x3.2

Si562 XO Quad 8 5x7, 3.2x5,

2.5x3.2

Pin 1 Control

Pin 2 Control

Pin 7 Control

Pin 8 Control

Pin 4 Output

Pin 5 Output

OE/NC NC/OE FS1 FS0 CLK+ CLK-

OE/NC/FS OE/NC/FS SDA/FS1 SCL/FS0 CLK+ CLK-

OE/NC NC/OE - - CLK+ CLK-

OE/FS FS/OE - - CLK+ CLK-

OE/NC NC/OE FS1 FS0 CLK+ CLK-

OE/NC/FS OE/NC/FS SDA/FS1 SCL/FS0 CLK+ CLK-

OE/NC NC/OE - - CLK+ CLK-

OE/FS FS/OE - - CLK+ CLK-

OE/NC NC/OE FS1 FS0 CLK+ CLK-

Si564 XO Single/Dual/

Quad (or

8 5x7, 3.2x5,

2.5x3.2

OE/NC/FS OE/NC/FS SDA/FS1 SCL/FS0 CLK+ CLK-

I2C)

Si590 XO Single (Diff) 6 5x7, 3.2x5 NC OE - - CLK+ CLK-

Si590 XO Single

6 5x7, 3.2x5 OE NC - - CLK NC

(CMOS)

Si591 XO Single 6 5x7, 3.2x5 OE NC - - CLK+ CLK-

Note:

1. The pin number headings in Table 6.1 apply to 6/8 pin parts only. 4-pin devices like the Single CMOS Si510 have the clock output

on pin 3 instead of pin 4. Please see the Si510/511 Data Sheet for more details on the pinout.

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Table 6.2. Pin Controlled VCXOs

UG298: Si5xxUC-EVB

Supported Devices - Stand-Alone Mode

SiLabs Device

Si515 VCXO Single

Si516 VCXO Dual

Si516 VCXO Dual (Diff) 6 5x7, 3.2x5,

Type # Freqs # Pins Pkg Sizes

(mm x mm)

6 5x7, 3.2x5,

(CMOS)

2.5x3.2

6 5x7, 3.2x5,

(Diff)

2.5x3.2

6 5x7, 3.2x5,

(CMOS)

2.5x3.2

Pin 1 Control

Pin 2 Control

Pin 7 Control

Pin 8 Control

Pin 4 Output

Pin 5 Output

Vc OE - - CLK NC

Vc OE - - CLK+ CLK-

Vc FS - - CLK NC

Vc FS - - CLK+ CLK-

2.5x3.2

Si550 VCXO Single 6 5x7 Vc OE - - CLK+ CLK-

Si552 VCXO Dual 6 5x7 Vc FS - - CLK+ CLK-

Si554 VCXO Quad 8 5x7 Vc OE FS1 FS0 CLK+ CLK-

Si565 VCXO Single 6 5x7, 3.2x5,

Vc OE - - CLK+ CLK-

2.5x3.2

Si566 VCXO Dual 6 5x7, 3.2x5,

Vc FS - - CLK+ CLK-

2.5x3.2

Si567 VCXO Quad 8 5x7, 3.2x5,

Vc OE FS1 FS0 CLK+ CLK-

2.5x3.2

Si569 VCXO Single/

Dual (or

8 5x7, 3.2x5,

2.5x3.2

Vc OE/FS SDA SCL CLK+ CLK-

I2C)

Si595 VCXO Single 6 5x7, 3.2x5 Vc OE - - CLK+ CLK-

Si596 VCXO Dual 6 5x7, 3.2x5 Vc FS - - CLK+ CLK-

Si597 VCXO Quad 8 5x7 Vc OE FS1 FS0 CLK+ CLK-

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UG298: Si5xxUC-EVB

Supported Devices - Software Controlled Mode - I2C

7. Supported Devices - Software Controlled Mode - I2C

If using the Si5XXUC-EVB with a device that utilizes the I2C bus for making frequency or other changes to the device, this “software controlled mode” section should be used to configure the EVB.

If you have a device installed that is either fixed frequency or has pin-controlled output frequency, refer to Section 6. Supported Devices

- Stand-Alone Mode.

The tables below show I2C XO and I2C VCXO devices supported by the Si5xxUC-EVB along with possible package sizes and control pin mapping. The control pin mapping can be used to determine the corresponding switch settings on the Si5xxUC-EVB when using software controlled mode.

Table 7.1. I2C XOs

SiLabs Device

Si514 XO I2C 6 5x7, 3.2x5,

Si544 XO

Si549 XO

Si564 XO

Si570 XO

Si598 XO

SiLabs Device

Si569 VCXO

Type # Freqs # Pins Pkg Sizes

(mm x mm)

2.5x3.2

I2C or (Single/ Dual/Quad)

I2C

Type # Freqs # Pins Pkg Sizes

I2C or (Single/ Dual)

8 5x7, 3.2x5,

2.5x3.2

8 5x7, 3.2x5,

2.5x3.2

8 5x7, 3.2x5,

2.5x3.2

8 5x7 NC OE SDA SCL CLK+ CLK-

(mm x mm)

8 5x7, 3.2x5,

2.5x3.2

Pin 1 Control

SDA SCL - - CLK+ CLK-

OE/NC/FS OE/NC/FS SDA/FS1 SCL/FS0 CLK+ CLK-

Table 7.2. I2C VCXOs

Pin 1 Control

Vc OE/FS SDA SCL CLK+ CLK-

Pin 2 Control

Pin 7 Control

Pin 8 Control

Pin 4 Output

Pin 5 Output

Si571 VCXO

Si599 VCXO

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I2C

8 5x7 Vc OE SDA SCL CLK+ CLK-

UG298: Si5xxUC-EVB

USB Port and External Powering

8. USB Port and External Powering

The USB port on the Si5xxUC-EVB utilizes a micro-USB connector that is located on the left edge of the board on the bottom side. A 2meter micro USB cable is provided with the EVB kit. Any micro USB cable can be used that supports full USB connectivity.

If powering the EVB via the USB port, make sure switch SW5 is in the “USB” position. If properly connected to a live USB port, the green VBUS_5V should illuminate.

If powering the board via an external +5 V power supply, make sure SW5 is in the “EXT” position. Once +5 V is connected to the board via the +5V_EXT connections, the green +5V_EXT LED should illuminate.

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UG298: Si5xxUC-EVB

Output Clock Terminations

9. Output Clock Terminations

The drawing in the figure below shows the default output termination circuit for CLK1 output of the Si5xxUC-EVB. This default source termination is for typical 3.3 V LVPECL. CLK2 and CLK3 are also terminated similarly for 3.3 V LVPECL. If not using LVPECL, this termination circuit may require component modification. The following table gives examples of recommended output termination components for various output formats when using Si51x, Si53x, Si54x, Si55x, Si56x, Si57x, and Si59x devices, but always refer to the spe-

cific device data sheet and/or appropriate application note for details of required output source termination for the specific device being evaluated.

Note that LVPECL, LVDS, and CML output formats require a 50 Ω termination of each output at the receiver (or 100 Ω differential). These termination components must be placed as close to the receiver as possible and are therefore not included on the Si5xxUC-EVB layout.

Figure 9.1. CLK1 Output Default Terminations

Table 9.1. Example Output Clock Source Terminations (Si51x, Si53x, Si54x, Si55x, Si56x, Si57x, and Si59x only)

Output Format Series Resistor Position (e.g.,

R4, R6)

LVPECL 3.3 V: AC coupled 0 Ω 130 Ω 0.1μF

LVPECL 2.5 V: AC coupled 0 Ω 90 Ω 0.1μF

LVPECL: DC coupled 0 Ω Remove replace w/ 0 Ω

LVDS : AC coupled 0 Ω Remove 0.1μF

LVDS : DC coupled 0 Ω Remove replace w/ 0 Ω

HCSL 0 Ω Remove replace w/ 0 Ω

CML 0 Ω Remove 0.1μF

LVCMOS : AC coupled 0 Ω Remove 0.1μF

LVCMOS : DC coupled 0 Ω Remove replace w/ 10 Ω

Parallel Resistor Position

(e.g., R5, R7)

Series Capacitor Position

(e.g., C3, C5)

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UG298: Si5xxUC-EVB

EVB Test Points and LEDs

10. EVB Test Points and LEDs

10.1 Test Points

The Si5xxUC-EVB has many test points that are useful for probing various nodes and/or making connections to external test equipment. Please refer to the schematic for the functionality of the various test points.

One set of test points in particular provides oscillator current sense capability and is shown in the drawing below. These two test points allow an external voltage measurement to be taken across the two test points to determine the current being used by the oscillator. Since the resistor value is 1 Ω, the voltage measured across these 2 test points corresponds to the current through the resistor. For example, if the measured voltage is 75 mV, the current flow is 75 mA. Each oscillator site has this current sense circuit.

Figure 10.1. Current Sense Test Points

10.2 LEDs

The Si5xxUC-EVB has 5 status LEDs as shown in table below. The board silkscreen identifies each LED.

Table 10.1. Status LEDs

LED name Color Location Description

+5V_EXT Green D1

VBUS_5V Green D5 USB +5 V is present (independent of +5V_SELECT (SW5) switch setting)

VDD_3.3 Green D4 On-board MCU 3.3 V is present

USB_ACT Red D3 USB port activity

Aux Red D2 TBD (spare)

External +5 V source is present (independent of +5V_SELECT (SW5) switch setting)

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UG298: Si5xxUC-EVB

VCXO Voltage Control Input Circuit

11. VCXO Voltage Control Input Circuit

The drawing below shows the VCXO control voltage input (VC_IN) circuit used for evaluation of VCXOs. The VCXO control voltage can be applied using the J1 SMA connector, or using TP3/TP6. A simple RC circuit is included to low-pass filter any noise on the input. The RC circuit components can be removed or modified as required for your application.

Figure 11.1. VCXO Control Voltage Input "VC_IN"

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UG298: Si5xxUC-EVB

Programmable Oscillator Calculator Tool

12. Programmable Oscillator Calculator Tool

The Programmable Oscillator Software Tool can be used with the Si5xxUC-EVB. This tool and corresponding Programmable Oscillator Software Tool User's Guide can be found on the Oscillator Software Tools page.

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13. Layout of Board

UG298: Si5xxUC-EVB

Layout of Board

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UG298: Si5xxUC-EVB

Layout of Board

13.1 Si56x XO and VCXO 2.5x3.2mm Footprint Recommendation

For optimal thermal relief, use two ground vias next to the GND pin of the oscillator. Each via should have a 50mm diameter with a 25mm drill. These vias should be directly connected to the board's internal ground layers without the use of thermal relief spokes. This two via design has been implemented in all Si5xxUC-EVBs REV 4.0 or greater.

Figure 13.1. Si56x 2.5x3.2mm Footprint

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14. Si5xxUC-EVB Schematic

UG298: Si5xxUC-EVB

Si5xxUC-EVB Schematic

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UG298: Si5xxUC-EVB

Si5xxUC-EVB Schematic

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Disclaimer

Silicon Labs intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using or intending to use the Silicon Labs products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific device, and "Typical" parameters provided can and do vary in different applications. Application examples described herein are for illustrative purposes only . Silicon Labs reserves the right to make changes without further notice to the product information, specifications, and descriptions herein, and does not give warranties as to the accuracy or completeness of the included information. Without prior notification, Silicon Labs may update product firmware during the manufacturing process for security or reliability reasons. Such changes will not alter the specifications or the performance of the product. Silicon Labs shall have no liability for the consequences of use of the information supplied in this document. This document does not imply or expressly grant any license to design or fabricate any integrated circuits. The products are not designed or authorized to be used within any FDA Class III devices, applications for which FDA premarket approval is required, or Life Support Systems without the specific written consent of Silicon Labs. A "Life Support System" is any product or system intended to support or sustain life and/or health, which, if it fails, can be reasonably expected to result in significant personal injury or death. Silicon Labs products are not designed or authorized for military applications. Silicon Labs products shall under no circumstances be used in weapons of mass destruction including (but not limited to) nuclear, biological or chemical weapons, or missiles capable of delivering such weapons. Silicon Labs disclaims all express and implied warranties and shall not be responsible or liable for any injuries or damages related to use of a Silicon Labs product in such unauthorized applications.

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Silicon Labs UG298 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1. Quick Start - Board Configuration Check List

2. Functional Description

3. General Operational Restrictions

3.1 Evaluate Only a Single Device at a Time

4. Power Supply and I2C Bus Control

5. Control Signal Switch Settings

5.1 Oscillator Pin 1 Control DIP Switch (Pin_1_Ctrl)

5.2 Oscillator Pin 2 Control DIP Switch (Pin_2_Ctrl)

5.3 Oscillator Pin 7 Control DIP Switch (Pin_7_Ctrl)

5.4 Oscillator Pin 8 Control DIP Switch (Pin_8_Ctrl)

6. Supported Devices - Stand-Alone Mode

7. Supported Devices - Software Controlled Mode - I2C

8. USB Port and External Powering

9. Output Clock Terminations

10. EVB Test Points and LEDs

10.1 Test Points

10.2 LEDs

11. VCXO Voltage Control Input Circuit

12. Programmable Oscillator Calculator Tool

13. Layout of Board

13.1 Si56x XO and VCXO 2.5x3.2mm Footprint Recommendation

14. Si5xxUC-EVB Schematic