Semtech SC120 Evaluation Board User guide

Brand: Semtech

Model: SC120 Evaluation Board

Type: User guide

POWER MANAGEMENT

SC120/SC121 EVB

Evaluation Board

User’s Guide

Description

SC120/SC121EVB is the evaluation board (EVB) for the

SC120 and SC121ULTRT Low Voltage Synchronous Boost

Converters. Both devices are available in the MLPD-UT

1.5×2 mm 6 lead package. The SC120 is also available in

the SOT23-6 package. The EVB is designed to provide a

working demonstration of the SC120 or SC121.

This guide contains information relating to the usage of

the EVB and should be used in conjunction with the data-

sheet for the device. Component values on the EVB may

vary per speci c customer requirements. The datasheet

contains detailed information including the electrical

characteristics and the detailed features of the device.

This guide can be used to familiarize the user with the

features of the device and for testing electrical character-

istics of particular interest to the reader.

April 23, 2010

Feature Content

Standard Schematic

Standard Bill of Materials

Layout

Operation

•

SC120/SC121 EVB

With SC120UL/SC121UL Device (MLPD-UT-6 1.5×2mm package)

SC120/SC121 EVB

SC120SK EVB

With SC120SK Device (SOT23-6 package)

Notice: All referenced brands, product names, service names and trademarks are the property of their respective owners.

SC120/SC121 EVB

Schematic Drawings

SW1

SW PUSHBUTTON

DPDT

SC120UL/

SC121UL

GND

OUT

PAD

Pop

1MΩ

499kΩ

10μF

100kΩ

VOUT

VIN

TP8

GND

JP2 - ENL

TP6

VOUT

0Ω

10μF

pop

TP1

JP1

J_LOOP

4.7μH

TP9

GND

TP7

GND

TP2

GND

TP3

VIN

TP4

10μF

Down

PTP2

SC120/SC121 EVB

SC120SK EVB

SW1

SW PUSHBUTTON

DPDT

SC120SK

GND

OUT

Pop

1MΩ

499kΩ

10μF

100kΩ

VOUT

VIN

TP8

GND

JP2 - ENL

TP6

VOUT

0Ω

10μF

pop

TP1

JP1

J_LOOP

4.7μH

TP9

GND

TP7

GND

TP2

GND

TP3

VIN

TP4

10μF

Down

PTP2

SC120/SC121 EVB

Standard Bill of Materials

Reference Value Footprint Hardware Notes

R1 499kΩ 0603

Valid for 1.8V output.

R2 1MΩ 0603

R3 100kΩ 0603 Pull-up resistor from EN to VIN

R4 0 0603

Shorting bar is provided o set, with only one terminal connect-

ed. Install shorting bar to bypass inductor current sense loop.

R5 No Pop 2512 Not populated, optional load resistor

R6 0 0603

R6 is connected in series with R1. R6 permits using two resistors

in series for a large (effective) value of R

(see datasheet).

SW1 DPDT Push-button switch, down position enables output.

TP1 Test point 0.040 LX pin voltage sense

TP3 Test point 0.040 IN pin voltage sense

TP4 Test point 0.040 EN pin voltage sense

TP5 Test point 0.040 FB pin voltage sense

TP6 Test point 0.040 OUT pin voltage sense

TP2, TP7, TP8, TP9 Test point 0.040 Ground

L1 4.7μH 7 x 4 (mm) Inductor

SC120UL or

SC121UL

1.5 x 2 (mm) Semtech integrated circuit — MLPD-UT-6 package

SC120SK 2.8 x 2.9 (mm) Semtech integrated circuit — SOT23-6 package

C1, C2 22μF 0805 Capacitor, X5R dielectric, 6.3V rating, Murata GRM21BR60J226M

C3, C4 No Pop 1206 Not populated

C5 No Pop 0603 Feedback capacitor — optional

JP1 Berg-2pin 2-100

Inductor current sense loop connections — external loop con-

nector provided

JP2 Berg-2pin 2-100 Short = 3.3V, open = resistor programmed

PTP2 SLX PRB-TP-5031

J1 Banana Jack Input

J2 Banana Jack Output

Note:

Component values on the EVB may vary per speci c customer requirements.

SC120/SC121 EVB

Layout Drawings — SC120/SC121 EVB

Top layer metal and silkscreen

SC120/SC121 EVB

Layout Drawings — SC120/SC121 EVB

Bottom layer metal (top-side view) with top-side silkscreen shown for reference

SC120/SC121 EVB

Layout Drawings — SC120SK EVB

Top layer metal and silkscreen

SC120/SC121 EVB

Layout Drawings — SC120SK EVB

Bottom layer metal (top-side view) with top-side silkscreen shown for reference

Semtech Corporation

Power Management Products Division

200 Flynn Road, Camarillo, CA 93012

Phone: (805) 498-2111 Fax: (805) 498-3804

www.semtech.com

Contact Information

SC120/SC121 EVB

Operation

The SC120/SC121 EVB provides con guration options for

any SC120 or SC121 application. The following describes

the standard con guration. If an EVB is requested with a

non-standard con guration, some of the standard values

or con gurations will di er from this description.

The output voltage can be set to 3.3V using internal pro-

gramming by installing a jumper on JP1. Any other

voltage from 1.8V to 5.0V can be programmed using resis-

tors R1, R2, R6, and capacitor C5. R1 and R2 are the

programming resistors described in the datasheet, there

designated R

and R

, respectively. The EVB is provided

with R1 = 499kΩ and R2 = 1MΩ, for an output voltage of

1.8V. R6 is in series with R1, and is useful for obtaining

high values for R

as the sum of R1 and R6, or for dividing

into two resistors to mitigate environmental concerns if

a large value of R

is desired. The EVB is provided with

R6 = 0Ω. C5 is also described in the datasheet, there des-

ignated C

. It is used to improve the PSAVE ripple

amplitude if needed, as described in the datasheet. The

EVB is provided with C5 removed.

The input supply is connected using banana jacks J1. The

IN sense test point (TP3) is provided for input monitoring,

or for Kelvin sense feedback to the input supply. The

output load is connected using banana jacks J2. The OUT

sense test point (TP6) provides a sense connection to the

output capacitor. Two sets of capacitor pads are provided

for both the input and output capacitors to permit devices

of di erent package sizes, either 0805 or 1206.

The enable pin is pulled up to IN with a 100kΩ resistor, R3.

The pushbutton switch connects EN to ground to disable

the SC120/SC121 when the button is in the up position.

When the pushbutton is in the down position, the switch

is open, EN is pulled high, and the SC120/SC121 is

enabled.

The inductor is connected from IN to LX by one of three

methods. A jumper can be installed on JP1 to complete

the inductor current path from the input supply. A wire

loop can be connected across JP1 for use with a current

probe to monitor inductor current. R4 is in parallel with

JP1. A shorting bar is included soldered to only one R4

pad. Replace the shorting bar across both R4 pads to

bypass the current sense loop. A Tektronix scope probe

connection point (PTP2) is provided to monitor the LX pin

voltage. Alternatively, LX pin voltage can be monitored

using TP1.

R5 is an unpopulated resistor pad that is provided for con-

nection of a  xed load resistor directly on the board.

Semtech SC120 Evaluation Board User guide

Brand: Semtech

Model: SC120 Evaluation Board

Type: User guide

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Semtech SC120 Evaluation Board User guide

Semtech SC120 Evaluation Board User guide

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