Semtech SC120 Evaluation Board User guide

Brand
Semtech
Model
SC120 Evaluation Board
Type
User guide
© 2010 Semtech Corporation
POWER MANAGEMENT
1
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
2
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
3
Schematic Drawings
R3
C4
SW1
SW PUSHBUTTON
DPDT
5
6
42
3
1
SC120UL/
SC121UL
LX
1
GND
2
IN
3
EN
4
FB
5
OUT
6
T
PAD
R1
C1
R2
C2
C3
R5
No
Pop
1MΩ
499kΩ
10μF
10μF
100kΩ
VOUT
J2
VIN
J1
U1
TP8
GND
JP2 - ENL
12
TP6
VOUT
R6
0Ω
10μF
C5
No
pop
TP1
LX
R4
0
JP1
J_LOOP
1
2
L1
4.7μH
TP9
GND
TP7
GND
TP2
GND
TP3
VIN
TP4
EN
10μF
Up
Down
PTP2
SC120/SC121 EVB
SC120SK EVB
R3
C4
SW1
SW PUSHBUTTON
DPDT
5
6
42
3
1
SC120SK
LX
3
GND
2
IN
1
EN
6
FB
5
OUT
4
R1
C1
R2
C2
C3
R5
No
Pop
1MΩ
499kΩ
10μF
10μF
100kΩ
VOUT
J2
VIN
J1
U1
TP8
GND
JP2 - ENL
12
TP6
VOUT
R6
0Ω
10μF
C5
No
pop
TP1
LX
R4
0
JP1
J_LOOP
1
2
L1
4.7μH
TP9
GND
TP7
GND
TP2
GND
TP3
VIN
TP4
EN
10μF
Up
Down
PTP2
SC120/SC121 EVB
4
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
1
(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
U1
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
5
Layout Drawings — SC120/SC121 EVB
Top layer metal and silkscreen
SC120/SC121 EVB
6
Layout Drawings — SC120/SC121 EVB
Bottom layer metal (top-side view) with top-side silkscreen shown for reference
SC120/SC121 EVB
7
Layout Drawings — SC120SK EVB
Top layer metal and silkscreen
SC120/SC121 EVB
8
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
9
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
1
and R
2
, 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
1
as the sum of R1 and R6, or for dividing
R
1
into two resistors to mitigate environmental concerns if
a large value of R
1
is desired. The EVB is provided with
R6 = 0Ω. C5 is also described in the datasheet, there des-
ignated C
FB
. 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.
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Semtech SC120 Evaluation Board User guide

Brand
Semtech
Model
SC120 Evaluation Board
Type
User guide
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