AC4868 868 MHz Transceiver
User’s Manual
Americas: +1-800-492-2320 Option 3
38
Laird Technologies
Europe: +44-1628-858-940
Hong Kong: +852 2923 0610
www.lairdtech.com/ramp
A
PPENDIX
I:
S
AMPLE
P
OWER
S
UPPLY
Below is a simple switching power supply that provides enough current to easily power any Laird Technologies
OEM module. It utilizes low cost, off the shelf components that fit into a small area. This supply has an input
voltage range of +6 volts to +18 volts and will 3.4 volts at 1.5 amps.
Included is a schematic, bill of materials with manufacture's name and part numbers and a sample PCB layout.
It is important to follow the layout suggestions and use large areas of copper to connect the devices as shown
in the layout. It is also important to hook up the ground traces as shown and use multiple vias to connect
input and output capacitors to the bottom side ground plane.
If the input voltage will be less than 12 volts then C1 and C2 can be replaced with a single 100uF 20 volt
capacitor (same part number as C7). This will reduce board space and lower costs further. If you are powering
an AC5124 module, R1 can be changed to a 373 ohm 1% resistor. This will change the output to +5 volts at
1.0 amps.
Bill of Materials
Qty Reference Value
Description
Mfg.
Mfg. Part #
1
R1
210
Res, 0603, 210, 1/16W, 1%
KOA
RK73H1JT2100F
1
R2
127
Res, 0603, 127, 1/16W, 1%
KOA
RK73H1JT1270F
2
C1 C2
47uF
Cap, Tant, 7343, 47uF, 35V
AVX
TPSE476M035R0200
3
C3 C4 C5 0.1uF
Cap, Cer, 0603, 0.1uF, Y5V,
25V
Murata
GRM39Y5V104Z025AD
1
C6
3300pF
Cap, Cer, 0603, 3300pF, X7R,
50V
Murata
GRM39X7R332K050AD
1
C7
100uF
Cap, Tant, 7343, 100uF, 20V
Kemet
T491X107K020A5
1
D1
B230/A
Diode, SMB, B230/A, 2A,
Schottkey
Diodes, Inc.
B230/A
1
D2
LL4148
Diode, MELF, LL4148, Switch
Diode
Diodes, Inc.
LL4148
1
L1
15uH
Xfmr, 2P, SMT, 15uH, 2A
Coiltronics
UP2.8B150
1
U1
CS51413 IC, CS51413, 8P, SO, Switch
Reg Ctrl.
On-Semicond. CS51413