PAM2861 User Guide

PAM2861
EVB User Guide
PAM2861EV Board User Guide
AE Department
1. Revision Information
Date
2008/8/18
Revision
V1.0
Description
Initial Release
Comment
2. EV Board Schematic
R2
VIN
LED+
R1
ISENSE
C3
VS ET
3
GND
2
1
L1
LX
4
IC1
LX
C1
VIN
5
D1
C2
VSET
LED-
This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice.
No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product.
PAM2861
EVB User Guide
3. EVB PAM2861 EB86AB Description
PAM2861 EB86AB is an evaluation board for the PAM2861/2 (SOT-23-5 package), a high power LED
buck driver. The board is targeted to be used in providing a simple and convenient evaluation environment
for the PAM2861/2. Efficiency on the board make it easy to be evaluated.
Use single power supply to drive 1-10 serials (PAM2861) or 1-6 serials (PAM2862) 1W or 3W power LED.
4. EV Board View
Control signal
EV board operational sequence:
a.
Connect power supply to Vin, (PAM2861 up to 40V, PAM2862 up to 24V).
b.
Connect LED- to power LED cathode and LED+ to power LED anode.
c.
Connect control signal to VSET if need external control, 0.4-2.5VDC voltage for analog dimming or
<500Hz PWM signal for PWM dimming.
This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice.
No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product.
PAM2861
EVB User Guide
5. EV Board BOM List
Item
Value
Type
X5R/X7R,
Ceramic/1206
X5R/X7R,
Ceramic/0603
Rating
Description
C1
10µF
25V
Input coupling CAP
C2
10nF
50V
comp CAP
C3
NC
L1
100µH
SDR75
0.7A
Inductor
D1
R1
IC1
PCB
SS14
0.3Ω
PAM2861/2
SMA
0805
SOT-23-5
PAM2861 EB86AB
1A/40V
1%
Schottky Diode
Iset Resistor
Power management IC
Vender and Part No.
Torch
TMK316BJ106KL-T
Murata
GRM188R71H103K
Wurth WE-PD2 type L
74477520 100uH
SS14
PAM2861/2
6. External Components Selection
Input Capacitors (C1) and Output Capacitor (C3)
(1) C1 Low ESR needed, 10uF, X5R/X7R ceramic recommended
(2) C3 can not used.
Soft start Capacitors (C2)
(1) This capacitor is to increase soft start, 10nF for 1.5mS.
(2) The capacitor can not use in normal application.
Iset Resistors (R1)
(1) R set the power LED current , ILED=0.1V/R R=R1//R2.
(2) R, 0.3Ω±1% for 1W LED (about 333mA).
(3) R, 0.143Ω±1% for 3W LED (about 700mA).
Inductor (L1)
(1) Low DCR needed, 100uH (rating 0.7A) recommended for 1W LED.
(2) Low DCR needed, 47uH (rating 1.2A) recommended for 3W LED.
Schottky Diode (D1,D2,D3,D4,D5)
(1) SS14 (1A, 40V) recommended.
(2) B140 (1A, 40V) recommended.
This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice.
No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product.
PAM2861
EVB User Guide
7. PCB Layout Guidelines
(1) Connect L1, LX, D1 with short and wide connections. Minimize the switching circuit area to avoid
unexpected radiation.
(2) Place the Iset resistor R1,R2 as close to the sense pin as possible.
(3) Make sure the current flow path has a wide trace. When current path need vias, use the multiple vias to
decrease impedance.
(4) PAM2861/2 integrate the power MOSFET. Make sure the heat dissipation area is large enough and
have a low thermal resistance to atmosphere.
8. PCB Layout Example
Top Layer
Bottom Layer
This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice.
No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product.