PAM2312 User Guide

PAM2312
EVB User Guide
PAM2312 EV Board User Guide
AE Department
1. Revision Information
Date
2010/09
Revision
V1.0
Description
Initial Release
Comment
2. PAM2312 General Description
The PAM2312 is a step-down, current mode, DC/DC converter. At heavy load, the constant frequency PWM
control performs excellent stability and transient response. To ensure the longest battery life in portable
applications, the PAM2312 have a power-saving Pulse-skipping Modulation (PSM) mode and reduce the
quiescent current under light load operation to save power.
The PAM2312 is supported with a range of input voltages from 2.5V to 5V, allowing the use of a single
Li+/Li-polymer cell, 3-cell Alkaline/NiMH batteries, USB, and other standard power sources. The output
voltage is adjustable from 0.6V to the input voltage, while the suffix part numbers PAM2312-XX indicate
pre-set voltage ranges of 3.3V, 1.8V, 1.5V or 1.2V. All versions include internal power switch and
synchronous rectifier for minimal external part count and high efficiency. During the shutdown, the input is
disconnected from the output and the shutdown current is less than 0.1µA. Other key features include
under-voltage lockout to prevent deep-battery discharge.
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.
PAM2312
EVB User Guide
3. Key Features
z
z
z
z
z
Efficiency up to 96%
40µA (typ) Quiescent Current
Internal Synchronous Rectifier
1.5MHz Switching frequency to minimize
inductor value
Soft Start
z
z
z
z
z
z
Under-Voltage Lockout
Short Circuit Protection
Up to 800mA output current
Thermal Shutdown
5-pin Small SOT23-5 Package
Pb-Free Package
4. EV Board Schematic
Vin
4
IC1
Vin
SW
EN
1
2
FB
1
EN
EN
VFB
C3
C2
5
R2
2
3
R1
SW
GND
C1
3
Vo
L1
5. EVB PAM2312 EB05AA Description
PAM2312 EB05AA is an evaluation board for the PAM2312, a DC/DC converter.
The board is targeted to be used in providing a simple and convenient evaluation environment for the
PAM2312. Requires parts, power supply jacks etc. on the board, which makes it easy to be evaluated.
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.
PAM2312
EVB User Guide
6. EV Board View
Top View
EV board operational sequence:
a.
Connect power supply to VIN and GND.
b.
Connect load to VO and GND.
c.
Connect EN up side to enable the chip.
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.
PAM2312
EVB User Guide
7. EV Board BOM List
Item
Value
C1
10µF
C2
10µF
C3
100pF
L1
IC1
PCB
4.7µH
PAM2312
Type
X5R/X7R,
Ceramic/0805
X5R/X7R,
Ceramic/0805
NPO/COG,
0603
3.7mm*3.0mm
SOT-23-5
PAM2312 EB05AA
VOUT = (1+R1/R2)×VREF
Vo
1.2V
1.5V
1.8V
2.5V
3.3V
Rating
Description
Vender and Part No.
10V
Input coupling CAP
JMK212BJ106MA
10V
Input coupling CAP
JMK212BJ106MA
50V
Forward CAP
UMK105 CG101JV-F
1.2A
Inductor
Power management IC
NR4012T 3R3M
PAM2312
(VREF = 0.6V)
R1
150k
225k
300k
475k
680k
R2
150k
150k
150k
150k
150k
8. External Compnents Selection
Input & output Capacitors (C1, C2)
(1) For lower output ripple, low ESR is required.
(2) Low leakage current needed, 10uF, X5R/X7R ceramic recommend
Feed forward capacitor (C3)
(1) Lower the output ripple
(2) Low leakage current needed, 20-100pF, NPO/COG ceramic recommend
Output Voltage programmer resistors (R1, R2)
(1) For programmer output voltage
(2) For accurate output voltage, 1% tolerance is required.
Inductor (L1)
(1) Low DCR for good efficiency
(2) Inductor rated Current must higher than the output current
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.
PAM2312
EVB User Guide
9. 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.