PAM2321 User Guide

PAM2321
EVB User Guide
PAM2321 TDFN3x3-10 EV Board User Guide
AE Department
1. Revision Information
Date
2011/09
Revision
V1.0
Description
Initial Release
Comment
2. PAM2321 General Description
The PAM2321 is a 2A step-down converter with a typical input voltage of 3.3V and a fixed output voltage of
1.2V or an adjustable output. The 3MHz switching frequency enables the use of small external components.
The ultra-small 3mm x 3mm footprint and high efficiency make the PAM2321 an ideal choice for portable
applications.
The PAM2321 delivers 2A maximum output current while consuming only 55µA no-load quiescent current.
Low RDS(ON) integrated MOSFETs and 100% duty cycle operation make the PAM2321 the ideal choice for
high output voltage, high current applications which require a low dropout threshold.
The PAM2321 provides excellent transient response and output accuracy across the operating range.
The PAM2321 maintains high efficiency throughout the load range. The PAM2321 automatically optimizes
efficiency during light load mode (PSM) and maintains constant frequency and low output ripple during
PWM mode.
Over-temperature and short circuit protection safeguard the PAM2321 and system components from
damage.
The PAM2321 is available in a Pb-free, ultra-small, low profile, TDFN 3X3-10 and DFN 3X3-6 package. The
product is rated over a temperature range of -40°C to +85°C.
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.
PAM2321
EVB User Guide
3. Key Features

2A Maximum Output Current

55µA No Load Quiescent Current

Tiny 0.47µH Chip Inductor

100% Duty Cycle Low-Dropout Operation

Excellent Transient Response

Internal Soft Start

Input Voltage: 2.7V to 5.5V

Over-Temperature and Current Limit

Fixed or Adjustable Output Voltage Options:

Protection
- Fixed Output Voltage: 1.2V

<1µA Shutdown Current
- Adjustable Output Voltage: 1.0V to 3.3V

-40°C to +85°C Temperature Range
High Efficiency with 3MHz Switching

Pb-Free/Halogen Free Package
Frequency

RoHS/REACH Compliant
4. EV Board Schematic
EN
1
2
3
IC1
EN
1
Vin
2
3
C2
C1
C6
4
FB 5
C3
R1
10
EN
PGND
PVIN
PGND
VIN
SW
AGND
SW
FB
AGND
9
L1
Vout
8
7
C4
C5
6
R2
Vout
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.
PAM2321
EVB User Guide
5. EVB PAM2321 EB19AA DFN33-10 Description
PAM2321 EB19AA DFN33-10 is an evaluation board for the PAM2321 TDFN3X3-10, a DC/DC converter.
The board is targeted to be used in providing a simple and convenient evaluation environment for the
PAM2321. Requires parts, power supply connectors etc. on the board, which makes it easy to be evaluated.
6. EV Board View
7. Resistor Slect for Output Voltage Setting
VOUT = (1+R1/R2) x VREF
Vo
1.2V
1.5V
1.8V
2.5V
3.3V
R1
150k
225k
300k
475k
680k
(VREF = 0.6V)
R2
150k
150k
150k
150k
150k
L
0.47µH
0.47µH
0.47µH
1.0µH
1.0µH
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.
PAM2321
EVB User Guide
8. External Components Selection
Input & Output Capacitors (C2, C6; C4)
(1) For lower output ripple, low ESR is required.
(2) Low leakage current needed, X5R/X7R ceramic recommend, multiple capacitor parallel connection.
Feed Forward Capacitor (C3)
(1) Lower the output ripple
(2) Low leakage current needed, 100pF, COH/CH 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) Inductance saturate current must higher than the output current
9. Evaluation Board BOM List
Item
Value
C2
10µF
C6
1µF
C4
10µF
C3
100pF
L1
1µH
R1
R2
IC1
680K
150K
PCB
Type
X5R/X7R,
Ceramic/0805
X5R/X7R,
Ceramic/0603
X5R/X7R,
Ceramic/0805
COH/CH,
Ceramic/0402
0603
0603
PAM2321
PAM2321 EB19AA
DFN33-10
Rating
Description
10V
Input coupling CAP
25V
Input coupling CAP
10V
Output CAP
50V
Feed forward CAP
>3A
Inductor
1%
1%
TDFN3x3-10
Vender and Part No.
TAIYO YUDEN
EMK212ABJ106KD-T
TAIYO YUDEN
TMK107 BJ105KA-T
TAIYO YUDEN
EMK212ABJ106KD-T
TAIYO YUDEN
UMK105CH101JV-F
744042001
Wurth
Voltage set RES
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.
PAM2321
EVB User Guide
10. PCB Layout Guideline
The following guidelines should be used to help ensure a proper layout:
1). The input capacitor should be close to IC as close as possible.
2). Must put a small decoupling capacitor between Vin Pin and AGND Pin.
3). Minimize the switching loop area to avoid excessive switching noise.
4). AGND and PGND should connect at input capacitor GND.
5). For the good thermal dissipation, PAM2321 has a heat dissipate pad in the bottom side, it should be
soldered to PCB surface. For the copper area can’t be large in the component side, so we can use
multiple vias connect to other side of the PCB.
11. PCB Layout Example
Top 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.
PAM2321
EVB User Guide
11. PCB Layout Example (cont.)
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.