DIODES PAM2321 TDFN3x3-10 EV Board User Guide

DIODES PAM2321 TDFN3x3-10 EV Board User Guide

Revision Information

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.

Key Features ****

• 2A Maximum Output Current
• Tiny 47µH Chip Inductor
• Excellent Transient Response
• Input Voltage: 7V to 5.5V
• Fixed or Adjustable Output Voltage Options:
  • Fixed Output Voltage: 2V
  • Adjustable Output Voltage: 0V to 3.3V
• High Efficiency with 3MHz Switching Frequency
• 55µA No Load Quiescent Current
• 100% Duty Cycle Low-Dropout Operation
• Internal Soft Start
• Over-Temperature and Current Limit Protection
• <1µA Shutdown Current
• -40°C to +85°C Temperature Range
• Pb-Free/Halogen Free Package
• RoHS/REACH Compliant

EV Board Schematic

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.

EV Board View ****

Resistor Slect for Output Voltage Setting

VOUT = (1+R1/R2) x VREF          (VREF = 0.6V)

External Components Selection

Input & Output Capacitors (C2, C6; C4)

1. For lower output ripple, low ESR is
2. Low leakage current needed, X5R/X7R ceramic recommend, multiple capacitor parallel

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

Inductor (L1)

1. Low DCR for good efficiency
2. Inductance saturate current must higher than the output current

Evaluation Board BOM List

Item| Value| Type| Rating| Description| Vender and Part No.
---|---|---|---|---|---
C2| 10µF| X5R/X7R,Ceramic/0805| 10V| Input coupling CAP| TAIYO YUDEN EMK212ABJ106KD-T
C6| 1µF| X5R/X7R,Ceramic/0603| 25V| Input coupling CAP| TAIYO YUDEN TMK107 BJ105KA-T
C4| 10µF| X5R/X7R,Ceramic/0805| 10V| Output CAP| TAIYO YUDEN EMK212ABJ106KD-T
C3| 100pF| COH/CH,Ceramic/0402| 50V| Feed forward CAP| TAIYO YUDEN UMK105CH101JV-F
L1| 1µH| | >3A| Inductor| 744042001Wurth
R1| 680K| 0603| 1%| Voltage set RES|
R2| 150K| 0603| 1%|
IC1| | PAM2321| TDFN3x3-10| |
PCB| | PAM2321 EB19AA DFN33-10| | |

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.

• AGND and PGND should connect at input capacitor
• 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 Layout Example

Top Layer

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.

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