Datasheet

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FAN2001/FAN2002 Rev. 1.0.2

www.fairchildsemi.com

April 2005

FAN2001/FAN2002 1A High-Efﬁciency Step-Down DC-DC Converter

FAN2001/FAN2002

1A High-Efﬁciency Step-Down DC-DC Converter

Features

■

96% Efﬁciency, Synchronous Operation

■

Adjustable Output Voltage Options from 0.8V to V

■

2.5V to 5.5V Input Voltage Range

■

Up to 1A Output Current

■

Fixed Frequency 1.3MHz PWM Operation

■

High Efﬁciency Power Save Mode

■

100% Duty Cycle Low Dropout Operation

■

Soft Start

■

Output Over-Voltage Protection

■

Dynamic Output Voltage Positioning

■

A Quiescent Current

■

Thermal Shutdown and Short Circuit Protection

■

Pb-Free 3x3mm 6-Lead MLP Package

Applications

■

Pocket PCs, PDAs

■

Cell Phones

■

Battery-Powered Portable Devices

■

Digital Cameras

■

Hard Disk Drives

■

Set-Top-Boxes

■

Point-of-Load Power

■

Notebook Computers

■

Communications Equipment

Description

Designed for use in battery-powered applications, the FAN2001/

FAN2002 is a high-efﬁciency, low-noise synchronous PWM cur-

rent mode and Pulse Skip (Power Save) mode DC-DC con-

verter. It can provide up to 1A of output current over a wide input

range from 2.5V to 5.5V. The output voltage can be externally

adjusted over a wide range of 0.8V to 5.5V by means of an

external voltage divider.

At moderate and light loads, pulse skipping modulation is used.

Dynamic voltage positioning is applied, and the output voltage is

shifted 0.8% above nominal value for increased headroom dur-

ing load transients. At higher loads the system automatically

switches over to current mode PWM control, operating at 1.3

MHz. A current mode control loop with fast transient response

ensures excellent line and load regulation. To achieve high efﬁ-

ciency and ensure long battery life, the quiescent current is

reduced to 25µA in Power Save mode, and the supply current

drops below 1µA in shut-down mode. The FAN2001/FAN2002 is

available in a 3x3mm 6-lead MLP package.

Typical Application

Figure 1. Typical Application

PGND

GND)

OUT

2 x 10µF

3.3µH

10µF

10K

Ω

1.2V (1A)

FAN2002

2 x 10µF

10µF

OUT

1.2V (1A)

PGND

GND)

3.3µH

10KΩ

5KΩ

FAN2001

Summary of content (11 pages)

PAGE 1
FAN2001/FAN2002 1A High-Efficiency Step-Down DC-DC Converter Features Description ■ ■ ■ ■ ■ ■ ■ 96% Efficiency, Synchronous Operation Adjustable Output Voltage Options from 0.8V to VIN 2.5V to 5.5V Input Voltage Range Up to 1A Output Current Fixed Frequency 1.
PAGE 2
Top View VIN 1 6 P1 PGND 2 EN 3 (AGND) SW FB 1 6 EN 5 VIN 4 PVIN P1 5 NC PGND 2 4 FB SW 3 FAN2001 (AGND) FAN2002 3x3mm 6-Lead MLP Figure 2. Pin Assignment Pin Description FAN2001 (3x3mm 6-Lead MLP) Pin No. Pin Name P1 AGND 1 VIN 2 PGND 3 EN Pin Description Analog Ground. P1 must be soldered to the PCB ground. Supply Voltage Input. Power Ground. This pin is connected to the internal MOSFET switches. This pin must be externally connected to AGND. Enable Input.
PAGE 3
Parameter Min Max Unit VIN, PVIN -0.3 7 V Voltage On Any Other Pin -0.3 VIN V Lead Soldering Temperature (10 seconds) 260 °C Junction Temperature 150 °C Storage Temperature -65 Thermal Resistance-Junction to Tab (θJC), 3x3mm 6-lead MLP (Note 2) Electrostatic Discharge Protection (ESD) Level (Note 3) HBM 4 CDM 1 Min Typ 150 °C 8 °C/W kV Recommended Operating Conditions Max Unit Supply Voltage Range Parameter 2.5 5.5 V Output Voltage Range, Adjustable Version 0.
PAGE 4
VIN = VOUT + 0.6V(min. 2.5V) to 5.5V, IOUT = 350mA, VOUT =1.2V, EN = VIN, TA = -40°C to +85°C, Unless otherwise noted. Typical values are at TA = 25°C. Symbol VIN IQ Parameter Input Voltage Quiescent Current Conditions Enable High Input Voltage VENL Enable Low Input Voltage Units 2.5 5.5 V 2.7 5.5 V 35 µA 20 R2 =10KΩ µA 50 R2 =100KΩ 0.1 1 µA µA 2.1 2.3 V 25 EN = GND Lockout VIN Rising Hysteresis VENH Max.
PAGE 5
TA = 25°C, CIN = 10µF, COUT = 20µF, L = 3.3µH, R2 = 10KΩ, unless otherwise noted. Efficiency vs. Load Current Efficiency vs. Load Current 100 95 Efficiency (%) Efficiency (%) 90 85 VIN = 5V 80 V OUT = 3.3V VIN = 3.6V 75 VIN = 3.6V V OUT = 3V VOUT = 1.2V 70 65 60 1 10 100 1000 100 95 90 85 80 75 70 65 60 55 50 45 40 35 V OUT = 3.3V VIN = 3.9V VIN = 5.5V 0.1 1 10 Load Current (mA) 100 1000 Load Current (mA) Efficiency vs. Load Current Output Voltage vs. Load Current 100 1.
PAGE 6
FAN2001/FAN2002 1A High-Efficiency Step-Down DC-DC Converter Typical Performance Characteristics (Contd.) TA = 25°C, CIN = 10µF, COUT = 20µF, L = 3.3µH, R2 = 10KΩ, unless otherwise noted. Power Save Mode Inductor Current (200mA/div) Time (1µs/div) Inductor Load Current Current Step (500mA/div) Load Transient Response 600mA 100mA VOUT = 1.2V Time (10µs/div) Load Transient Response 100mA 600mA VOUT = 1.
PAGE 7
VIN EN DIGITAL SOFT START UNDER-VOLTAGE LOCKOUT IS REF PFM COMP IS CURRENT SENSE FB ERROR AMP MOSFET LOGIC CONTROL COMP SW DRIVER 0.8V GND IS OVER VOLTAGE COMP OSC SLOPE COMPENSATION REF FB NEG. LIMIT COMP NEG. LIMIT SENSE GND Figure 3. Block Diagram Detailed Operation Description PFM mode the device operates with a variable frequency and constant peak current, thus reducing the quiescent current to minimum. Consequently, the high efficiency is maintained at light loads.
PAGE 8
This is calculated as follows: 1 – ( V OUT ⁄ V IN ) ∆I L = V OUT × ----------------------------------------L×f The reference and the circuit remain reset until the VIN crosses its UVLO threshold. The FAN2001/FAN2002 has an internal soft-start circuit that limits the in-rush current during start-up. This prevents possible voltage drops of the input voltage and eliminates the output voltage overshoot.
PAGE 9
For more board layout recommendations download the application note “PCB Grounding System and FAN2001/FAN2011 High Performance DC-DC Converters” (AN-42036). Figure 6. Recommended PCB Layout (FAN2002) FAN2001/FAN2002 Rev. 1.0.2 9 www.fairchildsemi.com FAN2001/FAN2002 1A High-Efficiency Step-Down DC-DC Converter Therefore, use wide traces for high current paths and place the input capacitor, the inductor, and the output capacitor as close as possible to the integrated circuit terminals.
PAGE 10
FAN2001/FAN2002 1A High-Efficiency Step-Down DC-DC Converter Mechanical Dimensions 3x3mm 6-Lead MLP Ordering Information Product Number Output Voltage Package Type Order Code FAN2001 Adjustable 3x3mm 6-Lead MLP FAN2001MPX FAN2002 Adjustable 3x3mm 6-Lead MLP FAN2002MPX FAN2001/FAN2002 Rev. 1.0.2 10 www.fairchildsemi.
PAGE 11
The following are registered and unregistered trademarks Fairchild Semiconductor owns or is authorized to use and is not intended to be an exhaustive list of all such trademarks. ACEx™ FAST ActiveArray™ FASTr™ Bottomless™ FPS™ CoolFET™ FRFET™ CROSSVOLT™ GlobalOptoisolator™ DOME™ GTO™ EcoSPARK™ HiSeC™ E2CMOS™ I2C™ EnSigna™ i-Lo™ FACT™ ImpliedDisconnect™ FACT Quiet Series™ IntelliMAX™ ISOPLANAR™ LittleFET™ MICROCOUPLER™ MicroFET™ MicroPak™ MICROWIRE™ MSX™ MSXPro™ OCX™ OCXPro™  Across the board.