Datasheet

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Compact, 600 mA, 3 MHz,

Step-Down DC-to-DC Converter

Data Sheet

ADP2108

Rev. G

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FEATURES

Peak efficiency: 95%

3 MHz fixed frequency operation

Typical quiescent current: 18 μA

Maximum load current: 600 mA

Input voltage: 2.3 V to 5.5 V

Uses tiny multilayer inductors and capacitors

Current mode architecture for fast load and line

transient response

100% duty cycle low dropout mode

Internal synchronous rectifier

Internal compensation

Internal soft start

Current overload protection

Thermal shutdown protection

Shutdown supply current: 0.2 μA

Available in

5-ball WLCSP

5-lead TSOT

Supported by ADIsimPower™ design tool

APPLICATIONS

PDAs and palmtop computers

Wireless handsets

Digital audio, portable media players

Digital cameras, GPS navigation units

GENERAL DESCRIPTION

The ADP2108 is a high efficiency, low quiescent current step-

down dc-to-dc converter manufactured in two different

packages. The total solution requires only three tiny external

components. It uses a proprietary, high speed current mode,

constant frequency PWM control scheme for excellent stability

and transient response. To ensure the longest battery life in

portable applications, the ADP2108 has a power save mode that

reduces the switching frequency under light load conditions.

The ADP2108 runs on input voltages of 2.3 V to 5.5 V, which

allows for single lithium or lithium polymer cell, multiple alkaline

or NiMH cell, PCMCIA, USB, and other standard power sources.

The maximum load current of 600 mA is achievable across the

input voltage range.

The ADP2108 is available in fixed output voltages of 3.3 V, 3.0 V,

2.5 V, 2.3 V, 1.82 V, 1.8 V, 1 . 5 V, 1.3 V, 1.2 V, 1.1 V, and 1.0 V. All

versions include an internal power switch and synchronous rect-

ifier for minimal external part count and high efficiency. The

ADP2108 has an internal soft start and is internally compensated.

During logic controlled shutdown, the input is disconnected

from the output and the ADP2108 draws less than 1 μA from

the input source.

Other key features include undervoltage lockout to prevent deep

battery discharge and soft start to prevent input current over-

shoot at startup. The ADP2108 is available in 5-ball WLCSP and

5-lead TSOT packages. The ADP2109 provides the same features

and operations as the ADP2108 and has the additional function

of a discharge switch in the WLCSP package.

TYPICAL APPLICATIONS CIRCUIT

Figure 1.

1.0V TO 3.3V

10µF

1µH

OFF

GND

4.7µF

07375-003

VIN

FBEN

2.3V TO 5.5V

ADP2108

Summary of content (20 pages)

PAGE 1
Compact, 600 mA, 3 MHz, Step-Down DC-to-DC Converter ADP2108 Data Sheet FEATURES GENERAL DESCRIPTION Peak efficiency: 95% 3 MHz fixed frequency operation Typical quiescent current: 18 μA Maximum load current: 600 mA Input voltage: 2.3 V to 5.
PAGE 2
ADP2108 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Enable/Shutdown ....................................................................... 11 Applications ....................................................................................... 1 Short-Circuit Protection............................................................ 12 General Description .............................................................
PAGE 3
Data Sheet ADP2108 SPECIFICATIONS VIN = 3.6 V, VOUT = 1.8 V, TJ = −40°C to +125°C for minimum/maximum specifications, and TA = 25°C for typical specifications, unless otherwise noted. 1 Table 1. Parameter INPUT CHARACTERISTICS Input Voltage Range Undervoltage Lockout Threshold OUTPUT CHARACTERISTICS Output Voltage Accuracy Test Conditions/Comments Min Typ Max Unit 2.15 5.5 2.3 2.25 V V V +2 +2.5 % % 2.3 VIN rising VIN falling 2.05 PWM mode VIN = 2.3 V to 5.5 V, PWM mode −2 −2.
PAGE 4
ADP2108 Data Sheet ABSOLUTE MAXIMUM RATINGS Table 2. Parameter VIN, EN FB, SW to GND Operating Ambient Temperature Range Operating Junction Temperature Range Storage Temperature Range Lead Temperature Range Soldering (10 sec) Vapor Phase (60 sec) Infrared (15 sec) ESD Human Body Model ESD Charged Device Model ESD Machine Model Rating −0.4 V to +6.5 V −1.0 V to (VIN + 0.
PAGE 5
Data Sheet ADP2108 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS BALL A1 INDICATOR 1 2 VIN GND A SW B EN FB TOP VIEW (BALL SIDE DOWN) Not to Scale 07375-002 C Figure 2. WLCSP Pin Configuration Table 4. WLCSP Pin Function Descriptions Mnemonic VIN A2 B C1 C2 GND SW EN FB Description Power Source Input. VIN is the source of the PFET high-side switch. Bypass VIN to GND with a 2.2 μF or greater capacitor as close to the ADP2108 as possible. Ground.
PAGE 6
ADP2108 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS VIN = 3.6 V, TA = 25°C, VEN = VIN, unless otherwise noted. 1400 24 +85°C 1300 1200 CURRENT LIMIT (mA) QUIESCENT CURRENT (µA) 22 20 +25°C 18 –40°C 16 1100 1000 900 800 14 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE (V) 600 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5 07375-014 INPUT VOLTAGE (V) Figure 7. PMOS Current Limit vs. Input Voltage 0.15 3400 0.14 3300 0.
PAGE 7
Data Sheet ADP2108 1.825 100 90 80 70 VIN = 2.7V VIN = 3.6V VIN = 4.5V VIN = 5.5V 1.805 EFFICIENCY (%) OUTPUT VOLTAGE (V) 1.815 1.795 60 50 VIN = 2.7V VIN = 3.6V VIN = 4.5V VIN = 5.5V 40 30 1.785 20 0 0.1 0.2 0.3 0.4 0.5 0.6 OUTPUT CURRENT (A) 0 0.001 07375-020 1.775 0.01 0.1 1 OUTPUT CURRENT (A) Figure 10. Load Regulation, VOUT = 1.8 V 07375-023 10 Figure 13. Efficiency, VOUT = 1.8 V 1.025 100 VIN = 2.7V VIN = 3.6V VIN = 4.5V VIN = 5.5V 1.
PAGE 8
ADP2108 Data Sheet VIN VIN 3 3 SW SW 4 4 VOUT 1 VOUT 07375-026 07375-029 1 CH1 50mV CH3 1V M 40µs T 10.80% CH4 2V A CH3 CH1 50mV CH3 1V 3.26V Figure 16. Line Transient, VOUT = 1.8 V, Power Save Mode, 20 mA CH4 2V M 40µs T 10.80% A CH3 4.4V Figure 19. Line Transient, VOUT = 3.3 V, PWM, 200 mA SW VIN 4 SW VOUT 1 3 4 VOUT IOUT 07375-027 07375-030 2 1 CH1 20mV CH3 1V M 40µs T 10.80% CH4 2V A CH3 CH1 50mV 3.26V CH2 200mA Ω CH4 2V M 40µs T 19.
PAGE 9
Data Sheet ADP2108 SW SW 4 4 VOUT IL 1 2 VOUT IOUT 1 2 CH2 50mA Ω CH4 2V M 40µs T 25.4% A CH2 12mA 07375-035 3 07375-032 CH1 50mV EN CH1 500mV CH2 500mA CH3 5V CH4 5V Figure 22. Load Transient, VOUT = 1.8 V, 5 mA to 50 mA M 40µs T 19.80% A CH3 2.1V Figure 25. Start-Up, VOUT = 1.0 V, 600 mA SW SW 4 4 IL IL 2 2 VOUT EN 3 07375-033 3 CH1 1V CH3 5V CH2 250mA CH4 5V EN 1 M 40µs T 10.80% A CH3 2V 07375-036 VOUT 1 CH2 250mA CH4 5V CH1 2V CH3 5V Figure 23.
PAGE 10
ADP2108 Data Sheet SW 4 IL 2 VOUT 07375-038 1 CH1 20mV CH2 200mA CH4 2V M 200ns T 20% A CH4 2.64V Figure 28. Typical PWM Waveform, 200 mA Rev.
PAGE 11
Data Sheet ADP2108 THEORY OF OPERATION GM ERROR AMP PWM COMP VIN SOFT START ILIMIT FB PSM COMP PWM/ LOW PSM CONTROL CURRENT SW DRIVER AND ANTISHOOTTHROUGH OSCILLATOR UNDERVOLTAGE LOCKOUT ADP2108 EN 07375-001 GND THERMAL SHUTDOWN Figure 29. Functional Block Diagram The ADP2108 is a step-down dc-to-dc converter that uses a fixed frequency and high speed current mode architecture. The high switching frequency allows for a small step-down, dc-to-dc converter solution.
PAGE 12
ADP2108 Data Sheet SHORT-CIRCUIT PROTECTION The ADP2108 includes frequency foldback to prevent output current runaway on a hard short. When the voltage at the feedback pin falls below half the target output voltage, indicating the possibility of a hard short at the output, the switching frequency is reduced to half the internal oscillator frequency. The reduction in the switching frequency allows more time for the inductor to discharge, preventing a runaway of output current.
PAGE 13
Data Sheet ADP2108 APPLICATIONS INFORMATION ADIsimPower DESIGN TOOL The ADP2108 is supported by ADIsimPower design tool set. ADIsimPower is a collection of tools that produce complete power designs optimized for a specific design goal. The tools enable the user to generate a full schematic, bill of materials, and calculate performance in minutes.
PAGE 14
ADP2108 Data Sheet THERMAL CONSIDERATIONS 12 Because of the high efficiency of the ADP2108, only a small amount of power is dissipated inside the ADP2108 package, which reduces thermal constraints. CAPACITANCE (µF) 10 8 However, in applications with maximum loads at high ambient temperature, low supply voltage, and high duty cycle, the heat dissipated in the package is great enough that it may cause the junction temperature of the die to exceed the maximum junction temperature of 125°C.
PAGE 15
Data Sheet ADP2108 EVALUATION BOARD VIN TB2 EN VIN A1 CIN 4.7µF EN A2 C1 TB5 VIN SW B 1 L1 1µH 2 GND EN FB C2 U1 GND IN VOUT TB3 VOUT COUT 10µF TB4 GND OUT 07375-004 ADP2108 TB1 07375-005 07375-041 Figure 31. Evaluation Board Schematic Figure 34. Recommended TSOT Top Layer 07375-042 07375-006 Figure 32. Recommended WLCSP Top Layer Figure 35. Recommended TSOT Bottom Layer Figure 33. Recommended WLCSP Bottom Layer Rev.
PAGE 16
ADP2108 Data Sheet OUTLINE DIMENSIONS 1.060 1.020 0.980 2 1 A BALL A1 IDENTIFIER 1.490 1.450 1.410 0.866 REF C 0.50 BSC TOP VIEW (BALL SIDE DOWN) 0.657 0.602 0.546 B 0.50 BSC BOTTOM VIEW 0.355 0.330 0.304 SIDE VIEW (BALL SIDE UP) COPLANARITY 0.04 0.330 0.310 0.290 0.280 0.250 0.220 06-11-2012-B SEATING PLANE Figure 36. 5-Ball Wafer Level Chip Scale Package [WLCSP] (CB-5-3) Dimensions shown in millimeters 2.90 BSC 5 4 2.80 BSC 1.60 BSC 1 2 3 0.95 BSC 1.90 BSC *1.00 MAX 0.
PAGE 17
Data Sheet ADP2108 ORDERING GUIDE Model 1 ADP2108ACBZ-1.0-R7 ADP2108ACBZ-1.1-R7 ADP2108ACBZ-1.2-R7 ADP2108ACBZ-1.3-R7 ADP2108ACBZ-1.5-R7 ADP2108ACBZ-1.8-R7 ADP2108ACBZ-1.82-R7 ADP2108ACBZ-2.3-R7 ADP2108ACBZ-2.5-R7 ADP2108ACBZ-3.0-R7 ADP2108ACBZ-3.3-R7 ADP2108AUJZ-1.0-R7 ADP2108AUJZ-1.1-R7 ADP2108AUJZ-1.2-R7 ADP2108AUJZ-1.3-R7 ADP2108AUJZ-1.5-R7 ADP2108AUJZ-1.8-R7 ADP2108AUJZ-1.82-R7 ADP2108AUJZ-2.3-R7 ADP2108AUJZ-2.5-R7 ADP2108AUJZ-3.0-R7 ADP2108AUJZ-3.3-R7 ADP2108-1.0-EVALZ ADP2108-1.1-EVALZ ADP2108-1.
PAGE 18
ADP2108 Data Sheet NOTES Rev.
PAGE 19
Data Sheet ADP2108 NOTES Rev.