1. FAN2564 300mA Low VIN LDO for Digital Applications
Product Release
Peter Khairolomour, Feb

2. Two type of loads: Digital and Analog
Before diving into FAN2564 product details it is important to understand that there are two major point of load categories in portable applications
Digital loads
application processors
baseband processors
memory
digital TV processors
GPS processors
graphics processors
Analog loads
audio amplifiers
RF amplifiers
camera sensors
PLL/FLL/VCO
GPS receivers
FAN2564 is targeted towards powering digital loads

3. Many digital loads in cell phones!
BaseBand Processor (BB)
Keyboard controller
Bluetooth transceiver with baseband processor
Graphics Processing Unit (GPU)
Digital Base Band Processor with Main Central Processor (CPU) and Digital Signal Processor (DSP)
Image Sensor Processor (ISP)

4. Characteristics of loads
Digital Loads…
Because of the inherent binary nature of digital loads, they are not as sensitive to power supply behavior such as ripple noise, thermal noise, or noise interference.
They have fast dynamics as the application load can vary quickly and substantially so parameters such as power supply transient response and Iq during standby become critical
They operate at low voltages because as core processor voltages go lower, power consumption is reduced. Typical range is 1.2V to 1.8V which FAN2564 will support.
Analog Loads
Because of the inherent sensitive nature of analog loads, noise issues that were not so much a concern for digital loads can now create problems
ripple and noise feed through are typically less tolerable for sensitive analog loads
analog loads typically do not share power supply inputs in order to preserve signal integrity
each analog IC may have different voltage levels optimized for performance and tend to operate at a higher voltage and lower current than digital ICs.

5. FAN2564 Low Vin / Low Vout, 300mA LDO
Features
Input Voltage 1.65V to 3.6V
Guaranteed 300mA Output
High Initial Output Voltage Accuracy: ±1%
Fixed Output Voltage options from 1.2V to 2.8V
Very Low Dropout: 100mV at 300mA
45µA Quiescent Current at No Load
PSRR of 60dB at 1kHz
100µs Startup Time
Stable with Ceramic Capacitors as Small as 0402
Thermal and Short-Circuit Protection
4-bump WLCSP, 0.93 x 1.41 x 0.60mm
6-pin UMLP, 2.0 x 2.0 x 0.55mm
Applications
Digital loads.
Post-regulator following standalone Buck or PMU
Availability
Production: NOW (1.2, 1.3, 1.5, 1.8V)
Pin-to-Pin Compatible with LP3991
but with better transient response

6. FAN2564 Case Study
This is an exercise to explore 3 different solutions to power digital loads. We will highlight tradeoffs in efficiency vs. footprint
The customer’s requirements are as follows:
VIN = 3.6V
VOUT1 = 150mA
VOUT2 = 150mA

7. Case 1: Traditional Method with Low efficiency
LDO connected directly to battery is not efficient

8. Case 2: Traditional method with high efficiency
Although efficient this solution can have large footprint and high cost

9. Case 3: FAN2564 Application Example
FAN2564 LDO is efficient because of Low VIN

10. Case Study Summary Assuming 150mA delivered to the 1.8V and 1.5V
Case 1: Efficiency=60%, Inductor footprint = 1x5mm^2 = 5mm^2
Case 2: Efficiency=90%, 2 Inductor footprint = 2x5mm^2 = 10mm^2
Case 3: Efficiency=83%, Inductor footprint = 1x5mm^2 =5mm^2
Conclusion: Case3 FAN2564 Low Vin LDO provides best compromise between solution footprint and efficiency

11. Low VIN LDO Competitive Analysis
- The important parameters are to have low Iq while supporting strong load transient response. Note that Iq parameters with * have dual supply. This means that there are both bias and input currents. The importance of this is that actual standby power is higher than single input scenario because bias pin is at a higher voltage. Refer to next page.
- Dropout is also critical especially because the purpose of a low VIN LDO is to bring VIN close to VOUT in order to improve efficiency. However, some devices such as On Semi, Ricoh, Micrel, and Torex have poor performing high dropout making them ineffective in applications such as VIN=1.8V  VOUT=1.5V.

12. Quiescent Current: Single vs Dual supply
Single supply – FAN2564
Dual supply – MIC5325
IIN = 45uA
PIN = 45uA*1.8V = 81mW
Conclusion: Standby Power = 81mW
IIN = 10uA
PIN = 10uA*1.8V = 18mW
IBAT = 25uA
PBAT = 25uA*3.6V = 90mW
Conclusion: Standby Power = 108mW
IBAT = 25uA
IIN = 45uA
IIN = 10uA

13. Who are the customers/applications that you should target?
Where
Powering core, graphics, application, GPS, digital TV, and other digital processors in space constrained portable applications. Remember that the FAN2564 is designed to compliment the PMIC in these systems.
Who
Cellular: Motorola, Nokia, HTC, Pantech Curitel, Samsung, LG, SonyEricsson, RIM, Kyocera, Qualcomm, EMP
MP3/PMP: Apple, iRiver, Sony, Creative Labs, Archos
GPS Navigation: TomTom, Garmin, Lowrance, Magellan, Averatec
Data Cards: Novatel, Option, Netgear, Kyocera, Fujitsu, Huawei, Sierra Wireless, Spreadtrum, Icera

14. Block Diagram and Package
GND
VOUT EN
VIN B1 A1 B2 A2
GND
VOUT EN
VIN
WLCSP
(Bumps Facing Down)
WLCSP
(Bumps Facing Up)
UMLP
(Leads Facing Down)

15. Value Proposition
Compared to a solution using a buck switcher, the FAN2564 reduces system footprint, cost, and EMI because it does not require an inductor.
Compared to traditional LDO’s which are connected directly to VBAT, the FAN2564 provides higher efficiency because power is converted from a Low VIN.
Compared to Low VIN LDO competitors, FAN2564 offers the best balance of Iq, transient response, number of pins, and package size.

16. Design-In support FAN2564 Datasheet
FAN2564 Product Overview
Evaluation Boards
Request via Sales Center or Contact Product Line

17. Contacts Marketing contacts Application support
Cell phones and data cards
Peter Khairolomour
All other customers
Stephen Stella
Application support
George Petre

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