ISL9305 Datasheet, PDF (1/17 Pages) Intersil Corporation – 3MHz Dual Step-Down Converters and Dual Low-Input LDOs

3MHz Dual Step-Down Converters and Dual Low-Input
LDOs with I²C Compatible Interface
ISL9305
The ISL9305 is an integrated mini Power Management IC
(mini-PMIC) ideal for applications of powering low-voltage
microprocessor or multiple voltage rails with battery as input
sources, such as a single Li-ion or Li-Polymer. ISL9305
integrates two high-efficiency 3MHz synchronous step-down
converters (DCD1 and DCD2) and two low-input, low-dropout
linear regulators (LDO1 and LDO2).
The 3MHz PWM switching frequency allows the use of very
small external inductors and capacitors. Both step-down
converters can enter skip mode under light load conditions to
further improve the efficiency and maximize the battery life.
For noise sensitive applications, they can also be programmed
through I²C interface to operate in forced PWM mode
regardless of the load current condition. The I²C interface
supports on-the-fly slew rate control of the output voltage from
0.825V to 3.6V at 25mV/step size for dynamic power saving.
Each step-down converter can supply up to 800mA load
current. The default output voltage can be set from 0.8V to V_IN
using external feedback resistors on the adjustable version, or
the ISL9305 can be ordered in factory pre-set power-up default
voltages in increments of 100mV from 0.9V to 3.6V.
The ISL9305 also provides two 300mA low dropout (LDO)
regulators. The input voltage range is 1.5V to 5.5V allowing
them to be powered from one of the on-chip step-down
converters or directly from the battery. The default LDO
power-up output comes with factory pre-set fixed output
voltage options between 0.9V to 3.3V.
The ISL9305 is available in a 4mmx4mm 16 Ld TQFN
package.
Related Literature
• FN7724, ISL9305H Data Sheet
• AN1564 “ISL9305IRTZEVAL1Z and ISL9305HIRTZEVAL1Z
Evaluation Boards”
Features
• Dual 800mA, Synchronous Step-down Converters and Dual
300mA, General-purpose LDOs
• Input Voltage Range
- DCD1/DCD2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3V to 5.5V
- LDO1/LDO2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5V to 5.5V
• 400kb/s I²C-bus Series Interface Transfers the Control Data
Between the Host Controller and the ISL9305
• Adjustable Output Voltage
- DCD1/DCD2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.8V to V_IN
- Fixed Output I²C Programmability
• At 25mV/step . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.825V to 3.6V
• LDO1/LDO2 Output Voltage I²C Programmability
- At 50mV/step. . . . . . . . . . . . . . . . . . . . . . . . . . . 0.9V to 3.3V
• 50μA I_Q (Typ) with DCD1/DCD2 in Skip Mode; 20μA I_Q (Typ)
for each Enabled LDO
• On-the-fly I²C Programming of DC/DC and LDO Output
Voltages
• DCD1/DCD2 I²C Programmable Skip Mode Under Light
Load or Forced Fixed Switching Frequency PWM Mode
• Small, Thin, 4mmx4mm TQFN Package
Applications
• Cellular Phones, Smart Phones
• PDAs, Portable Media Players, Portable Instruments
• Single Li-ion/Li-Polymer Battery-Powered Equipment
• DSP Core Power
November 8, 2010
FN7605.0
2.3V TO 5.5V
C₁₀
10µF
1.5V TO 5.5V
C₂
1µF
1.5V TO 5.5V
1Cµ³F
PG
VINDCD1
VINDCD2
SW1
FB1
L₁ = 1.5µH
R₁
SDAT
SCLK _ISL9305
VINLDO1
SW2
FB2
L₂ = 1.5µH
R₃
VINLDO2
VOLDO1
VOLDO2
GNDDCD1GNDDCD2GNDLDO
C₆
1µF
*
R₂
800mA
C₄
4.7µF
800mA
*
R₄
C₅
4.7µF
300mA
300mA
C₇
1µF
*Only for adjustable output version. For fixed output version, directly
connect the FB pin to the output of the buck converter.
FIGURE 1. TYPICAL APPLICATION DIAGRAM
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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