XC9235/XC9236/XC9237 Series
ETR0514-013
600mA Driver Tr. Built-In, Synchronous Step-Down DC/DC Converters
☆GreenOperation Compatible
■GENERAL DESCRIPTION
The XC9235/XC9236/XC9237 series is a group of synchronous-rectification type DC/DC converters with a built-in 0.42Ω
P-channel MOS driver transistor and 0.52ΩN-channel MOS switching transistor, designed to allow the use of ceramic
capacitors. Operating voltage range is from 2.0V to 6.0V (A～C types), 1.8V to 6.0V (D～G types). For the D/F types which
have a reference voltage of 0.8V (accuracy: ±2.0%), the output voltage can be set from 0.9V by using two external resistors.
The A/B/C/E/G types have a fixed output voltage from 0.8V to 4.0V in increments of 0.05V (accuracy: ±2.0%). The device
provides a high efficiency, stable power supply with an output current of 600mA to be configured using only a coil and two
capacitors connected externally.
With the built-in oscillator, either 1.2MHz or 3.0MHz can be selected for suiting to your
particular application. As for operation mode, the XC9235 series is PWM control, the XC9236 series is automatic PWM/PFM
switching control and the XC9237 series can be manually switched between the PWM control mode and the automatic
PWM/PFM switching control mode, allowing fast response, low ripple and high efficiency over the full range of loads (from light
load to heavy load).
The soft start and current control functions are internally optimized. During stand-by, all circuits are shutdown to reduce current
consumption to as low as 1.0μA or less. The B/F/G types have a high speed soft-start as fast as 0.25ms in typical for quick
turn-on. With the built-in UVLO (Under Voltage Lock Out) function, the internal P-channel MOS driver transistor is forced OFF
when input voltage becomes 1.4V or lower.
The B to G types integrate CL discharge function which enables the electric charge at the output capacitor CL to be discharged
via the internal discharge switch located between the LX and VSS pins. When the devices enter stand-by mode, output voltage
quickly returns to the VSS level as a result of this function.
Four types of package SOT-25, USP-6C, USP-6EL and WLP-5-03 are available.
■APPLICATIONS
●Mobile phones, Smart phones
●Bluetooth headsets
●Mobile WiMAX PDAs, MIDs, UMPCs
●Portable game consoles
●Digital cameras, Camcorders
●MP3 Players, Portable Media Players
●Notebook computers
■TYPICAL APPLICATION CIRCUIT
●XC9235/XC9236/XC9237
A/B/C/E/G types (Output Voltage Fixed)
■FEATURES
Driver Transistor Built-In
: 0.42Ω P-ch driver transistor
0.52Ω N-ch switch transistor
Input Voltage
: 2.0V ~ 6.0V (A/B/C types)
1.8V ~ 6.0V (D/E/F/G types)
Output Voltage
: 0.8V ~ 4.0V (Internally set)
0.9V ~ 6.0V (Externally set)
High Efficiency
: 92% (TYP.)*
Output Current
: 600mA
Oscillation Frequency
: 1.2MHz, 3.0MHz (+15%)
Maximum Duty Cycle
: 100%
Control Methods
: PWM (XC9235)
PWM/PFM Auto (XC9236)
PWM/PFM Manual (XC9237)
Function
: Current Limiter Circuit Built-In
(Constant Current & Latching)
CL Discharge (B/C/D/E/F/G types)
High Speed Soft Start (B/F/G type)
Capacitor
: Low ESR Ceramic Capacitor
Operating Ambient Temperature
:-40℃ ~ +85℃
Packages
: SOT-25 (A/B/C types only)
USP-6C
USP-6EL(A/B/C types only)
WLP-5-03(A/B types only)
Environmentally Friendly
: EU RoHS Compliant, Pb Free
* Performance depends on external components and wiring on the PCB.
■TYPICAL PERFORMANCE CHARACTERISTICS
●XC9235/XC9236/XC9237
●Efficiency vs. Output Current（fOSC=1.2MHz, VOUT=1.8V）
D/F types (Output Voltage Externally Set)
100
PWM/PFM Automatic Sw itching Control
90
Efficiency: EFFI (%)
Efficency:EFFI(%)
80
VIN= 4.2V
70
60
50
PWM Control
VIN= 4.2V
3.6V
2.4V
3.6V
2.4V
40
30
20
10
0
0.1
1
10
100
1000
Output Current:IOUT(mA)
1/34
