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PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

September 17, 2003 Ver. 2

P-Channel Driver Transistor Built-In

APPLICATIONS

Input Voltage Range

: 1.8V ~ 6.0V (XC9206/XC9207)

Mobile phones (PDC, GSM, CDMA, IMT2000 etc.)

: 2.0V ~ 6.0V (XC9208)

PDA, Portable communication modem

Output Voltage Range

: 0.9V ~ 4.0V

Portable game

Oscillation Frequency

: 300kHz, 600kHz, 1.2MHz

Camera, Digital camera, Camcorder

Output Current

: 500mA

Cordless phone

Maximum Duty Ratio

: 100%

Note book computer

Small Package

: SOT-25

PWM/PFM Switching Control (XC9207 / XC9208)

Ceramic Capacitor Compatible

GENERAL DESCRIPTION

FEATURES

P ch driver Tr. Built-in

ON resistance 0.4

Output Voltage Range

0.9V ~ 4.0V (100mV steps)

Fixed output voltage accuracy ±2%

Oscillation Frequency

300kHz, 600kHz, 1.2MHz

Fixed oscillation frequency

accuracy ±15%

Stand-by function

Istb = 1

A (MAX.)

Current Limiter Circuit built-in 600mA

Small Package

SOT-25

Soft start circuit built-in

TYPICAL APPLICATION CIRCUIT

TYPICAL PERFORMANCE CHARACTERISTICS

XC9206 / 9207/ 9208 Series

The XC9206/9207/9208 series is a group of DC/DC converters with a
built-in 0.4

P-channel driver transistor, offered in a SOT-25

package. The ICs are designed to provide high efficiencies and a
stable power supply with an output current of 500mA using only a
coil, a diode and two ceramic capacitors connected externally.
Minimum operating voltage of the XC9206/9207 is 1.8V and 2.0V for
XC9208. Output voltage is internally programmable in a range from
0.9V to 4.0V in increments of 100mV (accuracy:

2.0%).

Oscillation frequency is selectable from 300kHz, 600kHz and 1.2MHz
so that the frequency best suited to your particular application can be
selected.
Each series features different operation modes:
PWM control (XC9206 series), automatic PWM/PFM switching
control (XC9207 series) and manual PWM/PFM switching control
(XC9208 series). The series gives fast transient response, low ripple
and high efficiency over the full range of load (from light load to high
output current conditions). 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 1.0

A or less.

With the built-in U.V.L.O. (Under Voltage Lock Out) function, the
internal P-channel driver transistor is forced OFF when input voltage
becomes 1.4V or lower.

XC9208A18C

VOUT=1.8V (Oscillation Frequency 1.2MHz)

100

0.1

100

1000

Output Current IOUT (mA)

Efficiency EF

I
(

)

VIN=2.4V

3.6V

4.2V

PWM/PFM

Switching Control

PWM

Control

CIN:4.7

F,CL:10

F, L:4.7

H(CDRH3D16),

SD:CRS02, Topr=25

Semiconductor Ltd.

(ceramic)

CIN

(ceramic)

VIN

CE/MODE

VOUT

(500mA)

VOUT

CE/

MODE

VIN

VSS

Data Sheet

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

PIN CONFIGURATION

PIN ASSIGNMENT

SOT-25 (TOP VIEW)

PRODUCT CLASSIFICATION

Ordering Information

XC9206

: PWM Control

XC9207

: PWM / PFM Automatic Switching Control

XC9208

: PWM control, PWM / PFM Automatic Switching Control Manually Selectable

Transistor built-in, output voltage internally set (VOUT product), soft start internally set.
A : Current Limiter 600mA

Denotes output voltage :
ex. ) 1.5V Output

= 1,

= 5

1.85V Output

= 1,

= L

2.85V Output

= 2,

= L

Denotes oscillation frequency :
3 : 300kHz
6 : 600kHz
C : 1.2MHz
Denotes package types :
M : SOT-25

Denotes device orientation :
R : Embossed Tape : Standard Feed
L : Embossed Tape : Reverse Feed

* Output voltage 0.9V ~ 4.0V (100mV steps), 1.85V and 2.85V are standard products.
Output voltages other than these are available as semi-custom products.

PACKAGING INFORMATION

SOT-25

Output Voltage Sense

Chip Enable/Mode Switch

SYMBOL

Power Input

Switching Output

Ground

DESCRIPTION

VOUT

CE/MODE

VIN

VSS

XC9206 / 9207/ 9208 Series

PIN NAME

PIN NUMBER

FUNCTIONS

Semiconductor Ltd.

VOUT

CE/MODE

VSS

VIN

Data Sheet

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

MARKING RULE

SOT-25

Represents the product name and the type of DC/DC converters

* Character inversion is used.

Represents the integer of the output voltage and the oscillation frequency

Represents the decimal number of output voltage and the oscillation frequency

* Output voltage 0.9V ~ 4.0V (100mV steps), 1.85V and 2.85V are standard products.
Output voltages other than these are available as semi-custom products.

Represents the production lot number.

0 to 9, A to Z repeated (G, I, J, O, Q, W excepted)

OUTPUT VOLTAGE

FOSC=1.2MHz

(XC920 x x

x 6M x)

(XC920 x x

x CM x)

FOSC=300kHz

FOSC=600kHz

XC9206 / 9207/ 9208 Series

DESIGNATOR

PRODUCT NAME

XC9206A x x x M x

XC9207A x x x M x

XC9208A x x x M x

(XC920 x x

x 3M x)

4. X

0. X

1. X

2. X

3. X

OUTPUT VOLTAGE

FOSC=300kHz

FOSC=600kHz

FOSC=1.2MHz

(XC920 x x x

3M x)

(XC920 x x x

6M x)

(XC920 x x x

CM x)

DESIGNATOR

X. 0

X. 1

X. 2

X. 3

X. 4

X. 5

X. 6

X. 7

X. 8

X. 9

X. 85

1234

SOT-25

(TOP VIEW)

6
7
8

Semiconductor Ltd.

Data Sheet

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

BLOCK DIAGRAM

Note ) The signal from CE/MODE Control Logic to PWM/PFM Selector is being fixed to "L" level inside, and XC9206 series chooses PWM control.

The signal from CE/MODE Control Logic to PWM/PFM Selector is being fixed to "H" level inside, and XC9207 series chooses only

PWM/PFM automatic switching control.

ABSOLUTE MAXIMUM RATINGS

Ta = 25

XC9206 / 9207/ 9208 Series

V
V

VIN
VLx

VOUT

- 0.3 ~ + 6.5

Storage Temperature Range

Tstg

- 40 ~ + 85

- 55 ~ + 125

250

- 0.3 ~ V

+ 0.3

- 0.3 ~ + 6.5

ILx

- 0.3 ~ V

+ 0.3

1000

Topr

CE / MODE Pin Voltage

Lx Pin Current

Operating Temperature Range

Continuous Power Dissipation

PARAMETER

SYMBOL

RATINGS

UNITS

VIN Pin Voltage

Lx Pin Voltage

VOUT Pin Voltage

VCE

Semiconductor Ltd.

Current

Limit & Feedback

Buffer

Driver

Logic

Ramp Wave

Generator,

OSC

Phase

Compensation

CE/MODE

Control

Logic

Vref with
Soft Start,

PWM/PFM

Selector

U.V.L.O

PWM

Comparator

Error Amp.

U.V.L.O Comp.

Pch

Driver

Tr.

CE/MODE

VSS

VOUT

VIN

Data Sheet

XC9206 / 9207/ 9208 Series

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

ELECTRICAL CHARACTERISTICS

XC9206A18CMR, XC9207A18CMR, XC9208A18CMR

VOUT=1.8V, FOSC=1.2MHz, Ta=25

(XC9206, 9207)

(XC9208)

VOUT=0V, When CE voltage is

(XC9206, XC9207)

Test condition : Unless otherwise stated, VIN = 3.6V

*1 Including Hysteresis operating voltage range.

*2 EFFI = [ (Output Voltage x Output Current) / (Input Voltage x Input Current) ] x 100

*3 On resistance = VLx (measurement voltage) / 0.4

VCEL

CE "L" Voltage

Tlat

Latch Time

RLx

VCEH

ILIM

MAXDTY

MINDTY

EFFI

Supply Current 1

CE=VIN, VOUT=fixed voltage x 1.1V

CE=VSS, VOUT=fixed voltage x 1.1V

When connected to ext. components

FOSC

Istb

IDD1

IDD2

PFMDTY

SYMBOL

VUVLO

IOUTMAX

U.V.L.O Voltage

VIN

VOUT

PARAMETER

Output Voltage

Maximum Output Current

Operating Voltage Range

600

0.4

0.9

1.8

6.0

500

255

413

MHz

UNIT

1.764

1.800

1.836

2.0

6.0

CONDITIONS

VPWMH

VPWML

PWM "H" Voltage

PWM "L" Voltage

ICEL

Oscillation Frequency

PFM pulse width rate

Supply Current 2

Stand-by Current

TSS

Soft start time

ICEH

Maximum Duty Cycle

Minimum Duty Cycle

CE "H" Current

CE "L" Current

Efficiency (*2)

Current Limit

CE "H" Voltage

Lx SW ON Resistance

CIRCUIT

3
3

2
2
1

4
4

MAX

TYP

MIN

1.00

1.40

1.78

1.020

1.200

1.380

1.2

VIN

0.9

VIN

VSS

0.3

VIN-0.3

-0.1

0.1

VIN-1.0

(XC9208)

VOUT=0V, When CE voltage is applied Lx determine "L"

When connected to ext. components, CE=VIN, IOUT=100mA

CE=VIN, VOUT=0V, ILx=400mA (*3)

VIN=CE=5.0V, VOUT=0V

applied Lx determine "H"

CE=VIN, IOUT=30mA

When connected to ext. components

(XC9207, XC9208 only), CE=VIN, IOUT=1mA

12.0

-0.1

0.1

0.8

6.0

158

CE=VIN, VOUT=0V

100

IOUT=1mA (*4)

CE=VIN=5.5V, VOUT=0V

CE=0V, VIN=5.5V, VOUT=0V

When connected to ext. components
CE=0V

VIN, IOUT=1mA

When connected to ext. components
VIN=CE=5.0V, short VOUT by 1

resistance (*5)

CE=VOUT=VIN

When connected to ext. components (XC9208 only)

When connected to ext. components

CE=VIN, IOUT=30mA

IOUT=1mA (*4)

When connected to ext. components (XC9208 only)

When connected to ext. components
CE=VIN, VOUT=0V,
Voltage which Lx pin voltage holding "L" level (*1)

CE=VIN, VOUT=fixed voltage x 0.9V

The CE/MODE pin of the XC9208A series works also as an external PWM control and PWM/PFM control switching pin. When the IC is in
the operation, control is switched to the PWM mode when the CE/MODE pin voltage is equal to or greater than VIN minus 0.3 V, and to the
automatic PWM/PFM switching mode when the CE/MODE pin voltage is equal to or lower than VIN minus 1.0 V and equal to or greater
than VCEH.

Time until it short-circuits VOUT with GND through 1

of resistance from a state of operation and is set to VOUT=0V from current limit pulse

generating.

Semiconductor Ltd.

Data Sheet

XC9206 / 9207/ 9208 Series

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

ELECTRICAL CHARACTERISTICS

XC9206A25CMR, XC9207A25CMR, XC9208A25CMR

VOUT=2.5V, FOSC=1.2MHz, Ta=25

(XC9206, 9207)

VOUT=0V, When CE voltage is

(XC9206, XC9207)

Test condition : Unless otherwise stated, VIN = 3.6V

*1 Including Hysteresis operating voltage range.

*2 EFFI = [ (Output Voltage x Output Current) / (Input Voltage x Input Current) ] x 100

*3 On resistance = VLX (measurement voltage) / 0.4

Time until it short-circuits VOUT with GND through 1

of resistance from a state of operation and is set to VOUT=0V from current limit pulse

generating.

Latch Time

Tlat

When connected to ext. components (XC9208 only)

When connected to ext. components

CE "L" Voltage

VCEL

Soft start time

TSS

CE "H" Current

ICEH

PWM "L" Voltage

VPWML

0.9

VOUT=0V, When CE voltage is applied Lx determine "L"

VSS

(XC9208)

applied Lx determine "H"

Efficiency (*2)

EFFI

When connected to ext. components, CE=VIN, IOUT=100mA

1.2

2.0

6.0

Output Voltage

PARAMETER

SYMBOL

VOUT

Maximum Output Current

UNIT

MIN

TYP

CIRCUIT

CONDITIONS

IOUTMAX

1.8

Operating Voltage Range

VIN

(XC9208)

Supply Current 1

IDD1

CE=VIN, VOUT=0V,
Voltage which Lx pin voltage holding "L" level (*1)

U.V.L.O Voltage

VUVLO

CE=VIN, VOUT=fixed voltage x 0.9V

Supply Current 2

IDD2

Stand-by Current

Istb

Maximum Duty Cycle

MAXDTY CE=VIN, VOUT=0V

Oscillation Frequency

FOSC

When connected to ext. components

(XC9207, XC9208 only), CE=VIN, IOUT=1mA

PFM pulse width rate

PFMDTY

Minimum Duty Cycle

MINDTY

PWM "H" Voltage

VPWMH

Lx SW ON Resistance

RLx

CE "H" Voltage

VCEH

Current Limit

ILIM

CE "L" Current

ICEL

CE=VOUT=VIN

CE=VIN, VOUT=0V, ILx=400mA (*3)

CE=VIN, VOUT=fixed voltage x 1.1V

CE=VIN, IOUT=30mA

MAX

1.00

When connected to ext. components

2.450

2.500

2.550

6.0

When connected to ext. components

500

1.40

1.78

CE=VSS, VOUT=fixed voltage x 1.1V

158

413

100

When connected to ext. components

1.020

1.200

1.380

MHz

CE=VIN, IOUT=30mA

255

VIN=CE=5.0V, VOUT=0V

600

0.4

0.9

VIN

0.3

IOUT=1mA (*4)

When connected to ext. components (XC9208 only)

VIN-1.0

IOUT=1mA (*4)

VIN-0.3

0.1

CE=0V, VIN=5.5V, VOUT=0V

-0.1

0.1

CE=VIN=5.5V, VOUT=0V

-0.1

6.0

CE=0V

VIN, IOUT=1mA

When connected to ext. components

0.8

12.0

VIN=CE=5.0V, short VOUT by 1

resistance (*5)

Semiconductor Ltd.

Data Sheet

XC9206 / 9207/ 9208 Series

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

ELECTRICAL CHARACTERISTICS

XC9206A33CMR, XC9207A33CMR, XC9208A33CMR

VOUT=3.3V, FOSC=1.2MHz, Ta=25

VOUT=0V, When CE voltage is

(XC9206, XC9207)

Test condition : Unless otherwise stated, VIN = 5.0V

*1 Including Hysteresis operating voltage range.

*2 EFFI = [ (Output Voltage x Output Current) / (Input Voltage x Input Current) ] x 100

*3 On resistance = VLX (measurement voltage) / 0.4

CE=VIN, VOUT=0V,
Voltage which Lx pin voltage holding "L" level (*1)

VOUT

1.40

CONDITIONS

When connected to ext. components

500

(XC9208)

2.0

100

Maximum Duty Cycle

MAXDTY

Efficiency (*2)

EFFI

When connected to ext. components, CE=VIN, IOUT=100mA

Minimum Duty Cycle

MINDTY

CE=VIN, VOUT=0V

Supply Current 1

IDD1

Operating Voltage Range

VIN

U.V.L.O Voltage

VUVLO

Maximum Output Current

IOUTMAX

Output Voltage

MAX

UNIT

CIRCUIT

MIN

PARAMETER

SYMBOL

TYP

Stand-by Current

Istb

IDD2

CE=VIN, VOUT=fixed voltage x 1.1V

Supply Current 2

Oscillation Frequency

FOSC

PFM pulse width rate

PFMDTY

Lx SW ON Resistance

RLx

CE=VIN, VOUT=0V, ILx=400mA (*3)

0.4

0.9

Current Limit

ILIM

CE "H" Voltage

VCEH

VPWMH

CE "L" Voltage

VCEL

VOUT=0V, When CE voltage is applied

Lx determine "L"

VPWML

PWM "H" Voltage

Time until it short-circuits VOUT with GND through 1

of resistance from a state of operation and is set to VOUT=0V from current limit pulse

generating.

12.0

-0.1

0.8

When connected to ext. components

CE=0V

VIN, IOUT=1mA

-0.1

6.0

5
5

VIN-0.3

VSS

0.3

PWM "L" Voltage

0.1

CE "H" Current

ICEH

TSS

CE=0V, VIN=5.5V, VOUT=0V

Soft start time

CE "L" Current

ICEL

Latch Time

Tlat

VIN=CE=5.0V, short VOUT by 1

resistance (*5)

When connected to ext. components

CE=VIN=5.5V, VOUT=0V

When connected to ext. components (XC9208 only)

(XC9206, 9207)

When connected to ext. components

VIN=CE=5.0V, VOUT=0V

applied Lx determine "H"

(XC9208)

CE=VIN, IOUT=30mA

6.0

When connected to ext. components

3.234

3.300

3.366

1.8

6.0

1.78

CE=VIN, VOUT=fixed voltage x 0.9V

370

585

1.00

CE=VSS, VOUT=fixed voltage x 1.1V

120

1.200

1.380

MHz

180

CE=VIN, IOUT=30mA

When connected to ext. components

(XC9207, XC9208 only), CE=VIN, IOUT=1mA

1.020

CE=VOUT=VIN

600

0.9

VIN

1.2

VIN

When connected to ext. components (XC9208 only)

IOUT=1mA (*4)

VIN-1.0

0.1

Semiconductor Ltd.

Data Sheet

XC9206 / 9207/ 9208 Series

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

TYPICAL APPLICATION CIRCUIT

FOSC = 1.2MHz

FOSC = 600kHz

L :

4.7

(CDRH3D16 SUMIDA)

L :

(CDRH4D18C SUMIDA)

SD :

CRS02

(TOSHIBA)

SD :

CRS02

(TOSHIBA)

CIN :

4.7

(Ceramic)

CIN :

4.7

(Ceramic)

CL :

(Ceramic)

CL :

(Ceramic)

FOSC = 300kHz

L :

(CDRH4D28C SUMIDA)

SD :

CRS02

(TOSHIBA)

CIN :

4.7

(Ceramic)

* XC9206/9207/9208 series wire connection

CL :

(Ceramic)

NOTES ON USE

Application Information

Oscillation Wave Form (FOSC=1.2MHz)

VIN = 5.5V, VOUT=1.8V, IOUT=10mA

CH1 : Lx

4.7

CDRH3D16 SUMIDA

: CRS02

TOSHIBA

CIN

4.7

Ceramic

CH2 : VOUT

Ceramic

AC-COUPLED

Oscillation Wave Form (FOSC=1.2MHz)

VIN = 2.0V, VOUT=1.8V, IOUT=60mA

CH1 : Lx

4.7

CDRH3D16 SUMIDA

: CRS02

TOSHIBA

CH2 : VOUT

CIN

4.7

Ceramic

AC-COUPLED

Ceramic

2. Spike noise and ripple voltage arise in a switching regulator as with a DC/DC converter. These are greatly influenced by external component
selection, such as the coil inductance, capacitance values, and board layout of external components. Once the design has been completed,
verification with actual components should be done.

1. The XC9206/9207/9208 series are designed for use with an output ceramic capacitor. If, however, the potential difference between input and
output is too large, a ceramic capacitor may fail to absorb the resulting high switching energy and oscillation could occur on the output. If the input-
output potential difference is large, connect an electrolytic capacitor in parallel to compensate for insufficient capacitance.

3. When the difference between VIN and VOUT is large and the load current is light, very narrow pulses will be outputted, and there is the possibility
that some cycles may be skipped completely.

4. When the difference between VIN and VOUT is small, and the load current is heavy, very wide pulses will be outputted and there is the possibility
that some cycles may be skipped completely: in this case, the Lx pin may not go low at all.

Semiconductor Ltd.

(ceramic)

CIN

(ceramic)

VIN

CE/MODE

VOUT

(500mA)

VOUT

CE/

MODE

VIN

VSS

Data Sheet

XC9206 / 9207/ 9208 Series

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

Application Information (Continued)

Ipk = (VIN - VOUT) x On Duty / (2 x L x FOSC) + IOUT

OnDuty

: OnDuty ratio of Pch Driver Transistor

: Coil Inductance Value

FOSC

: Oscillation Frequency

The increase of ripple voltage (1.2MHz)

VIN=4.2V, VOUT=1.8V, IOUT=180mA

VIN=4.2V, VOUT=1.8V, IOUT=60mA

VIN=3.6V, VOUT=1.8V, IOUT=30mA

4.7

CDRH3D16 SUMIDA

: CRS02

TOSHIBA

CIN

4.7

Ceramic

7. When VIN is less than 2.4V, limit current may not be reached because voltage falls caused by ON resistance.

5. With the IC, the peak current of the coil is controlled by the current limit circuit. Since the peak current increases when dropout voltage or load
current is high, current limit starts operating, and this can lead to instability. When peak current becomes high, please adjust the coil inductance
value and fully check the circuit operation. In addition, please calculate the peak current according to the following formula:

6. When the peak current which exceeds limit current flows within the specified time, the built-in Pch driver transistor is turned off. During the time
until it detects limit current and before the built-in transistor can be turned off, the current for limit current flows; therefore, care must be taken when
selecting the rating for the coil or the schottky diode.

9. Use of the IC at voltages below the recommended voltage range may lead to instability.
10. This IC should be used within the stated absolute maximum ratings in order to prevent damage to the device.

8. Care must be taken when laying out the PC Board, in order to prevent misoperation of the current limit mode. Depending on the state of the PC
Board, latch time may become longer and latch operation may not work. In order to avoid the effect of noise, the board should be laid out so that
capacitors are placed as close to the chip as possible.

Semiconductor Ltd.

CH1:Lx

CH2:VOUT

AC-COUPLED

CH1:Lx

CH2:VOUT

AC-COUPLED

CH1:Lx

CH2:VOUT

AC-COUPLED

11. Depending on the input-output voltage differential, or load current, some pulses may be skipped, and the ripple voltage may increase.
When the series' duty cycle is digitally signalized, the linear duty cycle and the digitally signalized duty cycle cannot carry out completely the same
change, which means that the duty cycle does not change linearly. The output is stabilized by applying the phase compensation and adjusting the
duty cycle, even when the duty cycle loses the linear change in the whole circuit.
When the state where the output was stabilized is continued by applying phase compensation to duty cycle which lost linearity, ripple voltage does
not increase more than it.
The ripple voltage may increase to about several 10mV according to operating conditions. It is possible, by increasing the capacitance values, to
reduce the ripple voltage. The operating conditions are greatly influenced by the dropout voltage, the load current, the delay-time, or the external
components, such as the coil inductance, and the capacitance values. Verification with actual parts should be done.

Data Sheet

XC9206 / 9207/ 9208 Series

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

Instructions on Pattern Layout

OPERATIONAL EXPLANATION

< Reference Voltage Source >

The reference voltage source provides the reference voltage to ensure stable output voltage of the ICs.

< Ramp Wave Circuit >

< Error Amplifier >

< Current Limit >

4. Make sure that the PCB GND traces are as thick as possible, as
variations in ground potential caused by high ground currents at
the time of switching may result in instability.

2. Please mount each external component as close to the IC as
possible, and connect it to GND with the shortest possible PCB
traces.

The error amplifier is designed to monitor output voltage. The amplifier compares the reference voltage with the feedback voltage divided by the internal
resistors (R1 and R2). When a voltage lower than the reference voltage is fed back, the output voltage of the error amplifier increases. The gain and
frequency characteristics of the error amplifier output are fixed internally to deliver an optimized signal to the mixer.

The ramp wave circuit determines switching frequency. The frequency is fixed internally and can be selected from 300kHz, 600 kHz and 1.2 MHz. Clock
pulses generated in this circuit are used to produce ramp waveforms needed for PWM operation, and to synchronize all the internal circuits.

1. In order to stabilize VDD's voltage level, we recommend that a
by-pass capacitor (CIN) be connected as close as possible to the
VIN & VSS pins.

3. Wire external components as close to the IC as possible and
use thick, short connecting traces to reduce the circuit impedance.

Each unit of the XC9206/9207/9208 series consists of a reference voltage source, ramp wave circuit, error amplifier, PWM comparator, phase
compensation circuit, output voltage adjustment resistors, driver transistor, current limiter circuit, U.V.L.O. circuit and others. The series ICs compare,
using the error amplifier, the voltage of the internal voltage reference source with the feedback voltage from the VOUT pin through resistors R1 and R2.
Phase compensation is performed on the resulting error amplifier output, to input a signal to the PWM comparator to determine the turn-on time during
PWM operation. The PWM comparator compares, in terms of voltage level, the signal from the error amplifier with the ramp wave from the ramp wave
circuit, and delivers the resulting output to the buffer driver circuit to cause the Lx pin to output a switching duty cycle. This process is continuously
performed to ensure stable output voltage. The current feedback circuit monitors the P-channel MOS driver transistor current for each switching operation,
and modulates the error amplifier output signal to provide multiple feedback signals. This enables a stable feedback loop even when a low ESR capacitor,
such as a ceramic capacitor, is used, ensuring stable output voltage.

VIN

CE/

MODE

GND

VOUT

( Through Hole to SD )

CIN

VIN Line

GND Line

Other Line

VIN

CE/MODE

VOUT

IOUT

Current Limit LEVEL

Limit< #mS

Limit> #mS

Restart

VSS

0mA

Semiconductor Ltd.

The current limiter circuit of the XC9206/9207/9208 series monitors the current flowing through the P-channel MOS driver transistor connected to the Lx pin,
and features a combination of the constant-current type current limit mode and the operation suspension mode.

When the driver current is greater than a specific level, the constant-current type current limit function operates to turn off the pulses from the Lx pin at

any given timing.

When the driver transistor is turned off, the limiter circuit is then released from the current limit detection state.

At the next pulse, the driver transistor is turned on. However, the transistor is immediately turned off in the case of an over current state.

When the over current state is eliminated, the IC resumes its normal operation.

The IC waits for the over current state to end by repeating the steps

through

. If an over current state continues for several msec and the above three

steps are repeatedly performed, the IC performs the function of latching the OFF state of the driver transistor, and goes into operation suspension mode.
Once the IC is in suspension mode, operations can be resumed by either turning the IC off via the CE /MODE pin, or by restoring power to the VIN pin. The
suspension mode does not mean a complete shutdown, but a state in which pulse output is suspended; therefore, the internal circuitry remains in operation.
The constant-current type current limit of the XC9206A/9207A/9208A series can be set at 600 mA.

Data Sheet

XC9206 / 9207/ 9208 Series

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

OPERATIONAL EXPLANATION (Continued)

< U.V.L.O. Circuit>

< Function of CE/MODE pin >

XC9206A / 07A series - Examples of how to use CE/MODE pin

(A)

(B)

(A)

(B)

XC9208A series - Examples of how to use CE/MODE pin

(A)

(B)

(A)

(B)

Intermediate voltage can be generated by RM1 and RM2. Please set the value of each R1, R2, RM1, RM2 at around 100k

For switches, CPU open-drain I/O port and transistor can be used.

< PWM / PFM >

When the VIN pin voltage becomes 1.4 V or lower, the P-channel output driver transistor is forced OFF to prevent false pulse output caused by unstable
operation of the internal circuitry. When the VIN pin voltage becomes 1.8 V or higher, switching operation takes place. By releasing the U.V.L.O.
function, the IC performs the soft start function to initiate output startup operation. The soft start function operates even when the VIN pin voltage falls
momentarily below the U.V.L.O. operating voltage. The U.V.L.O. circuit does not cause a complete shutdown of the IC, but causes pulse output to be
suspended; therefore, the internal circuitry remains in operation.

The XC9206/9207/9208 series will enter into shut down state by inputting a low level signal to the CE/MODE pin. During a shut down state, the current
consumption of the IC becomes 0

A (TYP.), with a state of high impedance at the Lx pin and VOUT pin. The IC starts its operation by inputting a high

level signal to the CE/MODE pin. The input of the CE/MODE pin is a CMOS input and the sink current is 0

A (TYP.).

Chip Disable

PWM control (XC9206), PWM/PFM automatic switching control (XC9207)

SW_CE

OFF

STATUS

SW_CE

STATUS

PWM control (XC9206), PWM/PFM automatic switching control (XC9207)

Synchronous PWM control

OFF

Chip Disable

SW_CE

STATUS

OFF

Synchronous PWM control

Chip Disable

OFF

Non-synchronous PWM/PFM automatic switching control

SW_CE SW_PMW/PFM

STATUS

OFF

Non-synchronous PWM/PFM automatic switching control

Chip Disable

OFF

SW_PMW/PFM

XC9207/9208 series features PWM/PFM automatic switching control.
With the automatic PWM/PFM switching control function, the series ICs are automatically switched from PWM control to PFM control mode under light
load conditions. If during light load conditions the coil current becomes discontinuous and on-time rate falls lower than PFM duty, the PFM circuit
operates to output a pulse with a fixed on-time rate from the Lx pin. During PFM operation with this fixed on-time rate, pulses are generated at different
frequencies according to conditions of the moment. This causes a reduction in the number of switching operations per unit of time, resulting in
efficiency improvement under light load conditions. However, since pulse output frequency is not constant, consideration should be given if a noise
filter or the like is needed. Necessary conditions for switching to PFM operation depend on input voltage, load current, coil value and other factors.

Semiconductor Ltd.

CE/MODE

VIN

VDD

SW_CE

CE/MODE

VIN

VDD

SW_CE

CE/MODE

VIN

VDD

RM1

SW _PW M/PFM

RM2

SW_CE

CE/MODE

VIN

VDD

RM1

SW_PWM/PFM

RM2

SW_CE

Data Sheet

XC9206 / 9207/ 9208 Series

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

TYPICAL PERFORMANCE CHARACTERISTICS

(1) Output Voltage vs. Output Current

XC9208A18C

VOUT=1.8V (Oscillation Frequency1.2MHz)

1.5

1.6

1.7

1.8

1.9

0.1

100

1000

Output Current IOUT (mA)

Output Voltage VOUT (V)

CIN:4.7

F,CL:10

F, L:4.7

H(CDRH3D16),

SD:CRS02, Topr=25

VIN=2.4V

3.6V

4.2V

PWM/PFM

Switching Control

PWM

Control

XC9208A186

VOUT=1.8V (Oscillation Frequency 600kHz)

1.5

1.6

1.7

1.8

1.9

0.1

100

1000

Output Current IOUT (mA)

Output Voltage VOUT (V)

VIN=2.4V

3.6V, 4.2V

PWM/PFM

Switching Control

PWM

Control

CIN:4.7

F,CL:10

F, L:10

H(CDRH4D18C),

SD:CRS02, Topr=25

XC9208A183

VOUT=1.8V (Oscillation Frequency 300kHz)

1.5

1.6

1.7

1.8

1.9

0.1

100

1000

Output Current IOUT (mA)

Output Voltage VOUT (V)

VIN=2.4V

3.6V, 4.2V

PWM/PFM

Switching Control

PWM Control

CIN:4.7

F,CL:10

F, L:22

H(CDRH4D28C),

SD:CRS02, Topr=25

Semiconductor Ltd.

Data Sheet

XC9206 / 9207/ 9208 Series

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

(2) Efficiency vs. Output Current

XC9208A18C

VOUT=1.8V (Oscillation Frequency 1.2MHz)

100

0.1

100

1000

Output Current IOUT (mA)

Efficiency EF

I
(

)

VIN=2.4V

3.6V

4.2V

PWM/PFM

Switching Control

PWM

Control

XC9208A186

VOUT=1.8V (Oscillation Frequency 600kHz)

100

0.1

100

1000

Output Current IOUT (mA)

Efficiency EF

I
(

)

VIN=2.4V

3.6V

4.2V

PWM/PFM Switching

Control

PWM

Control

CIN:4.7

F,CL:10

F, L:10

H(CDRH4D18C),

SD:CRS02, Topr=25

XC9208A183

VOUT=1.8V (Oscillation Frequency 300kHz)

100

0.1

100

1000

Output Current IOUT (mA)

Efficiency EF

I
(

)

VIN=2.4V

3.6V

4.2V

PWM/PFM

Switching Control

PWM Control

CIN:4.7

F,CL:10

F, L:4.7

H(CDRH3D16),

SD:CRS02, Topr=25

CIN:4.7

F,CL:10

F, L:22

H(CDRH4D28C),

SD:CRS02, Topr=25

Semiconductor Ltd.

Data Sheet

XC9206 / 9207/ 9208 Series

PWM, PWM/PFM Switchable Step-Down DC/DC Converters with Driver Transistor Built-In

(3) Ripple Voltage vs. Output Current

Semiconductor Ltd.

XC9208A18C

VOUT=1.8V (Oscillation Frequency 1.2MHz)

100

0.1

100

1000

Output Current IOUT (mA)

Ripple Voltage Vr (mV)

VIN=2.4V

3.6V

4.2V

PWM/PFM Switching

Control

PWM Control

XC9208A186

VOUT=1.8V (Oscillation Frequency 600kHz)

100

0.1

100

1000

Output Current IOUT (mA)

Ripple Voltage Vr (mV)

VIN=2.4V

3.6V

PWM/PFM Switching

Control

PWM Control

4.2V

XC9208A183

VOUT=1.8V (Oscillation Frequency 300kHz)

100

0.1

100

1000

Output Current IOUT (mA)

Ripple Voltage Vr (mV)

VIN=2.4V

3.6V

PWM/PFM Switching

Control

PWM Control

4.2V

CIN:4.7

F,CL:10

F, L:22

H(CDRH3D28C),

SD:CRS02, Topr=25

CIN:4.7

F,CL:10

F, L:4.7

H(CDRH3D16),

SD:CRS02, Topr=25

CIN:4.7

F,CL:10

F, L:10

H(CDRH4D18C),

SD:CRS02, Topr=25

Data Sheet

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ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: XC92081L3ML