XC9201 Series
ETR0502_004
PWM Controlled Step-Down DC/DC Controllers
■GENERAL DESCRIPTION
The XC9201 series are step-down multiple current and voltage feedback DC/DC controller ICs. Current sense, clock
frequencies and amp feedback gain can all be externally regulated.
A stable power supply is possible with output currents of up to 3.0A. With output voltage fixed internally, output voltage is
selectable in 100mV increments (semi-custom) within a 1.2V ~ 16.0V range. (±2.5%).
For output voltages outside this range, we recommend the FB version which has a 0.9V internal reference voltage. Using this
version, the required output voltage can be set-up using 2 external resistors.
Switching frequencies can also be set-up externally within a range of 100kHz~600kHz and therefore frequencies suited to
your particular application can be selected.
With the current sense function, peak currents (which flow through the driver transistor and the coil) can be controlled.
Soft-start time can be adjusted using external resistors and capacitors.
During shutdown (CE pin =L), consumption current can be reduced to as little as 0.5μA (TYP.) or less and with U.V.L.O.
(Under Voltage Lock Out) built-in, the external transistor will be automatically shut off below the regulated voltage.
■APPLICATIONS
●Mobile, Cordless phones
●Palm top computers, PDAs
■FEATURES
Stable Operations via Current & Voltage Multiple
Feedback
Unlimited Options for Peripheral Selection
●Portable games
Current Protection Circuit
●Cameras, Digital cameras
Ceramic Capacitor Compatible
●Notebook computers
Input Voltage Range
: 2.5V ~20V
Output Voltage Range
: 1.2V ~ 16V
Oscillation Frequency Range : 100kHz ~ 600kHz
■TYPICAL APPLICATION CIRCUIT
Output Current
: Up To 3.0A
Package
: MSOP-8A
■TYPICAL PERFORMANCE
CHARACTERISTICS
VOUT:5.0V
FOSC:330kHz
1/24
XC9201 Series
■PIN CONFIGURATION
■PIN ASSIGNMENT
PIN NUMBER
PIN NAME
1
EXT
Driver
2
ISEN
Current Sense
3
VIN
Power Input
4
CE / SS
CE/Soft Start
MSOP-8A
(TOP VIEW)
FUNCTION
5
CLK
Clock Input
6
CC / GAIN
Phase Compensation
7
VOUT / FB
Voltage Sense
8
VSS
Ground
■PRODUCT CLASSIFICATION
●Ordering Information
XC9201 ①②③④⑤⑥
DESIGNATOR
DESCRIPTION
SYMBOL
①
Type of DC/DC
Controller
C
: VOUT (Fixed Voltage Type), Soft-start externally set-up
D
: FB voltage, Soft-start externally set-up
Integer
② ③
Output Voltage
Oscillation Frequency
⑤
Package
⑥
Device Orientation
: e.g. VOUT=2.3V → ②=2, ③=3
FB products → ②=0, ③=9 fixed
A
: Voltage above 10V
→ 10=A, 11=B, 12=C, 13=D, 14=E, 15=F, 16=H
e.g. VOUT=13.5V → ②=D, ③=5
: Adjustable
A~H
④
DESCRIPTION
K
: MSOP-8A
R
: Embossed tape, standard feed
L
: Embossed tape, reverse feed
The standard output voltages of the XC9201C series are 2.5V, 3.3V, and 5.0V.
Voltages other than those listed are semi-custom.
2/24
XC9201
Series
■BLOCK DIAGRAM
EXT
EXT timing
Control Logic
VSS
Current Limit
Protection
VOUT
ISEN
+
Verr
+
Limiter Comp.
+
PWM
MIX
-
R1
-
R2
+
+
CC/GAIN
-
-
VIN
Ierr
Internal Voltage
2.0V
Regulator
to internal
+
circuit
Ramp Wave,
Internal CLK
Generator
Sampling
CE/SS
Chip Enable,
Soft-Start up
U.V.L.O.
CE, U.V.L.O.
to internal
circuit
CLK
Vref Generator
0.9V
■ABSOLUTE MAXIMUM RATINGS
PARAMETER
EXT Pin Voltage
ISEN Pin Voltage
VIN Pin Voltage
CE/ SS Pin Voltage
CLK Pin Voltage
CC/ GAIN Pin Voltage
VOUT/ FB Pin Voltage
EXT Pin Current
Power Dissipation
Operating Ambient Temperature
Storage Temperature
SYMBOL
VEXT
VlSEN
VIN
VCE
VCLK
VCC
VOUT/FB
IEXT
Pd
Topr
Tstg
RATINGS
-0.3~VDD+0.3
-0.3~+22
-0.3~+22
-0.3~+22
-0.3~VDD+0.3
-0.3~VDD+0.3
-0.3～+22
±100
150
-40~+85
-55~+125
Ta = 25℃
UNITS
V
V
V
V
V
V
V
mA
mW
℃
℃
3/24
XC9201 Series
■ELECTRICAL CHARACTERISTICS
XC9201C25AKR
Ta=25℃
PARAMETER
SYMBOL
Output Voltage
VOUT
Maximum
Operating Voltage
Minimum
Operating Voltage
U.V.L.O. Voltage
MIN.
TYP.
MAX.
UNITS
CIRCUITS
2.438
2.500
2.562
V
①
VINmax
20
-
-
V
①
VINmin
-
-
2.200
V
①
1.0
1.4
2.0
V
⑤
VUVLO
CONDITIONS
IOUT=300mA
EXT voltage = High
Supply Current 1
IDD1
VIN=3.75V, CE=VIN=VOUT
-
115
220
μA
②
Supply Current 2
IDD2
VIN=20.0V, CE=VIN, VOUT=VSS
-
130
235
μA
②
Stand-by Current
ISTB
VIN=3.75V, CE=VOUT=VSS
-
0.5
2.0
μA
②
CLK
Oscillation Frequency
FOSC
RT=10.0kΩ, CT=220pF
280
330
380
kHz
③
-
±5
-
%
③
ΔFOSC
ΔVIN･FOSC
Frequency
ΔFOSC
Temperature Fluctuation ΔTOPR･FOSC
Maximum Duty Cycle
MAXDTY
Minimum Duty Cycle
MINDTY
Current Limiter Voltage
ILIM
ISEN Current
IISEN
Frequency Input Stability
VIN=2.5V～20V
VIN=3.75V
Topr=-40～+85℃
VOUT=VSS
VOUT=VIN
VIN pin voltage - ISEN pin voltage
-
±5
-
%
③
100
90
150
0
220
%
%
mV
④
④
⑥
VIN=3.75V, ISEN=3.75V
4.5
7.0
13.0
μA
⑥
CE "High" Current
ICEH
CE=VIN=20.0V, VOUT=0V
-0.1
0
0.1
μA
⑤
CE "Low" Current
ICEL
CE=0V, VIN=20.0V, VOUT=0V
-0.1
0
0.1
μA
⑤
CE "High" Voltage
VCEH
0.6
-
-
V
⑤
CE "Low" Voltage
VCEL
-
-
0.2
V
⑤
-
27
40
Ω
④
-
24
33
Ω
④
-
93
-
%
①
5
10
20
ms
①
-
400
-
kΩ
⑦
EXT "High"
ON Resistance
EXT "Low"
ON Resistance
Efficiency
(*2)
REXTH
REXTL
CLK Oscillation start,
VOUT=0V, CE：Voltage applied
CLK Oscillation stop,
VOUT=0V, CE：Voltage applied
EXT=VIN－0.4V,
CE=VOUT=VIN (*1)
EXT=0.4V, CE=VIN,
VOUT=VSS (*1)
EFFI
Soft-start Time
TSS
CC/GAIN Pin
Output Impedance
RCCGAIN
Connect CSS and RSS,
CE : 0V→3.75V
Unless otherwise stated, VIN=3.75V
NOTE:
*1: On resistance = 0.4V / measurement current
*2: EFFI = {[(output voltage) x (output current)] / [(input voltage) x (input current)]} x 100
*3: The capacity range of the condenser used to set the external CLK frequency is 180 ~ 300pF
4/24
XC9201
Series
■ELECTRICAL CHARACTERISTICS (Continued)
XC9201C33AKR
PARAMETER
Output Voltage
Maximum
Operating Voltage
Minimum
Operating Voltage
U.V.L.O. Voltage
Ta=25℃
SYMBOL
MIN.
TYP.
MAX.
UNITS
CIRCUITS
3.218
3.300
3.382
V
①
VINmax
20
-
-
V
①
VINmin
-
-
2.200
V
①
1.0
1.4
2.0
V
⑤
VOUT
VUVLO
CONDITIONS
IOUT=300mA
EXT voltage = High
Supply Current 1
IDD1
VIN=5.0V, CE=VIN=VOUT
-
115
220
μA
②
Supply Current 2
IDD2
VIN=20.0V, CE=VIN, VOUT=VSS
-
130
235
μA
②
Stand-by Current
ISTB
VIN=5.0V, CE=VOUT=VSS
-
0.5
2.0
μA
②
CLK
Oscillation Frequency
FOSC
RT=10.0kΩ, CT=220pF
280
330
380
kHz
③
VIN=2.5V～20V
-
±5
-
%
③
VIN=5.0V
Topr=-40～+85℃
-
±5
-
%
③
100
-
-
%
④
ΔFOSC
ΔVIN･FOSC
Frequency
ΔFOSC
Temperature Fluctuation ΔTOPR･FOSC
Maximum Duty Cycle
MAXDTY
Frequency Input Stability
VOUT=VSS
Minimum Duty Cycle
MINDTY
-
-
0
%
④
Current Limiter Voltage
ILIM
VIN pin voltage - ISEN pin voltage
90
150
220
mV
⑥
VOUT=VIN
ISEN Current
IISEN
VIN=5.0V, ISEN=5.0V
4.5
7
13
μA
⑥
CE "High" Current
ICEH
CE=VIN=20.0V, VOUT=0V
-0.1
0
0.1
μA
⑤
CE "Low" Current
ICEL
CE=0V, VIN=20.0V, VOUT=0V
-0.1
0
0.1
μA
⑤
CE "High" Voltage
VCEH
0.6
-
-
V
⑤
CE "Low" Voltage
VCEL
-
-
0.2
V
⑤
-
24
33
Ω
④
-
22
31
Ω
④
-
93
-
%
①
5
10
20
ms
①
-
400
-
kΩ
⑦
EXT "High"
ON Resistance
EXT "Low"
ON Resistance
(*2)
Efficiency
REXTH
REXTL
CLK Oscillation start,
VOUT=0V, CE：Voltage applied
CLK Oscillation stop,
VOUT=0V, CE：Voltage applied
EXT=VIN－0.4V,
CE=VOUT=VIN (*1)
EXT=0.4V, CE=VIN,
VOUT=Vss (*1)
EFFI
Soft-start Time
TSS
CC/GAIN Pin
Output Impedance
RCCGAIN
Connect CSS and RSS,
CE : 0V→5.0V
Unless otherwise stated, VIN=5.0V
NOTE:
*1: On resistance = 0.4V / measurement current
*2: EFFI = {[(output voltage) x (output current)] / [(input voltage) x (input current)]} x 100
*3: The capacity range of the condenser used to set the external CLK frequency is 180 ~ 300pF
5/24
XC9201 Series
■ELECTRICAL CHARACTERISTICS (Continued)
XC9201C50AKR
PARAMETER
Output Voltage
Maximum
Operating Voltage
Minimum
Operating Voltage
U.V.L.O. Voltage
Ta=25℃
SYMBOL
MIN.
TYP.
MAX.
UNITS.
CIRCUITS
4.875
5.000
5.125
V
①
VINmax
20
-
-
V
①
VINmin
-
-
2.200
V
①
1.0
1.4
2.0
V
⑤
VOUT
VUVLO
CONDITIONS
IOUT=300mA
EXT voltage = High
Supply Current 1
IDD1
VIN=7.5V, CE=VIN=VOUT
-
115
220
μA
②
Supply Current 2
IDD2
VIN=20.0V, CE=VIN, VOUT=VSS
-
130
235
μA
②
Stand-by Current
ISTB
VIN=7.5V, CE=VOUT=VSS
-
0.5
2.0
μA
②
CLK
Oscillation Frequency
FOSC
RT=10.0kΩ, CT=220pF
280
330
380
kHz
③
VIN=2.5V～20V
-
±5
-
%
③
VIN=7.5V
Topr=-40～+85℃
-
±5
-
%
③
100
-
-
%
④
ΔFOSC
ΔVIN･FOSC
Frequency
ΔFOSC
Temperature Fluctuation ΔTOPR･FOSC
Maximum Duty Cycle
MAXDTY
Frequency Input Stability
VOUT=VSS
Minimum Duty Cycle
MINDTY
-
-
0
%
④
Current Limiter Voltage
ILIM
VIN pin voltage - ISEN pin voltage
90
150
220
mV
⑥
VOUT=VIN
ISEN Current
IISEN
VIN=7.5V, ISEN=7.5V
4.5
7.0
13.0
μA
⑥
CE "High" Current
ICEH
CE=VIN=20.0V, VOUT=0V
-0.1
0
0.1
μA
⑤
CE "Low" Current
ICEL
CE=0V, VIN=20.0V, VOUT=0V
-0.1
0
0.1
μA
⑤
CE "High" Voltage
VCEH
0.6
-
-
V
⑤
CE "Low" Voltage
VCEL
-
-
0.2
V
⑤
-
21
29
Ω
④
-
20
27
Ω
④
-
93
-
%
①
5
10
20
ms
①
-
400
-
kΩ
⑦
EXT "High"
ON Resistance
EXT "Low"
ON Resistance
(*2)
Efficiency
REXTH
REXTL
CLK Oscillation start,
VOUT=0V, CE：Voltage applied
CLK Oscillation stop,
VOUT =0V, CE：Voltage applied
VEXT=VIN－0.4V,
CE= VOUT =VIN (*1)
VEXT=0.4V, CE=VIN,
VOUT =VSS (*1)
EFFI
Soft-start Time
Tss
CC/GAIN Pin
Output Impedance
RCCGAIN
Connect Css and Rss,
CE : 0V→7.5V
Unless otherwise stated, VIN=7.5V
NOTE:
*1: On resistance = 0.4V / measurement current
*2: EFFI = {[(output voltage) x (output current)] / [(input voltage) x (input current)]} x 100
*3: The capacity range of the condenser used to set the external CLK frequency is 180 ~ 300pF
6/24
XC9201
Series
■ELECTRICAL CHARACTERISTICS (Continued)
XC9201D09AKR
Ta=25℃
PARAMETER
SYMBOL
Output Voltage
VOUT
Maximum
Operating Voltage
Minimum
Operating Voltage
CONDITIONS
IOUT=300mA
MIN.
TYP.
MAX.
0.8775 0.9000 0.9225
UNITS
CIRCUITS
V
①
VINmax
20
-
-
V
①
VINmin
-
-
2.200
V
①
1.0
1.4
2.0
V
⑤
U.V.L.O. Voltage
VUVLO
EXT voltage = High
Supply Current 1
IDD1
VIN=4.0V, CE=VIN=FB
-
115
220
μA
②
Supply Current 2
IDD2
VIN=20.0V, CE=VIN, FB=VSS
-
130
235
μA
②
Stand-by Current
ISTB
VIN=4.0V, CE=FB=VSS
-
0.5
2.0
μA
②
CLK
Oscillation Frequency
FOSC
RT=10.0kΩ, CT=220pF
280
330
380
kHz
③
VIN=2.5V～20V
-
±5
-
%
③
VIN=4.0V
Topr=-40～+85℃
-
±5
-
%
③
100
-
-
%
④
Frequency
Temperature Fluctuation
ΔFOSC
ΔVIN･FOSC
ΔFOSC
ΔTOPR･FOSC
Maximum Duty Cycle
MAXDTY
FB=VSS
FB=VIN
Frequency Input Stability
Minimum Duty Cycle
MINDTY
-
-
0
%
④
Current Limiter Voltage
ILIM
VIN pin voltage - ISEN pin voltage
90
150
220
mV
⑥
ISEN Current
IISEN
VIN=4.0V, ISEN=4.0V
4.5
7
13
μA
⑥
CE "High" Current
ICEH
CE=VIN=20.0V, VOUT=0V
-0.1
0
0.1
μA
⑤
CE "Low" Current
ICEL
CE=0V, VIN=20.0V, VOUT=0V
-0.1
0
0.1
μA
⑤
CE "High" Voltage
VCEH
0.6
-
-
V
⑤
CE "Low" Voltage
VCEL
-
-
0.2
V
⑤
-
27
40
Ω
④
-
24
34
Ω
④
-
93
-
%
①
5
10
20
ms
①
-
400
-
kΩ
⑦
EXT "High"
ON Resistance
EXT "Low"
ON Resistance
Efficiency
(*2)
REXTH
REXTL
CLK Oscillation start,
VOUT =0V, CE：Voltage applied
CLK Oscillation stop,
VOUT=0V, CE：Voltage applied
EXT=VIN－0.4V,
CE=FB=VIN (*1)
EXT=0.4V, CE=VIN, FB=VSS (*1)
EFFI
Soft-start Time
Tss
CC/GAIN Pin
Output Impedance
RCCGAIN
Connect Css and Rss,
CE : 0V→4.0V
Unless otherwise stated, VIN=4.0V
NOTE:
*1: On resistance = 0.4V / measurement current
*2: EFFI = {[(output voltage) x (output current)] / [(input voltage) x (input current)]} x 100
*3: The capacity range of the condenser used to set the external CLK frequency is 180 ~ 300pF
7/24
XC9201 Series
■TYPICAL APPLICATION CIRCUITS
XC9201C33AKR
22uH
PMOS
1 EXT
2 ISEN
SD
VOUT 7
50mΩ
3 VIN
CC/GAIN 6
240kΩ
47uF
SD
CLK 5
4 CC/SS
7.2V
PMOS
Coil
Resistor
Capacitors
3.3V
~1.5A
VSS 8
0.22uF
1uF
220pF
470pF
~30kΩ
47uF (OS) or
10uF (ceramic) x 4
:
:
:
:
XP132A11A1SR (TOREX)
22μH (CR105 SUMIDA)
50mΩ for ISEN (NPR1 KOA), 30kΩ(trimmer) for CLK, 240kΩ for SS
220pF (ceramic) for CLK, 470pF (ceramic) for CC/GAIN, 0.22μF (any) for SS,1μF (ceramic) for Bypass
47μF (OS) or 10μF (ceramic) x 4 for CL, 47μF (tantalum) for CIN
: U3FWJ44N (TOSHIBA)
XC9201C50AKR
22uH
PMOS
1 EXT
2 ISEN
SD
3 VIN
4 CC/SS
12.0V
47uF
+ 220uF 0.33uF
SD
8/24
VOUT 7
50mΩ
240kΩ
PMOS
Coil
Resistor
Capacitors
5.0V
~1.5A
VSS 8
:
:
:
:
1uF
CC/GAIN 6
CLK 5
220pF
470pF
~30kΩ
47uF (OS) or
+ 220uF (any)
XP132A11A1SR (TOREX)
22μH (CDRH127 SUMIDA)
20mΩfor ISEN (NPR1 KOA), 30kΩ(trimmer) for CLK, 240kΩfor SS
220pF (ceramic) for CLK, 470pF (ceramic) for CC/GAIN, 0.33μF (any) for SS, 1μF (ceramic) for Bypass
47μF (OS) + 220μF (any) for CL, 47μF (tantalum) + 220μF (any) for CIN
: U3FWJ44N (TOSHIBA)
XC9201
Series
■TYPICAL APPLICATION CIRCUITS (Continued)
XC9201D09AKR
22uH
39pF
PMOS
SD
20mΩ
1 EXT
VSS 8
2 ISEN
FB 7
3 VIN
CC/GAIN 6
240kΩ
4 CC/SS
7.2V
47uF
+ 220uF 0.22uF
390kΩ
CLK 5
1uF
220pF
2.5V
~3A
220kΩ
470pF
47uF (OS) or
+ 220uF (any)
~30kΩ
PMOS
Coil
Resistors
: XP132A11A1SR (TOREX)
: 22μH (CDRH127 SUMIDA)
: 20mΩfor ISEN (NPR1 KOA), 30kΩ(trimmer) for CLK, 240kΩfor SS, 390kΩfor Output Voltage
220kΩfor Output Voltage
Capacitors : 220pF (ceramic) for CLK, 470pF (ceramic) for CC/GAIN, 0.22μF (any) for SS, 1μF (ceramic) for Bypass
39pF (ceramic) for FB, 47μF (OS) for CL, 47μF (tantalum) + 220μF(any) for CIN
SD
: U3FWJ44N (TOSHIBA)
XC9201D09AKR
47uH
56pF
PMOS
SD
50mΩ
1 EXT
VSS 8
2 ISEN
FB 7
3 VIN
240kΩ
4 CC/SS
20V
47uF
0.47uF
1uF
270kΩ
CC/GAIN 6
CLK 5
220pF
12V
~1.5A
22kΩ
470pF
~30kΩ
47uF (OS) or
+ 220uF (any)
PMOS
Coil
Resistor
: XP132A11A1SR (TOREX)
: 47μH (CR105 SUMIDA)
: 50mΩfor ISEN (NPR1 KOA), 30kΩ(trimmer) for CLK, 240kΩ for SS, 270kΩfor Output Voltage
22kΩ(trimmer) for Output Voltage
Capacitors : 220pF (ceramic) for CLK, 470pF (ceramic) for CC/GAIN, 0.47μF (any) for SS, 1μF (ceramic) for Bypass
56pF (ceramic) for FB, 47μF (OS) + 20μF (any) for CL, 47μF (tantalum) + 220μF (any) for CIN
SD
: U3FWJ44N (TOSHIBA)
9/24
XC9201 Series
■OPERATIONAL EXPLANATION
Step-down DC/DC converter controllers of the XC9201series carry out pulse width modulation (PWM) according to the
multiple feedback signals of the output voltage and coil current.
The internal circuits consist of different blocks that operate at VIN or the stabilized power (2.0V) of the internal regulator. The
output setting voltage of type C controller and the FB pin voltage (Vref=0.9 V) of type D controller have been adjusted and set
by laser-trimming.
<Clock>
With regard to clock pulses, a capacitor and resistor connected to the CLK pin generate ramp waveforms whose top and
bottom are 0.7V and 0.15V, respectively. The frequency can be set within a range of 100 to 600 kHz externally (refer to the
"Functional Settings" section for further information). The clock pulses are processed to generate a signal used for
synchronizing internal sequence circuits.
<Verr Amplifier>
The Verr amplifier is designed to monitor the output voltage. A fraction of the voltage applied to internal resistors R1, R2 in
the case of a type C controller, and the voltage of the FB pin in the case of a type D controller, are fed back and compared
with the reference voltage. In response to feedback of a voltage lower than the reference voltage, the output voltage of the
Verr amplifier increases.
The output of the Verr amplifier enters the mixer via resistor (RVerr). This signal works as a pulse width control signal during
PWM operations. By connecting an external capacitor and resistor through the CC/GAIN pin, it is possible to set the gain
and frequency characteristics of Verr amplifier signals (refer to the "Functional Settings" section for further information).
<Ierr Amplifier>
The Ierr amplifier monitors the coil current. The potential difference between the VIN and ISEN pins is sampled at each
switching operation. Then the potential difference is amplified or held, as necessary, and input to the mixer. The Ierr
amplifier outputs a signal ensuring that the greater the potential difference between the VIN and ISEN pins, the smaller the
switching current. The gain and frequency characteristics of this amplifier are fixed internally.
<Mixer and PWM>
The mixer modulates the signal sent from Verr by the signal from Ierr. The modulated signal enters the PWM comparator
for comparison with the saw-tooth pulses generated at the CLK pin. If the signal is greater than the saw-tooth waveforms, a
signal is sent to the output circuit to turn on the external switch.
<Current Limiter>
The current flowing through the coil is monitored by the limiter comparator via the VIN and ISEN pins. The limiter comparator
outputs a signal when the potential difference between the VIN and ISEN pins reaches 150mV or more. This signal is
converted to a logic signal and handled as a DFF reset signal for the internal limiter circuit. When a reset signal is input, a
signal is output immediately at the EXT pin to turn off the MOS switch. When the limiter comparator sends a signal to
enable data acceptance, a signal to turn on the MOS switch is output at the next clock pulse. If at this time the potential
difference between the VIN and ISEN pins is large, operation is repeated to turn off the MOS switch again. DFF operates in
synchronization with the clock signal of the CLK pin.
<Soft-Start>
The soft start function is made available by attaching a capacitor and resistor to the CE/SS pin. The Vref voltage applied to
the Verr amplifier is restricted by the start-up voltage of the CE/SS pin. This ensures that the Verr amplifier operates with its
two inputs in balance, thereby preventing the ON-TIME signal from becoming stronger than necessary. Consequently, soft
start time needs to be set sufficiently longer than the time set to CLK. The start-up time of the CE/SS pin equals the time set
for soft start (refer to the "Functional Settings" section for further information).
The soft start function operates when the voltage at the CE/SS pin is between 0V to 1.55V. If the voltage at the CE/SS pin
doesn't start from 0V but from a mid level voltage when the power is switched on, the soft start function will become
ineffective and the possibilities of large inrush currents and ripple voltages occurring will be increased.
Under Voltage Lock Out (U.V.L.O.) is also provided. This function is activated to turn off the MOS switch attached to the
EXT pin when the input voltage (VIN) decreases to approximately 1.4 V or below. The purpose of this function is to keep the
external MOS switch from turning on when a voltage at which the IC operates unstably is applied. U.V.L.O. also restricts
signals during soft start so that the external MOS switch does not turn on until the internal circuitry becomes stable.
10/24
XC9201
Series
■OPERATIONAL EXPLANATION (Continued)
●Functional Settings
1. Soft-Start
CE and soft-start (SS) functions are commonly assigned to the CE/SS pin. The soft start function is effective until the
voltage at the CE pin reaches approximately 1.55V rising from 0V. Soft start time is approximated by the equation below
according to values of Vcont, RSS, and CSS.
T=-Css x Rss x ln((Vcont-1.55)/Vcont)
Example: When Css=0.1μF, Rss=470kΩ, and Vcont=5V, T= - 0.1 x 10
-6
× 470 x 103 × In((5-1.55) / 5)=17.44ms.
Set the soft-start time to a value sufficiently longer than the period of a clock pulse.
> Circuit example 1: N-ch open drain
> Circuit example 2: CMOS logic (low current dissipation)
> Circuit example 3: CMOS logic (low current dissipation)
11/24
XC9201 Series
■OPERATIONAL EXPLANATION (Continued)
■OPERATIONAL EXPLANATION (Continued)
●Functional Settings (Continued)
2. Oscillation Frequency
The oscillation frequency of the internal clock generator is approximated by the following equation according to the values of
the capacitor and resistor attached to the CLK pin. To stabilize the IC's operation, set the oscillation frequency within a
range of 100kHz to 600kHz. Select a value for Cclk within a range of 180pF to 300pF and fix the frequency based on the
value for Rclk.
f=1/ (-Cclk x Rclk x ln 0.26)
-12
Example: When Cclk = 220pF and Rclk = 10 kΩ, f = 1/(- 220 x 10
3
x 10 x 10 x ln(0.26)) = 337.43 kHz.
3. Gain and Frequency Characteristics of the Verr Amplifier
The gain at output and frequency characteristics of the Verr amplifier are adjusted by the values of capacitor and resistor
attached to the CC/GAIN pin. It is generally recommended to attach a C_GAIN of 220 to 1,000pF without an R_GAIN. The
greater the C_GAIN value, the more stable the phase and the slower the transient response. When using the IC with
R_GAIN connected, it should be noted that if the R_GAIN resistance value is too high, abnormal oscillation may occur during
transient response time. The size of R_GAIN should be carefully determined and connected.
4. Current Limit
The current limit value is approximated by the following equation according to resistor RSEN inserted between the VIN and
ISEN pins. Double function, current FB input and current limit, is assigned to the ISEN pin. The current limit value is
approximated by the following equation according to the value for RSEN.
ILpeak_limit = 0.15 / RSEN
Example: When RSEN = 100 mΩ, ILpeak_limit = 0.15 / 0.1 = 1.5 A
Because of the feedback at the internal error amp with this IC (which is brought about as a result of the phase compensation
of the voltage generated at RSEN, which is in turn caused by current flowing through the coil when the PMOS is working.),
should the value of the RSEN resistor be too large, the feedback signal will also increase and intermittent oscillation may
occur. We therefore recommend that you carefully check the value for RSEN should you have a problem with oscillation.
During normal operations, a voltage will be generated at RSEN as a result of the coil's peak current. Please ensure that this
voltage is less than the current limit voltage, which is 90mV (min.).
For RSEN resistor's rated power, please refer to NOTES ON USE, External Components, RSENSE Resistor.
12/24
XC9201
Series
■OPERATIONAL EXPLANATION (Continued)
●Functional Settings (Continued)
5. FB Voltage and CFB
With regard to the XC9201D series, the output voltage is set by attaching externally divided resistors. The output voltage is
determined by the equation shown below according to the values of RFB1 and RFB2. In general, the sum of RFB1 and RFB2
should be 1 MΩor less.
VOUT = 0.9 x (RFB1+ RFB2) / RFB2
The value of CFB (phase compensation capacitor) is approximated by the following equation according to the values of RFB1
and fzfb. The value of fzfb should be 10 kHz, as a general rule.
CFB = 1/(2 x π x RFB1 x fzfb)
Example: When RFB1 = 455 kΩ and RFB2 = 100 kΩ : VOUT = 0.9 x (455 k + 100 k)/100 k = 4.995 V
: CFB= 1/(2 x π x 455 k x 10 k) = 34.98 pF.
■APPLICATION NOTES
1. The XC9201 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 side. If the input-output potential difference is large, connect an electrolytic capacitor in parallel
to compensate for insufficient capacitance.
2. The EXT pin of the XC9201 series is designed to minimize the through current that occurs in the internal circuitry.
However, the gate drive of external PMOS has a low impedance for the sake of speed. Therefore, if the input voltage is
high and the bypass capacitor is attached away from the IC, the charge/discharge current to the external PMOS may lead
to unstable operations due to switching operation of the EXT pin.
As a solution to this problem, place the bypass capacitor as close to the IC as possible, so that voltage variations at the VIN
and VSS pins caused by switching are minimized. If this is not effective, insert a resistor of several to several tens of
ohms between the EXT pin and PMOS gate. Remember that the insertion of a resistor slows down the switching speed
and may result in reduced efficiency.
3. A PNP transistor can be used in place of PMOS. If using a PNP transistor, insert a resistor (RB) and capacitor (CB)
between the EXT pin and the base of the PNP transistor in order to limit the base current without slowing the switching
speed. Adjust RB in a range of 500Ω to 1kΩ according to the load and hFE of the transistor. Use a ceramic capacitor
for CB, complying with CB ≦ 1/ ( 2 x π x RB x Fosc x 0.7), as a rule.
4. This IC incorporates a limit comparator to monitor the voltage produces across the RSEN resistor at the current peak of the
coil. It functions as a limiter when, for example, the output is short-circuited. In such a case, the limit comparator
senses that the voltage across the RSEN resistor has reached a current-limiting voltage (typically 150mV) and outputs a
signal to turn off the external transistor. After sensing a current-limit voltage, the limit comparator typically takes 200nsec
(TYP.) before it turns off the external resistor. During this time, the voltage across the RSEN resistor can exceed the
current-limit voltage, especially when the difference between the input voltage and the output voltage is large and the coil
inductance is small. Therefore, exercise great care in selecting absolute maximum ratings of the external transistor, coil,
and Schottky diode.
5. If the difference between the input voltage and the output voltage is large or small, the switching ON time or OFF time of
this IC becomes short and actual operation can be critically influenced by values of peripheral components 'inductance of
coil, resistance of CLK connection, capacitance of capacitor, etc.) Before use, it is recommended to evaluate this IC
thoroughly with an actual unit.
13/24
XC9201 Series
■APPLICATION NOTES (Continued)
6. The series are designed to operate in PWM control. However, there is the possibility that some cycles may be skipped
depending on the operational conditions. Please use the following output voltage vs. input voltage characteristics for
reference. Verification using actual devices is recommended. It should be noted that when CCLK is connected to VIN,
the influence of noise is lessened and the input and output voltage ranges as well as the output current range in which
stable operation is possible is widened. It is recommended that you refer to the "Oscillation Frequency" Functional
Settings for setting up the oscillation frequency. If using a MOSFET, please pay particular attention to the gate
breakdown voltage. In the following graphs, because the gate breakdown voltage of the MOSFET used was 20V, input
voltages over 16V were not measured. Please use a bipolar transistor in applications where higher input voltages are
required.
●Operational Control Characteristics
○XC9201D09AKR
VIN
R S EN SE
CCLK VIN Connection
L
Tr
VO U T
IC
CDD
C IN
G ND
R SS
CSS
SD
EX T
ISE N
VIN
CFB
CL
GAIN
CL K
C E/SS
VSS
R C LK
RFB 2
G ND
CC LK
CC LK V IN Con ne ction Circ uit
14/24
R FB1
FB
CCC
SD:
L:
CIN:
CL:
CDD:
RSEN:
RCLK:
CCLK:
CCC:
RCC:
RB(2SA1887):
RSS:
CSS:
RFB1:
CFB:
RFB2:
D1FH3
CDRH127 / LD-220 (22uH)
TMK432BJ106KM (25V / 10uF) x 3
JMK325BJ226MM (6.3V / 22uF) x 3
UMK325BJ105KH (50V / 1uF)
50mΩ
11kΩ (300kHz), 6.8kΩ (500kHz)
220pF
330pF
0Ω
7kΩ (300kHz), 16kΩ (500kHz)
1MΩ
0.1uF
330kΩ
47pF
0.9 x RFB1 / (VOUT-0.9V)
XC9201
Series
■APPLICATION NOTES (Continued)
●Operational Control Characteristics (Continued)
○XC9201D09AKR
VIN
RSE NS E
CCLK GND Connection
L
Tr
VO U T
CFB
IC
E XT
IS EN
VIN
C IN
GN D
R SS
C SS
CDD
SD
RFB 1
FB
CL
G AIN
CCL K
C LK
CE /S S
VSS
RFB 2
GND
R CLK
C CLK G ND Con ne cton Circuit
C CC
SD:
L:
CIN:
CL:
CDD:
RSEN:
RCLK:
CCLK:
CCC:
RCC:
RB(2SA1887):
RSS:
CSS:
RFB1:
CFB:
RFB2:
D1FH3
CDRH127 / LD-220 (22uH)
TMK432BJ106KM (25V / 10uF) x 3
JMK325BJ226MM (6.3V / 22uF) x 3
UMK325BJ105KH (50V / 1uF)
50mΩ
11kΩ (300kHz), 6.8kΩ (500kHz)
220pF
330pF
0Ω
7kΩ (300kHz), 16kΩ (500kHz)
1MΩ
0.1uF
330kΩ
47pF
0.9V x RFB1 / (VOUT-0.9V)
15/24
XC9201 Series
■INSTRUCTION ON PATTERN LAYOUT
①In order to stabilize VDD's voltage level, we recommend that a by-pass condenser (CDD) be connected as close as
possible to the VIN & VSS pins.
②In order to stabilize the GND voltage level which can fluctuate as a result of switching, we suggest that C_CLK's,
R_CLK's & C_GAIN's GND be separated from Power GND and connected as close as possible to the VSS pin (by-pass
condenser, CDD). Please use a multi layer board and check the wiring carefully.
Pattern Layout Examples
XC9201 Series (D Series)
2 layer Evaluation Board
8
7
6
5
8
7
6
5
16/24
XC9201
Series
■INSTRUCTION ON PATTERN LAYOUT (Continued)
1 layer Evaluation Board
8
7
6
5
■NOTES ON USE
Ensure that the absolute maximum ratings of the external components and the XC9201 DC/DC IC itself are not exceeded.
We recommend that sufficient counter measures are put in place to eliminate the heat that may be generated by the
external P-ch MOSFET as a result of switching losses.
Try to use a P-ch MOSFET with as small a gate capacitance as possible in order to avoid overly large output spike voltages
that may occur (such spikes occur in proportion to gate capacitance). The performance of the XC9201 DC/DC converter
is greatly influenced by not only its own characteristics, but also by those of the external components it is used with. We
recommend that you refer to the specifications of each component to be used and take sufficient care when selecting
components.
Wire external components as close to the IC as possible and use thick, short connecting wires to reduce wiring impedance.
In particular, minimize the distance between the by-pass capacitor and the IC.
Make sure that the GND wiring is as strong as possible as variations in ground potential caused by ground current at the
time of switching may result in unstable operation of the IC. Specifically, strengthen the ground wiring in the proximity of
the VSS pin.
●External Components
RSENSE Resistor
A low value resistor is defined as a resistor with a 10Ω value or lower. For RSENSE, the XC9201 series uses a resistor
with a value of either 50mΩor 100mΩ. Although resistors for RSENSE are classified as low resistance chip resistors or
current limit resistors (which may give the impression that the RSENSE resistor is expensive), it is not necessary to use
expensive low resistance chip resistors as general purpose chip resistors with values of 50mΩ or 100mΩ will do the job
just as well.
When choosing the RSENSE resistor, it is important to confirm the resistor's power consumption, which can be done using
the following equation:
W (Power Consumption) =I (Current) x V (Voltage)
=I (Current) x I (Current) x R (Resistance)
It is recommended that a resistor which has a power rating of more than 3 times the power consumption of RSENSE be
selected (refer to the example given below):
(ex.)
RSENSE = 100mΩ, I = 1A
I = 1A
RSENSE = 100mΩ(0.1Ω)
Power supply W = 1 x 1 x 0.1 = 0.1 [W]
0.5W, 100mΩ resistor should be used
17/24
XC9201 Series
■TEST CIRCUITS
Circuit ① (VOUT Type)
Circuit ① (FB Type)
Circuit ②
Circuit ③
Circuit ④
Circuit ⑤
Circuit ⑥
Circuit ⑦
18/24
XC9201
Series
■TYPICAL PERFORMANCE CHARACTERISTICS
XC9201D09AKR
(1) Output Voltage vs. Output Current
19/24
XC9201 Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(2) Efficiency vs. Output Current
20/24
XC9201
Series
■TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
(3) Ripple Voltage vs. Output Current
*Note: If the input and output voltage differential is large or small, the time of ON and OFF switching will be shorten.
This gives external components such as inductance value of coil, connecting a resistor to CLK, capacitor, will critically influence the
actual operation.
21/24
XC9201 Series
■PACKAGING INFORMATION
●MSOP-8A
22/24
XC9201
Series
■MARKING RULE
●MSOP-8A
①Represents product series
MARK
PRODUCT SERIES
1
XC9201xxxAKx
②Represents product type, DC/DC controller
MARK
TYPE
PRODUCT SERIES
C
D
VOUT, CE PIN
FB, CE PIN
XC9201CxxAKx
XC9201C09AKx
③Represents integral number of output voltage or FB type
MSOP-8A
(TOP VIEW)
MARK
VOLTAGE
PRODUCT SERIES
1
2
3
4
5
6
7
8
9
0
A
B
C
D
E
F
H
1.x
2.x
3.x
4.x
5.x
6.x
7.x
8.x
9.x
FB products
10.x
11.x
12.x
13.x
14.x
15.x
16.x
XC9201C1xAKx
XC9201C2xAKx
XC9201C3xAKx
XC9201C4xAKx
XC9201C5xAKx
XC9201C6xAKx
XC9201C7xAKx
XC9201C8xAKx
XC9201C9xAKx
XC9201D09AKx
XC9201CAxAKx
XC9201CxAKx
XC9201CCxAKx
XC9201CDxAKx
XC9201CExAKx
XC9201CFxAKx
XC9201CHxAKx
④Represents decimal number of output voltage
MARK
VOLTAGE
PRODUCT SERIES
0
3
9
x.0
x.3
FB products
XC9201Cx0AKx
XC9201Cx3AKx
XC9201D09AKx
⑤Represents oscillation frequency's control type
MARK
VOLTAGE
PRODUCT SERIES
A
Adjustable Frequency
XC9201xxxxAKx
⑥⑦ Represents production lot number
0 to 9,A to Z repeated (G, I, J, O, Q, W excepted).
Note: No character inversion used.
23/24
XC9201 Series
1. The products and product specifications contained herein are subject to change without
notice to improve performance characteristics.
Consult us, or our representatives
before use, to confirm that the information in this catalog is up to date.
2. We assume no responsibility for any infringement of patents, patent rights, or other
rights arising from the use of any information and circuitry in this catalog.
3. Please ensure suitable shipping controls (including fail-safe designs and aging
protection) are in force for equipment employing products listed in this catalog.
4. The products in this catalog are not developed, designed, or approved for use with such
equipment whose failure of malfunction can be reasonably expected to directly
endanger the life of, or cause significant injury to, the user.
(e.g. Atomic energy; aerospace; transport; combustion and associated safety
equipment thereof.)
5. Please use the products listed in this catalog within the specified ranges.
Should you wish to use the products under conditions exceeding the specifications,
please consult us or our representatives.
6. We assume no responsibility for damage or loss due to abnormal use.
7. All rights reserved. No part of this catalog may be copied or reproduced without the
prior permission of Torex Semiconductor Ltd.
24/24