Series
PWM Controlled Step-Down DC/DC Converters
◆Input Voltage Range
: 2.5V ~20V
■Applications
◆Output Voltage Range
: 1.2V ~ 16V
●Mobile, Cordless phones
◆Oscillation Frequency Range : 100kHz ~
600kHz
: up to 3.0A
◆Output Current
◆Ceramic Capacitor Compatible
●Palm top computers, PDAs
●Portable games
●Cameras, Digital cameras
●Laptops
◆MSOP-8A Package
5
■General Description
■Features
The XC9201 series are step-up 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, VOUT is selectable in 0.1V steps within a
●Stable Operations via Current & Voltage Multiple Feedback
●Unlimited Options for Peripheral Selection
●Current Protection Circuit
●Ceramic Capacitor Compatible
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
100~600 kHz 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.
■Typical Application Circuit
■Typical Performance
Characteristic
22μH
VOUT:5.0V FOSC:330kHz
XP132A11A1SR
U3FWJ44N
Vss 8
2 Isen
VOUT 7
3 VIN
GAIN 6
33mΩ
240kΩ
4 CE/SS
94μF
0.33μF
1μF
CLK 5
40μF+220μF
10KΩ
470pF
220pF
Efficiency：EFFI (%)
100
1 EXT
80
60
VIN=5.4V
7.2V
40
10.0V
12.0V
20
15.0V
0
0.1
1
10
100
1000
10000
Output Current：IOUT（mA）
535
XC9201Series
■Pin Configuration
■Pin Assignment
EXT
1
8
VSS
Isen
2
7
VOUT／FB
VIN
3
6
CC／GAIN
CE／SS
4
5
CLK
PIN NUMBER
PIN NAME
FUNCTION
1
EXT
Driver
2
Isen
Current Sense
■Product Classification
3
VIN
Power Input
4
CE／SS
CE/Soft Start
5
CLK
Clock Input
6
CC／GAIN
Phase Compensation
7
VOUT／FB
Voltage Sense
8
VSS
Ground
●Ordering Information
ＸＣ９２０１
5
DESIGNATOR SYMBOL
C
D
Number
DESCRIPTION
Soft-start externally set-up
Soft-start externally set-up
Output Voltage : For voltages above 10V, see below :
VOUT
FB
10=A, 11=B, 12=C, 13=D, 14=E, 15=F, 16=H
e.g. VOUT=2.3V → w=2, e=3
VOUT=13.5V → w=D, e=5
FB products → w=0, e=9 fixed
Adjustable Frequency
MSOP-8A
Embossed tape. Standard Feed
Embossed tape. Reverse Feed
A
K
R
L
The standard output voltages of the XC9201C series are 2.5V, 3.3V, and 5.0V.
Voltages other than those listed are semi-custom.
●MSOP-8A
4.90±0.10
3.00±0.10
0.15 +0.08
-0.02
3.00±0.10
0.86 -0.10
+0.20
1.02 -0.21
+0.11
0∼
(0.65)
536
0.00∼0.20
+0.08
0.30 -0.02
0.53±0.13
■Packaging Information
6ﾟ
XC9201
Series
■Marking
q Represents the product series
SYMBOL
PRODUCT NAME
1
XC9201***AK*
MSOP8A
q w e
w Represents the product type, DC/DC converter
SYMBOL
TYPE
C
VOUT、CE PIN
D
FB、CE PIN
r t y
PRODUCT NAME
XC9201C**AK*
XC9201D09AK*
e Represents integral number of output voltage,or FB type
SYMBOL VOLTAGE
1
1. X
2
2. X
3
3. X
4
4. X
5
5. X
6
6. X
7
7. X
8
8. X
9
9. X
0
FB products
PRODUCT NAME
XC9201C1*AK*
XC9201C2*AK*
SYMBOL VOLTAGE
PRODUCT NAME
XC9201CA*AK*
XC9201CB*AK*
A
10. X
B
11. X
XC9201C3*AK*
XC9201C4*AK*
C
12. X
D
13. X
XC9201C5*AK*
XC9201C6*AK*
E
14. X
F
15. X
XC9201CE*AK*
XC9201CF*AK*
XC9201C7*AK*
XC9201C8*AK*
H
16. X
XC9201CH*AK*
XC9201CC*AK*
XC9201CD*AK*
5
XC9201C9*AK*
XC9201D09AK*
r Represents decimal number of output voltage
SYMBOL
VOLTAGE
0
X. 0
3
X. 3
XC9201C*0AK*
XC9201C*3AK*
9
FB products
XC9201D09AK*
PRODUCT NAME
t Represents oscillator frequeney's control type
SYMBOL
TYPE
PRODUCT NAME
A
Adjustable Frequency
XC9201***AK*
537
XC9201Series
■Block Diagram
EXT timming
controll
logic
EXT
Current
Limit
Protection
VSS
VOUT
R1
Verr
ISEN
Limitter comp.
PWM
VIN
Internal
Voltage
Regulator
R2
MIX
CC/GAIN
Ierr
2.0V
to internal
circuit
Ramp Wave,
Internal CLK
generator
Sampling
5
CE/SS
Chip Enable,
Soft Start up,
U.V.L.O.
CE,UVLO
to internal
circuit
CLK
Vref generator
■Absolute Maximum Ratings
538
RATINGS
0.9V
Ta=25℃
PARAMETER
SYMBOL
EXT Pin Voltage
VEXT
−0.3∼VDD＋0.3
Ｖ
ISEN Pin Voltage
VIsen
−0.3∼＋22
Ｖ
UNITS
VIN Pin Voltage
VIN
−0.3∼＋22
Ｖ
CE/SS Pin Voltage
VCE
−0.3∼＋22
Ｖ
CLK Pin Voltage
VCLK
−0.3∼VDD＋0.3
Ｖ
CC/GAIN Pin Voltage
VCC
−0.3∼VDD＋0.3
Ｖ
VOUT/FB Pin Voltage
VOUT/FB
−0.3∼＋22
Ｖ
EXT Pin Current
IEXT
±100
mA
Pd
150
mW
Continuous Total
Power Dissipation
Operating Ambient
Temperature
Topr
−40∼＋85
℃
Storage Temperature
Tstg
−55∼＋125
℃
XC9201
Series
■Electrical Characteristics
XC9201C25AR
Ta=25℃
PARAMETER
SYMBOL
Output Voltage
VOUT
Maximum Operating
Voltage
Minimum Operating
Voltage
CONDITIONS
IOUT=300mA
VINmax
UNITS CIRCUITS
MIN.
TYP.
MAX.
2.438
2.500
2.562
V
q
20
−
−
V
q
−
2.200
V
q
1.400
2.0
V
t
VIN=3.75V, CE=VIN=VOUT
115
220
μA
w
VIN=20.0V, CE=VIN, VOUT=VSS
130
235
μA
w
ISTB
VIN=3.75V, CE=VOUT=VSS
0.5
2.0
μA
w
CLK Oscillation
Frequency
FOSC
RT=10.0kΩ, CT=220pF
330
380
kHz
e
Frequency Input
Stability
ΔFOSC
±5
%
e
±5
%
e
%
r
%
r
VINmin
U.V.L.O. Voltage
VUVLO
Supply Current 1
IDD1
Supply Current 2
IDD2
Stand-by Current
ΔVIN･FOSC
Frequency Temperature ΔFOSC
Fluctuation
ΔTOPR･FOSC
−
EXT voltage = High
1.0
280
VIN=2.5V∼20V
VIN=3.75V
TOPR=−40∼+85℃
Maximum Duty Cycle MAXDTY
VOUT=VSS
Minimum Duty Cycle
MINDTY
VOUT=VIN
Current Limiter Voltage
ILIM
VIN pin voltage - ISEN pin voltage
90
150
220
mV
y
ISEN Current
IISEN
VIN=3.75V, ISEN=3.75V
4.5
7
13
μA
y
CE "High" Current
ICEH
CE=VIN=20.0V, VOUT=0V
−0.1
0
0.1
μA
t
CE "Low" Current
ICEL
CE=0V, VIN=20.0V, VOUT=0V
−0.1
0
0.1
μA
t
V
t
0.2
V
t
CE "High" Voltage
VCEH
Existance of CLK Oscillation,
100
0
0.6
5
VOUT=0V, CE：Voltage applied
CE "Low" Voltage
VCEL
Dissapearance of CLK Oscillation,
VOUT=0V, CE：Voltage applied
EXT "High"
ON Resistance
EXT "Low"
ON Resistance
REXTH
EXT=VIN−0.4V, CE=VOUT=VIN *1
27
40
Ω
r
REXTL
EXT=0.4V, CE=VIN, VOUT=VSS *1
24
33
Ω
r
Efficiency (NOTE1)
EFFI
%
q
Soft-start Time
TSS
ms
q
CC/GAIN Pin
Output Impedance
RCCGAIN
kΩ
u
93
Connect CSS and RSS, CE : 0V → 3.75V
5
10
400
20
VIN = 3.75V unless specified
*1 : On resistance = 0.4V / measurement current
NOTE1 : EFFI = {[(Output Voltage) x (Output Current)] ÷ [(Input Voltage) x (Input Current)]} x 100
NOTE2 : The capacity range of the condenser used to set the external CLK frequency is 180 ∼ 300pF
539
XC9201Series
XC9201C33AR
PARAMETER
Output Voltage
Maximum Operating
Voltage
Minimum Operating
Voltage
VOUT
VINmax
U.V.L.O. Voltage
VUVLO
CONDITIONS
IOUT=300mA
VINmin
MIN.
TYP.
MAX.
3.218
3.300
3.382
V
q
20
−
−
V
q
−
2.200
V
q
1.400
2.0
V
t
−
EXT voltage = High
1.0
UNITS CIRCUITS
Supply Current 1
IDD1
VIN=5.0V, CE=VIN=VOUT
115
220
μA
w
Supply Current 2
IDD2
VIN=20.0V, CE=VIN, VOUT=VSS
130
235
μA
w
Stand-by Current
ISTB
VIN=5.0V, CE=VOUT=VSS
0.5
2.0
μA
w
CLK Oscillation
Frequency
FOSC
RT=10.0kΩ, CT=220pF
330
380
kHz
e
Frequency
ΔFOSC
±5
%
e
Input Stability
ΔVIN･FOSC
±5
%
e
Frequency Temperature
Fluctuation
5
Ta=25℃
SYMBOL
ΔFOSC
280
VIN=2.5V∼20V
VIN=5.0V
ΔTOPR･FOSC Topr=−40∼+85℃
Maximum Duty Cycle MAXDTY
VOUT=VSS
Minimum Duty Cycle
Current Limiter
Voltage
MINDTY
VOUT=VIN
ILIM
VIN pin voltage - ISEN pin voltage
%
r
0
%
r
220
mV
y
100
90
150
ISEN Current
IISEN
VIN=5.0V, ISEN=5.0V
4.5
7
13
μA
y
CE "High" Current
ICEH
CE=VIN=20.0V, VOUT=0V
−0.1
0
0.1
μA
t
CE "Low" Current
ICEL
CE=0V, VIN=20.0V, VOUT=0V
−0.1
0
0.1
μA
t
V
t
0.2
V
t
24
33
Ω
r
22
31
Ω
r
%
q
ms
q
kΩ
u
CE "High" Voltage
VCEH
Existance of CLK Oscillation,
0.6
VOUT = 0V, CE : Voltage applied
CE "Low" Voltage
VCEL
Dissapearance of CLK Oscillation,
VOUT = 0V, CE : Voltage applied
EXT "High"
ON Resistance
EXT "Low"
ON Resistance
REXTH
EXT=VIN - 0.4V, CE=VOUT=VIN *1
REXTL
EXT=0.4V, CE=VIN, VOUT=VSS *1
Efficiency (NOTE1)
EFFI
Soft-start Time
TSS
CC/GAIN Pin
Output Impedance
93
Connect CSS and RSS, CE : 0V → 5.0V
5
RCCGAIN
VIN = 5.0V unless specified
*1 : On resistance = 0.4V / measurement current
NOTE1 : EFFI = {[(Output Voltage) x (Output Current)] ÷ [(Input Voltage) x (Input Current)]} x 100
NOTE2 : The capacity range of the condenser used to set the external CLK frequency is 180 ∼ 300pF
540
10
400
20
XC9201
Series
XC9201C50AR
Ta=25℃
PARAMETER
SYMBOL
Output Voltage
Maximum Operating
Voltage
Minimum Operating
Voltage
VOUT
VINmax
U.V.L.O. Voltage
VUVLO
CONDITIONS
IOUT=300mA
VINmin
MIN.
TYP.
MAX.
4.875
5.000
5.125
V
q
20
−
−
V
q
−
2.200
V
q
1.400
2.0
V
t
−
EXT voltage = High
1.0
UNITS CIRCUITS
Supply Current 1
IDD1
VIN=7.5V, CE=VIN=VOUT
115
220
μA
w
Supply Current 2
IDD2
VIN=20.0V, CE=VIN, VOUT=VSS
130
235
μA
w
Stand-by Current
ISTB
VIN=7.5V, CE=VOUT=VSS
0.5
2.0
μA
w
CLK Oscillation
Frequency
FOSC
RT=10.0kΩ, CT=220pF
330
380
kHz
e
Frequency
ΔFOSC
±5
%
e
Input Stability
ΔVIN･FOSC
±5
%
e
Frequency Temperature ΔFOSC
Fluctuation
ΔTOPR･FOSC
280
VIN=2.5V∼20V
VIN=7.5V
TOPR=−40∼+85℃
Maximum Duty Cycle MAXDTY
VOUT=VSS
Minimum Duty Cycle
Current Limiter
Voltage
MINDTY
VOUT=VIN
ILIM
VIN pin voltage - ISEN pin voltage
%
r
0
%
r
220
mV
y
100
90
150
ISEN Current
IISEN
VIN=7.5V, ISEN=7.5V
4.5
7
13
μA
y
CE "High" Voltage
ICEH
CE=VIN=20.0V, VOUT=0V
−0.1
0
0.1
μA
t
CE "Low" Voltage
ICEL
CE=0V, VIN=20.0V, VOUT=0V
−0.1
0
0.1
μA
t
V
t
0.2
V
t
CE "High" Voltage
VCEH
Existance of CLK Oscillation,
0.6
5
VOUT=0V, CE：Voltage applied
CE "Low" Voltage
VCEL
Dissapearance of CLK Oscillation,
VOUT=0V、CE：Voltage applied
EXT "High"
ON Resistance
EXT "Low"
ON Resistance
REXTH
VEXT=VIN−0.4V, CE=VOUT=VIN *1
21
29
Ω
r
REXTL
VEXT=0.4V, CE=VIN, VOUT=VSS *1
20
27
Ω
r
Efficiency (NOTE1)
EFFI
%
q
Soft-start Time
TSS
ms
q
kΩ
u
CC/GAIN Pin
Output Impedance
93
Connect CSS and RSS, CE : 0V → 7.5V
5
RCCGAIN
10
400
20
VIN = 7.5V unless specified
*1 : On resistance = 0.4V / measurement current
NOTE1 : EFFI = {[(Output Voltage) x (Output Current)] ÷ [(Input Voltage) x (Input Current)]} x 100
NOTE2 : The capacity range of the condenser used to set the external CLK frequency is 180 ∼ 300pF
541
XC9201Series
XC9201D09AR
SYMBOL
FB Voltage
Maximum Operating
Voltage
Minimum Operating
Voltage
VINmax
U.V.L.O. Voltage
VUVLO
Supply Current 1
IDD1
VFB
CONDITIONS
IOUT=300mA
MIN.
TYP.
MAX.
0.8775
0.900
0.9225
20
UNITS CIRCUITS
V
q
V
q
2.200
V
q
1.400
2.0
V
t
VIN=4.0V, CE=VIN=FB
115
220
μA
w
VINmin
EXT voltage = High
1.0
Supply Current 2
IDD2
VIN=20.0V, CE=VIN, FB=VSS
130
235
μA
w
Stand-by Current
ISTB
VIN=4.0V, CE=FB=VSS
0.5
2.0
μA
w
CLK Oscillation
Frequency
FOSC
RT=10.0kΩ, CT=220pF
330
380
kHz
e
±5
%
e
±5
%
e
%
r
Frequency
ΔFOSC
Input Stability
ΔVIN･FOSC
Frequency Temperature
Fluctuation
5
Ta=25℃
PARAMETER
ΔFOSC
VIN=2.5V∼20V
VIN=4.0V
ΔTOPR･FOSC TOPR=−40∼+85℃
Maximum Duty Cycle MAXDTY
FB=VSS
MINDTY
FB=VIN
Minimum Duty Cycle
Current Limiter
Voltage
280
ILIM
VIN pin voltage - ISEN pin voltage
100
90
150
0
%
r
220
mV
y
y
ISEN Current
IISEN
VIN=4.0V, ISEN=4.0V
4.5
7
13
μA
CE "High" Current
ICEH
CE=VIN=20.0V, FB=0V
−0.1
0
0.1
μA
t
CE "Low" Current
ICEL
CE=0V, VIN=20.0V, FB=0V
−0.1
0
0.1
μA
t
CE "High" Voltage
VCEH
V
t
0.2
V
t
27
40
Ω
r
24
34
Ω
r
%
q
ms
q
kΩ
u
Existance of CLK Oscillation,
0.6
FB=0V, CE：Voltage applied
CE "Low" Voltage
VCEL
Dissapearance of CLK Oscillation,
FB=0V、CE：Voltage applied
EXT "High"
ON Resistance
EXT "Low"
ON Resistance
REXTH
EXT=VIN−0.4V, CE=FB=VIN *1
REXTL
EXT=0.4V, CE=VIN, FB=VSS *1
Efficiency (NOTE1)
EFFI
Soft-start Time
TSS
CC/GAIN Pin
Output Impedance
93
Connect CSS and RSS, CE : 0V → 4.0V
5
RCCGAIN
VIN = 4.0V unless specified
External components : RFB1 = 200kΩ, RFB2 = 100kΩ, CFB = 82pF
*1 : On resistance = 0.4V / measurement current
NOTE1 : EFFI = {[(Output Voltage) x (Output Current)] ÷ [(Input Voltage) x (Input Current)]} x 100
NOTE2 : The capacity range of the condenser used to set the external CLK frequency is 180 ∼ 300pF
542
10
400
20
XC9201
Series
■Typical Application Circuits
XC9201C33AKR
22μH
PMOS
1
EXT
VSS 8
2
Isen
VOUT 7
3
VIN
4
CE/SS
3.3V
∼1.5A
50mΩ
SD
CC/GAIN 6
240kΩ
7.2V
47μF
470pF
CLK 5
220pF
1μF
∼30kΩ
47μF(OS) or
10μF(ceramic)×4
0.22μF
PMOS
Coil
: XP132A11A1SR(TOREX)
: 22µH(CR105 SUMIDA)
Resistor
: 50mΩ for Isen (NPR1 KOWA), 30kΩ(trimmer) for CLK, 240kΩ for SS
5
Capacitors : 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
SD
: U3FWJ44N(TOSHIBA)
XC9201C50AKR
22μH
5.0V
∼1.5A
PMOS
1
EXT
VSS 8
2
Isen
VOUT 7
3
VIN
4
CE/SS
20mΩ
SD
CC/GAIN 6
240kΩ
CLK 5
470pF
12.0V
47μF
0.33μF 1μF
+220μF
220pF
PMOS
Coil
: XP132A11A1SR(TOREX)
: 22µH(CDRH127 SUMIDA)
Resistor
: 20mΩ for Isen (NPR1 KOWA), 30kΩ(trimmer) for CLK, 240kΩ for SS
∼30kΩ
47μF(OS)
+220μF(any)
Capacitors : 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
SD
: U3FWJ44N(TOSHIBA)
543
XC9201Series
XC9201D09AKR
22μH
39pF
PMOS
1
EXT
VSS 8
2
Isen
VOUT 7
3
VIN
4
CE/SS
2.5V
∼3A
20mΩ
SD
CLK 5
7.2V
47μF
0.22μF
+220μF
220kΩ
CC/GAIN 6
240kΩ
5
390kΩ
220pF
1μF
470pF
47uF(OS)
+220μF(any)
∼30kΩ
PMOS
Coil
: XP132A11A1SR(TOREX)
: 22µH(CDRH127 SUMIDA)
Resistors
: 20mΩ for Isen (NPR1 KOWA), 30kΩ(trimmer) for CLK, 240kΩ for SS, 390kΩ for Output Voltage
100kΩ(trimmer) for 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
47μH
56pF
PMOS
1
EXT
VSS 8
2
Isen
FB 7
3
VIN
4
CE/SS
270kΩ
50mΩ
SD
CLK 5
20V
47μF
0.47μF
1μF
22kΩ
CC/GAIN 6
240kΩ
220pF
470pF
∼30kΩ
PMOS
Coil
: XP132A11A1SR(TOREX)
: 47µH(CR105 SUMIDA)
Resistor
: 50mΩ for Isen (NPR1 KOWA), 30kΩ(trimmer) for CLK, 240kΩ for SS, 270kΩ for 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
100pF(ceramic) for FB, 47µF(OS) +220µF(any) for CL, 47µF(tantalum)+220µF(any) for CIN
SD
544
12V
∼1.5A
: U3FWJ44N(TOSHIBA)
47μF(OS)
+220μF
XC9201
Series
■Operation Description
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 (2.0 V) 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 0.7 V and
0.15 V, 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 CE/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).
5
<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 sawtooth pulses generated at the CLK pin. If the signal is greater than the sawtooth 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 150 mV 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.
Limiter signal
/RESET
PWM/PFM switching signal
CLK sync signal
D
CLK
Q
Output signal to EXT pin
PWM/PFM switchinig signal
<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.
Undervoltage 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.
545
XC9201Series
●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 1.55 V rising from 0 V. 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=-0.1e-6 × 470e3 × In((5-1.55)/5)=17.44ms.
CE/SS pin
〔Inside the IC〕
Rss
Vcont
CE,
UVLO
Css
Vref circuit
Set the soft start time to a value sufficiently longer than the period of a clock pulse.
5
> Circuit example 1: N-ch open drain
Vcont
〔Inside the IC〕
Rss
CE/SS pin
ON/OFF signal
Css
> Circuit example 2: CMOS logic (low current dissipation)
Vcont
〔Inside the IC〕
Rss
ON/OFF signal
CE/SS pin
Css
> Circuit example 3: CMOS logic (low current dissipation), quick off
Vcont
〔Inside the IC〕
Rss
ON/OFF signal
CE/SS pin
Css
546
To Verr amplifier
XC9201
Series
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)
Example: When Cclk = 220 pF and Rclk = 10 kΩ, f = 1/(-220e-12 x 10e3 x ln(0.26)) = 337.43 kHz.
〔Inside the IC〕
CLK pin
Rclk
Cclk
CLK Generater
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 1,000 pF 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.
5
〔Inside the IC〕
CC/GAIN pin
VOUT/FB
Verr
CC
RGAIN
Vref
RVerr
4.Current Limiting
The current limiting 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 limiting, is assigned to the ISEN pin. The current limiting 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
〔Inside the IC〕
Isen pin
Rsen
Limiter signal
VIN pin
Comparator with
150-mV offset
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 the note on the RSEN resistor on page 18.
547
XC9201Series
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 MEG Ω or 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.
〔Inside the IC〕
Output voltage
Cfb
Rfb1
FB pin
Verr
Rfb2
5
0.9V
Verr amplifier
■Directions for use
●Application Notes
1. The 9201 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 inputoutput 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.
〔Inside the IC〕
EXT pin
Rb
VIN
Cb
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-limiting
voltage, the limit comparator typically takes 200nsec before it turns off the external resistor. During this time, the voltage across the RSEN
resistor can exceed the current-limiting 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.
548
XC9201
Series
●Recommended Pattern Layout
q In 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.
w In 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
P-MOS
L
CDD
CFB
RFB1
SD
1
5
2
6
3
7
4
8
VDD Line
CL
IC GND
RSEN
C_GAIN
R_SS
VIN
CIN
RFB2
5
Power GND
R_CLK
C_SS
C_CLK
Through Hole
1
5
2
6
3
7
4
8
R_CLK,C_CLK,C_GAIN,RFB2 GND
Through Hole
549
XC9201Series
1 layer Evaluation Board
P-MOS
L
CDD
CFB
SD
1
5
2
6
3
7
4
8
VDD Line
RFB1
CL
IC GND
RSEN
Power GND
R_SS
VIN CIN
C_SS
5
RFB2
R_CLK C_CLK C_GAIN
●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-MOSFET as a result of
switching losses.
Try to use a P-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
50mΩ or 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]
550
0.5W, 100mΩ resistor should be used
XC9201
Series
■Test Circuits
・Fig. 1 (FB Type)
・Fig. 1 (VOUT Type)
47μH
22μH
PMOS
PMOS
SD
1 EXT
Vss 8
2 Isen
VOUT 7
SD
3 VIN
1μF
RL
GAIN 6
4 CE/SS CLK 5
47μF
2 Isen
Vss 8
FB 7
100mΩ
100mΩ
R_SS
RFB1
CFB
1 EXT
10KΩ
220pF
3 VIN
240kΩ
1μF
20μF
C_SS
V
RFB2
GAIN 6
47μF
470pF
20KΩ
470pF
V
RL
4 CE/SS CLK 5
22μF
165pF
0.047μF
XC9201C25A R_SS：188kΩ C_SS：0.1μF
XC9201C33A R_SS：270kΩ C_SS：0.1μF
XC9201C50A R_SS：430kΩ C_SS：0.1μF
・Fig. 2
・Fig. 3
1 EXT
1 EXT
Vss 8
3 VIN
5
Vss 8
2 IsenVOUT/FB 7
2 IsenVOUT/FB 7
3 VIN
GAIN 6
GAIN 6
4 CE/SS CLK 5
A
4 CE/SS CLK 5
220pF
・Fig. 4
OSC
10KΩ
0.1μF
10KΩ
0.1μF
220pF
・Fig. 5
H
1 EXT
A
1 EXT
Vss 8
L
3 VIN
3 VIN
GAIN 6
0.1μF
4 CE/SS CLK 5
A
220pF
10KΩ
220pF
・Fig. 6
V
・Fig. 7
1 EXT
1 EXT
Vss 8
3 VIN
A
3 VIN
GAIN 6
4 CE/SS CLK 5
0.1μF
Vss 8
2 IsenVOUT/FB 7
2 IsenVOUT/FB 7
V
GAIN 6
4 CE/SS CLK 5
10KΩ
0.1μF
Vss 8
2 IsenVOUT/FB 7
V
2 IsenVOUT/FB 7
GAIN 6
4 CE/SS CLK 5
220pF
0.1μF
1MΩ
V
10KΩ
551
XC9201Series
■Typical Performance Characteristics
XC9201D09AKR
(1) OUTPUT VOLTAGE vs. OUTPUT CURRENT
VOUT 1.5V, FOSC : 330kHz
VOUT 3.3V, FOSC : 330kHz
L=22µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
RSEN=50mΩ, CDD=1µF (Ceramic), SD:U3FWJ44N
L=22µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
RSEN=50mΩ, CDD=1µF (Ceramic), SD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP162A11C0PR
CGAIN=470pF (Ceramic), Tr:XP162A11C0PR
3.5
5
Output Voltage : VOUT (V)
Output Voltage : VOUT (V)
1.7
1.6
1.5
1.4
VIN=3.3V
5.0V
7.2V
3.4
3.3
VIN=4.0V
6.0V
8.0V
10.0V
12.0V
3.2
3.1
1.3
0.1
1
10
100
1000
0.1
10000
10
100
1000
10000
Output Current : IOUT (mA)
Output Current : IOUT (mA)
VOUT 5.0V, FOSC : 330kHz
VOUT 12.0V, FOSC : 100kHz
L=22µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
RSEN=50mΩ, CDD=1µF (Ceramic), SD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP162A11C0PR
L=68µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
RSEN=50mΩ, CDD=10µF (Ceramic), SD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP132A11C0PR
12.2
5.1
5.0
VIN=8.0V
10.0V
12.0V
15.0V
4.9
Output Voltage : VOUT (V)
5.2
Output Voltage : VOUT (V)
1
12.1
12.0
11.9
VIN=18.0V
4.8
11.8
0.1
1
10
100
1000
Output Current : IOUT (mA)
552
10000
0.1
1
10
100
1000
Output Current : IOUT (mA)
10000
XC9201
Series
(2) EFFICIENCY vs. OUTPUT CURRENT
VOUT 1.5V, FOSC : 330kHz
VOUT 3.3V, FOSC : 330kHz
L=22µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
L=22µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
RSEN=50mΩ, CDD=1µF (Ceramic), SD:U3FWJ44N
RSEN=50mΩ, CDD=1µF (Ceramic), SD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP162A11C0PR
100
80
80
Efficiency : EFFI (%)
Efficiency : EFFI (%)
CGAIN=470pF (Ceramic), Tr:XP162A11C0PR
100
60
VIN=3.3V
40
5.0V
20
60
6.0V
40
VIN=4.0V
8.0V
10.0V
20
7.2V
12.0V
0
0
0.1
1
10
100
1000
10000
0.1
Output Current : IOUT (mA)
1
10
100
1000
10000
Output Current : IOUT (mA)
5
VOUT 5.0V, FOSC : 330kHz
VOUT 12.0V, FOSC : 100kHz
L=22µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
L=68µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
RSEN=50mΩ, CDD=10µF (Ceramic), SD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP132A11C0PR
100
100
80
80
60
Efficiency : EFFI (%)
Efficiency : EFFI (%)
RSEN=50mΩ, CDD=1µF (Ceramic), SD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP162A11C0PR
10.0
40
VIN=8.0V
12.0V
15.0V
20
60
40
20
VIN=18.0V
0
0
0.1
1
10
100
1000
Output Current : IOUT (mA)
10000
0.1
1
10
100
1000
10000
Output Current : IOUT (mA)
553
XC9201Series
(3) RIPPLE VOLTAGE vs. OUTPUT CURRENT
VOUT 1.5V, FOSC : 330kHz
VOUT 3.3V, FOSC : 330kHz
L=22µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
RSEN=50mΩ, CDD=1µF (Ceramic), SD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP162A11C0PR
L=22µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
RSEN=50mΩ, CDD=1µF (Ceramic), CD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP162A11C0PR
100
VIN=3.3V
5.0V
7.2V
80
Ripple Voltage : Vr (mVp-p)
Ripple Voltage : Vr (mVp-p)
100
60
40
20
0
10.0V
80
12.0V
8.0V
60
6.0V
40
VIN=4.0V
20
0
0.1
1
10
100
1000
10000
0.1
Output Current : IOUT (mA)
5
1
10
100
1000
10000
Output Current : IOUT (mA)
VOUT 5.0V, FOSC : 330kHz
VOUT 12.0V, FOSC : 100kHz
L=22µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
L=68µH, CL=40µF (Ceramic), CIN=30µF (Ceramic)
RSEN=50mΩ, CDD=1µF (Ceramic), SD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP162A11C0PR
RSEN=50mΩ, CDD=10µF (Ceramic), SD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP132A11C0PR
100
100
15.0V
12.0V
60
10.0V
VIN=8.0V
40
20
Ripple Voltage : Vr (mVp-p)
Ripple Voltage : Vr (mVp-p)
VIN=18.0V
80
80
60
40
20
0
0
0.1
1
10
100
1000
0.1
10000
Output Current : IOUT (mA)
10
100
1000
10000
VOUT 1.5V, FOSC : 330kHz
VOUT 3.3V, FOSC : 330kHz
L=22µH, CL=47µF (Tantalum), CIN=47µF (Tantalum)
RSEN=50mΩ, CDD=1µF (Ceramic), SD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP162A11C0PR
L=22µH, CL=47µF (Tantalum), CIN=47µF (Tantalum)
RSEN=50mΩ, CDD=1µF (Ceramic), SD:U3FWJ44N
CGAIN=470pF (Ceramic), Tr:XP162A11C0PR
100
80
Ripple Voltage : Vr (mVp-p)
100
Ripple Voltage : Vr (mVp-p)
1
Output Current : IOUT (mA)
7.2V
60
VIN=3.3V
5.0V
40
20
12.0V
80
8.0V 10.0V
6.0V
60
VIN=4.0V
40
20
0
0
0.1
1
10
100
1000
Output Current : IOUT (mA)
10000
0.1
1
10
100
1000
10000
Output Current : IOUT (mA)
*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, condenser, will critically influence the
actual operation.
554