XC9128/XC9129 Series
ETR0411-006
1A Driver Transistor Built-In, Step-Up DC/DC Converters
■GENERAL DESCRIPTION
The XC9128/XC9129 series are synchronous step-up DC/DC converters with a 0.2Ω (TYP.) N-channel driver transistor and a
synchronous 0.2Ω (TYP.) P-channel switching transistor built-in. A highly efficient and stable current can be supplied up to
1.0A by reducing ON resistance of the built-in transistors. With a high switching frequency of 1.2MHz, a small inductor is
selectable making the series ideally suited for applications requiring low profile or space saving solutions. With the MODE
pin, the series provides mode selection of PWM control or PFM/PWM automatic switching control. In the PWM/PFM
automatic switching mode, the series switches from PWM to PFM to reduce switching loss when load current is small.
When load current is large, the series switches automatically to the PWM mode so that high efficiency is achievable over a
wide range of load conditions. The series also provides small output ripple from light to large loads by using the built-in
circuit which enables the smooth transition between PWM and PFM. With a adaptor enable function of the XC9128 series,
when a voltage higher than the input voltage is applied to the output, the input and the output become isolated making it
possible for the IC to work in parallel with the likes of an AC adaptor.
■APPLICATIONS
■ FEATURES
●Digital audio equipment
High Efficiency, Large Current Step-Up Converter
Output Current
: 150mA＠VOUT=3.3V, VIN=0.9V
500mA＠VOUT=3.3V, VIN=1.8V
Input Voltage Range
: 0.8V~6.0V
Output Voltage Setting
: 1.8V~5.3V (Externally set)
Range
Set up freely with a reference voltage
supply of 0.45V (±0.010V) & external
components
Oscillation Frequency
: 1.2MHz (Fixed oscillation frequency
accuracy ±15%)
Input Current
: 1.0A
Maximum Current Limit
: 1.2A (MIN.), 2.0A (MAX.)
Control
: PWM, PWM/PFM control
externally selectable
High Speed
:100mV @ VOUT=3.3V,
Transient Response
VIN=1.8V, IOUT=10mA→100mA
Protection Circuits
: Thermal shutdown
: Integral latch method (Over current
limit)
Soft-Start Time
: 5ms (TYP.) internally set
●Digital cameras, Video equipment
●Computer Mice
●Various multi-function power supplies using alkali cells (1
to 3 cells), nickel hydride batteries, or single lithium cells
Ceramic Capacitor Compatible
Adaptor Enable Function (XC9128 series)
Packages
: MSOP-10, USP-10B, SOP-8
Flag Output (XC9128 series) : Open-drain output
■TYPICAL APPLICATION CIRCUIT
■TYPICAL PERFORMANCE
CHARACTERISTICS
●Efficiency vs. Output Current
1
L
EN
FO
2
PGND
Lx
3
BAT
4
EN
5
FO
VOUT
MODE
MODE
9
FB
8
AGND
AEN/
XC9128B45CDx
VOUT
10
CFB
RFB1
VOUT=5.0V, fOSC=1.2MHz
CL
(ceramic)
L=4.7μH (CDRH4D28C), CIN=10μF, CL=32μF
100
7
6
RFB2
80
Efficiency : EFFI (%) CIN
VIN
60
3.7V
VIN=1.8V
40
20
PWM(MODE:H)
PWM/PFM(MODE:L)
0
0.1
1
10
100
Output Current : IOUT (mA)
1000
Output Current: IOUT (mA)
1/13
XC9128/XC9129 Series
■PIN CONFIGURATION
10 VOUT
PGND 1
Lx 2
9 MODE
BAT 3
7 AGND
FO 5
6 AEN/
6 AEN/
EN 4
7 AGND
USP-10B
(BOTTOM VIEW)
XC9128 Series
7 MODE
NC 5
6 NC
EN 4
7 AGND
8 FB
BAT 3
9 MODE
Lx 2
6 FB
BAT 3
10 VOUT
PGND 1
8 VOUT
Lx 2
9 MODE
Lx 2
MSOP-10
(TOP VIEW)
PGND 1
8 FB
BAT 3
8 FB
EN 4
FO 5
10 VOUT
PGND 1
5 AGND
EN 4
USP-10B
(BOTTOM VIEW)
XC9129 Series
SOP-8
(TOP VIEW)
Under Development
■PIN ASSIGNMENT
MSOP-10*
1
2
3
4
5
6
7
8
9
10
-
PIN NUMBER
USP-10B*
USP-10B*
(XC9128)
(XC9129)
1
1
2
2
3
3
4
4
5
6
7
7
8
8
9
9
10
10
5, 6
SOP-8 **
1
2
3
4
5
6
7
8
-
PIN NAME
FUNCTION
PGND
Lx
BAT
EN
FO
AEN/
AGND
FB
MODE
VOUT
NC
Power Ground
Output of Internal Power Switch
Battery Input
Chip Enable
Flag Output
Adaptor Enable
Analog Ground
Output Voltage Monitor
Mode Switch
Output Voltage
No Connection
* For MSOP-10 and USP-10B packages, please short the GND pins (pins 1 and 7).
*The dissipation pad for the USP-10B package should be solder-plated following the recommended mount pattern and metal masking
so as to enhance mounting strength and heat release. If the pad needs to be connected to other pins, it should be connected to the
Ground pins (pins 1 and 7).
** For SOP-8 package, please short the GND pins (pins 1 and 5).
2/13
XC9128/XC9129
Series
■FUNCTION CHART
1. EN, AEN/ Pin Function
●XC9128 Series
AEN/ PIN
FB PIN VOLTAGE
IC OPERATIONAL STATE
SOFT-START FUNCTION
L→H
L
-
Operation
Available
H
H→L
Lower than 0.45×0.8V
Operation
Available
H
H→L
Higher than 0.45×0.95V
Operation
Not Available
-
EN PIN
H
H
-
Step-Up Operation
Shut-Down
L
L
-
Disable
-
L
H
-
Disable
-
* Do not leave the EN and AEN/ Pins open.
●XC9129 Series
EN PIN
IC OPERATIONAL STATE
H
Operation
L
Disable
* Do not leave the EN Pin open.
2. MODE Pin Function
●XC9128/XC9129 Series
MODE PIN
H
L
FUNCTION
PWM Control
PWM/PFM Automatic Switching Control
■PRODUCT CLASSIFICATION
●Ordering Information
XC9128①②③④⑤⑥-⑦
*1)
XC9129①②③④⑤⑥-⑦
*1)
・・・・ MSOP-10, USP-10B
・・・・ USP-10B
SOP-8 (Under Development)
DESIGNATOR
DESCRIPTION
SYMBOL
①
Transistor Built-In,
Output Voltage Freely Set (FB voltage),
Integral Protection Type
B
With integral protection
D
Without integral protection
②③
Reference Voltage
45
④
Oscillation Frequency
C
AR
⑤⑥-⑦
Packages
Taping Type (*2)
AR-G
DR
DR-G
SR
(*1)
(*2)
DESCRIPTION
Fixed reference voltage 0.45Ｖ
②=4, ③=5
1.2MHz
MSOP-10
MSOP-10 (Halogen & Antimony free)
USP-10B
USP-10B (Halogen & Antimony free)
SOP-8 (under development)
The “-G” suffix indicates that the products are Halogen and Antimony free as well as being fully RoHS compliant.
The device orientation is fixed in its embossed tape pocket. For reverse orientation, please contact your local Torex sales office or
representative. (Standard orientation: ⑤R-⑦, Reverse orientation: ⑤L-⑦)
3/13
XC9128/XC9129 Series
■BLOCK DIAGRAM
●XC9128 Series
* XC9129 Series
The XC9129 series does not have AEN/ pin and FO pin.
■ABSOLUTE MAXIMUM RATINGS
Ta=25℃
PARAMETER
SYMBOL
RATINGS
UNITS
VOUT Pin Voltage
AEN/ Pin Voltage (*2)
FO Pin Voltage (*2)
FO Pin Current (*2)
FB Pin Voltage
BAT Pin Voltage
MODE Pin Voltage
EN Pin Voltage
LX Pin Voltage
LX Pin Current
MSOP-10
USP-10B
Power Dissipation
SOP-8
(Under Development)
Operating Temperature Range
Storage Temperature Range
VOUT
VAEN/
VFO
IFO
VFB
VBAT
VMODE
VEN
VLx
ILx
- 0.3～6.5
- 0.3～6.5
- 0.3～6.5
10
- 0.3～6.5
- 0.3～6.5
- 0.3～6.5
- 0.3～6.5
- 0.3～VOUT+0.3
2000
350 (*1)
150
V
V
V
mA
V
V
V
V
V
mA
Pd
Topr
Tstg
- 40～+85
- 55～+125
AGND, PGND is the standard voltage for all of voltages.
*1: When implemented on a PCB.
*2: The XC9129 series does not have AEN/ pin and FO pin. These pins are available only in the XC9128 series.
4/13
mW
300
o
o
C
C
XC9128/XC9129
Series
■ELECTRICAL CHARACTERISTICS
Topr=25 oC
XC9128/XC9129 Series
PARAMETER
SYMBOL
CONDITIONS
Input Voltage
VIN
-
MIN.
TYP.
MAX.
UNITS
CIRCUIT
-
-
6.0
V
-
0.44
0.45
0.46
V
④
1.8
-
5.3
V
①
-
-
0.8
V
①
-
-
0.9 (*1)
V
①
-
0.8
-
V
①
-
0.7
-
V
①
mA
②
μA
②
(*8)
Oscillation Start Voltage
VST2
Operation Hold Voltage
VHLD
VOUT=VIN=3.3V, VFO=0V
Voltage to start oscillation during
VFB= 0.46V → 0.44V
Connect to external components,
RL=1kΩ
Connect to external components,
RL=33Ω
Voltage to start oscillation during
VIN=0V → 1V, RL=1kΩ
Connect to external components, RL=1kΩ
Supply Current 1
IDD1
VIN = VOUT =3.3V, VFB=0.45×0.9
-
3
6
VIN = VOUT =3.3V
VFB=0.45×1.1 (Oscillation stop),
VMODE=0V
VIN =3.3V, VOUT =1.8V, VEN=0V
-
30
80
-
28
78
-
2
10
μA
③
-
2
10
μA
②
1.02
1.20
1.38
MHz
④
85
92
96
%
④
-
-
0
%
④
-
250
400
mA
①
-
93
-
%
①
-
0.20
0.35 (*1)
Ω
⑤
FB Voltage
VFB
Output Voltage Setting Range
VOUTSET
Operation Start Voltage
VST1
Supply Current 2 (XC9128)
Supply Current 2 (XC9129)
IDD2
Input Pin Current
IBAT
Stand-by Current
ISTB
Oscillation Frequency
fOSC
Maximum Duty Cycle
DMAX
Minimum Duty Cycle
DMIN
PFM Switching Current
IPFM
Efficiency (*2)
EFFI
LX SW "Pch" ON Resistance
RLxP
LX SW "Nch" ON Resistance
RLxN
VIN=VOUT=3.3V, Lx =50mV (*4)
-
0.20 (*1)
0.35 (*1)
Ω
⑦
LX Leak Current
ILXL
VIN=VOUT= VLX, VFB=0V
-
1
-
μA
⑤
VOUT>2.5V
1.2
1.5
2.0
A
①
-
3.5
-
ms
①
1.7
5.3
10.5
ms
④
-
0.02
0.04
ms
④
1.7
5.3
10.5
ms
④
Current Limit
(*5)
Integral Latch Time (XC9128)
ILIM
(*6)
Integral Latch Time (XC9129) (*6)
tLAT
Soft-Start Time 1
tSS1
Soft-Start Time 2 (*7)
tSS2
Soft-Start Time 3 (*7)
tSS3
Thermal Shutdown
Temperature
Hysteresis Width
VIN = VOUT =3.3V, VEN=0V
(*8)
VIN = VOUT =3.3V, VFO=0V ,
VFB=0.45×0.9
VIN = VOUT =3.3V, VFO=0V (*8),
VFB=0.45×0.9
VIN = VOUT =3.3V, VFO=0V (*8),
VFB=0.45×1.1
Connect to external components,
VMODE=0V, RL=330Ω
Connect to external components,
RL=33Ω
VIN=VLx=VOUT+50mV,
VFB=0.45×1.1 (*3)
Time to stop oscillation during
RL=33Ω → 3.3Ω, VFO=L → H
Time to stop oscillation during
RL=33Ω → 3.3Ω
Time to start oscillation during VEN=0V
→ VIN at VIN = VOUT =3.3V, VFO=0V,
VFB=0.45×0.95
VIN = VOUT =3.3V, VFO=0V,
VFB=0.45×0.95
Time to start oscillation during
VAEN/=VIN→0V.
VIN = VOUT =3.3V, VFO=0V,
VFB=0.45×0.8
Time to start oscillation during
VAEN/=VIN→0V
TTSD
-
-
150
-
o
C
-
THYS
VIN =3.3V
Voltage to stop oscillation during
VOUT=1.56V→1.3V
VIN =VOUT=3.3V, VFO=0.25V
-
20
-
o
C
-
1.3
1.48
1.56
V
⑥
1.3
1.7
2.2
mA
④
VIN = VOUT =3.3V, VEN=0V ,VFO=1V
-
0
1
μA
④
Output Voltage Drop
Protection (*6)
VLVP
FO Output Current (*7)
FO Leakage Current (*7)
IFO_OUT
IFO_Leak
5/13
XC9128/XC9129 Series
■ELECTRICAL CHARACTERISTICS (Continued)
Topr=25 oC
●XC9128/XC9129 Series (Continued)
PARAMETER
SYMBOL
CONDITIONS
MIN.
TYP.
MAX.
UNITS
CIRCUIT
0.65
-
6.0
V
④
-
-
0.2
V
④
(*8)
EN "H" Voltage
VENH
VIN =VOUT=3.3V, VFO=0V
Voltage to start oscillation during
VFB=0.45×0.9, VEN= 0.2V→0.65V
VIN = VOUT =3.3V, VFO=0V (*8)
Voltage to stop oscillation during
VFB=0.45×0.9,
VEN= 0.65V→0.2V
EN "L" Voltage
VENL
MODE "H" Voltage
VMODEH
RL =330Ω, Voltage operates at PWM control
0.65
-
6.0
V
①
MODE "L" Voltage
VMODEL
RL =330Ω, Voltage operates at PFM control
AGND
-
0.2
V
①
VAEN/
VIN = VOUT =3.3V, VFO=0V
Voltage to start oscillation during VAEN/= 0.9V→0.7V
0.7
0.8
0.9
V
④
EN "H" Current
IENH
VIN=VOUT=VFB=VEN=6.0V
-
-
0.1
μA
②
EN "L" Current
IENL
VIN=VOUT=VFB=6.0V, VEN=0V
-0.1
-
-
μA
②
MODE "H" Current
IMODEH
VIN=VOUT=VFB=VMODE=6.0V
-
-
0.1
μA
②
MODE "L" Current
AEN/ Voltage
(*7)
IMODEL
VIN=VOUT=VFB=6.0V, VMODE=0V
-0.1
-
-
μA
②
AEN/ "H" Current
(*7)
IAEN/H
VIN=VOUT=VFB=VAEN/=6.0V
-
-
0.1
μA
②
AEN/ "L" Current
(*7)
IAEN/L
VIN=VOUT=6.0V, VEN=0V, VAEN/=0V
-0.1
-
-
μA
②
FB "H" Current
IFBH
VIN=VOUT=VFB=6.0V
-
-
0.1
μA
②
FB "L" Current
IFBL
VIN=VOUT=6.0V, VFB=0V
-0.1
-
-
μA
②
Test Conditions:
For the Circuit No.1, unless otherwise stated, VIN=1.8V, VEN=VMODE=VFO=3.3V, VAEN/=0V
（*8）
For the Circuit No.2, unless otherwise stated, VIN=1.8V, VFB =0V, VEN=VMODE=3.3V, VAEN/=0V
（*8）
For the Circuit No.3, unless otherwise stated, VIN=1.8V, VOUT=VEN=VMODE=3.3V, FB=0V
For the Circuit No.4, unless otherwise stated, VIN=1.8V, VFB=0V, VEN=VMODE=Vpull=VFO=3.3V, VAEN/ =0V
For the Circuit No.5, unless otherwise stated, VIN=3.3V, VAEN/=0V
（*8）
（*8）
For the Circuit No.6, unless otherwise stated, VEN=VMODE=Vpull=VFO=3.3V, VFB=0V
（*8）
For the Circuit No.7, unless otherwise stated, VEN=VMODE=3.3V
External Components:
For the Circuit No.1, RFB1=270kΩ, RFB2=43kΩ, CFB=12pF, L=4.7μH（LTF5022 TDK）, CL1=22μF（ceramic）, CL2=10
μF（ceramic）, CIN=10μF（ceramic）
For the Circuit No.2,3, CIN=1μF（ceramic）
For the Circuit No.4,6, CIN=1μF（ceramic）, Rpull=300Ω
For the Circuit No.5, CIN=1μF（ceramic）, COUT=1μF（ceramic）
For the Circuit No.7, CIN=1μF（ceramic）, COUT=1μF（ceramic）, SBD =XBS304S17（TOREX）, Rpull=0.5Ω
*
1 : Designed value
*
2 : Efficiency ={(output voltage) X (output current)} ÷ {(input voltage) X (input current)} X 100
*
3 : LX SW "P-ch" ON resistance=（VLx-VOUT pin test voltage）÷100mA
*
4 : Testing method of LX SW "N-ch" ON resistance is stated at test circuits.
*
5 : Current flowing through the Nch driver transistor is limited.
*
6 : The XC9128D/XC9129D series does not have integral latch protection and VLVP function.
This is only available with the XC9128B/XC9129B series.
*
These pins are only available in the XC9128 series.
*
The AEN/FO functions are only effective for the test of the XC9128 series.
7 : The XC9129 series does not have FO and AEN/ pins.
8 : The XC9129 series does not have FO and AEN/ pins.
6/13
XC9128/XC9129
Series
■TYPICAL APPLICATION CIRCUIT
<Output Voltage Setting>
Output voltage can be set by adding external split resistors. Output voltage is determined by the following equation,
based on the values of RFB1 and RFB2. The sum of RFB1 and RFB2 should normally be 500kΩ or less.
VOUT=0.45 × (RFB1 + RFB2) / RFB2
The value of CFB, speed-up capacitor for phase compensation, should be fZFB = 1 / (2 x π x CFB1 x RFB1) which is in
the range of 10 kHz to 50 kHz. Adjustments are depending on application, inductance (L), load capacitance (CL) and
dropout voltage.
[Example of calculation]
When RFB1=270kΩ, RFB2=43kΩ,
VOUT1 = 0.45 × (270k+43k ) / 43k = 3.276V
[Typical example]
VOUT (V)
RFB1 (kΩ)
RFB2 (kΩ)
CFB (pF)
1.8
2.5
3.3
5.0
300
270
270
180
100
59
43
17.8
10
12
12
15
[External Components]
1.2MHz:
L : 4.7μH (CDRH4D28C SUMIDA)
CL1: 22μF (ceramic)
CL2: 10μF (ceramic)
CIN: 10μF (ceramic)
* CL1 should be selected in 10μF or higher.
Capacitance CL1 + CL2 is recommended 30μF or higher. (Ceramic capacitor compatible)
If CL1 is lower than 10μF, operation may be unstable.
In case of the usage CL1 + CL2 ＜30μF, output ripple may increase so that we recommend that you fully
check actual performance on the board.
* If using Tantalum or Electrolytic capacitors please be aware that ripple voltage will be higher due to the larger
ESR (Equivalent Series Resistance) values of those types of capacitors. Please also note that the IC’s
operation may become unstable with such capacitors so we recommend that you fully check actual
performance.
7/13
XC9128/XC9129 Series
■OPERATIONAL EXPLANATION
The XC9128/XC9129 series consists of a reference voltage source, ramp wave circuit, error amplifier, PWM comparator,
phase compensation circuit, N-channel driver transistor, P-channel synchronous rectification switching transistor and current
limiter circuit. The error amplifier compares the internal reference voltage with the FB pin feed back voltage via resistors
RFB1 and RFB2. Phase compensation is performed on the resulting error amplifier output, to input a signal to the PWM
comparator to determine the turn-on time of the N-channel driver transistor 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 N-channel driver
transistor’s turn-on 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.
<Reference Voltage Source>
The source provides the reference voltage to ensure stable output of the DC/DC converter.
<Ramp Wave Circuit>
The ramp wave circuit determines switching frequency. The frequency is fixed internally at 1.2MHz. The Clock generated
is used to produce ramp waveforms needed for PWM operation, and to synchronize all the internal circuits.
<Error Amplifier>
The error amplifier is designed to monitor output voltage. The amplifier compares the reference voltage with the feedback
voltage divided by the internal resistors (RFB1 and RFB2). When the FB pin is lower than the reference voltage, output
voltage of the error amplifier increases. The gain and frequency characteristics of the error amplifier are optimized
internally.
< Maximum Current Limit>
The current limiter circuit monitors the maximum current flowing through the N-channel driver transistor connected to the Lx
pin, and features a combination of the current limit and latch function.
1 When the driver current is greater than a specific level (equivalent to peak coil current), the maximum current limit
function starts to operate and the pulses from the Lx pin turn off the N-channel driver transistor at any given time.
2When the driver transistor is turned off, the limiter circuit is then released from the maximum current limit detection state.
3At the next pulse, the driver transistor is turned on. However, the transistor is immediately turned off in the case of an
over current state.
4 When the over current state is eliminated, the IC resumes its normal operation.
The XC9128B/XC9129B series waits for the over current state to end by repeating the steps 1 through 3. If an over current
state continues for several ms and the above three steps are repeatedly performed, the IC performs the function of latching the
OFF state of the N-channel driver transistor, and goes into operation suspension mode. After being put into suspension mode,
the IC can resume operation by turning itself off once and then re-starting via the EN pin, or by restoring power to the V IN pin.
The XC9128D/XC9129D series does not have this latch function, so operation steps 1 through 3 repeat until the over current
state ends.
Integral latch time may be released from a over current detection state because of the noise. Depending on the state of a
substrate, it may result in the case where the latch time may become longer or the operation may not be latched. Please locate
an input capacitor as close as possible.
Limit<# ms
8/13
Limit<# ms
XC9128/XC9129
Series
■OPERATIONAL EXPLANATION (Continued)
<Thermal Shutdown>
For protection against heat damage, the thermal shutdown function monitors chip temperature. When the chip’s
temperature reaches 150OC (TYP.), the thermal shutdown circuit starts operating and the driver transistor will be turned off.
At the same time, the output voltage decreases. When the temperature drops to 130OC (TYP.) after shutting off the current
flow, the IC performs the soft start function to initiate output startup operation.
<MODE>
The MODE pin operates in PWM mode by applying a high level voltage and in PFM/PWM automatic switching mode by
applying a low level voltage.
<Shut-Down>
The IC enters chip disable state by applying low level voltage to the EN pin. At this time, the P-ch synchronous switching
transistor turns on when VIN>VOUT and vise versa the transistor turns off when VIN<VOUT.
<Adaptor Enable>
While the XC9128 series using step-up DC/DC converters in parallel with an added power source such as AC adaptors, the
circuit needs the step-up DC/DC converter to be transient-efficient for sustaining output voltage in case the added power source
runs down. The AEN/ pin voltage determines whether the added power source is supplied or not so that high-speed following
operation is possible. The IC starts operating although the driver transistor is off when a high level voltage is applied to the
AEN/ pin after a high level voltage is also applied to the EN pin. If the AEN/ pin voltage changes from high level to low level
while the EN pin sustains a high level voltage, the step-up operation starts with high-speed following mode (without soft-start).
The XC9129 series does not have adaptor enable function.
<Error Flag >
For the XC9128 series, the FO pin becomes high impedance during over current state, over temperature state, soft-start period,
and shut-down period.
The XC9129 series does not have flag out function.
■NOTE ON USE
1. Please do not exceed the stated absolute maximum ratings values.
2. The DC/DC converter / controller IC's performance is greatly influenced by not only the ICs' characteristics, but also by
those of the external components. Care must be taken when selecting the external components.
3. 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 of the IC.
4. Please mount each external component as close to the IC as possible and use thick, short traces to reduce the circuit
impedance.
5. When the device is used in high step-up ratio, the current limit function may not work during excessive load current. In this
case, the maximum duty cycle limits maximum current.
6. When the adaptor enable function is used in the below circuit, please use a diode with low reverse bias current. The sum of
RAEN1’s and RAEN2’s resistance should be set to manage the reverse bias current.
9/13
XC9128/XC9129 Series
■NOTE ON USE (Continued)
7. P-ch synchronous switching transistor operation
The parasitic diode of the P-ch synchronous transistor is placed between Lx (anode) and VOUT (cathode), so that the
power line can not be turned off from Lx to VOUT. On the other hand, the power line switch from VOUT to Lx is shown in the
table below.
●XC9128 Series
EN Pin
AEN/Pin
P-channel Synchronous Switch Transistor Operation
H
H
L
L
H
L
H
L
OFF
Switching
OFF
Undefined
●XC9129 Series
EN Pin
P-channel Synchronous Switch Transistor Operation
H
L
Switching
Undefined
With the XC9128B/XC9129B series, when step-up operation stops as a result of the latch condition working when the
maximum current limit level is reached, the synchronous P-channel transistor will remain ON.
8. The maximum current limiter controls the limit of the N-channel driver transistor by monitoring current flow. This function
does not limit the current flow of the P-channel synchronous transistor.
9. The integral latch time of the XC9128B/XC9129B series could be released from the maximum current detection state as a
result of board mounting conditions. This may extend integral latch time or the level required for latch operation to
function may not be reached. Please connect the output capacitor as close to the IC as possible.
10. With the XC9128B/XC9129B series, when the EN pin is left open or applied in the range of 0.2V～0.65V, the integral
latch or the VLVP may not be able to release. Please make sure that the EN pin voltage is less than 0.2V or more than
0.65V, or use the XC9128D/XC9129D series which does not have the integral latch and the LVP functions.
11. With the XC9128B/XC9129B series, please make the VOUT pin voltage become more than 1.5V within the soft-start time,
otherwise the VLVP is detected. Also, the operation may become unstable, please test and verify the operation in the
actual circuits thoroughly before use.
12. When used in small step-up ratios, the device may skip pulses during PWM control mode.
10/13
XC9128/XC9129
Series
■TEST CIRCUITS *1
< Circuit No.1 >
Wave Form Measure Point
L
Lx
VOUT
BAT
MODE
A
CFB
RFB1
A
VIN
V
EN
CIN
CL2
VEN
RL
V
L : 4.7uH(LTF5022T-4R7N2R0 : TDK)
CIN : 10uF (ceramic)
CL1 : 22uF (ceramic)
CL2 : 10uF (ceramic)
VMODE
10kΩ
FO
※ External Components
CL1
FB
V
AEN/
VAEN/
RFB2
VFO
PGND
AGND
Wave Form Measure Point
< Circuit No.2 >
< Circuit No.3 >
A
A
CIN
Lx
VOUT
BAT
MODE
EN
A
A
A
FB
VMODE
FO
AEN/
VEN
PGND
BAT
MODE
FB
VOUT
VIN
VMODE
FO
A
VAEN/
AEN/
VFB
VEN
AGND
CIN
※ External Components
VOUT
EN
CIN
FB
VIN
Lx
PGND
: 1uF (ceramic)
AGND
※ External Components
< Circuit No.4 >
CIN
: 1uF (ceramic)
<Circuit No.5 >
Wave Form Measure Point
Rpull
Lx
VOUT
BAT
MODE
Lx
VOUT
BAT
MODE
Vpull
A
A
VIN
CIN
EN
FB
FO
AEN/
VMODE
CIN
A
VFO
※ External Components
FO
AEN/
PGND
AGND
COUT
VAEN/
VOUT
VFB
VIN
VAEN/
PGND
FB
VLx
FB
VEN
EN
AGND
※ External Components
CIN
: 1uF (ceramic)
Rpull : 300Ω
CIN : 1uF (ceramic)
COUT : 1uF (ceramic)
<Circuit No.7 >
<Circuit No.6 >
Wave Form Measure Point
Wave Form Measure Point
Rpull
Lx
VOUT
SBD
Vpull
A
VIN
BAT
EN
CIN
V
VMODE
FO
CLX
CIN
MODE
EN
FB
FO
AEN/
COUT
VEN
AGND
CIN : 1uF (ceramic)
Rpull : 300Ω
BAT
VIN
FB
PGND
※ External Components
AEN/
VOUT
Vpull
VOUT
FB
Lx
Rpull
MODE
VEN
A
VFO
V1
PGND
※ External Components
VOUT
VMODE
AGND
CIN
: 1uF (ceramic)
COUT : 1uF (ceramic)
SBD : XBS304S17(TOREX)
Rpull : 0.5Ω
Measurement method for ON resistance of the Lx switch
Using the layout of circuit No.7 above, set the LX pin voltage to 50mV by adjusting the Vpull voltage whilst the N-ch driver
transistor is turned on. Then, measure the voltage difference between both ends of Rpull. ON Resistance is calculated by using
the following formula:
RLXN=0.05 ÷ ((V1 – 0.05) ÷ 0.5)
where V1 is a voltage between SBD and Rpull. LX pin voltage and V1 are measured by an oscilloscope.
*1: The XC9129 series does not have the AEN/ pin and the FO pin. When the XC9129 series is measured, the FO and AEN
pins are not effective in the above mentioned test circuits, they are NC.
11/13
XC9128/XC9129 Series
■PACKAGING INFORMATION
●USP-10B
●SOP-8
(unit : mm)
+0.05
4.2±0.4
+0.4
6.1 -0.3
0.25～0.9
0.2 -0.1
+0.5
5.0 -0.2
0～0.25
1.5±0.1
0～
12/13
1.27±0.03
0.4±0.1
10 °
0. 4 ± 0. 0 3
1. 6 ± 0. 1
0. 2 5 ± 0. 1
MAX0 . 6
2. 6±0. 15
●MSOP-10
XC9128/XC9129
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 datasheet 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 datasheet.
3. Please ensure suitable shipping controls (including fail-safe designs and aging
protection) are in force for equipment employing products listed in this datasheet.
4. The products in this datasheet 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 datasheet 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 datasheet may be copied or reproduced without the
prior permission of TOREX SEMICONDUCTOR LTD.
13/13