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XC9128/XC9129 Series
1A Driver Transistor Built-In, Step-Up DC/DC Converters
ETR0411-004
The XC9128/XC9129 series are synchronous step-up DC/DC converters with a 0.2 (TYP.) N-channel driver transistor and a
GENERAL DESCRIPTION
synchronous 0.2 (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. When a voltage higher than the input voltage is applied to the output during shut-down, 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
Digital audio equipment 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
FEATURES
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 ( 0.01V) & 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=10mA100mA Protection Circuits : Thermal shutdown : Integral latch method (Over current limit) Soft-Start Time : 5ms (TYP.) internally set Ceramic Capacitor Compatible Adaptor Enable Function Packages : MSOP-10, USP-10B, SOP-8 Flag Output (FO) : Open-drain output
TYPICAL APPLICATION CIRCUIT
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs. Output Current XC9128B45CDx
VOUT=5.0V, fOSC=1.2MHz
100 80 Efficiency : EFFI (%) 60
L=4.7H (CDRH4D28C), CIN=10F, CL=32F
3.7V 40 20 0 0.1
VIN=1.8V
PWM(MODE:H) PWM/PFM(MODE:L) 1 10 100 Output Current : IOUT (mA)
Output Current: IOUT (mA)
1000
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XC9128/XC9129 Series
PIN CONFIGURATION
PGND 1 Lx 2 BAT 3 EN 4 FO 5 MSOP-10 (TOP VIEW) 10 VOUT 9 MODE 8 FB 7 AGND 6 AEN/ FO 5 EN 4 BAT 3 Lx 2 PGND 1 USP-10B (BOTTOM VIEW) 6 AEN/ 7 AGND 8 FB 9 MODE 10 VOUT
PGND 1
8 VOUT
Lx 2
7 MODE 6 FB
BAT 3
EN 4 SOP-8 (TOP VIEW) Under Development
5 AGND
PIN ASSIGNMENT
PIN NUMBER MSOP-10* USP-10B * 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 SOP-8 ** 1 2 3 4 5 6 7 8 PIN NAME PGND Lx BAT EN FO AEN/ AGND FB MODE VOUT FUNCTION Power Ground Output of Internal Power Switch Battery Input Chip Enable Flag Output Adaptor Enable Analog Ground Output Voltage Monitor Mode Switch Output Voltage
* 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).
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XC9128/XC9129
Series
FUNCTION CHART
1. EN, AEN/ Pin Function
EN PIN LH H H L L AEN/ PIN L HL H L H IC OPERATIONAL STATE Operation Operation Step-Up Operation Shut-Down Shut-Down Shut-Down SOFT-START FUNCTION Available Not Available -
* Do not leave the EN and AEN/ Pins open.
2. MODE Pin Function
MODE PIN H L FUNCTION PWM Control PWM/PFM Automatic Switching Control
* Do not leave the MODE Pin open.
PRODUCT CLASSIFICATION
Ordering Information
XC9128 MSOP-10, USP-10B XC9129 SOP-8 (Under Development)
DESIGNATOR
DESCRIPTION Transistor Built-In, Output Voltage Freely Set (FB voltage), Integral Protection Type Reference Voltage Oscillation Frequency Packages
SYMBOL B D 45 C A D S R L
DESCRIPTION : With integral protection : Without integral protection : Fixed reference voltage 0.45 =4, =5 : 1.2MHz : MSOP-10 : USP-10B : SOP-8 : Embossed tape, standard feed : Embossed tape, reverse feed

Device Orientation
3/14
XC9128/XC9129 Series
BLOCK DIAGRAM
XC9128 Series
XC9129 Series The AEN/Pin and FO Pin are not connected to the circuit in the block diagram of the XC9129 series.
ABSOLUTE MAXIMUM RATINGS
Ta=25 PARAMETER VOUT Pin Voltage AEN/ Pin Voltage FO Pin Voltage FO Pin Current 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
*1: When implemented on a PCB.
SYMBOL VOUT VAEN/ VFO IFO VFB VBAT VMODE VEN VLx ILx Pd Topr Tstg
RATINGS - 0.36.5 - 0.36.5 - 0.36.5 10 - 0.36.5 - 0.36.5 - 0.36.5 - 0.36.5 - 0.3VOUT+0.3 2000 350 (*1) 150 300 - 40+85 - 55+125
UNITS V V V mA V V V V V mA mW
o o
C C
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XC9128/XC9129
Series
ELECTRICAL CHARACTERISTICS
XC9128/XC9129 Series PARAMETER Input Voltage FB Voltage Output Voltage Setting Range Operation Start Voltage SYMBOL VIN VFB VOUTSET VST1 CONDITIONS
-
Topr=25 oC MIN. 0.44 1.8 1.02 85 1.2 1.7 TYP. 0.45 0.8 0.7 3 30 2 2 1.20 92 250 93 0.20 0.20 (*1) 1 1.5 3.5 5.3 MAX. 6.0 0.46 5.3 0.8 0.9 6 80 10 10 1.38 96 0 400 0.35 (*1) 0.35 (*1) 2.0 10.5
(*1)
UNITS V V V V V V V mA A A A MHz % % mA % A A ms ms
CIRCUIT -
VOUT=VIN=3.3V, Vpull=3.3V, VFO=0V Voltage to start oscillation during FB=0.46V 0.44V Connect to external components, RL =1k Connect to external components, RL =33 Voltage to start oscillation during VIN=0V 1V Connect to external components, RL=1k VIN = VOUT =3.3V, FB=VFBx0.9 VIN = VOUT =3.3V FB=VFBx1.1 (Oscillation stops), MODE=0V VIN =3.3V, VOUT =1.8V, EN=0V VIN = VOUT =3.3V, EN=0V VIN = VOUT =3.3V, VFO=0V, FB=VFBx0.9 VIN = VOUT =3.3V, VFO=0V, FB=VFBx0.9 VIN = VOUT =3.3V, VFO=0V, FB=VFBx1.1 Connect to external components, MODE=0V, IOUT=10mA Connect to external components, IOUT=100mA VIN=VOUT+50mV, (*3) FB=VFBx1.1, MODE=0V VIN=3.3V, VOUT=3.3V,Lx=50mV, FB=VFBx0.9 (*4) VOUT=VLx=VIN=3.3V, EN=0V, FB=0V, MODE=0V VOUT>2.5V Time to stop oscillation during RL=33 3.3, VFO=L H Time to start oscillation during VEN=0V VIN at VIN = VOUT =3.3V, VFO=0V, FB=VFBx0.95 VIN = VOUT =3.3V, VFO=0V, FB> VFBx0.95 Time to start oscillation during VAEN/=VIN0V. VIN = VOUT =3.3V, VFO=0V, FBOscillation Start Voltage Operation Hold Voltage Supply Current 1 Supply Current 2 Input Pin Current Stand-by Current Oscillation Frequency Maximum Duty Cycle Minimum Duty Cycle PFM Switching Current Efficiency (*2) LX SW "Pch" ON Resistance LX SW "Nch" ON Resistance LX Leak Current Current Limit (*5) Integral Latch Time (*6) Soft-Start Time 1
VST2 VHLD IDD1 IDD2 IBAT ISTB fOSC MAXDTY MINDTY IPFM EFFI RLxP RLxN ILXL ILIM TLAT TSS1
Soft-Start Time 2
TSS2
-
0.02
0.04
ms
Soft-Start Time 3 Thermal Shutdown Temperature Hysteresis Width Output Voltage Drop (*6) Protection FO Output Current (*7) FO Leak Current (*7)
TSS3 TTSD THYS LVP IFO_OUT IFO_Leak
1.7 1.3 1.3 -
5.3 150 20 1.48 1.7 0
10.5 1.56 2.2 1
ms
o o
C C
-
V mA A
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XC9128/XC9129 Series
ELECTRICAL CHARACTERISTICS (Continued)
XC9128/XC9129 Series (Continued) PARAMETER EN "H" Voltage SYMBOL VENH CONDITIONS VIN =VOUT=3.3V, VFO=0V Voltage to start oscillation during FB=VFBx0.9, EN= 0.2V0.65V VIN = VOUT =3.3V, VFO=0V EN "L" Voltage MODE "H" Voltage MODE "L" Voltage AEN/ Voltage (*7) EN "H" Current EN "L" Current MODE "H" Current MODE "L" Current AEN/ "H" Current (*7) AEN/ "L" Current FB "H" Current FB "L" Current
(*7)
Topr=25 oC MIN. 0.65 TYP. MAX. UNITS V CIRCUIT
VENL VMODEH VMODEL VAEN/ IENH IENL IMODEH IMODEL IAEN/H IAEN/L IFBH IFBL
Voltage to stop oscillation during FB=VFBx0.9, EN= 0.65V0.2V IOUT=10mA, Voltage operates at PWM control IOUT=10mA, Voltage operates at PFM control VIN = VOUT =3.3V, VFO=0V Voltage to start oscillation during AEN= 0.9V0.7V VOUT=FB=EN=6.0V VOUT=FB=6.0V, EN=0V VOUT=FB=MODE=6.0V VOUT=FB=6.0V, MODE=0V VOUT=FB=AEN/=6.0V VOUT=6.0V, EN=0V, AEN/=0V VOUT=FB=6.0V VOUT=6.0V, FB=0V
0.65 0.7 -0.1 -0.1 -0.1 -0.1
0.8 -
0.2 0.2 0.9 0.1 0.1 0.1 0.1 -
V V V V A A A A A A A A
Conditions: Unless otherwise stated, operate at VOUT=3.3V, VIN= 1.8V, EN=3.3V, FB=0V, MODE=3.3V, VFO=3.3V, Vpull=3.3V, AEN/=0V External Components: RFB1=270k, RFB2=43k, CFB=12pF, L=4.7 CL1=22 NOTE: * 1 : Designed value
* * * * * *
H (LTF5022 TDK) F(ceramic)
F(ceramic), CL2=10
F(ceramic), CIN=10
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 series does not have integral protection. 7 : The XC9129 series does not have FO or AEN/ pins. This is only available with the XC9128B series. These are only available with the XC9128 series.
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XC9128/XC9129
Series
TYPICAL APPLICATION CIRCUIT
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 500k or less. VOUT=0.45 x (RFB1 + RFB2) / RFB2 The value of CFB, speed-up capacitor for phase compensation, should be fZFB = 1 / (2 x 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=270k , RFB2=43k , VOUT1 = 0.45 x (270k+43k ) / 43k = 3.276V [Typical example] VOUT (V) 1.8 2.5 3.3 5.0 RFB1 (k ) 300 270 270 180 RFB2 (k ) 100 59 43 17.8 CFB (pF) 10 12 12 15
[External Components] 1.2MHz: L : 4.7 H (CDRH4D28C SUMIDA) CL1: 22 F (ceramic) CL2: 10 F (ceramic) CIN: 10 F (ceramic) * For CL, use output capacitors of 30 F or more. (Ceramic capacitor compatible) * 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.
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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 series compares, using the error amplifier, the internal reference voltage to the FB pin with the voltage fedback 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-ch 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. The source provides the reference voltage to ensure stable output of the DC/DC converter. 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. 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-ch 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-ch 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 Nch 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
Limit<# ms
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XC9128/XC9129
Series
OPERATIONAL EXPLANATION (Continued)
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. 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. 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 While 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 FO pin becomes high impedance during over current state, over temperature state, soft-start period, and shut-down period.
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.
9/14
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.
EN Pin H H L L
AEN/Pin H L H L
P-ch Synchronous Switch Transistor Operation OFF Switching OFF 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-ch transistor will remain ON. With the XC9128B/XC9129B series, when step-up operation stops as a result of the latch condition working when the low output voltage protection level is reached, the synchronous P-ch transistor will remain ON.
8. The maximum current limiter controls the limit of the N-ch driver transistor by monitoring current flow. This function does not limit the current flow of the P-ch 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. When used in small step-up ratios, the device may skip pulses during PWM control mode.
10/14
XC9128/XC9129
Series
TEST CIRCUITS
< Circuit No.1 >
Wave Form Measure Point
L
Lx
VOUT CFB MODE FB CL2 VMODE V RFB2 RFB1 External Components CL1 RL V A
BAT A VIN V CIN VEN 10k FO VFO PGND EN
AEN/
VAEN/
L : 4.7uH(LTF5022T-4R7N2R0 : TDK) CIN : 10uF (ceramic) CL1 : 22uF (ceramic) CL2 : 10uF (ceramic)
AGND
Wave Form Measure Point
< Circuit No.2 >
< Circuit No.3 >
Lx A A
VOUT A A VFB A
Lx
VOUT
BAT
MODE FB
BAT
MODE FB VMODE
CIN VIN
EN
VMODE VIN
CIN
EN
VOUT
FO VEN PGND
AEN/
A VAEN/
FO VEN PGND External Components CIN : 1uF (ceramic)
AEN/ VFB AGND
AGND
External Components CIN : 1uF (ceramic)
< Circuit No.4 >
Wave Form Measure Point Rpull Lx Vpull A VIN BAT MODE VOUT

Lx
VOUT
BAT A VMODE CIN VFB VLx FO VAEN VIN PGND External Components CIN : 1uF (ceramic) COUT: 1uF (ceramic)
MODE FB VAEN/ FB VOUT
CIN VEN A VFO
EN
FB
EN
COUT
FO
AEN/
AEN/
PGND External Components CIN : 1uF (ceramic) Rpull : 300
AGND
AGND

Wave Form Measure Point Rpull Lx Vpull A VIN BAT MODE FB VMODE A VFO FO AEN/ VFB PGND External Components CIN : 1uF (ceramic) Rpull : 300 AGND V V VOUT
CIN VEN
EN
11/14
XC9128/XC9129 Series
TEST CIRCUITS (Continued)
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, measured by an oscilloscope.
12/14
XC9128/XC9129
Series
PACKAGING INFORMATION
MSOP-10 USP-10B
MAX0 . 6
2. 60. 15
SOP-8
(unit : mm)
0.2 -0.1
+0.05
4.20.4
6.1 -0.3
+0.4
5.0 -0.2
+0.5
0.250.9
0
10
00.25
1.50.1
1.270.03
0.40.1
0. 4 0. 0 3
1. 6 0. 1
0. 2 5 0. 1
13/14
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.
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