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1.5A Synchronous Buck Converter with Integrated Power Devices
POWER MANAGEMENT Description
The SC196 is a synchronous step-down converter with integrated power devices designed for use in applications using a single-cell Li-ion battery. Its wide input voltage range also makes it suitable for use in systems with fixed 3.3V or 5V supply rails available. The switching frequency is nominally set to 1MHz, allowing the use of small inductors and capacitors. The current rating of the internal MOSFET switches allows a DC output current of 1.5A. The output voltage is set by connecting a resistor divider from the filter inductor to the feedback pin. See the SC196A for pin-programmable output voltages. The SC196 has a flexible clocking methodology that allows it to be synchronized to an external oscillator or controlled by the internal oscillator. The device operates in either forced PWM mode or in PSAVE mode. If PSAVE mode is enabled, the part will automatically enter PFM at light loads to maintain maximum efficiency across the full load range. For noise sensitive applications, PSAVE mode can be disabled by synchronizing to an external oscillator or pulling the SYNC/PWM pin high. Shutdown turns off all the control circuitry to achieve a typical shutdown current of 0.1A.
SC196
Features
Up to 95% efficiency VOUT adjustable from less than 0.8V to VIN Output current -- 1.5A Input range -- 2.5V to 5.5V Quiescent current -- 17A Fixed 1MHz frequency or 750kHz to 1.25MHz synchronized operation PSAVE operation to maximize efficiency at light loads Shutdown current <1A Fast transient response 100% duty cycle in dropout Soft-start Over-temperature and short-circuit protection Lead-free package -- MLPD10-UT, 3 x 3 x 0.6 mm
Applications
Cell phones Wireless communication chipset power Personal media players Microprocessor/DSP core/IO power PDAs and handheld computers WLAN peripherals USB powered modems 1 Li-Ion or 3 NiMH/NiCd powered devices
Typical Application Circuit
VIN 2.5V to 5.5V VIN CIN 10F PVIN MODE EN
L1 4.7H
SC196
LX VOUT ADJ
VOUT <0.8V to VIN 1.5A RFB1 RFB2 CFB1 10pF COUT 22F
SYNC/PWM
PGND GND
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SC196
POWER MANAGEMENT Absolute Maximum Rating
Exceeding the specifications below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not recommended.
PRELIMINARY
Parameter Input Supply Voltage Logic Inputs (N=SYNC/PWM, EN, MODE) Output Voltage ADJ Input LX Voltage Thermal Impedance Junction to Ambient(1) VOUT Short-Circuit to GND Operating Ambient Temperature Range Storage Temperature Junction Temperature Peak IR Reflow Temperature ESD Protection Level (2)
Symbol VIN VN VOUT VADJ VLX JA tSC TA TS TJ TPKG VESD
Maximum -0.3 to 7 -0.3 to VIN+0.3, 7V Max -0.3 to VIN+0.3, 7V Max -0.3 to VIN+0.3, 7V Max -1 to VIN +1, 7V Max 40 Continuous -40 to +85 -65 to +150 -40 to +150 260 2
Units V V V V V C/W s C C C C kV
Notes: (1) Calculated from package in still air, mounted to 3" x 4.5", 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards. (2) Tested according to JEDEC standard JESD22-A114-B.
Electrical Characteristics
Unless otherwise noted: VIN = 3.6V, VOUT = 1.8V, EN = VIN, SYNC/PWM = VIN, MODE = VIN , TA = -40 to 85C. Typical values are at TA = 25C.
Parameter Input Voltage Range UVLO Threshold (upper) UVLO Hysteresis Output Voltage Range FB Voltage Tolerance Load Regulation (PWM) PSAVE Regulation P-Channel Current Limit Quiescent Current Shutdown Current
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Symbol VIN VUVL VUVLHYS VOUT VFB VOUT LOAD VOUT PSAVE ILIM(P) IQ ISD
Conditions
Min 2.5 2.18
Typ
Max 5.5
Units V V mV
2.3 150
2.45
0.8 VIN = 2.5V to 5.5V, IOUT = 0mA to 1.5A IOUT = 0mA to 1.5A SYNC/PWM=GND,COUT = 22F, VIN = 2.5V to 5.5V, IOUT = 0mA to 1.5A VIN=2.5V to 5.5V SYNC/PWM = GND, IOUT = 0A, VOUT = 1.04 x VOUT(Programmed) EN = GND, LX = OPEN
2
VIN 0.5 0.5 2 0.515 1 3 3.57 28 1
V V % % A A A
0.485
1.96
2.8 17 0.1
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SC196
POWER MANAGEMENT Electrical Characteristics (Cont.)
Parameter P-Channel On Resistance N-Channel On Resistance LX Leakage Current PMOS LX Leakage Current NMOS Oscillator Frequency SYNC Frequency (upper) SYNC Frequency (lower) Start-Up Time Thermal Shutdown Thermal Shutdown Hysteresis Logic Input High(1) Logic Input Low(1) Logic Input Current High(1) Logic Input Current Low(1)
Note: (1) For EN, SYNC/PWM, MODE
PRELIMINARY
Symbol RDSP RDSN ILXP ILXN fOSC fSYNCU fSYNCL tSTART TSD TSD-HYS VIH VIL IIH IIL
Conditions ILX = 100mA ILX = 100mA LX = GND, EN = GND LX = 3.6V, EN = GND
Min
Typ 0.275 0.165 0.1
Max
Units
2
A A
-2 0.85 1.25
0.1 1.0 1.15
MHz MHz
750 5 145 10 1.2 0.4 -2 -2 0.1 0.1 2 2
kHz ms C C V V A A
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SC196
POWER MANAGEMENT Pin Configuration Ordering Information
DEVICE SC196ULTRT(1)(2) PACKAGE MLPD-UT10 3x3x0.6 Evaluation Board
PRELIMINARY
PVIN VIN SYNC/PWM EN VOUT
1 2 3 4
T
10 TOP VIEW 9 8 7 6
LX PGND GND MODE ADJ
Notes: 1) Lead-free packaging only. This product is fully WEEE and RoHS compliant. 2) Available in tape and reel only. A reel contains 3000 devices.
Ordering Information
SC196EVB
5
MLPD-UT: 3X3X0.6, 10 LEAD
Marking Information
196 yyww xxxx
yy = two digit year of manufacture ww = two digit week of manufacture xxxx = lot number
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SC196
POWER MANAGEMENT Pin Descriptions
Pin # 1 2 3 4 5 6 7 8 9 10 T Pin Name PVIN VIN SYNC/PWM EN VOUT ADJ MODE GND PGND LX THERMAL PAD Pin Function Input supply voltage connection to switching FETs -- connect the input capacitor between this pin and PGND directly. Input supply voltage for control circuits Oscillator synchronization input. Tie to VIN for forced PWM mode or GND to allow the part to enter PSAVE mode at light loads. Apply an external clock signal for frequency synchronization. Enable digital input; a high input enables the SC196, a low disables and reduces quiescent current to less than 1A. In shutdown, LX becomes high impedance. Regulated output voltage sense pin -- connect to the output capacitor allowing sensing of the output voltage. Output Voltage Adjust and feedback compensation pin - connect resistor divider between this pin and GND to set the desired output voltage level. MODE select pin -- MODE = VIN to select 100% duty cycle function, MODE = GND to disable this function. Ground Power Ground Inductor connection to the switching FETs Pad for heatsinking purposes -- not connected internally. Connects to ground plane using multiple vias.
PRELIMINARY
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SC196
POWER MANAGEMENT Block Diagram PRELIMINARY
Plimit Amp Current Amp
1 PVIN
EN
4
SYNC /PWM 3
OSC & Slope Generator Control Logic PWM Comp 10 LX
500mV Ref
Error Amp
PSAVE Comp
Nlimit Amp
MODE 7
9 PGND
VIN
2 8 5 GND VOUT
ADJ
6
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SC196
POWER MANAGEMENT Applications Information
SC196 Detailed Description The SC196 is a synchronous step-down Pulse Width Modulated (PWM), DC-DC converter utilizing a 1MHz fixed-frequency current mode architecture. The device is designed to operate in a fixed-frequency PWM mode across the full load range and can enter Power Save Mode (PSAVE), utilizing Pulse Frequency Modulation (PFM) at light loads to maximize efficiency. Operation During normal operation, the PMOS MOSFET is activated on each rising edge of the internal oscillator. Current feedback for the switching regulator uses the PMOS current path, and it is amplified and summed with the internal slope compensation network. The voltage feedback loop uses an external feedback divider. The ontime is determined by comparing the summed current feedback and the output of the error amplifier. The period is set by the onboard oscillator or by an external clock attached to the SYNC/PWM pin. The SC196 has an internal synchronous NMOS rectifier and does not require a Schottky diode on the LX pin. Output Voltage Selection The output voltage can be programmed using a resistor network connected from VOUT to ADJ to GND. The combined resistance of the divider chain should be greater than 10K and less than 1M. Table 1 lists appropriate resistors which limit the bias current required of the external feedback resistor chain and ensuring good noise immunity. The output voltage can be adjusted between less than 0.8V and VIN. The output voltage formula is:
VOUT 0 .5 RFB1 RFB2 1
PRELIMINARY
Table 1 -- Recommended ADJ Resistor Combinations
VOUT(V) 1 1.1 1.2 1.3 1.5 1.6 1.7 1.8 1.875 2.5 2.8 3 3.3 3.6 3.8 RFB2(k) 200 200 200 200 178 200 178 178 178 200 178 178 100 100 100 RFB1(k) 200 240 280 320 357 442 432 464 487 806 820 887 560 620 665
Continuous Conduction & Oscillator Synchronization The SC196 is designed to operate in continuous conduction, fixed-frequency mode. When the SYNC/PWM pin is tied high the part runs in PWM mode using the internal oscillator. The part can be synchronized to an external clock by driving a clock signal into the SYNC/ PWM pin. The part synchronizes to the rising edge of the clock. Protection Features The SC196 provides the following protection features: * Thermal Shutdown * Current Limit * Over-Voltage Protection * Soft-Start Thermal Shutdown The device has a thermal shutdown feature to protect the SC196 if the junction temperature exceeds 145C. In thermal shutdown, the on-chip power devices are disabled, effectively tri-stating the LX output. Switching will resume when the temperature drops by 10C. During this time,
VOUT = output voltage (V) RFB1 = feedback resistor from VOUT to ADJ () RFB2 = feedback resistor from ADJ to GND () Resistors with 1% or better tolerance are recommended to ensure voltage accuracy.
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SC196
POWER MANAGEMENT Applications Information (Cont.)
if the output voltage decreases by more than 60% of its programmed value, a soft-start will be invoked. Current Limit The PMOS and NMOS power devices of the buck switcher stage are protected by current limit functions. In the case of a short to ground on the output, the part enters frequency foldback mode, which causes the switching frequency to divide by a factor determined by the output voltage. This prevents the inductor current from "staircasing". Over-Voltage Protection Over-voltage protection is provided on the SC196. In the event of an over-voltage on the output, the PWM drive is disabled, effectively tri-stating the LX output. The part will not resume switching until the output voltage has fallen 2% below the regulation voltage. Soft-Start The soft-start mode is enabled after every shutdown cycle to limit in-rush current. In conjunction with the frequency foldback, this controls the maximum current during start-up. The PMOS current limit is stepped up through seven soft-start levels to the full value by a timer driven from the internal oscillator. During soft-start, the switching frequency is stepped through 1/8, 1/4, 1/2 and full internal oscillator frequency. The time at which these steps are made is controlled by the output voltage reaching predefined threshold levels. When the output voltage is within 2% of the regulation voltage, soft-start mode is disabled. Power Save Mode Operation The PSAVE mode may be selected by tying the SYNC/PWM pin to GND. Selecting PSAVE mode will enable the SC196 to automatically activate/deactivate operation at light loads, maximizing efficiency across the full load range. The SC196 automatically detects the load current at which it should enter PSAVE mode. The SC196 is optimized to track maximum efficiency with respect to VIN. In PSAVE mode, VOUT is driven from a lower level to an upper level by a switching burst. Once the upper level has been reached, the switching is stopped and the quiescent current is reduced. VOUT falls from the upper to lower levels in this low current state as the load current discharges the output capacitor. The burst-to-off period in PSAVE will decrease as the load current reduces. The PSAVE switching burst frequency is controlled so that the inductor current ripple is similar to that in PWM mode. The minimum switching frequency during this period is limited to 650kHz. The SC196 automatically detects when to exit PSAVE mode by monitoring VOUT . For the SC196 to exit PSAVE mode, the load must be increased, causing VOUT to decrease until the power save exit threshold is reached. PSAVE levels are set high to minimize the undershoot when exiting PSAVE. The lower PSAVE comparator level is set +0.7% above VOUT, and the upper comparator level at +1.5% above VOUT, with the exit threshold at -2% below VOUT. If PSAVE operation is required, then a 22F output capacitor must be used.
BURST OFF Higher Load Applied
PRELIMINARY
1.5% 0.7%
PSAVE Mode at Light Load VOUT PWM Mode at Medium/ High Load
-2%
Inductor Current
0A
Time
Figure 1 -- Power Save Operation 100% Duty Cycle Operation The 100% duty cycle mode may be selected by connecting the MODE pin high. This will allow the SC196 to maintain output regulation under conditions of low input voltage/ high output voltage conditions. In 100% duty cycle operation, as the input supply drops toward the output voltage, the PMOS on-time increases linearly above the maximum value in fixed-frequency operation until the PMOS is active continuously. Once
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SC196
POWER MANAGEMENT Applications Information (Cont.)
the PMOS is switched on continuously, the output voltage tracks the input voltage minus the voltage drop across the PMOS power device and inductor according to the following relationship: VOUT = VIN - IOUT x (RDSP + RIND) where VOUT = Output voltage VIN = Input voltage IOUT = Output current RDSP = PMOS switch ON resistance RIND = Series resistance of the inductor Inductor Selection The SC196 is designed for use with a 4.7H inductor. Where VOUT > 3.8V is required, a 10H inductor is recommended. The magnitude of the inductor current ripple depends on the inductor value and can be determined by the following equation:
IL VOUT VOUT 1 L fosc VIN
PRELIMINARY
Table 1 -- Recommended Inductors
Value (H) DCR () Rated Current (A) Tolerance (%) Dimensions LxWxH (mm)
Manufacturer/Part #
BI Technologies HM66404R1 Coilcraft D01608C-472ML TDK VLCF4020T- 4R7N1R2 Taiyo Yuden LMNP04SB4R7N TOKO D52LC Sumida CDRH3D16 Coilcraft LPS3015
4.1
0.057
1.95
20
5.7 x 5.7 x2.0
4.7
0.09
1.5
20
6.6 x 4.5 x 3.0
4.7
0.098
1.24
30
4.0 x 4.0 x 2.0
4.7
0.050
1.2
30
5.0 x 5.0 x 2.0
4.7
0.087
1.14
20
5.0 x 5.0 x 2.0
4.7
0.050
1.2
30
3.8 x 3.8 x 1.8
4.7
0.2
1.1
20
3.0 x 3.0 x 1.5
Note: recommended Inductors do not necessarily guarantee rated performance of the part.
This equation demonstrates the relationship between input voltage, output voltage, and inductor ripple current. The inductor should have a low DCR to minimize the conduction losses and maximize efficiency. As a minimum requirement, the DC current rating of the inductor should be equal to the maximum load current plus half of the inductor current ripple as shown by the following equation:
IL(PK) IOUT(MAX) IL 2
COUT Selection The internal compensation is designed to work with a certain output filter corner frequency defined by the equation:
fC 2 1 L COUT
This filter has a single pole and is designed to operate with a minimum output capacitor value of 10F. Larger output capacitor values will improve transient performance. If PSAVE operation is required, the minimum capacitor value is 22F. Output voltage ripple is a combination of the voltage ripple from the inductor current charging and discharging the output capacitor and the voltage created from the inductor current ripple through the output capacitor ESR. Selecting an output capacitor with a low ESR will reduce the output voltage ripple component, as can be seen in the following equation: VOUT(ESR) = IL(RIPPLE) x ESRCOUNT Capacitors with X7R or X5R ceramic dielectric are strongly recommended for their low ESR and superior temperature
Final inductor selection will depend on various design considerations such as efficiency, EMI, size and cost. Table 2 lists the manufacturers of practical inductor options. CIN Selection The source input current to a buck converter is noncontinuous. To prevent large input voltage ripple, a low ESR ceramic capacitor is required. A minimum value of 10F should be used for input voltage filtering, while a 22F capacitor is recommended for improved input voltage filtering.
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SC196
POWER MANAGEMENT Applications Information (Cont.)
and voltage characteristics. Y5V capacitors should not be used as their temperature coefficients make them unsuitable for this application. Attention should be paid to the DC voltage characteristics of the ceramic capacitors to be used for both input and output. Parts with different case sizes can vary significantly. For example a 22F X5R 0805 capacitor with 3.6V DC applied could have a capacitance as low as 12F. When a 1206 size part is used, the capacitance is approximately 20F. Table 3 lists the manufacturers of recommended capacitor options. Table 3 -- Recommended Capacitors
Manufacturer/Part # Value (F) Rated Voltage (VDC) Temperature Characteristic Case Size
PRELIMINARY
Murata GRM21BR60J226ME39L Murata GRM422X5R226 K16H533 Murata GRM188R60J106 MKE19 TDK C2012X5R0J106K
22
6.3
X5R
0805
22
16
X5R
1210
10
6.3
X5R
0603
10
6.3
X5R
0603
Note: Where PSAVE operation is required, 22F must be used for COUT.
Feed-Forward Compensation Capacitor A small 10pf compensation capacitor, CFB1 is required to ensure correct operation. This capacitor should be connected directly across feedback resistor RFB1. Capacitors with X7R or X5R ceramic dielectric are strongly recommended for their superior temperature characteristics.
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SC196
POWER MANAGEMENT Applications Information (Cont.)
PCB Layout Considerations Poor layout can degrade the performance of the DC-DC converter and can contribute to EMI problems, ground bounce and resistive voltage losses. Poor regulation and instability can result. A few simple design rules can be implemented to ensure good layout: 1. Place the inductor and filter capacitors as close to the device as possible and use short wide traces between the power components. 2. Route the output voltage feedback path away from the inductor and LX node to minimize noise and magnetic interference. Keep RFB1 and RFB2 close to the ADJ pin to avoid noise pickup. 3. Maximize ground metal on the component side to improve the return connection and thermal dissipation. Separation between the LX node and GND should be maintained to avoid coupling of switching noise to the ground plane. 4. Use a ground plane with several vias connecting to the component side ground to further reduce noise interference on sensitive circuit nodes.
PRELIMINARY
GND VIN CIN
LOUT
LX COUT
VOUT GND
SYNC/PWM EN MODE
SC196 CFB1 RFB2 RFB1
GND
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SC196
POWER MANAGEMENT Typical Characteristics
Efficiency vs. Load Current VOUT = 3.3V
100 90 80 70
RFB1+RFB2=10K
PRELIMINARY
Efficiency vs. Load Current VOUT = 2.5V
100 90 80 70
RFB1+RFB2=10K
VIN=3.9V PSAVE
VIN=3.3V PSAVE
Efficiency (%)
60 50 VIN=4.2V PSAVE 40 30 20 10 0 0.0001 0.001 0.01 VIN=5.0V PSAVE
Efficiency (%)
VIN=3.2V PWM VIN=4.2V PWM VIN=5.0V PWM
60 50 VIN=4.2V PSAVE 40 30 20 10 VIN=5.0V PSAVE
VIN=3.3V PWM VIN=4.2V PWM VIN=5.0V PWM
IOUT(A)
0.1
1
10
0 0.0001
0.001
0.01
IOUT(A)
0.1
1
10
Efficiency vs. Load Current VOUT = 1.8V
100 90 80 70
Efficiency (%)
RFB1+RFB2=10K
Efficiency vs. Load Current VOUT = 1.0V
100 90 80 70
Efficiency (%)
RFB1+RFB2=10K
VIN=2.7V PSAVE
VIN=2.7V PSAVE
VIN=2.7V PWM VIN=3.6V PSAVE VIN=4.2V PSAVE VIN=3.6V PWM VIN=4.2V PWM
60 50 40 30 20 10 0 0.0001 0.001 0.01 0.1 1 10
60 50 40 30 20 10 0 0.0001 0.001 0.01 0.1 1 10 VIN=4.2V PWM VIN=3.6V PSAVE VIN=4.2V PSAVE VIN=2.7V PWM VIN=3.6V PWM
IOUT(A)
IOUT(A)
Efficiency vs. Input Voltage
100 95 90
IOUT=750mA (PWM) / 50mA (PSAVE), RFB1+RFB2=10K
PWM to PSAVE Hysteresis
1.82 VIN=3.6V, VOUT=1.8V
VOUT=3.3V PWM
1.815
VOUT=3.3V PSAVE
VOUT(V)
Efficiency (%)
85 80 75 70 65 60 2.4
VOUT=1.0V PWM
1.81
VOUT=1.0V PSAVE
1.805
PSAVE Entry IOUT Decreasing
PSAVE Exit IOUT Increasing
1.8
2.8
3.2
3.6
4.0 VIN(V)
4.4
4.8
5.2
5.6
1.795 0
0.1
0.2
0.3 IOUT(A)
0.4
0.5
0.6
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SC196
POWER MANAGEMENT Typical Characteristics (Cont.)
VOUT vs. VIN
1.82 VOUT=1.8V, IOUT=750mA(PWM)/50mA(PSAVE) PSAVE 1.81
PRELIMINARY
Load Regulation
1.82 1.815 PSAVE 1.81 VIN=3.6V, VOUT=1.8V
PWM
VOUT(V)
1.8
VOUT(V)
1.805 1.8
1.79
PWM
1.78
1.795
1.77
1.79 1.785 0 0.2 0.4 0.6 0.8 IOUT(A) 1 1.2 1.4 1.6
1.76 2.4
2.8
3.2
3.6
4
4.4 VIN(V)
4.8
5.2
5.6
6
VOUT vs. Temperature VOUT=1.8V
1.798 1.796 1.794 1.792
VOUT(V)
VOUT(V)
Current Limit
2 1.8 1.6 VIN=3.6V, VOUT=1.8V, PWM
VIN=3.6V, VOUT=1.8V, IOUT=100mA
PSAVE
1.4 1.2 1 0.8 0.6
1.79 1.788 1.786 1.784 1.782 1.78 1.778 -60 -40 -20 0 20 TA(C) 40 60 80 100 PWM
0.4 0.2 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 IOUT(A) 1.6 1.8 2 2.2 2.4
Quiescent Current vs. Input Voltage, PSAVE Mode
22 21 20 PSAVE Mode
Quiescent Current vs. Input Voltage, PWM Mode
6 PWM Mode TA=85C 5.5 TA=-40C
TA=85C
Quiescent current (mA)
Quiescent current (A)
19 18 17 16 15 14 13 12 2.5 3 3.5 4 4.5 5 5.5 6 TA=-40C TA=25C
TA=25C 5
4.5
4
3.5
VIN(V)
3 2.5
3
3.5
4
VIN(V)
4.5
5
5.5
6
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SC196
POWER MANAGEMENT Typical Characteristics (Cont.)
P-Channel RDSON vs. Input Voltage
0.40
0.22
PRELIMINARY
N-Channel RDSON vs. Input Voltage
0.35 TA=85C
RDSON()
0.20 TA=85C
RDSON()
0.30 TA=25C 0.25 TA=-40C 0.20
0.18 TA=25C
0.16
0.14
TA=-40C
0.15
0.12
0.10 2.7
0.10
3.2
3.7
4.2 VIN(V)
4.7
5.2
2.7
3.2
3.7
4.2 VIN(V)
4.7
5.2
Switching Frequency vs. Temperature
1050 1040 1030
100% Duty Cycle Mode
VIN=3.4V, VOUT=3.3V, IOUT=150mA, PWM
VIN=5.5V VIN=3.6V
Switching Frequency (kHz)
VOUT (20mV/div) ILX (200mA/div)
1020 1010 1000 990 980 970 960 950 -50 -30 -10 10 30 50 70 90 110 130
VIN=2.7V
VLX (2V/div)
Time (2s/div)
TJ(C)
PSAVE Operation
VIN=3.6V, VOUT=1.8V, IOUT=150mA, PSAVE
PWM Operation
VIN=3.6V, VOUT=1.8V, IOUT=150mA, PWM
VOUT (50mV/div)
VOUT (20mV/div)
ILX (500mA/div)
ILX (500mA/div)
VLX (2V/div)
VLX (5V/div)
Time (2s/div)
Time (1s/div)
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SC196
POWER MANAGEMENT Typical Characteristics (Cont.)
PSAVE Start-up
VIN=3.6V, VOUT=1.8V, IOUT=10mA, PSAVE VEN (5V/div) VEN (5V/div)
PRELIMINARY
PWM Start-up
VIN=3.6V, VOUT=1.8V, IOUT=1.5A, PWM
VOUT (1V/div) VOUT (1V/div)
IIN (100mA/div) Time (100s/div)
IIN (500mA/div) Time (1ms/div)
Load Transient Response-1
VIN=3.6V, VOUT=1.8V, IOUT=10mA to 1.5A, PWM
Load Transient Response-2
VIN=3.6V, VOUT=1.8V, IOUT=100mA to 1.5A, PWM
VOUT (200mV/div)
VOUT (200mV/div)
IOUT (500mA/div)
IOUT (500mA/div)
Time (400s/div)
Time (400s/div)
Load Transient Response-3
VIN=3.6V, VOUT=1.8V, IOUT=10mA to 1.5A, PSAVE
Load Transient Response-4
VIN=3.6V, VOUT=1.8V, IOUT=100mA to 1.5A, PSAVE
VOUT (200mV/div)
VOUT (200mV/div)
IOUT (500mA/div)
IOUT (500mA/div)
Time (400s/div)
Time (400s/div)
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SC196
POWER MANAGEMENT Applications Circuits
VOUT Programmed to 1.2V, no PSAVE
PRELIMINARY
VIN 2.5V to 5.5V VIN CIN 10F PVIN MODE EN
L1 4.7H
SC196
VOUT 1.2V 1.5A RFB1 280k 0.1% RFB2 200k 0.1% CFB1 10pF COUT 10F
LX VOUT ADJ
SYNC/PWM
PGND GND
The output voltage is set at 1.2V by the selection of the two resistors RFB1 and RFB2, using resistor values from Table 1. PWM-only mode operation is selected by connecting the SYNC/PWM pin to the VIN pin. The 100% duty cycle capability is selected by connecting the MODE pin to the VIN pin. A 10F capacitor is selected for the output, as PSAVE operation is not required in this application.
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SC196
POWER MANAGEMENT Outline Drawing -- MLPD-UT10 3x3x0.6
DIMENSIONS INCHES MILLIMETERS DIM MIN NOM MAX MIN NOM MAX
A A1 A2 b C D E e L N aaa bbb (.006) .007 .009 .074 .079 .042 .048 .114 .118 .020 BSC .012 .016 10 .003 .004 .018 .000 .024 .002 .011 .083 .052 .122 .020 .60 0.05 (0.1524) 0.18 0.23 0.30 1.87 2.02 2.12 1.06 1.21 1.31 2.90 3.00 3.10 0.50 BSC 0.30 0.40 0.50 10 0.08 0.10 0.45 0.00
PRELIMINARY
A
E
B
E PIN 1 INDICATOR (LASER MARK)
A aaa C C 1 LxN 2 A1 A2
SEATING PLANE C
D
N e bxN bbb CAB
NOTES:
1. 2.
CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS TERMINALS.
(c) 2007 Semtech Corp.
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SC196
POWER MANAGEMENT Land Pattern -- MLPD-UT10 3x3x0.6 PRELIMINARY
K
DIMENSIONS
DIM
C G H K P X Y Z
INCHES
(.112) .075 .055 .087 .020 .012 .037 .150
MILLIMETERS
(2.85) 1.90 1.40 2.20 0.50 0.30 0.95 3.80
(C)
H
G
Z
Y X P
NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. 2. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE
Contact Information
Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805) 498-2111 FAX (805) 498-3804
www.semtech.com (c) 2007 Semtech Corp.
18
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