SEMTECH SC194AEVB

SC194A
1A Synchronous Buck Converter
with Integrated Power Devices
POWER MANAGEMENT
Description
Features
The SC194A is a synchronous step-down converter with
integrated power devices. The SC194A is designed for
single-cell Li-Ion battery applications, but can also be used
in fixed 3.3V or 5V applications. The switching frequency is
nominally set to 1MHz, allowing the use of small inductors
and capacitors. The 1.3A maximum current rating of the
internal MOSFET switches allows a DC output current of
1A.
‹
‹
‹
‹
‹
‹
‹
‹
‹
‹
‹
‹
‹
‹
The SC194A has a flexible clocking methodology that
allows it to be synchronized to an external oscillator or
controlled by the internal oscillator. The device can
operate 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.
Up to 93% efficiency
Output current - 1A
Input range - 2.7V to 5.5V
Quiescent current - 17μA
Four selectable output voltages
Dynamic voltage positioning capability
Fixed 1MHz frequency or 750kHz to 1.25MHz
synchronized operation
PSAVE operation to maximize efficiency at light loads
Minimal external components
Fast transient response
100% duty cycle in dropout
Soft-start
Over-temperature and short-circuit protection
Space-saving lead-free package - MLP-10, 3 x 3mm
Applications
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 0.1μA.
‹
‹
‹
‹
‹
‹
Cell phones
Wireless communication chipset power
Personal media player
Notebook and sub-notebook computers
PDAs and mobile communicators
WLAN peripherals
Typical Application Circuit
L1
SC194A
VIN
2.7V to 5.5V
CIN
10μF
July 05, 2006
VIN
EN
SYNC/PWM
VID0
VID1
MODE
VOUT
1.8V
1A
LX
4.7μH
VOUT
PGND
GND
1
COUT
10μF
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Absolute Maximum Ratings
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.
Parameter
Symbol
Maximum
Units
Input Supply Voltage
VIN
-0.3 to 7
V
Logic Inputs
(SYNC/PWM, EN, MODE, VID0, VID1)
VN
-0.3 to VIN+0.3, 7V Max
V
Output Voltage
VOUT
-0.3 to VIN+0.3, 7V Max
V
LX Voltage
VLX
-1 to VIN +1, 7V Max
V
Thermal Impedance Junction to Ambient(1)
θJA
40
°C/W
VOUT Short-Circuit to GND
tSC
Continuous
s
Operating Ambient Temperature Range
TA
-40 to +85
°C
Storage Temperature
TS
-60 to +160
°C
Junction Temperature
TJC
-40 to +150
°C
Peak IR Reflow Temperature
TLEAD
260
°C
ESD Protection Level (2)
VESD
2
kV
Note:
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, EN = VIN, SYNC/PWM = VIN, MODE = VIN , TA = -40 to 85°C. Typical values are at TA = 25°C.
Parameter
Symbol
Input Voltage Range
VIN
VOUT Accuracy
VOUT
VOUT Temperature Accuracy
VOUT(T)
Line Regulation
Conditions
Min
Typ
2.7
IOUT = 0.5A, TA = 25°C
Max
Units
5.5
V
±1
%
IOUT = 0.5A, TA = -40 to 85°C
±0.3
±0.7
%
VOUT LINE
VIN = 2.7V to 5.5V, VOUT = 1.8V,
IOUT = 0.5A, TA = -40 to 85°C
±0.4
±0.65
%
Load Regulation (PWM)
VOUT LOAD
IOUT = 0A to 1A, TA = -40 to 85°C
±0.3
±0.65
%
PSAVE Regulation
VOUT PSAVE
SYNC/PWM =GND, COUT=22 μF
+1.3
-0.3
+1.6
-0.6
%
P-Channel On Resistance
RDSP
ILX = 100mA
0.275
Ω
N-Channel On Resistance
RDSN
ILX = 100mA
0.165
Ω
Start-Up Time
TSTART
P-Channel Current Limit
ILIM(P)
© 2006 Semtech Corp.
1.33
2
1.9
5
ms
2.47
A
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Parameter
Symbol
Conditions
Quiescent Current
IQ
Shutdown Current
Min
Typ
Max
Units
SYNC/PWM = GND, IOUT = 0A,
VOUT = 1.04 x VOUT(Programmed)
17
28
μA
ISD
EN = GND, LX = OPEN
0.1
1
μA
LX Leakage Current PMOS
ILXP
LX = GND, EN = GND
0.1
2
μA
LX Leakage Current NMOS
ILXN
LX = 3.6V, EN = GND
Oscillator Frequency
-2
0.1
fOSC
0.85
1.0
SYNC Frequency (upper)
fSYNCU
1.25
SYNC Frequency (lower)
fSYNCL
UVLO Threshold (upper)
VUVL
UVLO Hysteresis
Thermal Shutdown
Thermal Shutdown Hysteresis
2.38
1.15
MHz
MHz
2.52
750
kHz
2.65
V
VUVLHYS
50
mV
TSD
145
°C
TSD-HYS
10
°C
Logic Input High
VIH
EN, SYNC/PWM, VID0, VID1, MODE
Logic Input Low
VIL
EN, SYNC/PWM, VID0, VID1, MODE
Logic Input Current High
IIH
EN, SYNC/PWM, VID0, VID1, MODE
-2
Logic Input Current Low
IIL
EN, SYNC/PWM, VID0, VID1, MODE
-2
© 2006 Semtech Corp.
μA
3
1.6
V
0.6
V
0.1
2
μA
0.1
2
μA
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Ordering Information
Pin Configuration
VIN
1
MODE
2
SYNC/
PWM
3
EN
4
VOUT
TOP VIEW
T
5
10
LX
9
PGND
8
GND
7
VID1
6
VID0
DEVICE
PACKAGE
SC194AMLTRT(1)(2)
MLP 3x3-10
SC194AEVB
Evaluation Board
Ordering Information
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.
Programmable Output Voltage
MLP10: 3X3 10 LEAD
VID1
VID0
SC194A VOUT
0
0
1.0V
0
1
1.2V
1
0
1.5V
1
1
1.8V
Marking Information
© 2006 Semtech Corp.
4
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Block Diagram
Plimit Amp
1
VIN
10
LX
9
PGND
8
GND
Current Amp
EN
4
SYNC
/PWM
3
OSC & Slope
Generator
Control
Logic
PWM
Comp
500mV
Ref
MODE
2
VID1
7
VID0
6
VOUT
5
© 2006 Semtech Corp.
Error Amp
PSAVE
Comp
Nlimit Amp
Voltage
Select
5
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Pin Descriptions
Pin #
Pin Name
1
VIN
2
MODE
3
SYNC/PWM
4
EN
5
VOUT
Regulated output voltage and feedback for SC194A
6
VID0
Logic level bit 0 used in conjunction with VID1 to set the output voltage. Connect high or low as required
to select the desired output voltage. If not connected, the output voltage will be indeterminate.
7
VID1
Logic level bit 1 used in conjunction with VID0 to set the output voltage. Connect high or low as required
to select the desired output voltage. If not connected, the output voltage will be indeterminate.
8
GND
Ground
9
PGND
10
LX
T
THERMAL
PAD
© 2006 Semtech Corp.
Pin Function
Input power supply voltage
MODE select pin - MODE = VIN to select 100% duty cycle function, MODE = GND to disable
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 SC194A, a low disables and reduces quiescent current to
less than 1μA. In shutdown, LX becomes high impedance.
Power Ground
Inductor connection to the switching FETs
Pad for heatsinking purposes - not connected internally. Connects to ground plane using
multiple vias.
6
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Applications Information
SC194A Detailed Description
The SC194A 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.
• Over-voltage protection
• Soft-start
Thermal Shutdown
The device has a thermal shutdown feature to protect the
SC194A if the junction temperature exceeds 145°C. In
thermal shutdown the on-chip power devices are disabled,
tri-stating the LX output. Switching will resume when the
temperature drops by 10°C. During this time if the output
voltage decreases by more than 60% of its programmed
value, a soft-start will be invoked.
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 internal 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.
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, that causes the switching
frequency to divide by a factor determined by the output
voltage. This prevents the inductor current from "staircasing".
The SC194A has an internal synchronous NMOS rectifier
and does not require a Schottky diode on the LX pin.
Over-Voltage Protection
Over-voltage protection is provided on the SC194A. In the
event of an over-voltage on the output in switcher mode,
the PWM drive is disabled, tri-stating the LX output. The
part will not resume switching until the output voltage has
fallen below 2% of the regulation voltage.
Programmable Output Voltage
The SC194A has four pre-determined output voltage
values which can be individually selected by the correct
programming of the VID0 and VID1 pins (see Programmable
Output Voltage table on Page 4). This eliminates the need
for external programming resistors saving PCB area and
inventory. The VID pins can be statically tied to GND or
VIN for fixed output configurations or they may be driven
by a microprocessor enabling the possibility of dynamic
voltage adjustment for host equipment "sleep" states.
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 startup. 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 by 1/8, 1/4, and 1/2 of the internal
oscillator frequency up to the full value, under control of
three output voltage thresholds. As soon as the output
voltage is within 2% of the regulation voltage, soft-start
mode is disabled.
Continuous Conduction & Oscillator Synchronization
The SC194A 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.
Power Save Mode Operation
The PSAVE mode may be selected by tying the SYNC/PWM
pin to GND. Selecting PSAVE mode will enable the SC194A
to automatically activate/deactivate operation at light
loads maximizing efficiency across the full load range. The
SC194A automatically detects the load current at which it
should enter PSAVE mode. The SC194A is optimized to
track maximum efficiency with respect to VIN.
Protection Features
The SC194A provides the following protection features:
• Thermal shutdown
• Current limit
© 2006 Semtech Corp.
7
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Applications Information (Cont.)
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.
100% Duty Cycle Operation
The 100% duty cycle mode may be selected by connecting
the MODE pin high. This will allow the SC194A to maintain
output regulation under 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
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:
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 SC194A automatically detects when to exit PSAVE
mode by monitoring VOUT . For the SC194A 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.
VOUT = VI N − IOUT × ( RDSP + RIND )
where,
VOUT
VIN
IOUT
RDSP
RIND
If PSAVE operation is required then a 22μF output
capacitor must be used.
The 100% duty cycle can only operate for a programmed
output voltage of 1.8V.
With an output voltage of 1.8V, 100% duty cycle mode will
only be required to maintain regulation if VIN falls below a
minimum value shown in the graph below.
Power Save Operation
BURST
OFF
= Output voltage
= Input voltage
= Output current
= PMOS switch ON resistance
= Series resistance of the inductor
Higher Load
Applied
Minimum VIN for Fixed Frequency Operation Vs. RIND
1.5%
3
0.7%
PSAVE Mode at Light Load
PWM Mode at Medium/
High Load
VOUT
2.95
-2%
VIN (V)
2.9
2.85
Inductor Current
2.8
2.75
VOUT = 1.8V
IOUT =1A
0A
2.7
0.05
Time
0.1
0.15
0.2
0.25
0.3
Inductor DC R esistance (Ω)
© 2006 Semtech Corp.
8
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Applications Information (Cont.)
The SC194A is designed for use with a 4.7μH inductor.
The magnitude of the inductor current ripple is dependent
on the inductor value and can be determined by the
following equation:
VOUT
ΔIL = ———
L × fOSC
(
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
1 - ———
VIN
ΔVOUT(ESR) = ΔIL(ripple) × ESRCOUT
This equation demonstrates the relationship between
input voltage, output voltage, and inductor ripple current.
Capacitors with X7R or X5R ceramic dielectric are
strongly recommended for their low ESR and superior
temperature and voltage characteristics. Y5V capacitors
should not be used as their temperature coefficients
make them unsuitable for this application. Table 2 lists
the manufacturers of recommended capacitor options.
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:
ΔIL
IL(PK) = IOUT(MAX) + ——
2
Final inductor selection will depend on various design
considerations such as efficiency, EMI, size and cost.
Table 1 lists the manufacturers of practical inductor
options.
Table 1: Recommended Inductors
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
10μF should be used for sufficient input voltage filtering
and a 22μF should be used for improved input voltage
filtering.
1
2π√L × COUT
This single pole filter is designed to operate with a
minimum output capacitor value of 10μF. Larger output
capacitor values will improve transient performance. If
PSAVE operation is required the minimum capacitor value
is 22μF.
© 2006 Semtech Corp.
DCR
Ω
Saturation
Current
A
Tolerance
±%
Dimensions
(LxWxH)
mm
BI Technologies
HM66304R7
4.7
0.072
1.32
20
4.7 × 4.7 × 3.0
Coilcraft
D01608C-472ML
4.7
0.09
1.5
20
6.6 × 4.5 × 3.0
TDK
VLCF4018T- 4R7N1R0-2
4.7
0.101
1.07
30
4.3 × 4.0 × 1.8
Table 2: Recommended Capacitors
COUT Selection
The internal compensation is designed to work with a
certain output filter corner frequency defined by the
equation:
fc =
Value
μH
Manufacturer/Part #
Manufacturer/Part #
Value
μF
Rated
Voltage
VDC
Temperature
Characteristic
Case Size
Murata
GRM21BR60J226ME39L
22
6.3
X5R
0805
Murata
GRM188R60J106
MKE19
10
6.3
X5R
0603
TDK
C2012X5R0J106K
10
6.3
X5R
0603
Note: Where PSAVE operation is required 22μF must be used for COUT.
9
www.semtech.com
SC194A
PRELIMINARY
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.
2. Route the output voltage feedback path away from the
inductor and LX node to minimize noise and magnetic
interference.
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.
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.
© 2006 Semtech Corp.
10
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Typical Characteristics
Efficiency vs. Load Current VOUT = 1.8V
Efficiency vs. Load Current VOUT = 1.5V
100
100
90
90
80
60
VIN=3.6V PSAVE
VIN=2.7V PSAVE
VIN=4.2V PWM
50
40
VIN=3.6V PWM
30
60
VIN=2.7V PSAVE
50
VIN=4.2V PWM
40
VIN=3.6V PWM
30
VIN=2.7V PWM
20
20
10
10
VIN=2.7V PWM
0
0
0.0001
0.001
0.01
IOUT (A)
0.1
0.0001
1
Efficiency vs. Load Current VOUT = 1.2V
100
90
90
80
0.01
IOUT (A)
0.1
1
80
VIN=4.2V PSAVE
70
VIN=2.7V PSAVE
50
VIN=4.2V PWM
40
VIN=3.6V PWM
30
60
50
VIN=2.7V PWM
VIN=3.6V PSAVE
VIN=4.2V PSAVE
VIN=3.6V PWM
40
30
VIN=4.2V PWM
VIN=2.7V PWM
20
VIN=2.7V PSAVE
70
VIN=3.6V PSAVE
Efficiency (%)
60
0.001
Efficiency vs. Load Current VOUT = 1.0V
100
Efficiency (%)
VIN=4.2V PSAVE
70
VIN=3.6V PSAVE
Efficiency (%)
Efficiency (%)
80
VIN=4.2V PSAVE
70
20
10
10
0
0.0001
0
0.001
0.01
IOUT (A)
0.1
1
0.0001
Efficiency vs. Input Voltage
0.001
0.01
IOUT (A)
0.1
1
PWM to PSAVE Hysteresis
95
100
PSAVE Exit for increasing IOUT
PSAVE Entry for decreasing IOUT
95
90
VOUT=1.8V,PWM
VOUT=1.8V,PSAVE
Efficiency (%)
Eff(%)
90
85
PSAVE Mode IOUT increasing
85
PSAVE MODE IOUT decreasing
PWM Mode
80
80
VOUTt=1V,PSAVE
VOUT=1V,PWM
75
75
70
2.5
3.5
3.0
4.0
Vin(V)
4.5
5.0
70
0.001
5.5
0.01
IOUT (A)
0.1
1
IOUT=500 mA(PWM)/50 mA(PSAVE)
© 2006 Semtech Corp.
11
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Typical Characteristics (Cont.)
VOUT vs. IOUT, VOUT=1.8V, PWM
VOUT vs. VIN
1.84
1.8025
1.8020
1.8015
VOUT=1.8V PSAVE
IOUT=50mA
1.8010
1.8005
VOUT (V)
VOUT (V)
1.83
1.82
1.8000
1.7995
VOUT=1.8V PWM
IOUT=500mA
1.7990
1.81
1.7985
1.7980
1.80
2.5
1.7975
3.0
3.5
4.0
4.5
5.0
5.5
0.4
0.2
0
6.0
VOUT vs. Temperature
1.8090
22
1.8085
PSAVE Mode
TA = 85 °C
20
Quiescent Current (μA)
1.8075
1.8070
Vout(V)
1.2
21
1.8080
1.8065
1.8060
1.8055
19
18
16
15
14
1.8045
13
1.8040
-50 -40 -30 -20 -10
0
10 20
TA(°C)
30
40
50
60
70
80
12
2.5
90
TA = 25 °C
17
1.8050
TA = 40 °C
3
3.5
4
VIN (V)
4.5
5
5.5
6
P-Channel RDSON vs. Input Voltage
Quiescent Current vs. Input Voltage
PWM Mode
0.40
TA = 85 °C
TA = -40 °C
0.35
5.5
TA = 85 °C
TA = 25 °C
0.30
5
TA = 25 °C
R DSON (Ω)
Quiescent Current (mA)
1
Quiescent Current vs. Input Voltage
VOUT=1.8V, PWM
6
0.8
0.6
IOUT (A)
VIN (V)
4.5
0.25
TA = -40 °C
4
0.20
3.5
0.15
3
2.5
3
© 2006 Semtech Corp.
3.5
4
VIN (V)
4.5
5
5.5
0.10
2.7
6
12
3.2
3.7
VIN (V)
4.2
4.7
5.2
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Typical Characteristics (Cont.)
N-Channel RDSON vs. Input Voltage
Switching Frequency vs. Temperature
1050
0.22
VIN = 5.5V
1040
0.20
1030
Switching Frequency (kHz)
TA = 85 °C
R DSON (Ω)
0.18
TA = 25 °C
0.16
TA = -40 °C
0.14
VIN = 3.6V
1020
VIN = 2.7V
1010
1000
990
980
970
0.12
960
0.10
2.7
3.2
3.7
4.2
VIN (V)
4.7
950
-50
5.2
-30
-10
10
30
50
70
90
110
130
TJ = (°C)
PSAVE Operation
100% Duty Cycle Mode
VOUT (50mV/div)
VOUT (20mV/div)
ILOAD (1A/div)
IL (200mA/div)
VLX (5V/div)
VLX (2V/div)
Time (1us/div)
Condition VIN=3.6V, VOUT=1.8V, lOUT=150mA,
SYNC/PWM=GND
Time (400ns/div)
Condition VIN=2.6V, VOUT=1.8V, lOUT=1.4A,
SYNC/PWM=1.15MHz ext clock
PSAVE Start up
PWM Operation
VOUT (10mV/div)
EN (2V/div)
IL (200mA/div)
VOUT (1V/div)
VLX (5V/div)
lIN (100mA/div)
Time (1us/div)
Condition VIN=3.6V, VOUT=1.8V, lOUT=150mA,
SYNC/PWM=VIN
© 2006 Semtech Corp.
Time (200us/div)
Condition VIN=3.6V, VOUT=1.8V, lOUT=10mA,
SYNC/PWM=GND
13
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Typical Characteristics (Cont.)
PWM Start-up
Load Transient Response PWM
EN (2V/div)
VOUT (1V/div)
VOUT (100mV/div)
ILOAD (1A/div)
lIN (100mA/div)
Time (200us/div)
Condition VIN=3.6V, VOUT=1.8V, lOUT=10mA,
SYNC/PWM=VIN
Time (100us/div)
Condition VIN=3.6V, VOUT=1.8V, lOUT=1A to 100mA,
SYNC/PWM=VIN
Load Transient Response PSAVE
VID Code Change
VID0 (2V/div)
VOUT (100mV/div)
VOUT (200mV/div)
ILOAD (1A/div)
Time (100us/div)
Condition VIN=3.6V, VOUT=1.8V, lOUT=1A to 100 mA,
SYNC/PWM=GND
© 2006 Semtech Corp.
Time (400us/div)
Condition VIN=3.6V, VOUT=1.8V to 1.5V, lOUT=1A,
SYNC/PWM=VIN
14
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Applications Circuits
VOUT = 1.8V with PSAVE and 100% Duty Cycle
L1
SC194A
VIN
2.7V to 5.5V
CIN
10μF
VIN
EN
SYNC/PWM
VID0
VID1
MODE
VOUT
1.8V
1A
LX
4.7μH
VOUT
COUT
PGND
GND
22μF
Mobile Voltage Positioning for Reduced System Dissipation in "Sleep" Modes
VIN
2.7V to 5.5V
CIN
10μF
L1
SC194A
“Sleep” Flag from
uProc
Changes voltage
from 1.8V to 1.2V
VIN
EN
SYNC/PWM
VID0
VID1
MODE
VOUT
1.8V
norm
VOUT
1.2V
“sleep”
LX
4.7μH
VOUT
COUT
PGND
GND
22μF
VOUT = 1.0V with Forced PWM and no 100% Duty Cycle
L1
SC194A
VIN
2.7V to 5.5V
CIN
10μF
© 2006 Semtech Corp.
VIN
EN
SYNC/PWM
VID0
VID1
MODE
VOUT
1V
1A
LX
4.7μH
VOUT
PGND
GND
15
COUT
10μF
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Outline Drawing - MLP-10
A
E
B
DIM
A
A1
A2
b
C
D
E
e
L
N
aaa
bbb
E
PIN 1
INDICATOR
(LASER MARK)
A
aaa C
A1
C
1
DIMENSIONS
INCHES
MILLIMETERS
MIN NOM MAX MIN NOM MAX
.031
.039
.002
.000
(.008)
.007 .009 .011
.074 .079 .083
.042 .048 .052
.114 .118 .122
.020 BSC
.012 .016 .020
10
.003
.004
0.80
1.00
0.00
0.05
(0.20)
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
SEATING
PLANE
C
A2
2
LxN
D
N
e
bxN
bbb
C A B
NOTES:
1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS TERMINALS.
© 2006 Semtech Corp.
16
www.semtech.com
SC194A
PRELIMINARY
POWER MANAGEMENT
Land Pattern - MLP-10
DIMENSIONS
K
DIM
(C)
H
G
C
G
H
K
P
X
Y
Z
Z
Y
X
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
P
NOTES:
1.
THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.
CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR
COMPANY'S MANUFACTURING GUIDELINES ARE MET.
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
© 2006 Semtech Corp.
17
www.semtech.com