POWER MANAGEMENT
Features
2.5MHz, 1.5A Synchronous
Step Down Regulator
Description
The SC189 is a high efficiency, synchronous step-down
regulator providing up to 1.5A output current in either
an ultra-small 2mm x 2mm, low profile package or a low
cost SOT23-5 package. The device requires only three
external filter components for a complete step down
regulator solution. The input voltage range is 2.9 to 5.5V
with either factory programmed outputs from 1.0 to 3.3V
or adjustable output via an external resistor divider.
The converter operates at fixed 2.5MHz switching
frequency allowing small L/C filtering components.
The voltage mode architecture is compatible with chip
inductors and capacitors for minimum PCB footprint and
lowest overall system cost. Total footprint of 25mm
2
can
be achieved - making the SC189 the ideal solution for
high density systems. Solution height of <1mm is also
possible.
Up to 93% efficiency is achieved with low R
DS(ON)
internal
switches. PWM constant frequency operation ensures
low output ripple across the load range. 100% duty-cycle
provides 360mV dropout voltage at 1.5A which extends
the minimum input voltage for 2.5V and 3.3V outputs.
Excellent transient response is achieved with no external
compensation components.
The SC189 provides input under-voltage, output over-
voltage, output short circuit and over-temperature
protection to safeguard the device and system under fault
conditions. The regulator provides integrated soft-start to
minimize inrush currents. Standby quiescient current is
less than 1µA.
The SC189 is available in SOT23-5 and a thermally
enhanced 2mm x 2mm x 0.6mm MLPD-UT6 package.
SC189
V
IN
Range: 2.9 – 5.5V
V
OUT
Options: 1.0 - 3.3V
Up to 1.5A Output Current
Ultra-Small Footprint, <1mm Height Solution
2.5MHz Switching Frequency
Efficiency Up to 93%
Low Output Noise Across Load Range
Excellent Transient Response
Start Up into Pre-Bias Output
100% Duty-Cycle Low Dropout Operation
<1µA Shutdown Current
Internal Soft Start
Input Under-Voltage Lockout
Output Over-Voltage, Current Limit Protection
Over-Temperature Protection
Adjustable Output Voltage
Available in SOT23-5 package and 2mm x 2mm x
0.6mm thermally enhanced MLPD-UT6 package
-40 to +85°C Temperature Range
Fully WEEE and RoHS Compliant
Applications
Bluetooth Radios
DSC and PMPs
GPS Devices
xDSL Systems
POL Regulators
Portable HDD
Wireless LAN
Typical Application Circuit
SC189C
V
IN
2.9V to 5.5V
VIN
C
IN
10µF
EN
LX
VOUT
GND
L
1µH
Total PCB Area ~25mm
2
V
OUT
1.20V/1.5A
C
OUT
22µF
L
Chip
C
OUT
0805
SC189
C
IN
0603
Actual Size
August 27, 2010
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SC189
Pin Configuration
NC
EN
VIN
1
2
3
6
5
Ordering Information
Device
TOP VIEW
Package & Description
2mm x 2mm x 0.6mm MLPD-UT6
SOT23-5
Evaluation Board for MLPD-UT6
- Standard Size
(i.e., Wire Wound Inductor)
Evaluation Board for MLPD-UT6
- Small Size
(i.e., Chip Inductor)
Evaluation Board for SOT23-5
- Standard Size
(i.e., Wire Wound Inductor)
Evaluation Board for SOT23-5
- Small Size
(i.e., Chip Inductor)
VOUT
GND
LX
SC189xULTRT
(2)(3)(4)
SC189xSKTRT
2)(3)(4)
SC189xEVB
(5)
T
4
2mm x 2mm x 0.6mm MLPD-UT6
θ
JA
= 60°C/W
(1)
SC189xEVB-1
(5)
VIN
GND
EN
1
TOP VIEW
5
LX
SC189xEVB-2
(5)
2
SC189xEVB-3
4
(5)
3
VOUT
SOT23-5
θ
JA
= 90°C/W
(1)
Marking Information
FLx
Notes:
(1) Measured in free convection, mounted on 10mm x 10mm, 2 layer
FR4 PCB shown in figure 7 ( for MLPD-UT6 package) and figure 8 (
for SOT23-5 package) with copper of 1oz for each layer.
(2) Available in tape and reel only. A reel contains 3,000 devices.
(3) Available in lead-free package only. Device is WEEE and RoHS
compliant.
(4) “x” is the code of the output voltage. See Table 1 for the code. For
example, the device number for VOUT= 1.20V is SC189CULTRT.
(5) “x” is the code of the output voltage. See Table 1 for the code.
For example, the EVB for MLPD-UT6 package with VOUT= 1.20V is
SC189CEVB (Standard Size) or SC189CEVB-1 (Small Size).
Table 1: Available Output Voltages
Marking for 2mm x 2mm MLPD-UT 6 Lead Package:
x = Code of the output voltage (Example: C for VOUT=1.20V)
oyw = Pin 1 and Datecode (Reference Package Marking Design
Guidelines, Appendix A)
Code
for MLPD-UT6
A
B
C
E
F
H
L
N
T
Not Available
Code
for SOT23-5
A
B
C
Not Available
Not Available
VOUT
(1)
1.00
1.10
1.20
1.28
1.30
1.50
1.80
2.00
2.50
2.70
3.30
Top Mark
Bottom Mark
189
x
Marking for SOT23, 5 Lead Package:
x = Code of the output voltage (Example: C for VOUT=1.20V)
yyww = Datecode (Example: 0852)
H
L
Not Available
Y
V
Z
Z
Notes:
(1) Contact factory for unavaliable output voltage options.
© 2009 Semtech Corp.
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SC189
Absolute Maximum Ratings
VIN Supply Voltage ……………………………… -0.3 to 6.0V
LX Voltage
………….. -1 to V
IN
+1V, -3V (20ns Max), 6V Max
……………………………… -0.3 to V
IN
+0.3V
VOUT Voltage
Recommended Operating Conditions
VIN Supply Voltage ……………………………… 2.9 to 5.5V
Maximum Output Current
(3)
…………………………… 1.5A
EN Voltage …………………………………. -0.3 to V
IN
+0.3V
Peak IR Reflow temperature …………………………. 260°C
ESD Protection Level
(2)
………………………………….
3kV
Thermal Information
Thermal Resistance, Junction to Ambient
(1)
MLPD-UT6 Package ……………………………… 60°C/W
SOT23-5 Package
……………………………… 90°C/W
Operating Junction Temperature …………… -40 to +125˚C
Maximum Junction Temperature …………………… +150°C
Storage Temperature Range ………………… -65 to +150 °C
Exceeding the absolute maximum ratings may result in permanent damage to the device and/or device malfunction. Operation outside of the
parameters specified in the Electrical Characteristics section is not recommended.
NOTES:
(1) Measured in free convection, mounted on 10mm x 10mm, 2 layer FR4 PCB shown in figure 7 ( for MLPD-UT6 package) and figure 8 ( for SOT23-
5 package) with copper of 1oz for each layer.
(2) Tested according to JEDEC standard JESD22-A114-B.
(3) For SOT23-5 package, the limit of the maximum power dissiption shown in figure 2 may reduce the maximum output current.
Electrical Characteristics
Unless specified: V
IN
= 5.0V, C
IN
=10µF, C
OUT
=10µF; L=2.2µH; -40°C<T
A
<+85 °C; T
J(MAX)
=125°C; Unless otherwise noted typical values are T
A
=+25 °C.
Parameter
Under-Voltage Lockout
Output Voltage Tolerance
(1)
Current Limit
VIN Supply Current
VIN Shutdown Current
High Side Switch Resistance
Symbol
UVLO
ΔV
OUT
I
LIMIT
I
Q
I
SHDN
R
DSON_P
Conditions
Rising V
IN
Hysteresis
V
IN
=3.6V to 5.0V; No Load
Peak inductor current
EN= VIN, No Load
EN= GND
I
LX
= 100mA, for MLPD-UT6
I
LX
= -100mA, for SOT23-5
I
LX
= -100mA, for MLPD-UT6
I
LX
= -100mA, for SOT23-5
V
IN
=5.5V; L
X
=0V; EN=GND
V
IN
=5.5V; L
X
=5.0V; EN=GND
V
IN
= 3.6 – 5.0V; I
OUT
=0A
V
IN
= 5.0V; I
OUT
=10mA – 1.5A
Min
2.60
Typ
2.70
250
Max
2.80
Units
V
mV
-2.5
2.0
7.5
1
0.13
0.15
0.10
0.125
1
-10
-1
±1.0
±1.0
2.0
2.5
100
+2.5
%
A
mA
10
µA
Ω
Low Side Switch Resistance
R
DSON_N
LX Leakage Current
Line Regulation
Load Regulation
(2)
Oscillator Frequency
Soft-Start Time
(2)
EN Input High Current
I
LK(LX)
ΔV
LINE-REG
ΔV
LOAD-REG
F
OSC
T
SS
I
EN_HI
10
µA
%
%
3.0
MHz
µs
EN=VIN
-2.0
2.0
µA
© 2009 Semtech Corp.
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SC189
Electrical Characteristics (continued)
Unless specified: V
IN
= 5.0V, C
IN
=10µF, C
OUT
=10µF; L=2.2µH; -40°C<T
A
<+85 °C; T
J(MAX)
=125°C; Unless otherwise noted typical values are T
A
=+25 °C.
Parameter
EN Input Low Current
EN Input High Threshold
EN Input Low Threshold
VOUT Over Voltage Protection
(2)
Thermal Shutdown Temperature
(2)
Thermal Shutdown Hysteresis
(2)
Symbol
I
EN_LO
V
EN_HI
V
EN_LO
V
OVP
T
SD
T
SD_HYS
Conditions
EN=GND
Min
-2.0
1.2
Typ
Max
2.0
Units
µA
V
0.4
115
Junction Temperature
Junction Temperature
+160
10
V
%
°C
°C
Notes:
(1) The “Output Voltage Tolerance” includes output voltage accuracy, voltage drift over temperature and the line regulation.
(2) Guaranteed by design.
© 2009 Semtech Corp.
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SC189
Typical Characteristics
Circuit Conditions: C
IN
= 10uF/6.3V; C
OUT
= 10uF/6.3V for L=2.2uH; C
OUT
= 22uF/6.3V for L=1uH.
Unless otherwise noted, L= 2.2uH (TOKO: 1071AS-2R2M) and SC189 in MLPD-UT6 package.
Efficiency vs. Load Current (V
OUT
=1.5V)
Efficiency
100%
95%
90%
100%
95%
90%
Efficiency
Efficiency vs. Load Current (V
OUT
=3.3V)
V
IN
= 4.0V
V
IN
= 5.0V
Efficiency (%)
85%
80%
75%
Efficiency (%)
85%
80%
75%
70%
65%
60%
V
IN
= 5.0V
V
IN
= 3.3V
70%
65%
60%
0.0
0.3
0.6
0.9
1.2
1.5
Output Current (A)
V
OUT
= 1.50V
T
A
=25°
C
V
OUT
= 3.30V
T
A
=25°
C
0.0
0.3
0.6
0.9
1.2
1.5
Output Current (A)
Efficiency
Efficiency vs. Load Current (V
IN
=5.0V, V
OUT
=1.0V)
100%
95%
90%
Efficiency vs. Load Current (V
IN
=5.0V, V
OUT
=3.3V)
Efficiency
100%
L=1071AS-2R2N (50m_typ)
L=1071AS-1R0N (33m_typ)
L=1071AS-2R2N (50m_typ)
95%
90%
Efficiency (%)
Efficiency (%)
85%
80%
75%
70%
65%
60%
0.0
0.3
L=MDT2520-CR1R0M (60m_typ)
85%
L=1071AS-1R0N (33m_typ)
80%
L=MDT2520-CR1R0M (60m_typ)
75%
70%
65%
60%
V
IN
= 5.0V
V
OUT
= 1.0V
T
A
=25°
C
L=LQM2HPN1R0MG0 (55m_typ)
0.6
0.9
1.2
1.5
V
IN
= 5.0V
V
OUT
= 3.3V
T
A
=25°
C
0.0
0.3
L=LQM2HP1R0MG0 (55m_typ)
0.6
0.9
1.2
1.5
Output Current (A)
Output Current (A)
Total Loss vs. Load
Losses
Current (V
OUT
=1.5V)
800
800
Total Loss vs. Load
Losses
Current (V
OUT
=3.3V)
V
OUT
= 3.30V
T
A
=25°
C
V
OUT
= 1.50V
T
A
=25°
C
600
Loss (mW)
V
IN
= 3.3V
Loss (mW)
600
400
400
V
IN
= 5.0V
200
200
V
IN
= 5.0V
V
IN
= 4.0V
0
0.0
0.3
0.6
0.9
1.2
1.5
Output Current (A)
0
0.0
0.3
0.6
0.9
1.2
1.5
Output Current (A)
© 2009 Semtech Corp.
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