SwitchReg™
AAT1150
1MHz 1A Step-Down DC/DC Converter
1150.2006.09.1.5 1
General Description
The AAT1150 SwitchReg™ is a step-down switch-
ing converter ideal for applications where high effi-
ciency, small size, and low ripple are critical. Able
to deliver 1A with internal power MOSFETs, the
current-mode controlled IC provides high efficiency
using synchronous rectification. Fully internally
compensated, the AAT1150 simplifies system
design and lowers external parts count.
The AAT1150 is available in a Pb-free MSOP-8
package and is rated over the -40°C to +85°C tem-
perature range.
Features
•V
IN Range: 2.7V to 5.5V
• Up to 95% Efficiency
• 110mΩRDS(ON) MOSFET Switch
• <1.0μA of Shutdown Current
• 1MHz Switching Frequency
• Fixed or Adjustable VOUT: 1.0V to 4.2V
• High Initial Accuracy: ±1%
• 1.0A Peak Current
• Integrated Power Switches
• Synchronous Rectification
• Internally Compensated Current Mode Control
• Constant PWM Mode for Low Output Ripple
• Internal Soft Start
• Current Limit Protection
• Over-Temperature Protection
• MSOP-8 package
• -40°C to +85°C Temperature Range
Applications
• Cable/DSL Modems
• Computer Peripherals
• High Efficiency Conversion From 5V or 3.3V
Supply
• Network Cards
• Set-Top Boxes
Typical Application
OUTPUT
4.1μH
3x 22μF
10μF
0.1μF
100Ω
LX
VP
INPUT
FB
SGND
AAT1150
ENABLE
VCC
PGND
AAT1150
1MHz 1A Step-Down DC/DC Converter
21150.2006.09.1.5
Pin Descriptions
Pin Configuration
MSOP-8
(Top View)
1 2
LX
PGND
LX
VP
FB
SGND
EN
VCC
1
2
3
4
8
7
6
5
Pin # Symbol Function
1 FB Feedback input pin. This pin must be connected to the converter’s output. It is
used to set the output of the converter to regulate to the desired value.
2 SGND Signal ground.
3 EN Enable input pin. When connected high, the AAT1150 is in normal operation.
When connected low, it is powered down. This pin should not be left floating.
4 VCC Power supply. It supplies power for the internal circuitry.
5 VP Input supply voltage for converter power stage.
6, 7 LX Inductor connection pins. These pins should be connected to the output
inductor. Internally, Pins 6 and 7 are connected to the drains of the P-chan-
nel switch and N-channel synchronous rectifier.
8 PGND Power ground return for the output stage.
AAT1150
1MHz 1A Step-Down DC/DC Converter
1150.2006.09.1.5 3
Absolute Maximum Ratings1
TA= 25°C, unless otherwise noted.
Thermal Characteristics3
Recommended Operating Conditions
Symbol Description Rating Units
T Ambient Temperature Range -40 to +85 °C
Symbol Description Value Units
ΘJA Maximum Thermal Resistance (MSOP-8) 150 °C/W
PDMaximum Power Dissipation (MSOP-8, TA= 25°C)4667 mW
Symbol Description Value Units
VCC, VPVCC, VP to GND 6 V
VLX LX to GND -0.3 to VP+ 0.3 V
VFB FB to GND -0.3 to VCC + 0.3 V
VEN EN to GND -0.3 to 6 V
TJOperating Junction Temperature Range -40 to 150 °C
VESD ESD Rating2- HBM 3000 V
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi-
tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Human body model is a 100pF capacitor discharged through a 1.5kΩresistor into each pin.
3. Mounted on a demo board.
4. Derate 6.7mW/°C above 25°C.
AAT1150
1MHz 1A Step-Down DC/DC Converter
41150.2006.09.1.5
Electrical Characteristics
VIN = VCC = VP= 5V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= 25°C.
Symbol Description Conditions Min Typ Max Units
VIN Input Voltage Range 2.7 5.5 V
VOUT Output Voltage Tolerance VIN = VOUT + 0.3 to 5.5V, -4.0 4.0 %
IOUT = 0 to 1A
ΔVOUT (VOUT*ΔVIN) Load Regulation VIN = 4.2V, ILOAD = 0 to 1A 3.0 %
ΔVOUT/VOUT Line Regulation VIN = 2.7V to 5.5V 0.2 %/V
VUVLO Under-Voltage Lockout VIN Rising 2.5 V
VIN Falling 1.2
VUVLO(HYS) Under-Voltage Lockout Hysteresis 250 mV
IQQuiescent Supply Current No Load, VFB = 0 160 300 μA
ISHDN Shutdown Current VEN = 0V, VIN = 5.5V 1.0 μA
ILIM Current Limit TA= 25°C 1.2 A
RDS(ON)H High Side Switch On Resistance TA= 25°C 110 150 mΩ
RDS(ON)L Low Side Switch On Resistance TA= 25°C 100 150 mΩ
ηEfficiency VIN = 5V, VOUT = 3.3V, 93 %
IOUT = 600mA
VEN(L) Enable Low Voltage VIN = 2.7V to 5.5V 0.6 V
VEN(H) Enable High Voltage VIN = 2.7V to 5.5V 1.4 V
IEN Enable Pin Leakage Current VEN = 5.5V 1.0 μA
FOSC Oscillator Frequency TA= 25°C 700 1000 1200 kHz
TSD Over-Temperature Shutdown 140 °C
Threshold
THYS
Over-Temperature Shutdown 15 °C
Hysteresis
Typical Characteristics
Enable Threshold vs. Input Voltage
0.7
0.8
0.9
1
1.1
1.2
2.5 3 3.5 4 4.5 5 5.5
Input Voltage (V)
Enable Threshold (V)
V
EN
(H)
V
EN
(L)
R
DS(ON)
vs. Input Voltage
80
90
100
110
120
130
2.5 3 3.5 4 4.5 5 5.5
Input Voltage (V)
R
DS(ON)
(m
Ω
)
High Side
Low Side
Low Side R
DS(ON)
vs. Temperature
70
90
110
130
150
170
-20 0 20 40 60 80 100 120
Temperature (
°
C)
R
DS(ON)
(m
Ω
)
2.7V
3.6V
4.2V
5.5V
High Side R
DS(ON)
vs. Temperature
70
90
110
130
150
170
-20 0 20 40 60 80 100 120
Temperature (°C)
R
DS(ON)
(m
Ω
)
2.7V
3.6V
4.2V 5.5V
Efficiency vs. Output Current
(V
OUT
= 3.3V)
0
10
20
30
40
50
60
70
80
90
100
10 100 1000
Output Current (mA)
Efficiency (%)
V
IN
= 5.0V
Efficiency vs. Output Current
(V
OUT
= 1.5V)
0
20
40
60
80
100
10 100 1000
Output Current (mA)
Efficiency (%)
2.7V
3.6V
4.2V
AAT1150
1MHz 1A Step-Down DC/DC Converter
1150.2006.09.1.5 5
AAT1150
1MHz 1A Step-Down DC/DC Converter
61150.2006.09.1.5
Typical Characteristics
Load Regulation
(V
OUT
= 3.3V; V
IN
= 5.0V)
-5
-4
-3
-2
-1
0
0 150 300 450 600 750 900 1050
Output Current (mA)
V
OUT
Error (%)
Load Regulation
(V
OUT
= 1.5V; V
IN
= 3.6V)
-5
-4
-3
-2
-1
0
0 150 300 450 600 750 900
I
OUT
(mA)
Error (%)
Line Regulation
(V
OUT
= 1.5V)
-0.25
-0.15
-0.05
0.05
0.15
0.25
2.5 3 3.5 4 4.5 5.5
5
Input Voltage (V)
Accuracy (%)
I
OUT
= 0.4A
I
OUT
= 1.0A
Output Voltage vs. Temperature
(I
OUT
= 900mA; V
OUT
= 1.5V)
-1.0
-0.6
-0.2
0.2
0.6
1.0
-20 0 20 40 60 80 100
Temperature (
C)
Output Voltage Error (%)
V
IN
= 2.7V
V
IN
= 3.6V
Oscillator Frequency Variation vs. Temperature
(V
IN
= 3.6V)
-10
-6
-2
2
6
10
-20 0 20 40 60 80 100
Temperature (°C)
Variation (%)
Oscillator Frequency Variation vs.
Supply Voltage
-1.5
-0.5
0.5
1.5
2.5
3.5
2.5 3 3.5 4 4.5 5 5.5
Supply Voltage (V)
Variation (%)
Typical Characteristics
Transient Response
(V
IN
= 3.6V; V
OUT
= 1.5V; I
LOAD
= 0.25 to 1.2A)
Time (20µs/div)
V
OUT
50mV/div
Inductor Current
500mA/div
Switching Waveform
(V
IN
= 3.6V; V
OUT
= 1.5V; I
OUT
= 1.2A)
Time (500ns/div)
V
(LX)
2V/div
I
L
500mA/div
Non-Switching I
Q
vs. Temperature
(FB = 0V; V
P
= V
CC
)
100
110
120
130
140
150
160
170
180
190
200
-20 -5 10 25 40 55 70 85
Temperature (°C)
Operating Current (μA)
V
CC
= 5.0V
V
CC
= 2.7V
V
CC
= 3.6V
V
CC
= 4.2V
V
CC
= 5.5V
No Load Input Current vs. Temperature
(V
CC
= V
P
)
0
2
4
6
8
10
12
-20 -5 10 25 40 55 70 85
Temperature (°C)
Input Current (mA)
V
CC
= 5.0V
V
CC
= 2.7VV
CC
= 3.6VV
CC
= 4.2V
V
CC
= 5.5V
AAT1150 Loop Gain and Phase
(C
O
= 22μ
μ
F; V
O
= 1.5V; V
IN
= 3.6V; I
O
= 1A)
Frequency (kHz)
Gain (dB)
Phase (degrees)
-20
-16
-12
-8
-4
0
4
8
12
16
20
10 100 1000
-200
-160
-120
-80
-40
0
40
80
120
160
200
Gain
Phase
3 x 22μF
5 x 22μF
4 x 22μF
Efficiency vs. Input Voltage
(V
OUT
= 1.5V)
50
60
70
80
90
100
2.5 3 3.5 4 4.5 5 5.5
Input Voltage (V)
Efficiency (%)
I
O
= 1A
I
O
= 0.4A
AAT1150
1MHz 1A Step-Down DC/DC Converter
1150.2006.09.1.5 7
AAT1150
1MHz 1A Step-Down DC/DC Converter
81150.2006.09.1.5
Typical Characteristics
Time (200µs/div)
V
OUT
1V/div
I
L
0.5A/div
Enable
2V/div
Inrush Limit
(V
IN
= 3.6V; V
OUT
= 1.5V; I
L
= 1A)
Output Ripple
(V
IN
= 5.0V; V
OUT
= 3.3V; I
OUT
= 1A)
Time (500ns/div)
V
OUT
5mV/div
BW = 20MHz
LX
2V/div
Output Ripple
(V
IN
= 5.0V; V
OUT
= 3.3V; I
OUT
= 0A)
Time (500nsec/div)
V
OUT
5mV/div
BW = 20MHz
LX
2V/div
Output Ripple
(V
IN
= 3.6V; V
OUT
= 1.5V; I
OUT
= 1A)
Time (500ns/div)
V
OUT
5mV/div
BW = 20MHz
LX
2V/div
Output Ripple
(V
IN
= 3.6V; V
OUT
= 1.5V; I
OUT
= 0A)
Time (500ns/div)
V
OUT
5mV/div
BW = 20MHz
LX
2V/div
AAT1150
1MHz 1A Step-Down DC/DC Converter
1150.2006.09.1.5 9
Functional Block Diagram
VP = 2.7V- 5.5VVCC
ENSGND PGND
LOGIC
1.0V REF
Temp.
Sensing
OSC
OP. AMP
LX
FB
DH
DL
CMP
1MΩ
Applications Information
Control Loop
The AAT1150 is a peak current mode buck con-
verter. The inner wide bandwidth loop controls the
peak current of the output inductor. The output
inductor current is sensed through the P-channel
MOSFET (high side) and is also used for short-cir-
cuit and overload protection. A fixed slope com-
pensation signal is added to the sensed current to
maintain stability. The loop appears as a voltage-
programmed current source in parallel with the out-
put capacitor.
The voltage error amplifier output programs the
current loop for the necessary inductor current to
force a constant output voltage for all load and line
conditions. The feedback resistive divider is inter-
nal, dividing the output voltage to the error amplifi-
er reference voltage of 1.0V. The error amplifier
does not have a large DC gain typical of most error
amplifiers. This eliminates the need for external
compensation components while still providing suf-
ficient DC loop gain for load regulation. The
crossover frequency and phase margin are set by
the output capacitor value only.
Soft Start/Enable
Soft start increases the inductor current limit point in
discrete steps when the input voltage or enable
input is applied. It limits the current surge seen at the
input and eliminates output voltage overshoot. The
enable input, when pulled low, forces the AAT1150
into a low power, non-switching state. The total input
current during shutdown is less than 1μA.
AAT1150
1MHz 1A Step-Down DC/DC Converter
10 1150.2006.09.1.5
Figure 1: Lithium-Ion to 1.5V Converter.
Figure 2: 5V Input to 3.3V Output Converter.
Efficiency vs. Output Current
(V
OUT
= 3.3V)
0
10
20
30
40
50
60
70
80
90
100
10 100 1000
Output Current (mA)
Efficiency (%)
V
IN
= 5.0V
L1
4.1μHC2, C3, C4
3x 22μF
6.3V
C1
10μF
R1 100
C7
0.1μF
C1 Murata 10μF 6.3V X5R GRM42-6X 5R106K6.3
L1 Sumida CDRH5D18-4R1μH
R2
100k
C2, C3, C4 MuRata 22μF 6.3V GRM21BR60J226ME39L X5R 0805
V
OUT
3.3V 1A3.5V-5.5V
RTN
FB
SGND
EN
VCC
VP
LX
LX
PGND
AAT1150-3.3
Efficiency vs. Output Current
(V
OUT
= 1.5V)
0
20
40
60
80
100
10 100 1000
Output Current (mA)
Efficiency (%)
2.7V
3.6V
4.2V
L1
4.1μHC2, C3, C4
3x 22μF
6.3V
C1
10μF
R1 100
C7
0.1μF
C1 Murata 10μF 6.3V X5R GRM42-6X 5R106K6.3
L1 Sumida CDRH5D18-4R1μH
R2
100k
C2, C3, C4 MuRata 22μF 6.3V GRM21BR60J226ME39L 0805 X5R
V
OUT
1.5V 1A
2.7V-5.5V
RTN
FB
SGND
EN
VCC
VP
LX
LX
PGND
AAT1150-1.5
Power and Signal Source
Separate small signal ground and power supply
pins isolate the internal control circuitry from the
noise associated with the output MOSFET switch-
ing. The low pass filter R1 and C3 in schematic
Figures 1 and 2 filters the noise associated with the
power switching.
Current Limit and Over-Temperature
Protection
For overload conditions, the peak input current is lim-
ited. Figure 3 displays the current limit characteris-
tics. As load impedance decreases and the output
voltage falls closer to zero, more power is dissipated
internally, raising the device temperature. Thermal
protection completely disables switching when inter-
nal dissipation becomes excessive, protecting the
device from damage. The junction over-temperature
threshold is 140°C with 15°C of hysteresis.
AAT1150
1MHz 1A Step-Down DC/DC Converter
1150.2006.09.1.5 11
Inductor
The output inductor is selected to limit the ripple
current to some predetermined value, typically
20% to 40% of the full load current at the maximum
input voltage. Manufacturer's specifications list
both the inductor DC current rating, which is a ther-
mal limitation, and the peak current rating, which is
determined by the saturation characteristics. The
inductor should not show any appreciable satura-
tion under normal load conditions. During overload
and short-circuit conditions, the average current in
the inductor can meet or exceed the ILIMIT point of
the AAT1150 without affecting converter perform-
ance. Some inductors may have sufficient peak
and average current ratings yet result in excessive
losses due to a high DCR. Always consider the
losses associated with the DCR and its effect on
the total converter efficiency when selecting an
inductor.
For a 1.0A load and the ripple set to 30% at the
maximum input voltage, the maximum peak-to-
peak ripple current is 300mA. The inductance
value required is 3.9μH.
The factor "k" is the fraction of full load selected for
the ripple current at the maximum input voltage.
The corresponding inductor RMS current is:
IRMS = ⎛Io2+ ΔI2⎞≈Io= 1.0A
⎝ 12⎠
ΔI is the peak-to-peak ripple current which is fixed by
the inductor selection above. For a peak-to-peak
current of 30% of the full load current, the peak cur-
rent at full load will be 115% of the full load. The
4.1μH inductor selected from the Sumida
CDRH5D18 series has a 57mΩDCR and a 1.95A
DC current rating. At full load, the inductor DC loss
is 57mW which amounts to a 3.8% loss in efficiency.
Input Capacitor
The primary function of the input capacitor is to pro-
vide a low impedance loop for the edges of pulsed
current drawn by the AAT1150. A low ESR/ESL
ceramic capacitor is ideal for this function. To mini-
mize stray inductance, the capacitor should be
placed as closely as possible to the IC. This keeps
the high frequency content of the input current
localized, minimizing radiated and conducted EMI
while facilitating optimum performance of the
AAT1150. Ceramic X5R or X7R capacitors are
ideal for this function. The size required will vary
depending on the load, output voltage, and input
voltage source impedance characteristics. A typi-
cal value is around 10μF. The input capacitor RMS
V
OUT
V
OUT
1.5
V
1.5V
L = ⋅ 1 -
L = 3.9μH
L = ⋅ 1 -
I
O
⋅ k ⋅ F
S
V
IN
1.0A ⋅ 0.3 ⋅ 830kHz
4.2V
⎛
⎝⎞
⎠
⎛
⎝⎞
⎠
Figure 3: Current Limit Characteristics.
0
0.5
1
1.5
2
2.5
3
3.5
0 0.5 1 1.5 2 2.5
Output Current (A)
Output Voltage (V)
V
CC
= V
P
= 3.6V
V
O
= 1.5V
Figure 1 Schematic
V
CC
= V
P
= 5.0V
V
O
= 3.3V
Figure 2 Schematic
AAT1150
1MHz 1A Step-Down DC/DC Converter
12 1150.2006.09.1.5
current varies with the input voltage and the output
voltage. The equation for the RMS current in the
input capacitor is:
The input capacitor RMS ripple current reaches a
maximum when VIN is two times the output voltage
where it is approximately one half of the load cur-
rent. Losses associated with the input ceramic
capacitor are typically minimal and are not an
issue. Proper placement of the input capacitor can
be seen in the reference design layout shown in
Figures 4 and 5.
Output Capacitor
Since there are no external compensation compo-
nents, the output capacitor has a strong effect on
loop stability. Larger output capacitance will
reduce the crossover frequency with greater phase
margin. For the 1.5V 1.0A design using the 4.1μH
inductor, three 22μF 6.3V X5R capacitors provide a
stable output. In addition to assisting stability, the
output capacitor limits the output ripple and pro-
vides holdup during large load transitions.
The output capacitor RMS ripple current is given by:
For a ceramic capacitor, the dissipation due to the
RMS current of the capacitor is not a concern.
Tantalum capacitors, with sufficiently low ESR to
meet output voltage ripple requirements, also have
an RMS current rating much greater than that actu-
ally seen in this application.
Adjustable Output
For applications requiring an output other than the
fixed outputs available, the 1V version can be pro-
grammed externally (see Figure 6). Resistors R3
and R4 force the output to regulate higher than
1V. R4 should be 100 times less than the internal
1mΩresistance of the FB pin. Once R4 is selected,
R3 can be calculated. For a 1.25V output with R4
set to 10kΩ, R3 is 2.55kΩ.
Layout Considerations
Figures 4 and 5 display the suggested PCB layout
for the AAT1150. The most critical aspect of the lay-
out is the placement of the input capacitor C1. For
proper operation, C1 must be placed as closely as
possible to the AAT1150.
Thermal Calculations
There are two types of losses associated with the
AAT1150 output switching MOSFET: switching
losses and conduction losses. Conduction losses
are associated with the RDS(ON) characteristics of
the output switching device. At full load, assuming
continuous conduction mode (CCM), a simplified
form of the total losses is:
Once the total losses have been determined, the
junction temperature can be derived from the ΘJA
for the MSOP-8 package.
I
O
2
⋅ (R
DS(ON)H
⋅ V
O
+ R
DS(ON)L
⋅ (V
IN
- V
O
))
P
LOSS
=
V
IN
+t
sw
⋅ F
S
⋅ I
O
⋅ V
IN
+ I
Q
⋅ V
IN
R3 = (V
O
- 1) ⋅ R4 = 0.25 ⋅ 10.0kΩ = 2.55kΩ
V
OUT
⋅
(V
IN
- V
OUT
)
1
I
RMS
=
⋅
L
⋅
F
S
⋅
V
IN
2
⋅
3
V
O
⎛
V
O
⎞
I
RMS
= I
O
⋅ ⋅ 1 -
V
IN
⎝ V
IN
⎠
AAT1150
1MHz 1A Step-Down DC/DC Converter
1150.2006.09.1.5 13
Figure 4: AAT1150 Evaluation Figure 5: AAT1150 Evaluation
Board Layout Top Layer. Board Layout Bottom Layer.
Figure 6: 3.3V to 1.25V Converter (Adjustable Output).
L1
2.7μHC2, C3, C4
3x 22μF
6.3V
C1
10μF
R1 100
C7
0.1μF
C1 Murata 10μF 6.3V X5R GRM42-6X 5R106K6.3
L1 Sumida CDRH4D28-2R7μH
R2
100k
C2, C3, C4 MuRata 22μF 6.3V GRM21BR60J226ME39L X5R 0805
V
O
+ 1.25V 1A
V
IN
+ 3.3V
V-
FB
SGND
EN
VCC
VP
LX
PGND
AAT1150-1.0 R3
2.55k 1%
R4
10k 1%
LX
EN
Design Example
Specifications
IOUT = 1.0A
IRIPPLE = 30% of Full Load at Max VIN
VOUT = 1.5V
VIN = 2.7V to 4.2V (3.6V nominal)
Fs= 830kHz
Maximum Input Capacitor Ripple
Inductor Selection
Select Sumida inductor CDRH5D18, 4.1μH, 57mΩ, 2.0mm height.
Output Capacitor Dissipation
I
RMS
V
OUT
⋅
(V
IN
- V
OUT
)
1.5V
⋅
(4.2V - 1.5V)
L
⋅
F
S
⋅
V
IN
4.1μH
⋅
830kHz
⋅
4.2V
=⋅⋅= = 82mA
RMS
⋅⋅
1
23
1
23
P
ESR
= ESR
COUT
⋅ I
RMS
2
= 5mΩ ⋅ 0.082
2
A = 33μW
V
O
V
O
1.5
V
1.5V
ΔI = ⋅ 1 - = ⋅ 1- = 280mA
L ⋅ F
S
V
IN
4.1μH ⋅ 830kHz
4.2V
I
PK
= I
OUT
+ ΔI = 1.0A + 0.14A = 1.14A
2
P = I
O
2
⋅ DCR = 57mW
⎛
⎝⎞
⎠
⎛
⎝⎞
⎠
V
OUT
V
OUT
1.5
V
1.5V
L = ⋅ 1 - = ⋅ 1 - = 3.9μH
I
O
⋅ k ⋅ F
S
V
IN
1.0A ⋅ 0.3 ⋅ 830kHz
4.2V
⎛
⎝⎞
⎠⎛
⎝⎞
⎠
V
O
⎛
V
O
⎞
I
O
I
RMS
= I
O
⋅ ⋅ 1- = = 0.5A
RMS
, V
IN
= 2 ⋅ V
O
V
IN
⎝
V
IN
⎠
2
P = ESR
COUT
⋅ I
RMS
2
= 5mΩ ⋅ 0.5
2
A = 1.25mW
AAT1150
1MHz 1A Step-Down DC/DC Converter
14 1150.2006.09.1.5
AAT1150 Dissipation
Table 1: Surface Mount Inductors.
Table 2: Surface Mount Capacitors.
Manufacturer Part Number Value Voltage Temp. Co. Case
MuRata GRM40 X5R 106K 6.3 10μF 6.3V X5R 0805
MuRata GRM42-6 X5R 106K 6.3 10μF 6.3V X5R 1206
MuRata GRM21BR60J226ME39L 22μF 6.3V X5R 0805
MuRata GRM21BR60J106ME39L 10μF 6.3V X5R 0805
Max DC Size (mm)
Manufacturer Part Number Value Current DCR L ××W ××H Type
TaiyoYuden NPO5DB4R7M 4.7μH 1.4A 0.038 5.9 ×6.1 ×2.8 Shielded
Toko A914BYW-3R5M-D52LC 3.5μH 1.34A 0.073 5.0 ×5.0 ×2.0 Shielded
Sumida CDRH5D28-4R2 4.2μH 2.2A 0.031 5.7 ×5.7 ×3.0 Shielded
Sumida CDRH5D18-4R1 4.1μH 1.95A 0.057 5.7 ×5.7 ×2.0 Shielded
MuRata LQH55DN4R7M03 4.7μH 2.7A 0.041 5.0 ×5.0 ×4.7 Non-Shielded
MuRata LQH66SN4R7M03 4.7μH 2.2A 0.025 6.3
×6.3 ×4.7 Shielded
T
J(MAX)
= T
AMB
+ Θ
JA
⋅
P
LOSS
= 85°C + 150°C/W
⋅
0.203W = 115°C
P + (t
sw
⋅
F
S
⋅
I
O
+ I
Q
)
⋅
V
IN
I
O
2
⋅
(R
DS(ON)H
⋅
V
O
+ R
DS(ON)L
⋅
(V
IN
-V
O
))
V
IN
=
=
+ (20nsec
⋅
830kHz
⋅
1.0A + 0.3mA)
⋅
3.6V = 0.203W
(0.14Ω
⋅
1.5V + 0.145Ω
⋅
(3.6V - 1.5V))
3.6V
AAT1150
1MHz 1A Step-Down DC/DC Converter
1150.2006.09.1.5 15
AAT1150
1MHz 1A Step-Down DC/DC Converter
16 1150.2006.09.1.5
Ordering Information
Package Information
MSOP-8
All dimensions in millimeters.
PIN 1
1.95 BSC
0.254 BSC
0.155
±
0.075
0.60
±
0.20
3.00
±
0.10
0.95
±
0.15
0.95 REF
0.85
±
0.10
3.00
±
0.10
10
°
±
5
°
4
°
±
4
°
0.65 BSC 0.30
±
0.08
0.075
±
0.075
4.90
±
0.10
GAUGE PLANE
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means
semiconductor products that are in compliance with current RoHS standards, including
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more
information, please visit our website at http://www.analogictech.com/pbfree.
Output Voltage1Package Marking2Part Number (Tape and Reel)3
1.0V (Adj VOUT ≥1.0V) MSOP-8 JZXYY AAT1150IKS-1.0-T1
1.5V MSOP-8 HYXYY AAT1150IKS-1.5-T1
1.8V MSOP-8 KAXYY AAT1150IKS-1.8-T1
2.5V MSOP-8 KCXYY AAT1150IKS-2.5-T1
3.3V MSOP-8 HZXYY AAT1150IKS-3.3-T1
1. Contact sales for custom voltage options.
2. XYY = assembly and date code.
3. Sample stock is held on part numbers listed in BOLD.
AAT1150
1MHz 1A Step-Down DC/DC Converter
1150.2006.09.1.5 17
Advanced Analogic Technologies, Inc.
830 E. Arques Avenue, Sunnyvale, CA 94085
Phone (408) 737-4600
Fax (408) 737-4611
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