AME5170A/DC-DC Boost Converter

AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n General Description
The AME5170A is a fixed off-time step-up DC/DC converter in a small SOT-25 package. The AME5170A is
ideal for LCD panels requiring low current and high efficiency as well as LED application for cellular phone backlighting, PDAs, and other hand-held devices. The low
400ns off time allows the use of tiny external components. AME5170A is designed to drive up to four white
LEDs in series with a constant current from a single Lilon battery. To control LED brightness, the LED current
can be adjusted by applying a PWM (pulse width modulated) signal with a frequency range of 100Hz to 50KHz
to the EN pin.
n Typical Application
L1
2.2µH
VIN
1.5V to 5V
CIN
4.7µF
IN
VOUT = 5V
C OUT
4.7µF
SW
R1
100KΩ
AME5170A
CF
20pF
EN
FB
GND
R2
33KΩ
Figure.1 Typical 5V Application
n Features
l 0.7Ω Internal Switch
L1
10µH
VIN
1.5V to 5.5V
CIN
4.7µF
VOUT = 12V
COUT
IN
l Use Small Surface Mount Components
l Adjust Output Voltage up to 28V
SW
R1
240KΩ
AME5170A
l Input under Voltage Lockout
1µF
EN
l 0.1µA Shutdown Current Typical
GND
l Small SOT-25 Package
FB
R2
27KΩ
l All AME's Lead Free Products Meet RoHS
Standards
Figure.2 Typical 12V Application
n Applications
l LCD Bias Supplies
l White LED Back-Lighting
l Handheld Devices
L1
10µH
VIN
1.5V to 5.5V
CIN
4.7µF
IN
VOUT = 20V
l Digital Cameras
l Portable Applications
COUT
1µF
SW
AME5170A
R1
510KΩ
EN
GND
FB
R2
33KΩ
Figure.3 Typical 20V Application
Rev.A.01
1
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Typical Application
L1
10µH
VIN
2.7V to 5.5V
CIN
4.7µF
IN
VOUT
COUT
1µF
SW
AME5170A
EN
FB
GND
R2
62Ω
Figure.4 White LED Application
n Function Block Diagram
SW
IN
+
Enable
Comp
FB
1:8
VIN
CL
Adjust
Current
Limit
+
VREF
400ns one
Shot
Cs
Logic
Control
Driver
UVP
EN
GND
Figure.5 Function Block Diagram
2
Rev.A.01
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Pin Configuration
SOT-25/TSOT-25
Top View
5
AME5170AAEEV
4
1. SW
2. GND
AME5170
3. FB
4. EN
1
2
5. IN
3
Die Attach:
Conductive Epoxy
n Pin Description
Pin Number
Pin Name
Pin Description
1
SW
Power Switch input.
This is the drain of the internal NMOS power switch. Minimize the metal
trace area connected to this pin to minimize EMI.
2
GND
Ground.
Tie directly to ground plane.
Output voltage feedback input.
Set the output voltage by selecting values for R1 and R2 using:
3
FB
 V

R 1 = R 2  out − 1 
 1 . 23 V

Connect the ground of the feedback network to an AGND(Analog Ground)
plane which should be tied directly to the GND pin.
Rev.A.01
4
EN
Enable control input, active high.
The enable pin is an active high control. Tie this pin above 1.5V to enable
the device. Tie this pin below 0.4V to turn off the device.
5
IN
Analog and Power input.
Input Supply Pin. Bypass this pin with a capacitor as close to the device
as possible.
3
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Ordering Information
AME5170A x x x x xxx x
Special Feature
Output Voltage
Number of Pins
Package Type
Operating Ambient Temperature Range
Pin Configuration
Pin
Configuration
A
(SOT-25)
(TSOT-25)
Operating Ambient
Temperature Range
1. SW
2. GND
3. FB
4. EN
5. IN
E: -40OC to +85OC
Package
Type
E: SOT-2X
Number
of
Pins
Output Voltage
Special Feature
V: 5
ADJ: Adjustable
Z: Lead free
Y: Lead free
& Low profile
n Ordering Information
Output Voltage Package
Operating Ambient
Temperature Range
Part Number
Marking*
AME5170AAEEVADJZ
CAEww
ADJ
SOT-25
-40OC to +85OC
AME5170AAEEVADJY
CAEww
ADJ
TSOT-25
-40OC to +85OC
Note: ww represents the date code and pls refer to Date Code Rule on Package Dimension.
* A line on top of the first letter represents lead free plating such as CAEww.
Please consult AME sales office or authorized Rep./Distributor for the availability of package type.
4
Rev.A.01
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Absolute Maximum Ratings
Parameter
Symbol
Maximum
Unit
VIN
6
V
EN,VFB
VIN
V
SW Voltage
VSW
VOUT + 0.3
V
N-Channel Switch Sink Current
ISW
600
mA
Input Supply Voltage
EN, FB Voltages
B*
ESD Classification
Caution: Stress above the listed absolute rating may cause permanent damage to the device.
* HBM B: 2000~3999V
n Recommented Operating Conditions
Parameter
Symbol
Rating
Ambient Temperature Range
TA
- 40 to +85
Junction Temperature Range
TJ
- 40 to +125
Storage Temperature Range
TSTG
- 65 to +150
Unit
O
C
n Thermal Information
Parameter
Package
Die Attach
Symbol
Maximum
θ JC
81
Thermal Resistance*
(Junction to Case)
Thermal Resistance
(Junction to Ambient)
Unit
o
SOT-25
TSOT-25
Conductive Epoxy
Internal Power Dissipation
Solder Iron (10Sec)**
θJA
260
PD
400
350
C/W
mW
o
C
* Measure θJC on backside center of molding compund if IC has no tab.
** MIL-STD-202G 210F
Rev.A.01
5
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Electrical Specifications
VIN = 3.6V, EN = VIN, TA = 25oC, CIN = 4.7µF, IL = 0A, unless otherwise noted.
Parameter
Input Voltage
Symbol
Test Condition
VIN
Min
1.5
Output Voltage Line Regulation
Max
Units
5.5
V
0.05
%V
Quiescent Current
IQ
VIN = 2V
65
75
µA
Shutdown Current
ISD
EN = 0V
0.1
1
µA
FB Regulation Voltage
VFB
1.23
1.26
V
FB Comparator Hysteresis
ICL
FB Pin Bias Current
IFB
Switch Off Time
Input Undervoltage Lockout
EN Input Threshold
(High) (Enable the device)
EN Input Threshold
(Low) (Shutdown)
1.20
VFB Hysteresis
Switch Current Limit
Switch RDSON
6
Typ
RDSON
5
340
425
VFB = 1.23V
0.6
1.0
tOFF
400
UVLO
1.2
mV
510
mA
1.0
µA
1.4
Ω
nS
1.4
V
1.5
EN Threshold
V
0.4
Rev.A.01
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Detailed Description
The AME5170A features a constant off-time control
scheme. Operation can be best understood by referring
to Figure 5. When the voltage at the FB pin is less than
1.23V, the Enable Comp in Figure.5 enables the device
and the NMOS switch is turned on, pulling the SW pin to
ground. When the NMOS switch is on, load current is
supplied by the output capacitor COUT. Once the current
in the inductor reaches the peak current limit, the 400ns
One Shot turns off the NMOS switch. The SW voltage
will then rise to the output voltage plus a diode drop and
inductor current will begin to decrease as shown in Figure3. During this time the energy stored in the inductor
is transferred to COUT and the load. After the 400ns offtime the NMOS switch is turned on and energy is stored
in the inductor again. This energy transfer from the inductor to the output causes a stepping effect in the output ripple.
This cycle is continued until the voltage at FB pin
reaches 1.23V. When FB pin reaches this voltage, the
enable comparator then disables the device turning off
the NMOS switch and reducing the quiescent current of
the device to 65µA typical. The load current is then supplied solely by COUT indicated by the gradually decreasing slope at the output. When the FB pin drops slightly
below 1.23V, the enable comparator enables the device
and begins the cycle described previously. The EN pin
can be used to turn off the AME5170A and reduce the IQ
to 0.1µA. In shutdown mode the output voltage will be a
diode drop lower than the input voltage.
For the AME5170A constant-off time control scheme,
the NMOS power switch is turned off when the current
limit is reached. There is approximately a 200ns delay
from the time the current limit is reached in the NMOS
power switch and when the internal logic actually turns
off the switch. During this 200ns delay, the peak inductor
current will increase. This increase in inductor current demands a larger saturation current rating for the inductor.
This saturation current can be approximated by the following equation:
 VIN (max)
I PK = I CL + 
 L
Rev.A.01

 × 200ns

DIODE SELECTION
To maintain high efficiency, the average current rating
of the schottky diode should be larger than the peak inductor current. Schottky diodes with a low forward drop
and fast switching speeds are ideal for increasing efficiency in portable applications. Choose a reverse breakdown of the schottky diode larger than the output voltage
CAPACITOR SELECTION
Choose low ESR capacitors for the output to minimize
output voltage ripple. Multilayer ceramic capacitors are
the best choice. For most applications, a 1µF ceramic
capacitor is sufficient. For some applications a reduction in output voltage ripple can be achieved by increasing the output capacitor. Local bypassing for the input is
needed on the AME5170A. Multilayer ceramic capacitors are a good choice for this as well. A 4.7µF capacitor
is sufficient for most applications. For additional bypassing, a 100nF ceramic capacitor can be used to shunt
high frequency ripple on the input.
LAYOUT CONSIDERATIONS
The input bypass capacitor CIN, as shown in Figure 3,
must be placed close to the IC. This will reduce copper
trace resistance which effects input voltage ripple of the
IC. For additional input voltage filtering, a 100nF bypass
capacitor can be placed in parallel with CIN to shunt any
high frequency noise to ground. The output capacitor,
COUT, should also be placed close to the IC. Any copper
trace connections for the COUT capacitor can increase
the series resistance, which directly effects output voltage ripple. The feedback network, resistors R1 and R2,
should be kept close to the FB pin to minimize copper
trace connections that can inject noise into the system.
The ground connection for the feedback resistor network
should connect directly to an analog ground plane. The
analog ground plane should tie directly to the GND pin. If
no analog ground plane is available, the ground connection for the feedback network should tie directly to the
GND pin. Trace connections made to the inductor and
schottky diode should be minimized to reduce power
dissipation and increase overall efficiency.
7
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Characterization Curve(For reference only)
IFB vs Temperature
Switch off Time vs Temperature
1.0
700
0.9
0.8
0.7
600
IFB(µA)
Switch off time (ns)
650
550
0.6
0.5
0.4
500
0.3
450
0.2
400
-40
-15
+10
+35
+60
0.1
-40
+85
-15
+10
+35
+60
+85
Temperature(oC)
o
Temperature( C)
EN Thershold High vs Temperature
IQ vs Temperature
1.5
75
1.4
1.3
EN Threshold(V)
I Q(µA)
60
45
30
15
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0
-40
-15
+10
+35
o
+60
0.4
-40
+85
+10
+35
+60
+85
Temperature( oC)
EN Threshold Low vs Temperature
Switch Current Limit vs Temperature
700
1.5
Switch Current Limit(mA)
1.4
1.3
EN Threshold(V)
-15
Temperature( C)
1.2
1.1
1.0
0.9
0.8
0.7
0.6
600
500
400
300
0.5
0.4
-40
-15
+10
+35
o
Temperature( C)
8
+60
+85
200
-40
-15
+10
+35
Temperature(oC)
+60
+85
Rev.A.01
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Characterization Curve(For reference only)
RDSON vs Temperature
VFB vs Temperature
1.26
1.4
1.3
1.25
1.24
1.1
VFB(V)
RDSON (Ω)
1.2
1.0
0.9
1.23
1.22
0.8
0.7
1.21
0.6
0.5
-40
-15
+10
+35
o
+60
1.20
-40
+85
-15
+10
+35
+60
+85
Temperature(oC)
Temperature( C)
Efficiency vs Load Current
UVLO vs Temperature
95
1.50
1.45
85
1.40
Efficiency(%)
UVLO(V)
1.35
1.30
1.25
1.20
1.15
1.10
VIN=4.2V
75
65
VIN=3.3V
VIN=2.5V
55
45
VOUT=20V
1.05
35
1.00
-40
-15
+10
+35
+60
+85
1
4
8
Temperature(oC)
12
16
20
24
28
Load Current (mA)
Output Voltage vs Load Current
Efficiency vs Load Current
20.20
95
VIN=5.0V
20.15
20.10
VIN=4.2V
20.05
Efficiency(%)
Output Voltage(V)
85
VIN=2.5V
20.00
VIN=3.3V
19.95
VIN=4.2V
75
V IN=2.5V
65
VIN=3.3V
55
19.90
45
COUT =1µF
VOUT =20V
19.85
VOUT=12V
19.80
1
4
8
12
16
20
Load Current(mA)
Rev.A.01
24
28
35
1
8
16
24
32
40
48
56
64
72
Load Current(mA)
9
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Characterization Curve(For reference only)
Output Voltage vs Load Current
Efficiency vs Load Current
12.40
95
85
12.20
Efficiency(%)
Ou tput Voltage(V)
VIN=5.0V
VIN=2.5V
12.30
12.10
12.00
VIN=3.3V
V IN=4.2V
11.90
8
16
24
32
40
48
56
64
55
35
72
1
24
48
Load Current(mA)
72
96
120
144
168
Load Current(mA)
Output Voltage vs Load Current
Current Limit vs Temperature
5.20
700
Current Limit(mV)
C OUT=4.7µF
VOUT=5V
5.10
Output Voltage(V)
V IN=3.3V
65
V OUT=5V
11.70
1
V IN=2.5V
45
COUT =1µF
VOUT= 12V
11.80
VIN =4.2V
75
5.00
VIN=2.5V
4.90
VIN =3.3V
4.80
VIN=4.2V
600
500
400
4.70
4.60
1
24
48
72
96
120
Load Current(mA)
10
144
168
300
-40
-15
+10
+35
+60
+85
Temperature(oC)
Rev.A.01
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Date Code Rule
Marking
Date Code
Year
A
A
A
W
W
xxx0
A
A
A
W
W
xxx1
A
A
A
W
W
xxx2
A
A
A
W
W
xxx3
A
A
A
W
W
xxx4
A
A
A
W
W
xxx5
A
A
A
W
W
xxx6
A
A
A
W
W
xxx7
A
A
A
W
W
xxx8
A
A
A
W
W
xxx9
n Tape and Reel Dimension
SOT-25
P
W
AME
AME
PIN 1
Carrier Tape, Number of Components Per Reel and Reel Size
Rev.A.01
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
SOT-25
8.0±0.1 mm
4.0±0.1 mm
3000pcs
180±1 mm
11
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Tape and Reel Dimension
TSOT-25
P
W
AME
AME
PIN 1
Carrier Tape, Number of Components Per Reel and Reel Size
12
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
TSOT-25
8.0±0.1 mm
4.0±0.1 mm
3000pcs
180±1 mm
Rev.A.01
AME
Low Cost Micro Power
Boost DC/DC Converter
AME5170A
n Package Dimension
SOT-25
Top View
Side View
SYMBOLS
D
MILLIMETERS
MIN
θ1
1.20REF
E
H
A
L
S1
0.0472REF
0.15
0.0000
0.0059
b
0.30
0.55
0.0118
0.0217
D
2.70
3.10
0.1063
0.1220
E
1.40
1.80
0.0551
0.0709
1.90 BSC
e
θ1
2.60
0.07480 BSC
3.00
0.37BSC
0
o
10
0.10236 0.11811
0.0146BSC
o
0o
10o
0.95BSC
0.0374BSC
MILLIMETERS
INCHES
S1
A1
A
MAX
0.00
L
Front View
MIN
A1
H
e
MAX
INCHES
b
TSOT-25
Top View
Side View
D
E
H
θ1
L
S1
SYMBOLS
MIN
MAX
MIN
MAX
A+A1
0.90
1.25
0.0354
0.0492
b
0.30
0.50
0.0118
0.0197
D
2.70
3.10
0.1063
0.1220
E
1.40
1.80
0.0551
0.0709
H
e
1.90 BSC
e
2.40
θ1
0
o
10
0.95BSC
0.09449 0.11811
0.0138BSC
o
0
o
10
o
0.0374BSC
b
Rev.A.01
A1
A
S1
3.00
0.35BSC
L
Front View
0.07480 BSC
13
www.ame.com.tw
E-Mail: sales@ame.com.tw
Life Support Policy:
These products of AME, Inc. are not authorized for use as critical components in life-support
devices or systems, without the express written approval of the president
of AME, Inc.
AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and
advises its customers to obtain the latest version of relevant information.
 AME, Inc. , November 2009
Document: 1231-DS5170A-A.01
Corporate Headquarter
AME, Inc.
2F, 302 Rui-Guang Road, Nei-Hu District
Taipei 114, Taiwan, R.O.C.
Tel: 886 2 2627-8687
Fax: 886 2 2659-2989