EVALUATION BOARD DATA SHEET
EV149
Evaluation Board for the AAT4672 Power Supply Selector Switch
Introduction
The AAT4672 SmartSwitch™ is a member of Skyworks' Application Specific Power Management IC™ family. This device
is a dual input, single output power supply selector switch, designed to operate from USB ports, AC adapter inputs,
batteries, or any other power supply with an input voltage up to 6V.
The AAT4672 connects the supply on MAIN to OUT through a very low on-resistance power MOSFET when the device
is enabled with the MAIN voltage above UVLO and greater than the AUX voltage. AUX powers the output only when the
MAIN voltage drops 0.2V below the AUX voltage and the AUX voltage is above UVLO. If both inputs are below the UVLO,
then the output floats.
The two power switches are current limited and the thresholds can be programmed through the resistors on the IMAIN
and IAUX pins respectively.
A power level selection pin, PWRSEL, is provided to toggle the AUX current limit between 100% and 20% of the current
limit setting. This is particularly useful for USB applications where the power supply can be powered by either a 500mA
or a 100mA USB port.
The AAT4672 is available in a thermally enhanced, space-saving, Pb-free 12-pin TSOPJW package and is specified for
operation over the -40°C to +85°C temperature range.
Operating Specification
Specification
Description/Conditions
MAIN
AUX
VIH(EN)
VIL(EN)
VIH(PWRSEL)
VIL(PWRSEL)
Current Limit Range
Min
Input Voltage Sources
2.5
Disabling
Enabling
ICLAUX (20% of programmed AUX current limit)
ICLAUX (100% of programmed AUX current limit)
R2 and/or R3 = 49.9kΩ
R2 and/or R3 = 499kΩ
1.6
Typ
Max
Units
6
V
0.4
1.6
0.4
2
0.2
V
V
A
Table 1: AAT4672 Evaluation Board Operating Specification.
Schematic
C1*
2.2µF
MAIN
AUX
J1
C2*
2.2µF
2
1
Header 2
1
2
3
4
5
6
U1
MAIN
MAIN
AUX
AUX
EN
GND
OUT
OUT
IMAIN
IAUX
SELECT
GND
12
11
10
9
8
7
AAT4672
EN
R1
100K
C3*
2.2µF
OUT
IAUX
IMAIN
R3
49.9K
GND
R2
49.9K
PWRSEL
*: C1, C2 and C3 can choose capacitors with different values.
Figure 1: AAT4672 Evaluation Board Schematic.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202274A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 17, 2012
1
EVALUATION BOARD DATA SHEET
EV149
Evaluation Board for the AAT4672 Power Supply Selector Switch
Bill of Materials (BOM)
Component
Part Number
Description
Manufacturer
U1
AAT4672
C1608X5R1C225K
GRM188R61A225K
CRCW06031003F
CRCW06034992F
PRPN401PAEN
Power Supply Selector Switch
Skyworks
TDK
Murata
Vishay
Vishay
Sullins Electronics
C1-C3
R1
R2, R3
J1
2.2µF, ≥10V, 0603, X5R or X7R
100kΩ, 0603, 1%
49.9kΩ, 0603, 1%
Connecting Header, 2mm
Table 2: Component Listing.
Setup [see Figure 2]
1. Jumper 1 placement options are illustrated in Figure 2.
2. Connect two voltage sources to the MAIN and AUX terminals with values between 2.5V and 6V.
3.The EN terminal must be kept open (not connected to a voltage source), the Jumper 1 connects the EN pin to the
power supply connected to the MAIN terminal. When Jumper 1 is removed the EN pin is connected to ground
through the R1 resistor; under this condition the AAT4672 will be enabled.
4. With R2 and R3 equal to 49.9kΩ, the current limit set for MAIN and AUX voltage sources is 2A (typ).
2
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202274A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 17, 2012
EVALUATION BOARD DATA SHEET
EV149
Evaluation Board for the AAT4672 Power Supply Selector Switch
Figure 2: AAT4672 Evaluation Board Connection Diagram with Jumper 1 Settings.
Evaluation/Testing
Enabling [Jumper 1 initially in OFF position on EN]
1.Turn-Off
With both input voltage sources applied (MAIN and AUX), insert Jumper 1. The output voltage will decay to zero.
2.Turn-On
With both input voltage sources applied (MAIN and AUX), remove Jumper 1. The output voltage will recover to its
nominal DC value equal to VMAIN (≥VAUX + 0.2V) or VAUX (≥VMAIN + 0.2V).
Current Limit Setting
1. R2 and R3 are currently set to 49.9kΩ, which results in a typical 2A current limit.
2. A lower current limit setting can be accomplished by increasing the R2 and/or R3 values, with an upper limit of
499kΩ for a 0.2A current limit.
3. The AUX input supply current limit can be toggled between 2A and 0.4A, using the PWRSEL pin voltage. A logic
‘1’ (VPWRSEL ≥ 1.6V) results in the current limit threshold being 100% of R3 programmed current limit, and conversely a logic ’0’ (VPWRSEL ≤ 0.4V) results in the current limit threshold being 20% of the R3 programmed current
limit.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202274A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 17, 2012
3
EVALUATION BOARD DATA SHEET
EV149
Evaluation Board for the AAT4672 Power Supply Selector Switch
Printed Circuit Board
Figure 3: AAT4672 Evaluation Board Top Layer (not to scale).
Figure 4: AAT4672 Evaluation Board Bottom Layer (not to scale).
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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202274A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 17, 2012