Ap3440, Pin description – Diodes AP3440 User Manual
Page 2
AP3440
Document number: DS36691 Rev. 2 - 2
2 of 15
March 2014
© Diodes Incorporated
AP3440
A Product Line of
Diodes Incorporated
N
E
W
P
R
O
D
U
C
T
Typical Applications Circuit
VIN
VIN
VIN
PGD
EN
COMP
SS
RT/CLK
SW
SW
SW
BOOT
FB
GND
GND
AGND
L1 1.5
m
H
V
OUT
=1.8V
R6 12.5k
Ω
R7
10k
Ω
V
IN
=5V
R4
100k
Ω
16
1
2
14
15
7
8
9
10
11
12
13
6
4
5
3
C5
Optional
C2
C7
0.01
m
F
C4
2.7nF
R3
7.5k
Ω
R5
180k
Ω
R1
R2
AP3440
C3
C9
22
m
F
C1
10
m
F
0.1
m
F
C8
22
m
F
U1
C6
0.1
m
F
R8 2.2
Ω
(Optional)
C10 2.2nF
(Optional)
Pin Description
Pin Number
Pin Name
Function
1,2,16
VIN
Supply input pin. A capacitor should be connected between the VIN and GND pin to keep the
DC input voltage constant
3,4
GND
Power ground. This pin should be electrically connected to the power pad under the IC
5
AGND
Analog ground. This pin should be electrically connected to GND close to the device
6
FB
Feedback pin. Inverting node of the transconductance error amplifier
7
COMP
Compensation pin. This pin is the output of the transconductance error amplifier and the input
to the current comparator. Connect external compensation elements to this pin to stabilize the
control loop
8
RT/CLK
Resistor timing or external clock input pin
9
SS
Soft-start pin. An external capacitor connected to this pin sets the output voltage rise time. This
pin can also be used for tracking
10,11,12
SW
Internal power switch output pin. This pin is connected to the inductor and bootstrap capacitor
13
BOOT
Bootstrap pin. A bootstrap capacitor is connected between the BOOT pin and SW pin. The
voltage across the bootstrap capacitor drives the internal high-side power MOSFET
14
PGD
Power good indicator output. Asserts low if output voltage is low due to thermal shutdown,
over-current, over/under-voltage or EN shut down
15
EN
Enable pin, internal pull-up current source. Pull below 1.2V to disable. Float to enable. Can be
used to set the on/off threshold (adjust UVLO) with two additional resistors
EP
Exposed Thermal Pad
Exposed Pad can be connected to GND, for best thermal performance thermal vias are
recommended under the package