LP3907 Datasheet, PDF (6/44 Pages) National Semiconductor (TI) – Dual High-Current Step-Down DC/DC and Dual Linear Regulator with I2C Compatible Interface

Pin Descriptions
LLP Pin No.
1
micro SMD
pin no.
B4, B5
Name
VINLDO12
2
C4
EN_T
3
C3
nPOR
4
C5
GND_SW1
5
D5
SW1
6
E5
VIN1
7
D4
ENSW1
8
E4
FB1
9
D3
GND_C
10
E3
AVDD
11
E2
FB2
12
D2
ENSW2
13
E1
VIN2
14
D1
SW2
15
C1
GND_SW2
16
C2
SDA
17
B2
SCL
18
B1
GND_L
19
A1
VINLDO1
20
A2
LDO1
21
B3
ENLDO1
22
A3
ENLDO2
23
A4
LDO2
24
A5
VINLDO2
A: Analog Pin D: Digital Pin G: Ground Pin
I/O
Type
Description
I
PWR
Analog Power for Internal Functions (VREF, BIAS, I2C,
Logic)
I
D
Enable for preset power on sequence. (see page 20)
O
D
nPOR Power on reset pin for both Buck1 and Buck 2.
Open drain logic output 100K pullup resistor. nPOR is
pulled to ground when the voltages on these supplies are
not good. See nPOR section for more info.
G
G
Buck1 NMOS Power Ground
O
PWR
Buck1 switcher output pin
I
PWR
Power in from either DC source or Battery to Buck1
I
D
Enable Pin for Buck1 switcher, a logic HIGH enables
Buck1
I
A
Buck1 input feedback terminal
G
G
Non switching core ground pin
I
PWR
Analog Power for Buck converters
I
A
Buck2 input feedback terminal
I
D
Enable Pin for Buck2 switcher, a logic HIGH enables
Buck2
I
PWR
Power in from either DC source or Battery to Buck2
O
PWR
Buck2 switcher output pin
G
G
Buck2 NMOS Power ground
I/O
D
I²C Data (bidirectional)
I
D
I²C Clock
G
G
LDO ground
I
PWR
Power in from either DC source or battery to input
terminal to LDO1
O
PWR
LDO1 Output
I
D
LDO1 enable pin, a logic HIGH enables the LDO1
I
D
LDO2 enable pin, a logic HIGH enables the LDO2
O
PWR
LDO2 Output
I
PWR
Power in from either DC source or battery to input
terminal to LDO2
PWR: Power Pin I: Input Pin I/O: Input/Output Pin O: Output Pin.
Power Block Input
VINLDO12
AVDD
VIN1
VIN2
LDO 1
LDO 2
Power Block Operation
Enabled
Disabled
VIN+
VIN+
VIN+
VIN+
VIN+
VIN+ or 0V
VIN+
VIN+ or 0V
≤ VIN+
≤ VIN+
≤ VIN+
≤ VIN+
VIN+ is the largest potential voltage on the device.
Note
Always Powered
Always Powered
If Enabled, Min Vin is 1.74V
If Enabled, Min Vin is 1.74V
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