34701_07 Datasheet, PDF (3/38 Pages) Freescale Semiconductor, Inc – 1.5 A Switch-Mode Power Supply with Linear Regulator

PIN CONNECTIONS
PIN CONNECTIONS
FREQ
1
INV
2
VOUT
3
VIN2
4
VIN2
5
SW
6
SW
7
GND
8
GND
9
PGND
10
PGND
11
VBD
12
VBST
13
BOOT
14
SDA
15
SCL
16
32
CLKSYN
31
CLKSEL
30
RST
29
RT
28
EN2
27
EN1
26
ADDR
25
GND
24
GND
23
VDD1
22
VIN1
21
LDRV
20
CS
19
LDO
18
LFB
17
LCMP
Figure 3. Pin Connections
Table 1. Pin Function Description
A functional description of each pin can be found in the FUNCTIONAL PIN DESCRIPTION section beginning on page 16.
Pin
Pin Name
Formal Name
Definition
1
FREQ
Oscillator Frequency
This switcher frequency selection pin can be adjusted by connecting external
resistor RF to the FREQ pin. The default switching frequency (FREQ pin left open or
tied to VDDI) is set to 300 kHz.
2
INV
3
VOUT
Inverting Input
Output Voltage
Buck Controller Error Amplifier inverting input.
Output voltage of the buck converter. Input pin of the switching regulator power
sequence control circuit.
4, 5
VIN2
Input Voltage 2
Buck regulator power input. Drain of the high-side power MOSFET.
6, 7
SW
Switch
Buck regulator switching node. This pin is connected to the inductor.
8, 9
24, 25
GND
Ground
Analog ground of the IC, thermal heatsinking.
10, 11
PGND
Power Ground
Buck regulator power ground.
12
VBD
Boost Drain
Drain of the internal boost regulator power MOSFET.
13
VBST
Boost Voltage
Internal boost regulator output voltage. The internal boost regulator provides a
20 mA output current to supply the drive circuits for the integrated power MOSFETs
and the external N-channel power MOSFET of the linear regulator. The voltage at
the VBST pin is 7.75V nominal.
14
BOOT
15
SDA
16
SCL
Bootstrap
Serial Data
Serial Clock
Bootstrap capacitor input.
I²C bus pin. Serial data.
I²C bus pin. Serial clock.
17
LCMP
Linear Compensation Linear regulator compensation pin.
18
LFB
Linear Feedback
Linear regulator feedback pin.
19
LDO
Linear Regulator
Input pin of the linear regulator power sequence control circuit.
Analog Integrated Circuit Device Data
Freescale Semiconductor
34701
3