33702 Datasheet, PDF (3/24 Pages) Motorola, Inc – 3.0 A Switch-Mode Power Supply with Linear Regulator

Freescale Semiconductor, Inc.
FREQ
1
INV
2
V_OUT
3
V_IN2
4
V_IN2
5
SW
6
SW
7
GND
8
GND
9
PGND
10
PGND
11
V_BD
12
V_BST
13
BOOT
14
SDA
15
SCL
16
32
CLKSYN
31
CLKSEL
30
RESET
29
RT
28
EN2
27
EN1
26
ADDR
25
GND
24
GND
23
V_DD1
22
V_IN1
21
LDRV
20
CS
19
LDO
18
LFB
17
LCMP
PIN FUNCTION DESCRIPTION
Pin
Pin Name
Formal Name
1
FREQ
Oscillator Frequency
2
3
4, 5
6, 7
8, 9
24, 25
10, 11
12
13
INV
V_OUT
V_IN2
SW
GND
PGND
V_BD
V_BST
Inverting Input
Output Voltage
Input Voltage 2
Switch
Ground
Power Ground
Boost Drain
Boost Voltage
14
BOOT
15
SDA
Bootstrap
Serial Data
16
SCL
Serial Clock
17
LCMP
Linear Compensation
18
LFB
Linear Feedback
19
LDO
Linear Regulator
20
CS
Current Sense
21
LDRV
22
V_IN1
Linear Drive
Input Voltage 1
Definition
This selection switcher pin can be adjusted by connecting external resistor R_F to the
FREQ pin. The default switching frequency (FREQ pin left open or tied to V_DDI) is set
to 300 kHz.
Buck Controller Error Amplifier inverting input.
Output voltage of the buck converter. Input pin of the switching regulator power
sequence control circuit.
Buck regulator power input. Drain of the high-side power MOSFET.
Buck regulator switching node. This pin is connected to the inductor.
Analog ground of the IC, thermal heatsinking.
Buck regulator power ground.
Drain of the internal boost regulator power MOSFET.
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 V_BST pin
is 8.0 V nominal.
Bootstrap capacitor input.
I²C bus pin. Serial data.
I²C bus pin. Serial clock.
Linear regulator compensation pin.
Linear regulator feedback pin.
Input pin of the linear regulator power sequence control circuit.
Current sense pin of the LDO. Overcurrent protection of the linear regulator external
power MOSFET. The voltage drop over the LDO current sense resistor R_S is sensed
between the CS and LDO pins. The LDO current limit can be adjusted by selecting the
proper value of the current sensing resistor R_S.
LDO gate drive of the external pass N-channel MOSFET.
The input supply pin for the integrated circuit. The internal circuits of the IC are supplied
through this pin.
MOTOROLA ANALOG INTEGRATED CI_FRC_oU_rIT_MD_oE_rV_eICE_InD_fA_oT_rA_{mation On This Product,}
Go to: www.freescale.com
33702
3