MB3870 Datasheet, PDF (3/25 Pages) Fujitsu Component Limited. – Pentium II DC/DC Converter IC

MB3870
s PIN DESCRIPTION
Pin no.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Symbol
RT
RS
SGND
CS
–IN
FB
ENB
OUT1
VS
CB
OUT2
PGND
VB
VD0
VD1
VD2
VD3
VD4
CTL
VSENSE
PWRGOOD
CSCP
VCC
VREF
I/O
Descriptions
— Triangular wave frequency setting resistor connection pin
— Discharging resistor connection pin for soft start capacitor
— Ground pin
— Soft start capacitor connection pin (Also used for discharge control)
I Error amplifier inverted input pin
O Error amplifier output pin
I Discharge control function enable/disable switch control pin
O Totem-pole output pin (External main-side FET gate drive)
— External main-side FET source-side connection
— Output bootstrap pin
Insert a capacitor between the CB and VS pins, to bootstrap the IC internal
output transistor.
O Totem-pole output pin (External synchronous rectifier-side FET gate drive)
— Ground pin
— Output circuit power supply pin
I 5-bit digital input pin used to set DC/DC converter output voltage
I 5-bit digital input pin used to set DC/DC converter output voltage
I 5-bit digital input pin used to set DC/DC converter output voltage
I 5-bit digital input pin used to set DC/DC converter output voltage
I 5-bit digital input pin used to set DC/DC converter output voltage
I Power supply control pin
The CTL pin is set to “L” level to place the IC in standby mode.
I PWRGOOD circuit input pin
O PWRGOOD output pin (open-drain output)
Outputs a “H” level signal when the output voltage is within the range from
VTLOW to VTHIGH.
— Timer-latch short-circuit protection capacitor connection pin
— Power supply pin for reference power and control circuit
O Reference voltage output pin
3