1
Features
• Full compliance with USB spec Rev 1.0
• Four downstream ports
• Full speed and low speed data transfers
• Self-Powered or Bus-Powered modes of operation
• Per port overcurrent monitoring
• Individual port power switch control
• USB connection status indicators
Description
The AT43312 is a 5 port USB hub chip supporting one upstream and four downstream
ports. The AT43312 connects to an upstream hub or Host/Root Hub via Port0 and the
other ports connect to external downstream USB devices. The hub re-transmits the
USB differential signal between Port0 and Ports[1:4] in both directions. A USB hub
with the AT43312 can operate as a bus-powered or self-powered through chip’s
power mode configuration pin. The AT43312 is pin- and function-compatible with the
AT43311 and can be used as a replacement for the AT43310 with one pin modifica-
tion.
The AT43312 supports the 12 Mb/s full-speed as well as 1.5 Mb/s slow-speed USB
transactions. To reduce EMI, the AT43312’s oscillator frequency is 6 MHz even
though some internal circuitry operates at 48 MHz.
Self- and Bus-
Powered USB
Hub Controller
AT43312
Rev. 1002A-A–01/98
Pin Configurations
SOIC/DIP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
PWR2
PWR3
PWR4
VCC5
GND
OSC1
OSC2
LFT
VCCA
OVL4
OVL3
OVL2
OVL1
VREF
BUS/SELF
STAT4
PWR1
DP4
DM4
DP3
DM3
GND
DP2
DM2
VCC3
DP1
DM1
DP0
DM0
STAT1
STAT2
STAT3