鈥?/div>
Full Compliance with USB Spec Rev 1.1
Four Downstream Ports
Full-speed and Low-speed Data Transfers
Per Port Overcurrent Monitoring
Individual Port Power Control
USB Connection Status Indicators
Overview
Introduction
The AT43312A is a 5-port USB hub chip supporting one upstream and four down-
stream ports. The AT43312A connects to an upstream hub or Host/Root Hub via Port0
and the other ports connect to external downstream USB devices. The hub re-trans-
mits the USB differential signal between Port0 and Ports[1:4] in both directions. A USB
hub with the AT43312A can operate as a bus-powered or self-powered through chip鈥檚
power mode configuration pin. In the self-powered mode, port power can be switched
or unswitched. Overcurrent reporting and port power control can be individual or glo-
bal. An on-chip power supply eliminates the need for an external 3.3V supply.
The AT43312A supports the 12 Mb/s full speed as well as 1.5 Mb/s slow speed USB
transactions. To reduce EMI, the AT43312A鈥檚 oscillator frequency is 6 MHz even
though some internal circuitry operates at 48 MHz.
The AT43312A consists of a Serial Interface Engine, a Hub Repeater, and a Hub
Controller.
Self- and Bus-
powered USB
Hub Controller
AT43312A
PDIP/SOIC
PWR2
PWR3
PWR4
VCC5
VSS
OSC1
OSC2
LFT
TEST
OVC4
OVC3
OVC2
OVC1
LPSTAT
SELF/BUS
STAT4
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
PWR1
DP4
DM4
DP3
DM3
VSS
DP2
DM2
CEXT
DP1
DM1
DP0
DM0
STAT1
STAT2
STAT3
LQFP Top View
DM3
VSS
DP2
DM2
CEXT
DP1
DM1
DP0
32
31
30
29
28
27
26
25
DP3
DM4
DP4
PWR1
PWR2
PWR3
PWR4
VCC5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
24
23
22
21
20
19
18
17
DMO
STAT1
STAT2
STAT3
STAT4
SELF/BUS
LPSTAT
OVC1
VSS
OSC1
OSC2
LFT
TEST
OVC4
OVC3
OVC2
Rev. 1255C鈥?2/01
1