STHS2375A, STHS2375L, STHS2376A,
STHS2376L, STHS2377A, STHS2377L
IEEE 802.3af PoE Powered Device (PD) interface controller
Features
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■
■
■
■
■
■
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■
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IEEE 802.3af-compliant interface for Powered
Devices (PDs)
Integrated 100V, 500mA power MOSFET
Resistor-programmable inrush current limit
Normal operation current limit 460mA
External 25kΩ signature resistor
Resistor-programmable classification current
(Class 0-4)
Power Good output (active-high), open drain
Undervoltage Lockout (UVLO) - standard,
programmable, and legacy (see
Table 1)
Thermal overload protection
Latch (L) or auto-retry (A) after hard current
overload or repetitive thermal overload
Industrial temperature range: –40 to +85°C
8-pin SO and 8-pin TSSOP packages
RoHS compliant
Device options
External
signature
resistor (1%)
24.9kΩ
24.9kΩ
8
1
SO8 (M)
TSSOP8 (DW)
Applications
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Voice over IP (VOIP) phones
Web cameras
WLAN access points
Table 1.
Order code
STHS2375A
STHS2375L
STHS2376A
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O
STHS2376L
STHS2377A
STHS2377L
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UVLO
Standard
Standard
Programmable
Programmable
Legacy
Legacy
so
b
Internet appliances
POS terminals
RFID readers
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UVLO
threshold,
rising (V)
39.3
39.3
2.49
2.49
35.1
35.1
UVLO
threshold,
falling (V)
30.5
30.5
1.93
1.93
30.5
30.5
Protection
mode
Auto
Latch
Auto
Latch
Auto
Latch
24.9kΩ
24.9kΩ
24.9kΩ
24.9kΩ
July 2007
Rev 4
1/20
www.st.com
1
Contents
STHS237x
Contents
1
Summary description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1
Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1.1
1.1.2
1.1.3
1.1.4
1.1.5
1.1.6
1.1.7
1.1.8
Current limit (I
LIM
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Classification (CLASS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Detection resistor (DET) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Ground (V
SS
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Return (RTN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Power Good output (PG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Undervoltage Lockout Input (UVLO, STHS2376A/L only) . . . . . . . . . . . . 7
Power supply (V
DD
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2
3
4
5
6
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. . . . . 12
Electrical parameters STHS237xA, STHS237xL . . . . . . . .
du
.
....
r
.
o
. . . . . . . . . . . 15
Package mechanical data . . . . . . . . . . . . . . . . . . . .
P
. .
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Part numbering . . . . . . . . . . . . . . . . . . .
ol
. . . . . . . . . . . . . . . . . . . . . . 18
...
s
b
Revision history . . . . . . . . . . .
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
...
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Absolute maximum ratings STHS237xA, STHS237xL . . . . . . . . . . . . . 11
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STHS237x
List of figures
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
STHS2375A/L, STHS2377A/L pin connections (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . 6
STHS2376A/L pin connections (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Application circuit overview (STHS2375A/L, STHS2377A/L) . . . . . . . . . . . . . . . . . . . . . . . . 8
STHS237xA block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
STHS237xL block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
SO8 – 8-lead plastic small outline, 150 mils width, package outline. . . . . . . . . . . . . . . . . . 16
TSSOP8 – 8-lead, thin shrink small outline, 3x4.4mm, package outline . . . . . . . . . . . . . . 17
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List of tables
STHS237x
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
Device options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
IEEE802.3af PD power classes and corresponding R
CLASS
values. . . . . . . . . . . . . . . . . . . 8
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Electrical parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
DC characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
SO8 – 8-lead plastic small outline, 150 mils width, package mechanical data . . . . . . . . . . 16
TSSOP8 – 8-lead, thin shrink small outline, 3x4.4mm, package mechanical data. . . . . . . 17
Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
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STHS237x
Summary description
1
Summary description
The STHS237x is an IEEE802.3af-compliant family of interface controllers for Power over
Ethernet (PoE) Powered Device (PD) applications. The devices consist of two main
sections:
●
●
The IEEE802.3af interface to the PoE powered RJ-45 wall socket, and
the Hot Swap Controller (HSC) functions required to protect the PD during insertion,
operation, and withdrawal from the RJ-45 socket.
These devices have an integrated high voltage power MOSFET (low-side switch) with low
R
DS ON
and the capability to accept transients as high as 100V. Since the pins (such as V
DD
and V
SS
) which interface to the RJ-45 socket can routinely see high peak voltages in excess
of 100V, it is strongly recommended that board designers protect the PD device with a
transient voltage suppressor, such as the SMAJ58A (available from STMicroelectronics),
connected between the V
DD
and V
SS
pins (see
Figure 4 on page 8).
The IEEE802.3af-compliant interface includes the basic PD Detection and Classification
functions, whereas the 'Hot Swap' functions include other basic features, such as Inrush
Current Limiting, Undervoltage Lockout (UVLO), and Thermal Overload Protection. All of the
devices include an open drain Power Good (PG) signal to indicate normal steady operation
(see
Figure 1 on page 6
and
Table 2 on page 6).
The STHS237x family also incorporates a
voltage offset (two series diodes) to accommodate the input diode bridge used to make the
PD polarity insensitive.
The STHS237x family comprises devices for all the UVLO limits configurations: IEEE
standard compliant (STHS2375), programmable (STHS2376) and for legacy systems
(STHS2377). See
Table 1 on page 1.
Each of the basic part types, the STHS2375, STHS2376 and the STHS2377, is available
either with Latched Operation (L) Mode or with Automatic Retry (A) Mode after fault
conditions. For product options overview see
Table 1 on page 1.
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