OMO ElectronicOMO Electronic
Expand menu
Hello, Sign inMy Account
0 Cart

LT4321IUF#PBF

P1-P3P4-P6P7-P9P10-P12
LT4321
1
4321f
For more information www.linear.com/LT4321
Typical applicaTion
FeaTures DescripTion
PoE Ideal Diode Bridge
Controller
The LT
®
4321 is a dual ideal diode bridge controller that
enables a Power over Ethernet (PoE) powered device
(PD) to receive power in either voltage polarity from
RJ-45 data pairs, spare pairs, or both. The LT4321 and
eight N-channel MOSFETs replace the eight diodes in a
passive PoE rectifier bridge. The LT4321 eases thermal
design and increases delivered power.
An internal charge pump allows an all-NMOS bridge
eliminating larger and more costly PMOS switches. The
LT4321 works with 2-pair and 4-pair applications. High
impedance input sense pins prevent reverse current on
unused pairs. If the power source fails or is shorted, a
fast turn-off minimizes reverse current transients. Unlike
discrete ideal bridge solutions, the LT4321 will operate
through transients without enabling the MOSFETs on
unpowered pairs.
Powered Device for PoE (to 13W), PoE
+
(to 25.5W), or Linear LTPoE
++
(to 90W) Systems
applicaTions
L, LT, LTC , LT M, Linear Technology and the Linear logo are registered trademarks and
PowerPath and LTPoE
++
are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
n
Reduces Heat, Eliminates Thermal Design Problems
n
Maximizes Power Efficiency
n
Less than 800µA Quiescent Operating Current
n
Fully Compatible with IEEE 802.3 Detection and
Classification
n
IEEE 802.3 Compliant When Paired with a Powered
Device (PD) Controller
n
Works with 2-Pair and 4-Pair PoE Applications
n
Compatible with PoE, PoE
+
, and LTPoE
++
™
n
100V Absolute Maximum Voltage
n
H-Grade Version Operates Up to 125°C
n
16-Lead 4mm × 4mm QFN Package
n
PoE/PoE
+
/ LTPoE
++
Powered Devices
n
DC Polarity Correction and Ideal Diode-ORing of
Telecom Supplies
4321 TA01
LT4321
TG36BG12 BG36
IN36
IN45
IN78
IN12
DATA
PAIRS
1
2
3
6
4
5
8
7
SPARE
PAIRS
OUTN
EN
OUTP
VPORT
PWRGD
HSGATE
LT4275
GND
EN
TG12
BG78TG45 TG78BG45
HSSRC
10µF
ISOLATED
POWER
SUPPLY
GND
RUN
V
OUT
V
IN
0.1µF SMAJ60A
–
+
+
LT4321
2
4321f
For more information www.linear.com/LT4321
pin conFiguraTionabsoluTe MaxiMuM raTings
OUTP-OUTN ............................................. –0.3V to 100V
IN12, IN36, IN45, IN78 ....................... –2V to OUTP + 2V
BG12, BG36, BG45, BG78 Voltages .......... –0.3V to 100V
TG12, TG36, TG45, TG78
Voltages
....................................... –0.3V to OUTP + 12V
TG12-IN12 Voltage ......................................–0.3V to 12V
TG36-IN36 Voltage .....................................–0.3V to 12V
TG45-IN45 Voltage .....................................–0.3V to 12V
TG78-IN78 Voltage ......................................–0.3V to 12V
EN, EN, ..................................................... –0.3V to 100V
Operating Ambient Temperature Range
LT4321I ................................................ –40°C to 85°C
LT4321H ............................................. –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
(Notes 1, 2)
16 15 14 13
5 6 7 8
TOP VIEW
17
OUTN
UF PACKAGE
16-LEAD (4mm ×
4mm) PLASTIC QFN
9
10
11
12
4
3
2
1
TG36
IN36
IN45
TG45
OUTP
EN
EN
OUTN
TG12
IN12
BG12
BG36
TG78
IN78
BG78
BG45
T
JMAX
= 125°C, θ
JC
= 4.5°C/W
EXPOSED PAD (PIN 17) IS OUTN, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT4321IUF#PBF LT4321IUF#TRPBF 4321 16-Lead 4mm × 4mm Plastic QFN –40°C to 85°C
LT4321HUF#PBF LT4321HUF#TRPBF 4321 16-Lead 4mm × 4mm Plastic QFN –40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
LT4321
3
4321f
For more information www.linear.com/LT4321
elecTrical characTerisTics
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Operating Supply Range |IN12-IN36|, |IN45-IN78|, OUTP
l
20 80 V
V
UVLO
Undervoltage Lockout OUTP-OUTN
l
15 17 18 V
I
S
(DET) Total Supply Current in Detect Region OUTP < 10V
l
0.8 5 µA
I
S
(OFF) Total Supply Current in Shutdown OUTP > 12V, EN < V
IL
and EN > V
IH
l
32 60 µA
I
S
(ON) Total Operating Supply Current EN > V
IH
or EN < V
IL
, OUTP > 20V
l
0.5 0.8 mA
Top Gate Drive INn = OUTP + ∆V
SD(MAX)
+ 5mV, 10µA Out of
TGn (Note 3)
l
7.7 9.5 11 V
V
BG
Bottom Gate Drive 10µA Out of BGn (Note 3)
l
10 11.5 13 V
Top Gate Pull-Up Current TGn = INn (Note 3)
l
50 120 250 µA
Top Gate Pull-Down Current INn = OUTP – 0.25V; TGn – INn = 5V
l
1.25 mA
Bottom Gate Pull-Up Current BGn < V
BG
(Note 3)
l
15 30 45 µA
Bottom Gate Pull-Down Current BGn = 5V
l
3 mA
EN Pull-Up Resistance (Active Low) OUTP = 55V
l
160 250 310 kΩ
EN Pull-Down Resistance (Active High) OUTP = 55V
l
160 250 310 kΩ
V
IH
Digital Input High EN, EN
l
2.6 V
V
IL
Digital Input Low EN, EN
l
0.5 V
V
ENOC
EN Open Circuit Voltage OUTP = 55V
l
2 2.5 3 V
∆V
SD
Topside Forward Regulation Voltage INn - OUTP
l
2 10 18 mV
Bottom Comparator Turn-On Threshold INn - OUTN
l
–30 –15 0 mV
Bottom Comparator Turn-Off Threshold INn - OUTN
l
2 15 30 mV
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, OUTP = 20V to 80V unless otherwise noted.
Note 2: Referenced with respect to OUTN unless otherwise specified.
Note 3: All conditions for external MOSFET turn on must be met. See
Table 1 and Table 2.
P1-P3P4-P6P7-P9P10-P12

LT4321IUF#PBF

Mfr. #:
Buy LT4321IUF#PBF
Manufacturer:
Analog Devices Inc.
Description:
Power Management Specialized - PMIC PoE Ideal Diode Bridge Cntr
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union

Products related to this Datasheet