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TMI7321 V1.1 2023.12 1
TMI7321
TOLL Microelectronic13W 802.3af PoE Powered Device
Interface with Flyback/Buck DC/DC Converter
Features
Compatible with 802.3af Specifications
Support 13W PoE Power Application
100V, 0.6Ω Integrated Pass Switch
150mA DC Input Current Limit
450mA PD Operation Current Limit
Intelligent Maintain Power Signature (MPS)
Integrated 160V Switching Power MOSFET
Supports Primary-Side Regulated Flyback
without Opto-Coupler Feedback
Supports Low-side Switch Buck Converter
3A Programmable Switching Current Limit
OLP, OVP, OTP and Open-Circuit Protection
Minimal External Components
QFN4x5-28 Package
Application
IEEE 802.3af-Compliant Devices
Security Camera
VoIP Phones
WLAN Access Points
IoT Devices
Description
The TMI7321 is an integrated IEEE 802.3af PoE
compliant Powered Device (PD) power supply
solution. It includes a PD interface and an
isolated/non-isolated fly-back or Buck converter.
The PD interface includes detection and all the
functions of IEEE 802.3af, classification, 150mA
inrush current, 450mA operation current limit as
well as 100V Hot-swap MOSFET.
The DC/DC converter uses fixed peak current and
variable frequency discontinuous conduction mode
(DCM) to regulate constant output voltage. The
primary-side regulation without opto-coupler
feedback in fly-back mode simplifies the design
while buck mode continues minimizes the solution
size for non-isolated applications. A 160V
integrated power MOSFET optimizes the device for
various wide voltage applications
It incorporates over current, open-circuit, and over-
voltage protection and thermal shutdown.
The TMI7321 supports a front-end solution for
PoE-PD application with minimal external
components and is available in QFN4x5-28
package.
2 TMI7321 V1.1 2023.12
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TMI7321
Typical Application
DET
ILIM
SW
MODE
PG
VDD
VCC
CLASS
FB1
IC
C1
C3
C4
C2
R8
68nF/100V
TMI7321
MPS
VSS
RTN
GND
D1
R5
R6
R2
R1
R7
D6
T1
Np
Ns
Na
GND
GND
GND
GND
GND1
GND1
Vout
C7
FB2
GND
GND
AGND
D2
D5
R4
VSS
R9
C5
R10
3.9K/1210
24.9K
1K
10K
10nF/200V
1.5K
2.49K
R13
2.49K
22uF/25V
22uF/25V
1uF/25V
49.9K
18K
52.3K
GND
R11
R12
20K
220K
+
C8
47uF/100V
+
C9
220uF/25V
C10
R14
1nF/100V
L1
10uH
GND
2.2uF/100V
C11
VDD
GND1
GND
1000p/2000V/1206
C12
12V/1A
2.2uF/100V
10/1210
TMI7321 Flyback Typical Application Circuit
TMI7321 Buck Typical Application Circuit