TMI and SUNTO are the brands of TOLL microelectronic www.toll-semi.com
TMI7321 V0.4 2023.03 1
TMI7321
13W 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.
TMI7321 V0.4 2023.03 2
www.toll-semi.com TMI and SUNTO are the brands of TOLL microelectronic
TMI7321
Typical Application
DET
ILIM
SW
MODE
PG
VDD
VCC
CLASS
FB1
IC
C1
C3
C4
C2
R8
0.68µF
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
4K
24.9K
1K
2.2uF
10K
10nF
1K
2.49K
R13
2.49K
22uF
22uF
1uF
57.6K
20K
49.9K
GND
R11
R12
20K
220K
+
C8
47uF
+
C9
220uF
C10
R14
20
1nF
L1
10uH
GND
2.2uF
C11
VDD
GND1
GND
1000p/2000V
C12
TMI7321 Flyback Typical Application Circuit
DET
ILIM
SW
MODE
PG
VDD
VCC
CLASS
FB1
IC
C1
C3
C4
C2
R8
0.68µF
TMI7321
MPS
VSS
RTN
GND
D1
R5
R6
R2
R1
GND
GND
GND
GND1
Vout
FB2
GND
AGND
R4
VSS
C5
R10
4K
24.9K
1K
2.2uF
2.49K
R13
2.49K
22uF
22uF
1uF
51K
107K
10K
GND
R11
R12
20K
220K
+
C8
47uF
+
C9
220uF
L1
10uH
GND
2.2uF
C11
VDD
GND
D2
L2
22uH
TMI7321 Buck Typical Application Circuit