Infineon TLF4277 Demoboard Installation and operating instructions

TLF4277 Demoboard
Automotive Power
Application Note
Rev. 1.1, 2012-04-25

TLF4277 Demoboard
Introduction
Application Note 2 Rev. 1.1, 2012-04-25
1 Introduction
The TLF4277 Demoboard is a demonstration of the Infineon low drop out linear voltage regulator with integrated
current monitor. The TLF4277 is the ideal companion IC to supply active antennas for car infotainment
applications. The adjustable output voltage makes the TLF4277 capable of supplying the majority of standard
active antennas.
This application note contains the main information for the TLF4277 Demoboard.
1.1 General Description
The TLF4277 is a monolithic integrated low drop out voltage regulator capable of supplying loads up to 200 mA.
For an input voltage up to 40 V the TLF4277 provides an adjustable output voltage in a range from 5 V up to 12 V.
The integrated current monitor function is a unique feature that provides diagnosis and system protection
functionality. Fault conditions such as overtemperature and output overvoltage are monitored and indicated at the
current sense output. The maximum output current limit of the device is adjustable to provide additional protection
to the connected load.
The IC can be disabled via the Enable function to lower the power consumption. The PG-SSOP14 EP package
provides an enhanced thermal performance within a SO8 body size.
1.2 TLF4277 Feature List
1.3 Block Diagram
Figure 1 Block and simplified application diagram of TLF4277
• Integrated Current Monitor
• Adjustable Current Limitation
• Adjustable Output Voltage
• Overvoltage Detection
• Output Current up to 200 mA
• Very Low Current Consumption
• Very Low Dropout Voltage
• Wide Input Voltage Range up to 40 V
• Reverse Polarity Protection
• Short Circuit Protected
• Overtemperature Shutdown
• Green Product (RoHS and WEEE compliant)
• AEC Qualified
Bandgap
Reference
GND
Q
I
B l ockD i agram .v sd
CQ
VBAT
Regulated
Output Voltage
ADJ
R
CS 1
Current
Monitor
Internal
Supply
R
SHUNT
Protection circuits
CSO
CSO
CI
Load
E.g.
Antenna
Amplifier
RSO
TLF4277
CS1
EN
CS2

TLF4277 Demoboard
Technical Specification
Application Note 3 Rev. 1.1, 2012-04-25
2 Technical Specification
The chapter provides a brief technical description of TLF4277.
2.1 Adjustable Output Voltage
The output voltage of the TLF4277 can be adjusted between 5 V and 12 V by an external output voltage divider,
closing the control loop to the voltage adjust pin ADJ.
The voltage at pin ADJ is compared to the internal reference of typical 1.22 V through an error amplifier. The error
amplifier controls the output voltage.
Figure 2 Application detail external components at output for variable voltage regulator
The output voltage is calculated according to Equation (1):
VQ= (R1+ R2)/R2x VREF,int, neglecting IADJ (1)
VREF,int is typically 1.22 V.
To avoid errors caused by leakage current IADJ, we recommend to choose the resistor value for R2< 27 kΩ.
For example, for 8V output voltage the following resistors can be selected:
R1= 56.2 kΩ
R2= 10 kΩ
VQ= (R1+ R2)/R2x VREF,int = (56.2 + 10)/ 10 x 1.22 = 8.076 V
The accuracy of the resistors for the external voltage divider can lead to a higher tolerance of the output voltage.To
achieve a reasonable accuracy resistors with a tolerance of 1% or lower are recommended for the feedback
divider.
Bandgap
Reference
GND
Q
B D _V oltageR egulator _A djus t.v sd
Saturation Control
Current Limitation
CQ
I
Q
ADJ
R
1
R
2

TLF4277 Demoboard
Technical Specification
Application Note 4 Rev. 1.1, 2012-04-25
2.2 Current and Protection Monitor Functions
The TLF4277 Demoboard provides a set of advanced monitor functionality. The current flowing into the power
stage can be monitored at the CSO output. In addition the current limitation can be adjusted via external resistors.
Events of the implemented protection functions are reported through dedicated voltage levels at the CSO output.
This information can be processed by an external µC for system analysis and failure identification. The monitored
events are over-current, overvoltage, and temperature shutdown.
Figure 3 Block diagram current and protection monitor
To reduce possible effects from the supply voltage VBAT additional filtering of the supply voltage is recommended.
A combination of a 100 nF capacitor and an additional buffer capacitor of 10 µF or higher should be placed as
close as possible to the IC terminal, which are connected to VBAT.
Figure 4 shows the output level at the CSO pin versus the operation or fault condition. The graph is valid for the
following set up of external components:
RSHUNT = 1Ω
RCS1 = 100 Ω
CCSO = 2.2 µF
RCSO = 1.5 kΩ
GND
Current _ Monitor .vsd
V
BAT
R
CS1
Current
Monitor
R
SHUNT
CSO
C
CSO
R
CSO
CS1 CS2
Buffer
OV- Detection
TSD-Detection
OC-Detection
Monitor Circuits
I
CS2
I
CS 1
I
CSO
to power stage

TLF4277 Demoboard
Technical Specification
Application Note 5 Rev. 1.1, 2012-04-25
Figure 4 Output levels and functionality of the CSO output1)
2.2.1 Linear Current Monitor
Inside the linear current monitor area the current driven out of the CSO pin is proportional to the voltage which is
measured between pin CS1 and CS2.
The level of the current ICSO can be adjusted according to Equation (2):
Adjustment ICSO (2)
Adjustment of the voltage level for VCSO (3)
1) The graph is just an example and only valid for an certain configuration of the external components
Short Circuit to VBAT
3.1 V typical
163 170 I
CS2
[mA]
V
CSO
[V]
Linear Current Sense Band
up to 2.45 V
0
3,2
3,0
2,95
2,65
2,45
Thermal Shut Down
2.80 V typical
Current limitation and SC to GND
2.55 V typical
ICSO
VBAT VCS2 –
RCS1
-------------------------------- I CS2
RSHUNT
RCS1
--------------------
×==
VCSO
VBAT VCS2 –()RCSO ×
RCS1
--------------------------------------------------------- V SHUNT
RCSO
RCS1
-------------
×==

TLF4277 Demoboard
Technical Specification
Application Note 6 Rev. 1.1, 2012-04-25
2.2.2 Adjustable Output Current Limitation
The TLF4277 has an adjustable current limitation for the current flowing into the power stage (pin CS2). If the level
of the voltage drop across the sense resistorRSHUNT is higher than the desired linear monitor range the output
current of the TLF4277 will be limited.
Setting of the adjustable current limitation (4)
A voltage level of 2.55 V typical, as shown in Figure 4, will be applied at the CSO pin.
To achieve a current limitation of 170mA the following configuration can be used:
RSHUNT = 1Ω
RCS1 = 100Ω
RCSO = 1.5kΩ
2.2.3 Overvoltage Detection
To detect a possible short circuit of the output to a higher supply rail the TLF4277 has an overvoltage detection
implemented. An overvoltage will be detected, if the voltage level at the ADJ pin is 20% higher than the internal
reference voltage VREF,int, which is typically 1.22 V.
Under this condition the CSO pin will be driven through an internal voltage buffer with the voltage level of 3.10 V
typical as shown in Figure 4.
2.2.4 Thermal Shutdown Detection
If the junction temperature exceeds the overtemperature shutdown threshold defined in [1], the TLF4277 will
disable the output voltage. In such a case the voltage level of 2.80 V typical will be applied at the CSO pin, as
shown in Figure 4.
2.3 Enable Function
The TLF4277 can be turned on or turned off via the EN Input. When voltage levels higher than VEN,high are applied
to the EN Input the device will be completely turned on. A voltage level lower than VEN,low sets the device to low
quiescent current mode. In this condition the device is turned off and is not functional. The Enable Input has a
build-in hysteresis to avoid toggling between ON/OFF states, if signals with slow slope are applied to the input.
ICS2,lim
2.55V RCS1 ×
RSHUNT R×CSO
---------------------------------------=
ICS2,lim
2.55V 100Ω×
1Ω1.5kΩ×
----------------------------------- 170mA==

TLF4277 Demoboard
Demoboard
Application Note 7 Rev. 1.1, 2012-04-25
3 Demoboard
The TLF4277 Demoboard is equipped with TLF4277 and the necessary external components.
Figure 5 TLF4277 Demoboard V1.1
3.1 Operating Conditions
To avoid damage of the Demoboard, the maximum of the operating range defined in Table 1 must be followed.
1) The demo board is operating at ambient temperature of 25°C.
2) The max. value depends on the max. rating of external components on the board.
Table 1 Input / output operating range 1)
Parameter Symbol Limit Values Unit
Min. Max.
Board Supply VIN 9 40 2) V
Regulator Output VOUT 5 12 2) V
Current Monitor Out CSO 0 5 V
Enable Input LOW ENlow 00.8V
Enable Input HIGH ENhigh 2.0 40 V

TLF4277 Demoboard
Demoboard
Application Note 8 Rev. 1.1, 2012-04-25
3.2 Quick Start Procedure
1. Set the jumpers on the board to select the desired test setup (refer to Chapter 3.3).
2. With power off, connect the input power supply to VIN and GND.
3. Connect the load between VOUT and GND. Preset the load current at 10 mA.
4. Turn on the input power supply. Make sure that the input voltage does not exceed 40 V.
5. Slowly increase or decrease the load current while monitoring the voltage at VOUT and CSO.
3.3 Board Configuration
The TLF4277 Demoboard can be easily configured with the jumpers on the board. The board provides the
following configuration options:
• Output voltage: 5 V or 8 V.
• Current limitation: 54 mA or 170 mA.
• Enable function.
3.3.1 Output Voltage Setting
The TLF4277 Demoboard provides two output voltage options 5 V and 8 V, which can be configured by setting
the jumpers JP2 and JP3 (see Figure 9).
1) Nominal value.
3.3.2 Current Limitation Setting
The TLF4277 Demoboard provides two output voltage options 54 mA and 170 mA, which can be configured by
setting the jumpers JP4 and JP5 (see Figure 9).
1) Nominal value.
3.3.3 Enable Function
The jumper JP1 on the TLF4277 Demoboard can be used to deactivate the Enable function by connecting the EN
pin to the input pin, then the linear regulator is always on while it is supplied. When J1 is open, the Enable signal
can be supplied from the EN test point on the board.
Table 2 Jumper setting for output voltage
JP2 JP3 Output Voltage
close open 5.075 V1)
open close 8.076 V1)
Table 3 Jumper setting for current limitation
JP4 JP5 Current Limitation
close open 54.25 mA1)
open close 170.00 mA1)
Table 4 Jumper setting for enable function
JP1 Enable Function
close EN is connected to input, the Enable function is deactivated.
open EN can be supplied externally, the Enable function can be used.

TLF4277 Demoboard
Demoboard
Application Note 9 Rev. 1.1, 2012-04-25
3.4 Typical Performance
In this chapter, the typical performance of the current and protection monitor functions are shown with lab
measurement results. All measurements are done on TLF4277 Demoboard under the following condition:
•T
ambient = 25°C
•V
in = 13.5 V
3.4.1 Current Monitor Performance
Setup 1:
8 V output voltage (JP2 open, JP3 close)
170 mA current limitation (JP4 open, JP5 close)
The typical current monitor performance is shown in Figure 6. The current sense accuracy is specified in section
7.2 on page 17 of the TLF4277 data sheet [1].
Figure 6 Current monitor performance with setup 1
0
0,5
1
1,5
2
2,5
3
0
0,5
1
1,5
2
2,5
3
0 50 100 150 200
Accuracy(%)
V_CSO(V)
I_CS2(mA)
V_CSO
Accuracy

TLF4277 Demoboard
Demoboard
Application Note 10 Rev. 1.1, 2012-04-25
Setup 2:
5 V output voltage (JP2 close, JP3 open)
54 mA current limitation (JP4 close, JP5 open)
The typical current monitor performance is shown in Figure 7. The current sense accuracy is specified in section
7.2 on page 17 of the TLF4277 data sheet [1].
Figure 7 Current monitor performance with setup 2
3.4.2 Current Limitation Performance
Setup 1:
8 V output voltage (JP2 open, JP3 close)
170 mA current limitation (JP4 open, JP5 close)
The typical current limitation performance is shown in Table 5 in comparison with the nominal value. The current
limitation accuracy is specified in section 7.2 on page 17 of the TLF4277 data sheet [1].
Setup 2:
5 V output voltage (JP2 open, JP3 close)
54 mA current limitation (JP4 open, JP5 close)
The typical current limitation value is shown in Table 6 in comparison with the nominal value. The current limitation
accuracy is specified in section 7.2 on page 17 of the TLF4277 data sheet [1].
Table 5 Current limitation value with setup 1
Nominal value Measured typical value
170.00 mA 171.65 mA
Table 6 Current limitation value with setup 2
Nominal value Measured typical value
54.25 mA 55.32 mA
0
0,5
1
1,5
2
2,5
3
0
0,5
1
1,5
2
2,5
3
0 102030405060
Accuracy(%)
V_CSO(V)
I_CS2(mA)
V_CSO
Accuracy

TLF4277 Demoboard
Demoboard
Application Note 11 Rev. 1.1, 2012-04-25
3.4.3 Thermal Shutdown
While the output voltage is switched off due to overtemperature, the voltage measured at CSO pin is shown in
Table 7 in comparison with the typical value in the TLF4277 data sheet [1].
3.4.4 Overvoltage Detection
When VOUT is short connected to VIN, an overvoltage will be detected. Under this condition the voltage measured
at CSO pin is shown in Table 8 in comparison with the typical value in the TLF4277 data sheet [1].
3.5 Schematic
Figure 8 TLF4277 Demoboard V1.1 schematic
Table 7 CSO output voltage during thermal shutdown
Value in data sheet (Typ.) Measured typical value
2.8 V 2.809 V
Table 8 CSO output voltage during overvoltage
Value in data sheet (Typ.) Measured typical value
3.1 V 3.115 V

TLF4277 Demoboard
Demoboard
Application Note 12 Rev. 1.1, 2012-04-25
3.6 Bill of Material
Table 9 Bill of material
Part Value Package
B1 Banana jack BABU4MM
B3 Banana jack BABU4MM
B4 Banana jack BABU4MM
B5 Banana jack BABU4MM
B6 Banana jack BABU4MM
C1 10u/50V C2220K
C2 100u/50V CPOL-EUE
C3 10u/16V not mounted C1206
C4 2u2/10V C0805
C5 10u/16V C0805
C6 100n C0805
EN LSP10 LSP10
IC1 TLF4277 SSOP-14
JP1 Jumper JP1E
JP2 Jumper JP1E
JP3 Jumper JP1E
JP4 Jumper JP1E
JP5 Jumper JP1E
R1 1R/1%/1W R2010
R2 100R R0805
R3 31.6k/0.1% R0805
R4 56.2k/0.1% R0805
R5 10k/1% R0805
R6 4k7/1% R0805
R7 1k5/1% R0805

TLF4277 Demoboard
Demoboard
Application Note 13 Rev. 1.1, 2012-04-25
3.7 Board Layout
Figure 9 TLF4277 Demoboard V1.1 top layer component placement
Figure 10 TLF4277 Demoboard V1.1 top layer

TLF4277 Demoboard
Demoboard
Application Note 14 Rev. 1.1, 2012-04-25
Figure 11 TLF4277 Demoboard V1.1 bottom layer

TLF4277 Demoboard
Restrictions
Application Note 15 Rev. 1.1, 2012-04-25
4 Restrictions
This Demoboard is offering limited features allowing you only to evaluate and test the Infineon products. The
Demoboard is not an end product (or finished appliance), nor is it intended or authorized by Infineon to be
integrated into end products. You are not authorized to use the Demoboard in any production system.

TLF4277 Demoboard
Reference
Application Note 16 Rev. 1.1, 2012-04-25
5 Reference
[1] TLF4277 Data Sheet

TLF4277 Demoboard
Revision History
Application Note 17 Rev. 1.1, 2012-04-25
6 Revision History
TLF4277 Demoboard
Revision History: Rev. 1.1, 2012-04-25
Previous Version(s): Rev. 1.0, 2012-03-12
Page Subjects (major changes since last revision)
15 Restrictions disclaimer added.

Edition 2012-04-25
Published by
Infineon Technologies AG
81726 Munich, Germany
©2012 Infineon Technologies AG
All Rights Reserved.
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Infineon Technologies Office (www.infineon.com).
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