SMT Current Sense Transformers
EP 7 Core
Series/Type: B78417
Ordering code:
Date: 2017-02-02
Version:
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Identification/Classification 1
(header 1 + top left bar):
SMT Current Sense Transformers
Identification/Classification 2
(header 2 + bottom left header bar):
EP 7 Core
Ordering code: (top right header bar)
Series/Type: (bottom right header bar) B78417
Preliminary data (optional):
Department: MAG TF T
Date: 2017-02-02
Version:
SMT Current Sense Transformers
EP 7 Core B78417
2017-02-02
Please read Cautions and warnings and Page 2 of 8
Important notes at the end of this document.
Construction
• Ferrite core
• Primary winding: frame molded in
• Secondary winding: copper wire
• Creepage distance Np/(Ns, core) 5 mm
• Clearance distance Np/Ns (CuL) 3.2 mm
• Clearance distance Np/core 3.5 mm
• Plastic bobbin (UL94-V0, CTI ≥ 175)
Features
• Very low DC resistance
• Different turns ratios
• Small SMD package
• RoHS compatible
• Qualified to AEC-Q200
• Insulation distances in compliance with IEC 60664
(Basic insulation, working voltage rms 500 V)
• UL 1446 Class 155 (F) electrical insulation system
Applications
• Switch-mode power supplies
• Feedback control
• Overload sensing
• Load drop/shut-down detection
Terminals
• L-Pins
Marking
• Product brand, middle block of ordering code, date code, pin 1 marker, production place
identification code
Delivery mode and packing units
• Blister tape
• Packing unit 320 pcs
SMT Current Sense Transformers
EP 7 Core B78417
2017-02-02
Please read Cautions and warnings and Page 3 of 8
Important notes at the end of this document.
Dimensional drawing
SMT Current Sense Transformers
EP 7 Core B78417
2017-02-02
Please read Cautions and warnings and Page 4 of 8
Important notes at the end of this document.
Application circuit and pinning
Technical data and measuring conditions
Typical frequency range 50 … 250 kHz
High voltage test 2400 V AC, 50 Hz, 1 s (winding to winding)
Type test 60 s
Inductance L (5-4) Measured at 20 kHz, 10 mV, +25 °C
DC resistance Rmax (1-2) Measured at +25 °C
DC resistance Rmax (5-4) Measured at +25 °C
Sensed current: Iprim, RMS The max. primary current of 20 A causes approx.
+40 °C temperature rise
Couple capacitance Cp (1-5) Measured at 10 kHz, 1 V, +25 °C
Resistance to reflow soldering
heat
In accordance with JEDEC J-STD-020D
+245 °C for 20 seconds
Operating temperature range −40 °C … +150 °C (component)
Pollution degree P2 (to IEC 60664)
Insulation thermal class 155°C (F) (to IEC 60085)
Weight Approx. 2.5 g
Approvals UL 1446 class 155 (F) (E320370)
SMT Current Sense Transformers
EP 7 Core B78417
2017-02-02
Please read Cautions and warnings and Page 5 of 8
Important notes at the end of this document.
=, ×
×
×
With:
Maximum magnetic flux density in the ferrite core of the current sense transformer
, Maximum output voltage of the measurement signal
Maximum duty cycle
Number of turns of the secondary winding of the current sense transformer
Effective magnetic area of the ferrite core
Operating frequency of the switching operator IC
Typical value for : 10.6 x 10-6 m2
Typical : < 220 mT
=, ×
,
With:
Resistance of burden resistor
, Maximum output voltage of the measurement signal
Number of turns on the secondary side of the CST
, Maximum primary current (peak current)
Characteristics and ordering codes
Lmin
(5-4)
mH
Turns
ratio
Np : Ns
Voltage-
time product
+120 °C
V · µs
Cp
pF
Rmax
(1-2)
mΩ
Rmax
(4-5)
Ω
Recommended.
RT
Ω
Ordering Code
1.7 1:50 116 4 1.9 2.1 50 B78417A2285A003
3.0 1:70 163 4 1.9 2.9 70 B78417A2286A003
7.0 1:100 233 4 1.9 5.0 100 B78417A2185A003
11.0 1:125 291 4 1.9 5.3 125 B78417A2287A003
SMT Current Sense Transformers
EP 7 Core B78417
2017-02-02
Please read Cautions and warnings and Page 6 of 8
Important notes at the end of this document.
Taping and packing
Blister tape
Reel
Cautions and warnings
MAG TF T 2017-02-02
Please read Cautions and warnings and Page 7 of 8
Important notes at the end of this document.
■ Please note the recommendations in our Inductors data book (latest edition) and in the data
sheets.
– Particular attention should be paid to the derating curves given there.
– The soldering conditions should also be observed. Temperatures quoted in relation to wave
soldering refer to the pin, not the housing.
■ If the components are to be washed varnished it is necessary to check whether the washing
varnish agent that is used has a negative effect on the wire insulation, any plastics that are used,
or on glued joints. In particular, it is possible for washing varnish agent residues to have a
negative effect in the long-term on wire insulation Washing processes may damage the product due
to the possible static or cyclic mechanical loads (e.g. ultrasonic cleaning). They may cause cracks to
develop on the product and its parts,
which might lead to reduced reliability or lifetime.
■ The following points must be observed if the components are potted in customer applications:
– Many potting materials shrink as they harden. They therefore exert a pressure on the plastic
housing or core. This pressure can have a deleterious effect on electrical properties, and in
extreme cases can damage the core or plastic housing mechanically.
– It is necessary to check whether the potting material used attacks or destroys the wire
insulation, plastics or glue.
– The effect of the potting material can change the high-frequency behaviour of the
components.
■ Ferrites are sensitive to direct impact. This can cause the core material to flake, or lead to breakage
of the core.
■ Even for customer-specific products, conclusive validation of the component in the circuit can only
be carried out by the customer.
Display of ordering codes for EPCOS products
The ordering code for one and the same EPCOS product can be represented differently in data
sheets, data books, other publications, on the EPCOS website, or in order-related documents such as
shipping notes, order confirmations and product labels. The varying representations of the
ordering codes are due to different processes employed and do not affect the specifications of
the respective products. Detailed information can be found on the Internet under
www.epcos.com/orderingcodes
Page 8 of 8
Important notes
The following applies to all products named in this publication:
1. Some parts of this publication contain statements about the suitability of our products for certain areas
of application. These statements are based on our knowledge of typical requirements that are often placed
on our products in the areas of application concerned. We nevertheless expressly point out that such
statements cannot be regarded as binding statements about the suitability of our products for a
particular customer application. As a rule we are either unfamiliar with individual customer applications or
less familiar with them than the customers themselves. For these reasons, it is always ultimately incumbent
on the customer to check and decide whether a product with the properties described in the product
specification is suitable for use in a particular customer application.
2. We also point out that in individual cases, a malfunction of electronic components or failure before
the end of their usual service life cannot be completely ruled out in the current state of the art, even
if they are operated as specified. In customer applications requiring a very high level of operational safety
and especially in customer applications in which the malfunction or failure of an electronic component could
endanger human life or health (e.g. in accident prevention or life-saving systems), it must therefore be
ensured by means of suitable design of the customer application or other action taken by the customer (e.g.
installation of protective circuitry or redundancy) that no injury or damage is sustained by third parties in the
event of malfunction or failure of an electronic component.
3. The warnings, cautions and product-specific notes must be observed.
4. In order to satisfy certain technical requirements, some of the products described in this publication
may contain substances subject to restrictions in certain jurisdictions (e.g. because they are
classed as hazardous). Useful information on this will be found in our Material Data Sheets on the Internet
(www.tdk-electronics.tdk.com/material). Should you have any more detailed questions, please contact our
sales offices.
5. We constantly strive to improve our products. Consequently, the products described in this publication
may change from time to time. The same is true of the corresponding product specifications. Please
check therefore to what extent product descriptions and specifications contained in this publication are still
applicable before or when you place an order.
We also reserve the right to discontinue production and delivery of products. Consequently, we
cannot guarantee that all products named in this publication will always be available. The aforementioned
does not apply in the case of individual agreements deviating from the foregoing for customer-specific
products.
6. Unless otherwise agreed in individual contracts, all orders are subject to our General Terms and
Conditions of Supply.
7. Our manufacturing sites serving the automotive business apply the IATF 16949 standard. The IATF
certifications confirm our compliance with requirements regarding the quality management system in the
automotive industry. Referring to customer requirements and customer specific requirements (“CSR”) TDK
always has and will continue to have the policy of respecting individual agreements. Even if IATF 16949
may appear to support the acceptance of unilateral requirements, we hereby like to emphasize that only
requirements mutually agreed upon can and will be implemented in our Quality Management
System. For clarification purposes we like to point out that obligations from IATF 16949 shall only become
legally binding if individually agreed upon.
8. The trade names EPCOS, CeraCharge, CeraDiode, CeraLink, CeraPad, CeraPlas, CSMP, CTVS,
DeltaCap, DigiSiMic, ExoCore, FilterCap, FormFit, LeaXield, MiniBlue, MiniCell, MKD, MKK, MotorCap,
PCC, PhaseCap, PhaseCube, PhaseMod, PhiCap, PowerHap, PQSine, PQvar, SIFERRIT, SIFI, SIKOREL,
SilverCap, SIMDAD, SiMic, SIMID, SineFormer, SIOV, ThermoFuse, WindCap are trademarks registered
or pending in Europe and in other countries. Further information will be found on the Internet at www.tdk-
electronics.tdk.com/trademarks.
Release 2018-10
