DC1051A - LINEAR TECHNOLOGY

dc1051af

DEMO MANUAL DC1051A

Description

LTC4217

2A Integrated

Hot Swap Controller

Demonstration circuit 1051A includes two separate circuits

for performance evaluation of the LT C

4217 2A integrated

Hot Swap™ controller. This integrated circuit includes

a power MOSFET to save board area and to minimize

external component count. The standard version of the

controller (LTC4217) is intended to operate with 2.9V to

26.5V rails, while the LTC4217-12 has internal adjustment

for 12V applications.

The circuit of DC1051A located on the upper board area

is assembled with the LTC4217 configured for operation

with a 24V rail. The lower circuit includes the LTC4217-12.

Current limit features of both circuits are identical, with

5% accuracy and a distinctive foldback property.

The LTC4217 features a ground-referred current monitor.

The current monitor sources a current that is proportional

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and Hot

Swap is a trademark of Linear Technology Corporation. All other trademarks are the property of

their respective owners.

performance summary

to the sense voltage and it may be converted to a voltage

signal with an appropriate resistor.

The current limit may be reduced by placing an external

resistor between GND and the ISET pin.

The DC1051A schematic allows the LTC4217 to operate in

turn-on and turn-off modes as well as in the steady-state

mode with different loads, and in the fault mode.

The LTC4217 features an overtemperature protection

circuit, and protects the load from overvoltage and un-

dervoltage conditions.

Design files for this circuit board are available at

http://www.linear.com/demo

Specifications are at TA = 25°C

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

24V Circuit

VDD Input Supply Range Typical Value 19.9 24 26.3 V

VDD(UVL) Input Supply Undervoltage Range VDD Rising 19.12 19.9 20.30 V

VDD(OVH) Input Supply Overvoltage Range VDD Rising 25.32 26.3 27.38 V

tTIMER Timer Period 0.9 1.235 1.76 ms

ILIM Current Limit Value VFB = 1.235V (VOUT in the Range 20.3V to 21.2V) 1.9 2 2.1 A

VFB = 0V to 0.15V (VOUT in the Range 0V to 2.5V) 0.35 0.5 0.7 A

CMAX24 Maximal Load Capacitance For Successful Power-Up 900 µF

CMIN24 Minimal Load Capacitance For Unsuccessful Power-Up 3500 µF

12V Circuit

VDD Input Supply Range Typical Value 9.88 12 15.05 V

VDD(UVL) Input Supply Undervoltage Range VDD Rising 9.6 9.88 10.2 V

VDD(OVH) Input Supply Overvoltage Range VDD Rising 14.7 15.05 15.4 V

tTIMER Timer Period VTIMER Rising 0.9 1.235 1.76 ms

ILIM Current Limit Value VFB = 1.235V (VOUT in the Range 10.15V to 10.6V) 1.9 2 2.1 A

VFB = 0V to 0.15V (VOUT in the Range 0V to 1.15V) 0.35 0.5 0.7 A

CMAX12 Maximal Load Capacitance For Successful Power-Up 1000 µF

CMIN12 Minimal Load Capacitance For Unsuccessful Power-Up 4000 µF

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DEMO MANUAL DC1051A

operating principles

The LTC4217 is suited for low voltage applications such as

hot board insertion and removal. The LTC4217 has a rich

set of features to support Hot Swap applications including:

• Integrated power MOSFET for a compact Hot Swap

solution

• 2%accurate undervoltage and overvoltage protection

• Adjustable 5% accurate current limit

• Adjustable inrush current control

• Load current monitoring

• Adjustable current limit timer before power is turned

off

• Power good signaling

Quick start proceDure

Demonstration circuit 1051 is easy to set up to evaluate

the performance of the LTC4217. Refer to Figure 1 for

the proper measurement equipment setup and follow the

procedure below.

For the 24V circuit:

1. Place jumpers in the following positions:

JP1 FAULT Signal

JP2 AUX_UV ON

2. With power off, connect the 24V power supply terminals

to the 24VIN (E1) and GND (E3) turrets.

3. Turn on the 24V supply and verify the output voltage

between the VOUT (E7) and GND (E8) turrets. Tw o green

LEDs, 24VIN (D2) and VOUT (D6), should light up.

4. Check the current limit using an electronic or resistive

load. It should be in the range of 1.9A to 2.1A if an

overcurrent condition occurs while the output is high

(after powering up properly). If the output is shorted

initially, the load current will be limited in the range of

0.475A to 0.525A due to the foldback characteristic.

Current may be monitored on the IMON test point

during this measurement. The IMON signal scale is

1V/A.

An overcurrent condition is indicated by red LED FAULT

(D3) and red LED PG (D4).

5. Check the output voltage slew rate with an oscilloscope,

without a load connected. It takes 43.6ms to 160ms

for the output voltage to power up completely.

6. Use a 900μF capacitive load to demonstrate that power

up mode completes successfully. Use a current probe

to verify that inrush current is limited initially by the

foldback characteristic and later by the low output

voltage slew rate.

7. Use a 3500μF capacitive load to demonstrate that the

part not only enters into the current limit state but

operates in this state until the timer period expires.

For the 12V circuit:

8. Place jumpers in the following positions:

JP3 FAULT Signal

JP4 AUX_UV ON

9. With power off, connect the 12V power supply terminals

to the 12VIN (E9) and GND (E12) turrets.

10. Turn on the 12V supply and verify the output voltage

at the VOUT (E15) and GND (E16) turrets. Green LEDs

12VIN (D8) and VOUT (D12) should light.

11. Check the current limit using an electronic or resis-

tive load. It should be in the range of 1.9A to 2.1A.

During this measurement verify the current monitor

performance. The monitor signal related to the current

limit level should be 1.9V to 2.1V.

12. Check the output

voltage slew rate with an oscilloscope,

without a load connected. It should take from 21ms

to 80ms for the output voltage to rise to 12V.

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DEMO MANUAL DC1051A

Quick start proceDure

13. Use a 1000μF capacitive load to demonstrate that the

part powers up without fault. Use a current probe to

observe that inrush current is limited by the low output

voltage slew rate.

14. Use a 4000μF capacitive load to demonstrate that the

part enters the current limit state, and operates in this

state until the timer period expires. The FAULT red LED

(D9) indicates this state accompanied by the PG red

LED, which shows that the output voltage is lower than

the power good level.

Figure 1. Measurement Equipment Setup

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DEMO MANUAL DC1051A

parts list

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

1 3 C2, C3, C5 CAP., CER X7R 0.1µF 16V 0603 AVX 0603YC104KAT2A

2 0 C1, C4, CIN1, CIN2, COUT1, COUT2 OPTIONAL

3 8 E2, E4, E5, E6, E10, E11, E13, E14 TURRET, TEST PIN, .061" MILL-MAX 2308-2-00-44

4 8 E1, E3, E7, E8, E9, E12, E15, E16 TURRET, TEST PIN, .095" MILL-MAX 2501-2

5 4 JP1 - JP4 JUMPER, 0.079, 3PIN SAMTEC, TMM-103-02-L-S

6 4 JP1 - JP4 SHUNT SAMTEC, 2SN-BK-G

7 4 D3, D4, D9, D10 LED, SMT RED PANASONIC, LN1251C

8 4 D2, D6, D8, D12 LED, SMT GREEN PANASONIC, LN1351C

9 1 D1 DIODE, 400W TRANSIENT VOLTAGE

SUPPRESSOR

DIODES INC., SMAJ24A

10 1 D7 DIODE, 400W TRANSIENT VOLTAGE

SUPPRESSOR

DIODES INC., SMAJ12A

11 1 R6 RES., CHIP, 3.24k 1/16W 1% 0603 VISHAY, CRCW06033K24FKTA

12 4 R11, R13, R14, R15 RES., CHIP, 3.30k 1/16W 5% 0603 VISHAY, CRCW06033K30JEA

13 4 R1, R3, R4, R8 RES., CHIP, 6.80k 1/4W 5% 1206 VISHAY, CRCW12066K80JNEA

14 2 R7, R10 RES., CHIP, 10k 1/16W 1% 0603 VISHAY, CRCW060310K0FEA

15 2 RMON1, RMON2 RES., CHIP, 20k 1/16W 5% 0805 VISHAY, CRCW080520K0JEA

16 1 R9 RES., CHIP, 158k 1/16W 1% 0603 VISHAY, CRCW0603158KFEA

17 1 R5 RES., CHIP, 200k 1/16W 1% 0603 VISHAY, CRCW06032003F

18 0 RSET1, RSET2, R2, R12 OPTIONAL OPT

19 1 U1 IC., HOT SWAP CONTROLLER LINEAR, LTC4217CFE

20 1 U2 IC., HOT SWAP CONTROLLER LINEAR, LTC4217CDHC-12

dc1051af

DEMO MANUAL DC1051A

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-

tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

schematic Diagram

A A

B B

C C

D D

Customer Notice

Linear Technology Has Made A Best Effort To Design A

Circuit That Meets Customer-Supplied Specifications;

However, It Remains The Customer's Responsibility To

Verify Proper And Reliable Operation In The Actual

Application. Component Substitution And Printed

Circuit Board Layout May Significantly Affect Circuit

Performance Or Reliability. Contact Linear Technology

Applications Engineering For Assistance.

This Circuit Is Proprietary To Linear Technology And

Supplied For Use With Linear Technology Parts.

LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY

120612061206

1206

VOUT

FAULT

OFF

AUX_UV

Auto-Retry

FAULT

Auto-Retry

Signal

FAULT

Signal

Demo Circuit 1051A

Positive 24V, Positive 12V Integrated Hot Swap

LINEAR TECHNOLOGY CORPORATION

1630 McCARTHY BLVD.

MILPITAS, CA. 95035

PHONE (408) 954-8400 FAX (408) 434-0507

1 1

Wednesday, February 15, 2006

Title

Size Document Number Rev

Date: Sheet of

LTC4217CFE

10 11

VDD

GND

SENSE

TIMER

INTVCC

OUT

SENSE SENSE

OUT

GATE

FAULT

IMON

ISET

VDD

SENSE

LED

(GRN)

2 1

E11

RMON2

20K

R14

3.3K

FAULT SIGNAL

D12

LED

(GRN)

2 1

0.1uF

16V

E14

ISET

LED

(GRN)

2 1

(Opt.)

6.8K

158K

LED

(RED)

2 1

GND

24V/2A

IMON

E16

GND

E13

IMON

R11

3.3K

E12

GND

RSET1

(Opt.)

ISET

SMAJ12A

2 1

LED

(RED)

2 1

3.24K

6.8K

E15

12V/2A

R13

3.3K

200K

10K

6.8K

CIN1

(Opt.)

2.2uF

35V

(Opt.)

RMON1

20K

6.8K

LED

(GRN)

2 1

24VIN

0.1uF

16V

CIN2

(Opt.)

R12

(Opt.)

LED

(RED)

2 1

SMAJ24A

2 1

R10

10K

LTC4217CDHC

8 9

TIMER

OUT

VDD

INTVCC

GND

OUT OUT

GATE

FAULT

IMON

ISET

VDD

R15

3.3K

E10

FAULT SIGNAL

D10

LED

(RED)

2 1

0.1uF

16V

12VIN

2.2uF

35V

RSET2

(Opt.)

GND

JP1

JP2

JP3

dc1051af

DEMO MANUAL DC1051A

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com

 LINEAR TECHNOLOGY CORPORATION 2013

LT 0513 • PRINTED IN USA

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This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT

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in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety

measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union

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If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date

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observe good laboratory practice standards. Common sense is encouraged.

This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LT C applica-

tion engineer.

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Milpitas, CA 95035