Datasheet

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LTC4223-1/LTC4223-2

422312f

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

Dual Supply Hot Swap

Controller for Advanced

Mezzanine Card

The LTC

4223 positive voltage Hot Swap

controller

allows a board to be safely inserted and removed from

a live AMC or MicroTCA backplane. It controls the main

12V supply with an external N-channel MOSFET and the

3.3V auxiliary supply with an integrated switch. The 12V

output ramp rate is adjustable and includes inrush current

limiting. The 12V output is also protected against short

circuit faults with a fast acting current limit and a 5%

accurate timed circuit breaker. The 3.3V output includes

both soft start and overcurrent protection.

The LTC4223 features a current monitor output for the

12V supply, and reports fault and power-good status for

both supplies. It also detects card presence and allows

independent control of the 12V and auxiliary 3.3V sup-

ply outputs. The LTC4223-1 features a latch-off circuit

breaker, while the LTC4223-2 provides automatic retry

after a fault.

Advanced Mezzanine Card Application

■

Allows Safe Insertion into Live AMC or MicroTCA

Backplane

■

Controls 12V Main and 3.3V Auxiliary Supplies

■

Limits Peak Fault Current in ≤1μs

■

Adjustable Current Limit with Circuit Breaker

■

Integrated 0.3Ω AUX Switch

■

High Side Current Sense

■

Gate Drive for External N-Channel MOSFET

■

Adjustable Response Time for Overcurrent Protection

■

Adjustable Supply Voltage Power-Up Rate

■

Thermal Shutdown Protection

■

LTC4223-1: Latch Off After Fault

■

LTC4223-2: Automatic Retry After Fault

■

16-Lead SSOP and 5mm × 4mm DFN Packages

■

Advanced Mezzanine Card, MicroTCA Systems

■

Workstations and Server I/O

■

Telecom Networks

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Normal Power-Up Waveform

422312 TA01a

12V

SENSE

12V

GATE

12V

OUT

12V

AUXIN

AUXOUT

AUXON

12ON

AUXPGOOD

12PGOOD

FAULT

12V

3.3V

6mΩ Si7336ADP

CARRIER

CONNECTOR

MODULE

CONNECTOR

TIMER

LTC4223-1/LTC4223-2

GND

12V

7.4A

3.3V

150mA

10Ω

51Ω

330nF

0.1μF

47Ω

15nF

IPMC

12IMON

ADC

20ms/DIV

12PGOOD

5V/DIV

AUXOUT

5V/DIV

12V

OUT

5V/DIV

AUXPGOOD

5V/DIV

422312 TA01b

Summary of content (24 pages)

PAGE 1
LTC4223-1/LTC4223-2 Dual Supply Hot Swap Controller for Advanced Mezzanine Card DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Allows Safe Insertion into Live AMC or MicroTCA Backplane Controls 12V Main and 3.3V Auxiliary Supplies Limits Peak Fault Current in ≤1μs Adjustable Current Limit with Circuit Breaker Integrated 0.
PAGE 2
LTC4223-1/LTC4223-2 ABSOLUTE MAXIMUM RATINGS (Note 1) Supply Voltages 12VIN ..................................................... –0.3V to 20V AUXIN .................................................... –0.3V to 10V VCC........................................................... –0.3V to 7V Input Voltages 12ON, AUXON, ⎯E⎯N ................................... –0.3V to 7V TIMER..........................................–0.3V to VCC + 0.3V 12VSENSE ............................................... –0.
PAGE 3
LTC4223-1/LTC4223-2 ELECTRICAL CHARACTERISTICS The ● denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are TA = 25°C, VCC = 3.3V, VAUXIN = 3.3V, V12VIN =12V, unless otherwise speciﬁed.
PAGE 4
LTC4223-1/LTC4223-2 ELECTRICAL CHARACTERISTICS The ● denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are TA = 25°C, VCC = 3.3V, VAUXIN = 3.3V, V12VIN =12V, unless otherwise speciﬁed.
PAGE 5
LTC4223-1/LTC4223-2 TYPICAL PERFORMANCE CHARACTERISTICS Speciﬁcations are TA = 25°C, VCC = 3.3V, VAUXIN = 3.3V, V12VIN =12V, unless otherwise speciﬁed. ICC vs VCC 1.0 SUPPLY CURRENT (mA) 1.2 0.8 0.4 35 0.8 VCC 0.6 12VIN 12IMON GAIN RATIO (V/V) 1.6 ICC (mA) 12IMON Gain Ratio vs Temperature Supply Current vs Temperature AUXIN 0.4 34 33 32 0.2 0 – 50 0 2.5 3.0 3.5 4.0 4.5 VCC (V) 5.0 5.5 6.
PAGE 6
LTC4223-1/LTC4223-2 TYPICAL PERFORMANCE CHARACTERISTICS Speciﬁcations are TA = 25°C, VCC = 3.3V, VAUXIN = 3.3V, V12VIN =12V, unless otherwise speciﬁed. AUX Switch On Resistance vs Temperature Gate Drive vs Temperature 0.3 0.2 GATE DRIVE (ΔVGATE) (V) 6 0.4 6.2 6.1 6.0 –25 0 25 50 TEMPERATURE (°C) 75 5.
PAGE 7
LTC4223-1/LTC4223-2 PIN FUNCTIONS 12VSENSE (Pin 1): 12V Current Sense Input. Connect this pin to the output of the current sense resistor. The electronic circuit breaker trips if the voltage across the sense resistor exceeds 50mV for more than a fault ﬁlter delay. 12VIN (Pin 2): 12V Supply Input. Undervoltage lockout disables the 12V supply until the input at 12VIN exceeds 9.7V. 12IMON (Pin 3): 12V Current Sense Monitoring Output. This pin monitors the sense voltage between 12VIN and 12VSENSE.
PAGE 8
LTC4223-1/LTC4223-2 FUNCTIONAL DIAGRAM RIN 5k + – A1 12IMON ROUT 165k 10μA CHARGE PUMP 12VGATE 60mV 12VIN +– 12VSENSE + – 50mV +– + – 6.2V ACL 1mA 12VOUT GATE DRIVER ECB 12V PWRGD PG2 10.3V VCC 12V SUPPLY CONTROL 12ON + – 10μA 12V FET ON 12PGOOD VCC R2 EN CARD PRESENCE VCC 9.7V + – 2.45V + – 12VIN VCC VCC VCC AUXIN 200μA 10μA 2.5V 0.2V TIMER 1.
PAGE 9
LTC4223-1/LTC4223-2 OPERATION The LTC4223 is designed to control the power on an Advanced Mezzanine Card (AMC) or MicroTCA backplane, allowing boards to be safely inserted and removed. It controls the 12V main and 3.3V auxiliary power through an external N-channel MOSFET and integrated pass transistor. These two supplies can be turned on and off independently by their respective ON control pins.
PAGE 10
LTC4223-1/LTC4223-2 APPLICATIONS INFORMATION RS 6mΩ CARRIER AMC MODULE AMC CONNECTOR CONNECTOR Q1 Si7336ADP PWR 12V BULK SUPPLY BYPASS CAPACITOR 2 5 3.3V R2 51Ω BULK SUPPLY BYPASS CAPACITOR 6 C2 330nF 7 PWR ENABLE 4 3.3V R6* 10k MP GOOD 3.3V R5* 10k R4* 10k PWR GOOD FAULT 1 16 12VSENSE 12VGATE AUXIN 12VOUT AUXOUT MP ENABLE 3.3V CG RG 15nF 47Ω R3 10Ω 12VIN 12V 7.4A 15 12 MP 10 PS1 3.3V 150mA VCC AUXON 12ON LTC4223-1 11 14 13 AUXPGOOD 12PGOOD FAULT 3.
PAGE 11
LTC4223-1/LTC4223-2 APPLICATIONS INFORMATION Several conditions must be met before the external and internal switches are allowed to turn on. First VCC and the input supplies (12VIN, AUXIN) must exceed their undervoltage lockout thresholds. Next TIMER must be <0.2V and ⎯E⎯N must be pulled low. Once these conditions are met, a debounce timing cycle is initiated when AUXON or 12ON pin is toggled from low to high. These two control pins turn on/off the 3.3V auxiliary and 12V supplies.
PAGE 12
LTC4223-1/LTC4223-2 APPLICATIONS INFORMATION Turn-Off Sequence The switches can be turned off by various conditions and this is summarized in Table 1. When the 12ON pin goes low, the external switch is turned off with the GATE pin pulled to ground by 1mA current sink. The ⎯1⎯2⎯P⎯G⎯O⎯O⎯D pin pulls high indicating that power is no longer good, while an internal N-channel transistor discharges the output to ground.
PAGE 13
LTC4223-1/LTC4223-2 APPLICATIONS INFORMATION As the TIMER capacitor is used for fault ﬁltering during power-up for both the auxiliary and 12V supplies, only one supply can be started up at any one time. The other supply waits until the power-good signal is generated by the powering-up supply and the TIMER pin voltage falls below 0.2V. By default, the 3.3V auxiliary supply starts up ﬁrst if both AUXON and 12ON are high at the end of the debounce cycle.
PAGE 14
LTC4223-1/LTC4223-2 APPLICATIONS INFORMATION There are two different modes of fault time-out for the 3.3V auxiliary supply: adjustable delay through TIMER capacitor during power-up when ⎯A⎯U⎯X⎯P⎯G⎯O⎯O⎯D not asserted; ﬁxed 25μs delay after power-up when ⎯A⎯U⎯X⎯P⎯G⎯O⎯O⎯D asserted low. Under the situation whereby AUXON toggles low then high for short duration after power-up while ⎯A⎯U⎯X⎯P⎯G⎯O⎯O⎯D still pulling low due to output load capacitor, 25μs fault time-out applies.
PAGE 15
LTC4223-1/LTC4223-2 APPLICATIONS INFORMATION Power-Good Monitor Auto-Retry after a Fault (LTC4223-2) Internal circuitry monitors the output voltages, AUXOUT and 12VOUT. The power-good status is reported via their ⎯ U ⎯ X ⎯ P ⎯ G ⎯ O ⎯ O ⎯ D ⎯ and 1⎯ 2⎯ P ⎯ G ⎯ O ⎯ O ⎯ D ⎯ . respective open drain outputs, A Several conditions must be met before the power-good outputs assert low. At time point 1 in Figure 8, if a fault latched-off the 3.3V auxiliary supply after power-up, a cool-off cycle begins.
PAGE 16
LTC4223-1/LTC4223-2 APPLICATIONS INFORMATION GATE Pin Voltage The gate drive at 12VGATE is compatible with any logic level MOSFET. The guaranteed range of gate drive is 4.5V to 7.9V, with a typical of 6.2V. Active Current Loop Compensation The compensation network consisting of resistor RG and gate slew rate control capacitor CG stabilizes the internal active current limit circuit. The value of CG is selected based on the inrush current allowed. The suggested value for RG is 47Ω.
PAGE 17
LTC4223-1/LTC4223-2 APPLICATIONS INFORMATION END OF DEBOUNCE CYCLE FAULT PULLS LOW DUE TO 12V OVERCURRENT FAULT START OF COOL-OFF CYCLE START 12V GATE RAMP WHEN STARTUP CONDITIONS ARE MET 12V OUTPUT IN CURRENT LIMIT START OF DEBOUNCE CYCLE 1 2 FAULT PULLS LOW AND RESTART OF COOL-OFF CYCLE RESET FAULT HIGH 3 4 5 6 7 RESTART OF DEBOUNCE CYCLE 8 FAULT 200μA VTMR 2μA 10μA VTMR 2μA 200μA VTMR 2μA 10μA TIMER FILTER DELAY COOL-OFF CYCLE COOL-OFF CYCLE DEBOUNCE CYCLE 12VGATE REGULATES 12
PAGE 18
LTC4223-1/LTC4223-2 APPLICATIONS INFORMATION CURRENT FLOW TO LOAD R2 51Ω AUXIN C2 330nF SENSE RESISTOR POWER PAK SO-8 CURRENT FLOW TO LOAD VCC 12VIN W 12VOUT W 422312 F11 Figure 11. RC Network for VCC Filtering TRACK WIDTH W: 0.03" PER AMPERE ON 1OZ Cu FOIL R3 12VGATE • RG VIA TO GND PLANE CG PCB Layout Considerations For proper operation of the LTC4223’s circuit breaker, Kelvin-connection to the sense resistor is strongly recommended.
PAGE 19
LTC4223-1/LTC4223-2 APPLICATIONS INFORMATION ITRIP(MIN) = ITRIP(MAX ) = ΔVSENSE(CB)(MIN) RSENSE(MAX ) = ΔVSENSE(CB)(MAX ) RSENSE(MIN) 47.5m mV = 7.8 A 6.06mΩ = 52.5mV = 8.8 A 5.94mΩ For proper operation, ITRIP(MIN) must exceed the maximum load current with margin, so RSENSE = 6mΩ should sufﬁce for the 12V supply.
PAGE 20
LTC4223-1/LTC4223-2 TYPICAL APPLICATION Card Resident Application with 5V Auxiliary Supply BACKPLANE CARD CONNECTOR CONNECTOR RS 4mΩ Q1 Si7336ADP 12V 10A 12V Z1 SMAJ13A R1 10Ω R3 10Ω C1 100nF 12VIN + CG RG 15nF 47Ω CL1 1000μF 12VSENSE 12VGATE 12VOUT 5V AUXIN R6 Z2 10k SMAJ7.0A R7 2.
PAGE 21
LTC4223-1/LTC4223-2 TYPICAL APPLICATION Card Resident Application with 12V Power Up First Followed by 3.3V Auxiliary BACKPLANE CARD CONNECTOR CONNECTOR RS 4mΩ Q1 Si7336ADP 12V 10A 12V R1 10Ω Z1 SMAJ13A R3 10Ω C1 100nF 12VIN + CG RG 15nF 47Ω CL1 1000μF 12VSENSE 12VGATE 12VOUT 3.3V AUXIN R7 2.7Ω C3 100nF Z2 SMAJ5.0A 3.3VAUX 150mA AUXOUT R2 51Ω C2 330nF PWREN + VCC CL2 150μF 12ON R8 10k 3.3V R9 10k 3.3V 3.3V R5 10k 3.3V Q2 2N7002K R4 10k LTC4223-1 AUXPGOOD AUXON 12PGOOD R6 10k 3.
PAGE 22
LTC4223-1/LTC4223-2 PACKAGE DESCRIPTION GN Package 16-Lead Plastic SSOP (Narrow .150 Inch) (Reference LTC DWG # 05-08-1641) .189 – .196* (4.801 – 4.978) .045 ±.005 16 15 14 13 12 11 10 9 .254 MIN .009 (0.229) REF .150 – .165 .229 – .244 (5.817 – 6.198) .0165 ± .0015 .150 – .157** (3.810 – 3.988) .0250 BSC RECOMMENDED SOLDER PAD LAYOUT 1 .015 ± .004 × 45° (0.38 ± 0.10) .007 – .0098 (0.178 – 0.249) .0532 – .0688 (1.35 – 1.75) 2 3 4 5 6 7 8 .004 – .0098 (0.102 – 0.249) 0° – 8° TYP .016 – .
PAGE 23
LTC4223-1/LTC4223-2 PACKAGE DESCRIPTION DHD Package 16-Lead Plastic DFN (5mm × 4mm) (Reference LTC DWG # 05-08-1707) 0.70 ±0.05 4.50 ±0.05 3.10 ±0.05 2.44 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 4.34 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS R = 0.115 TYP 5.00 ±0.10 (2 SIDES) R = 0.20 TYP 4.00 ±0.10 (2 SIDES) 9 0.40 ± 0.10 16 2.44 ± 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) PIN 1 NOTCH (DHD16) DFN 0504 8 0.200 REF 1 0.25 ± 0.05 0.50 BSC 0.75 ±0.05 0.00 – 0.05 4.
PAGE 24
LTC4223-1/LTC4223-2 TYPICAL APPLICATION 12V/18A Card Resident Application BACKPLANE CARD CONNECTOR CONNECTOR RS 2.5m Q1 HAT2160H 12V 18A 12V R1 10Ω Z1 SMAJ13A R3 10Ω C1 100nF 12VIN + CG RG 15nF 47Ω CL1 1000μF 12VSENSE 12VGATE 12VOUT 3.3V AUXIN Z2 SMAJ5.0A R7 2.7Ω C3 100nF 3.3VAUX 150mA AUXOUT R2 51Ω + CL2 150μF VCC C2 330nF 3.3V R9 10k AUXON R8 10k BD_SEL R4 10k LTC4223-1 R5 10k R6 10k AUXPGOOD 12PGOOD FAULT 12ON EN 3..