EC2630QI-E - ALTERA - Product.Network

05996 10/04/2011 Rev: A

www.enpirion.com

EC2630QI

12V DC-DC Intermediate Voltage

Bus Converter, 27W and 4.5A

Description

The Enpirion EC2630QI is a high density DC-

DC Intermediate Voltage Bus Converter which

generates a highly efficient output voltage.

EC2630QI that tracks one half the input

voltage and is designed to work with Enpirion’s

highly integrated DC to DC point-of-load

converter products for a complete 12V solution.

EC2630QI provides the means to condition

power from a 12V input, to supply multiple

lower voltage converters while enabling high

efficiency and small PCB area. Due to its

extremely high efficiency, it avoids the common

two stage power conversion penalty and is

equivalent or better than direct regulation.

This Enpirion solution significantly helps in

system design and productivity by offering

greatly simplified board design, layout and

manufacturing requirements. In addition, a

reduction in the number of vendors required for

the complete power solution helps to enable an

overall system cost savings. All Enpirion

products are RoHS compliant and use a lead-

free manufacturing environment.

Figure 1: Typical Application Schematic Optimized

for Maximum Efficiency

** 1-2 of Cout can be eliminated using downstream input

bypass capacitance (e.g. PoL converters).

Features

• Complete power conditioning solution from

a 12 volt power bus.

• Wide system input voltage range of 8V to

13.2V.

• High and flat efficiency, up to 97.5%.

• 4.5A Continuous Output Current Capability

• Adjustable operating frequency with

optional external clock input.

• Master/Slave Mode for Parallel Operation

• Output Enable pin, VOUT_OK, VIN_OK

• Pre-programmed soft-start time.

• Thermal shutdown, short circuit, Overload,

OVLO and UVLO protection.

• RoHS compliant, MSL level 3, 260C reflow.

Applications

• Applications requiring down conversion

from a 12V bus to a well regulated output

voltage with high efficiency, in a compact

foot print (Note: The total system

application involves two or more Enpirion

products.)

• Enterprise, Industrial, Embedded, and

Telecommunication applications

• Multi-rail computer & network interface

applications such as PCIe and ATCA AMC

cards.

• 12V Industrial and Consumer Applications

such as Audio/Video Home Theater, Tuners

22µF

1206

IN VOUT

CFLYP

47µF**

22µF

VOUT

VIN

GND

V3P3

PVIN

ENA

PGND

CFLYN

0 . 1µF

47µF

VBOOT 0 . 1µF

FADJ

100kΩ

0402

EC2630QI

1206 3x

1206

30.1Ω

0402

05996 10/04/2011 Rev: A

EC2630QI

Ordering Information

Part Number Temp Rating

(°C) Package

EC2630QI -40 to +85 36 pin 5.5 x5.5

QFN Package

EC2630QI-E QFN Evaluation Board

Pin Configuration

Below is a top view diagram of EC2630QI package.

Figure 2: Pin-out diagram, top view of EC2630QI QFN Package.

NOTE: NC pins are not to be electrically connected to each other or to any external signal, ground, or voltage. Failure to

follow this guideline may result in damage to the Device.

NOTE: All pins must be soldered to PCB.

05996 10/04/2011 Rev: A

EC2630QI

Pin Descriptions

PIN NAME FUNCTION

1 V3P3 Internal Regulated Supply Output. Connect bypass capacitor from

V3P3 to GND.

2 FADJ Frequency Adjust pin used to set the switching frequency. See

Theory of Operation Section for selecting the required resistor.

3, 8 GND Internal Regulated Supply Ground. Must tie directly to ground plane

with a via right next to each pin.

4 VIN_OK Vin OK is an open drain transistor for power system state indication

for nominal 12V operation. VIN_OK is a logic high when Vin is

greater than 9V.

5 VOUT_OK VOUT_OK is an open drain transistor for power system state

indication. VOUT_OK is a logic high when Vout is greater than 85%

of expected nominal Vout. This pin should be used to control the

ENABLE signals of downstream converters powered by the EC2630.

6 ENABLE This pin should be tied to VIN all the time. Contact Enpirion

Applications Support for more information.

7 NC NO CONNECT –– Do not electrically connect these pins to each

other or to any other electrical signal. CAUTION: May be internally

connected.

9 M/S Master/Slave pin for clock synchronization. Logic low = Master.

Logic high = Slave.

10 NC NO CONNECT –– Do not electrically connect these pins to each

other or to any other electrical signal. CAUTION: May be internally

connected.

11 SYNCH_I External Synchronizing Clock Input, input accepted in Slave mode.

From an IBC in master mode.

12 SYNCH_O Synchronizing Clock Output. Frequency scaled output of internal

oscillator.

13-18 PGND Power ground for the switching voltage attenuator

19-21 CFLYN Negative Terminal of Flying Capacitor

22-24 VOUT Converter Output Voltage

25-27 CFLYP Positive Terminal of Flying Capacitor

28-33 PVIN Main Input Supply

34 VBOOT Internal power Supply for high-side drive to which boot-strap

capacitor is tied.

35 AVIN Input Supply for Controller

36 NC NO CONNECT – Do not electrically connect these pins to each other

or to any other electrical signal. CAUTION: May be internally

connected.

37 TGND This pad is a thermal gnd. Needs to be thermally and electrically

connected to the ground plane through a matrix of vias.

05996 10/04/2011 Rev: A

EC2630QI

Block Diagram

Figure 3: Block diagram.

05996 10/04/2011 Rev: A

EC2630QI

Absolute Maximum Ratings

CAUTION: Absolute Maximum ratings are stress ratings only. Functional operation beyond

recommended operating conditions is not implied. Stress beyond absolute maximum ratings may

cause permanent damage to the device. Exposure to absolute maximum rated conditions for

extended periods may affect device reliability.

PARAMETER SYMBOL MIN MAX UNITS

Input Supply Voltage – PVIN, AVIN VIN -0.5 15 V

Transient Input Supply Voltage, 2 ms maximum

duration, 100 Hz repetition rate 20 V

Input Voltage – ENA, VIN_OK, VOUT_OK, CFLYN,

CFLYP, Vout -0.5 VIN V

Input Voltage – V3P3, FADJ, M_S, SYNC_I, SYNC_O -0.5 3.5 V

Input Voltage - VBOOT -0.5 VIN + 8 V

Storage Temperature Range TSTG -65 150 °C

Maximum Operating Junction Temperature TJ-ABS MAX 150 °C

Reflow Temp, 10 Sec, MSL3 JEDEC J-STD-020A 260 °C

ESD Rating (based on Human Body Model): AVIN Positive

Negative

1500

2000 V

ESD Rating (based on Human Body Model): All other

pins 2000

ESD Rating (based on Charged Device Model) 500

Thermal Characteristics

PARAMETER SYMBOL MIN TYP MAX UNITS

Operating Junction Temp TJ -40 +125 °C

Thermal Shutdown TSD 155 °C

Thermal Shutdown Hysteresis TSDH 25 °C

Thermal Resistance: Junction to Case

JC 1 °C/W

Thermal Resistance: Junction to Ambient

JA 19 °C/W

Electrical Characteristics

NOTE: VIN=12.0V over operating temperature range unless otherwise noted. Typical values are at TA

= 25°C.

PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS

Operating Input Voltage VIN 8 12 13.2 V

Operating Boot Strap Voltage VBOOT @ Vin =12V, with 0.1uF

capacitor between VBOOT

and CFLYN

17 V

Internal Regulated Supply

Output

V3P3 @ Vin =12V 2.97 3.3 3.63 V

Under Voltage Lockout VUVLO 4.5 5 5.5 V

Input Voltage Indication Rising VIN_OK 9 V

Input Voltage Indication Falling 8 V

Over Voltage Lockout VOVLO 13.35 14.2 15.05 V

No Load Operating Current IOP @ 12V input and 125kHz

switching

2 mA

05996 10/04/2011 Rev: A

EC2630QI

PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS

Switching Frequency (Internal

Oscillator)

FOSC RFADJUST= 100 K

68 115 165 kHz

Frequency Adjust Voltage FADJ 1.2 V

Output Voltage VOUT Fraction of input voltage

with no load current

50 %

Output Voltage Indication

Threshold Rising

VOUT_OK As a percentage of

expected output voltage

85% V

Output Voltage Indication

Threshold Falling

VOUT_OK As a percentage of

expected output voltage

70% V

Output Impedance ROUT

VOUT/

ILOAD

RFADJUST= 100 KΩ,

90 m

Continuous Output Current IOUT Max 0 4.5 A

Overload Trip Level VOCP Vin=12V, Overload sensed

as a drop in output voltage

5.2 V

Enable Threshold Logic Low ENA_VIL Max voltage to ensure the

converter is disabled

0.3 V

Enable Threshold Logic High ENA_VIH 6V ≤ VIN ≤ 13.2V 1.8 VIN V

Logic Threshold Low

M_S

VIL -0.3

0.3 V

Logic Threshold High

M_S

VIH

V3P3

- 0.6

V3P3 V3P3 +

0.3

External Clock frequency FEXT 0.01

1 MHz

Clock Input Logic Low SYNC_I_VIL

0.3 V

Clock Input Logic High SYNC_I_VIH 1.8

3.3 V

Clock Output Logic Low SYNC_O_VOL

0.3 V

Clock Output Logic High SYNC_O_VOH @ 1mA V3P3

- 0.6 V

VIN_OK, VOUT_OK sink

capability POK low voltage = 0.1V 1 mA

05996 10/04/2011 Rev: A

EC2630QI

Typical Performance Characteristics

Fig. 4: Nominal Efficiency (%) vs. Load (A)

@ VIN = 13.2/12/10/8V, CIN=3x22uF, COUT=3X47uF, CFLY=3x47uF with RFADJUST= 100 KΩ,

Start-up / Shutdow n Wave forms with Enable tied to VIN

Fig. 6a: Ch.1: VOUT, Ch.4: VIN

Fig. 6b: Ch.1: VOUT, Ch.4: VIN

Theory of Operation

Bus Voltage Divider

The EC2630QI is an open loop voltage divider.

It generates an output voltage which is

approximately half the input voltage value. The

device uses switched capacitors to divide the

input voltage by a factor of 2. External

capacitors are charged in series during one

half of a clock cycle and the capacitors are

then connected in parallel during the second

half of the clock cycle. Since there is no

feedback to regulate the output voltage, the

output voltage depends on the input voltage as

well as the load current. Temperature

dependence is a function of load current.

This device has been designed specifically for

use along with the Enpirion’s point-of-load

products for output voltage regulation.

The Voltage Divider has the following features:

0.1

0.3

0.5

0.7

0.9

1.1

1.3

1.5

1.7

1.9

2.1

2.3

2.5

2.7

2.9

3.1

3.3

3.5

3.7

3.9

4.1

4.3

4.5

Iout (A)

Efficiency (%)

Vin=13.2

Vin=12

Vin=11

Vin=10

Vin=9

Vin=8

05996 10/04/2011 Rev: A

EC2630QI

• Over-current protection (to protect the IC

from excessive load current)

• Thermal shutdown with hysteresis.

• Under-voltage lockout circuit to disable the

converter output when the input voltage is

less than approximately 5V

• Over-voltage lockout circuit to disable the

converter output when the input voltage is

greater than approximately 14.2V

• Switching frequency is internally

generated. However, a clock signal may be

applied externally when the device is

configured in Slave mode.

• When in Master mode, the device will

output its internal frequency scaled clock to

the SYNCH_O pin.

• Soft-start circuit, to limit the in-rush current

when the converter is powered up.

• VIN_OK and VOUT_OK indicator signals.

Enable Operation

A logic high on this pin will turn the device

on, and logic low will disable the output.

Under normal operation, the ENABLE pin

needs to be tied to PVIN. The device is

then turned on and off by ramping the input

voltage up and down. Contact Enpirion

Applications Support for further details.

Frequency Synch (Master/Slave)

In Slave mode, an external clock may be

used for switching the bus converter by

connecting such a source to SYNC_I pin

when the device is configured. In Master

mode, the internal switching frequency of

the Master device is outputted through

SYNCH_O pin. This clock signal can be

used to drive other EC2630QI devices for

synchronization or parallel operation.

Soft-Start Operation

Soft start is a means to reduce the in-rush

current when the device is enabled. When the

device is enabled by ramping up the input

voltage, and the output capacitors are

discharged, a large current flow is averted by

modulating the gate drive of the NFET during

the soft start interval. This interval is pre-

programmed and not user programmable.

Overload Protection

The overload function is achieved by sensing

the output voltage. An overload state is entered

when the device is out of soft start and the

output voltage drops below ~85% of the

expected voltage. This overload state will

initiate a fresh soft-start and the device will stay

looping in soft-start as long as the overload

condition exists.

Over-Voltage Protection

When the input voltage exceeds 14.2V, the

flying capacitor is placed in parallel with the

output capacitor during OVLO and the device

does not switch.

Thermal Overload Protection

Thermal shutdown will disable operation when

the Junction temperature exceeds the value

given in the Electrical Characteristics table.

Once the junction temperature drops by the

hysteresis temperature, the converter will re-

start with a normal soft-start.

Input Under-voltage Lock-out

Internal circuits ensure that the converter will

not start switching until the input voltage is

above the specified minimum voltage of ~5V.

Frequency Adjustment

The device is optimized to run at 125kHz

switching frequency (with RFADJ= 100 KΩ)

independent of load current. The internal

oscillator frequency can be adjusted by altering

the value of the resistor between the FADJ pin

and AGND (see chart below). Contact Enpirion

Applications Support for further details.

Frequency vs. Resistance

100

150

200

250

300

350

400

450

500

0 25 50 75 100 125 150 175 200 225 250

Resistance (K-Ohm s)

Oscillator Frequency (KHz)

05996 10/04/2011 Rev: A

EC2630QI

Application Schematic

Figure 7: EC2630 connected to a 12V input supp ly supplying 3 point-of-load E npirion DC-DC switchers.

Figure 7 shows a typical application where the EC2630 is powering up three downstream Enpirion

point-of-load (POL) converters. As shown in Figure 7, the EC2630 VOUT_OK signal should be used

to control the ENABLE pins of the downstream converters. This ensures that the intermediate bus

voltage is up before the POL converters start switching. In addition please use only POL converters

rated for up to 6.6V input voltage operation.

05996 10/04/2011 Rev: A

EC2630QI

Capacitor Selection

The EC2630QI requires a range of capacitance

depending on application configuration.

Capacitor selection is dependent upon power

level, efficiency, space, and cost requirements.

Low-cost, low-ESR X5R or X7R ceramic

capacitors should be used. Either 1206 or 1210

case sizes are recommended. In general, 1210

capacitors exhibit less voltage coefficient than

1206 capacitors, providing more capacitance per

unit volume-volt. Y5V or equivalent dielectric

formulations must not be used as they lose

capacitance with frequency, temperature and

bias voltage.

Capacitor selection guidelines to support full

output load (4.5A) optimized for efficiency:

• Input Capacitors- a typical implementation

might use 3x22μF, 1206 MLCC capacitors

• Output Capacitors- a typical

implementation might use 3X47μF, 1206

output

• Flying Capacitors- a typical

implementation might use 3x47μF 1206.

• A portion of the output capacitance or

flying capacitance can be allocated to the

underside of the board. In addition, a

portion of Cout can be shared with

downstream input bypass capacitance

(e.g. PoL converters).

Optional External Over-Current Protection (OCP)

For some applications, output load levels that

drive the EC2630 into very high-current

conditions with VOUT at nominal VIN/2 voltages

can lead to EC2630 device damage. Enpirion

has observed that high-current conditions over

6A - while VOUT is regulating at VIN/2 - can lead

to device failure. When the EC2630 fails, the

device will stop regulating to VOUT=VIN/2, and the

output will drop to approximately 2V. A failure

event has not been found to damage

downstream devices since VOUT drops during the

event. When an EC2630 device fails, it draws

excessive current from the 12V input supply at its

PVIN pin.

Figure 8 shows a recommended circuit for

external over-current protection. Applications that

implement other means of over-current and

short-circuit protection by using other supervisory

or control circuits do not need to use the circuit

shown in Figure 8. Please contact Enpirion

Applications support for more details.

This circuit interfaces to the following pins on the

EC2630: AVIN, FADJ, ENABLE, VOUTOK, and

GND. It uses the VOUT_OK signal to decide if

there is an over-current condition. If VOUT_OK is

high, then the circuit allows the EC2630 to

operate normally. As soon as VOUT_OK goes to

a logic low, it is interpreted as an over-current

condition, and the circuit lowers the device

operating frequency, and causes it to go into a

hiccup mode. The hiccup mode continues

indefinitely until VOUT_OK goes high.

There are two timers in this circuit. C1 and its

associated resistors sets up a soft-start timer,

and C2 and its associated resistors set up a

hiccup timer. The active components in this

circuit were chosen based on device availability.

Similar components can be used as long as the

performance is comparable to the ones shown in

Figure 8. Please note the circuit also requires an

external 3.3V, low-current rail.

If an over-current or short-circuit condition is

encountered while using the circuit of Figure 8

with the EC2630, leave the power on for at least

2 seconds before turning it off, and wait an

additional 2 seconds before re-applying power.

Please note when using the circuit of Figure 8,

the EC2630 ENABLE pin is not tied to VIN any

more. This pin needs be toggled by the circuit for

proper OCP operation.

05996 10/04/2011 Rev: A

EC2630QI

Figure 8: Optional External Ov er-Current Protection Circuit

05996 10/04/2011 Rev: A

EC2630QI

Mechanical Information

Figure 9: EC2630 Package Dimensions

Figure 10: Recommended PCB footprint.

05996 10/04/2011 Rev: A

EC2630QI

Contact Information

Enpirion, Inc.

Perryville III Corporate Park

53 Frontage Road, Suite 210

Hampton, NJ 08827

USA

Phone: +1-908-894-6000

Fax: +1-908-894-6090

www.enpirion.com

Enpirion reserves the right to make changes in circuit design and/or specifications at any time without notice. Information

furnished by Enpirion is believed to be accurate and reliable. Enpirion assumes no responsibility for its use or for

infringement of patents or other third party rights, which may result from its use. Enpirion products are not authorized for

use in nuclear control systems, as critical components in life support systems or equipment used in hazardous

environment without the express written authority from Enpirion.