MAX1545 Datasheet_PDF文件下载_芯片资料查询

Dual-Phase, Quick-PWM Controllers for

Programmable CPU Core Power Supplies

If the calculated V

IN(MIN)

is greater than the required

minimum input voltage, then reduce the operating fre-

quency or add output capacitance to obtain an accept-

able V

SAG

. If operation near dropout is anticipated,

calculate V

SAG

to be sure of adequate transient

response.

Dropout design example:

V

FB

= 1.4V

K

MIN

= 3碌s for f

SW

= 300kHz

t

OFF(MIN)

= 400ns

V

VPS

= 3mV/A

脳

30A = 90mV

V

DROP1

= V

DROP2

= 150mV (30A load)

h = 1.5 and

畏

OUTPH

= 2

铮?/div>

1.4 V

鈭?/div>

90mV

+

150mV

铮?/div>

V

IN(MIN)

=

2 x

铮?/div>

1

鈭?/div>

2 x (0.4

碌

s x 1.5 / 3.0

碌

s

铮?/div>

+

150mV

鈭?/div>

150mV

+

90mV

=

4.96V

Calculating again with h = 1 gives the absolute limit of

dropout:

铮?/div>

1.4 V

鈭?/div>

90mV

+

150mV

铮?/div>

V

IN(MIN)

=

2 x

铮?/div>

1

鈭?/div>

2 x (0.4

碌

s x 1.0 / 3.0

碌

s

铮?/div>

+

150mV

鈭?/div>

150mV

+

90mV

=

4.07V

Therefore, V

IN

must be greater than 4.1V, even with very

large output capacitance, and a practical input voltage

with reasonable output capacitance would be 5V.

5)

3)

Each slave controller should also have a separate

analog ground. Return the appropriate noise-sen-

sitive slave components to this plane. Since the

reference in the master is sometimes connected

to the slave, it may be necessary to couple the

analog ground in the master to the analog ground

in the slave to prevent ground offsets. A low-value

(鈮?0鈩? resistor is sufficient to link the two grounds.

Keep the power traces and load connections short.

This is essential for high efficiency. The use of thick

copper PC boards (2oz vs. 1oz) can enhance full-

load efficiency by 1% or more. Correctly routing PC

board traces is a difficult task that must be

approached in terms of fractions of centimeters,

where a single m鈩?of excess trace resistance caus-

es a measurable efficiency penalty.

Keep the high-current, gate-driver traces (DL, DH,

LX, and BST) short and wide to minimize trace

resistance and inductance. This is essential for

high-power MOSFETs that require low-impedance

gate drivers to avoid shoot-through currents.

C_P, C_N, OAIN+, and OAIN- connections for cur-

rent limiting and voltage positioning must be made

using Kelvin-sense connections to guarantee the

current-sense accuracy.

When trade-offs in trace lengths must be made, it

is preferable to allow the inductor-charging path to

be made longer than the discharge path. For

example, it is better to allow some extra distance

between the input capacitors and the high-side

MOSFET than to allow distance between the

inductor and the low-side MOSFET or between the

inductor and the output filter capacitor.

Route high-speed switching nodes away from

sensitive analog areas (REF, CCV, CCI, FB, C_P,

C_N, etc). Make all pin-strap control input connec-

tions (SHDN, ILIM,

SKIP,

SUS, S_, TON) to analog

ground or V

CC

rather than power ground or V

DD

.

MAX1519/MAX1545

4)

6)

7)

Applications Information

PC Board Layout Guidelines

Careful PC board layout is critical to achieve low

switching losses and clean, stable operation. The

switching power stage requires particular attention

(Figure 11). If possible, mount all of the power compo-

nents on the topside of the board with their ground ter-

minals flush against one another. Follow these

guidelines for good PC board layout:

1) Keep the high-current paths short, especially at

the ground terminals. This is essential for stable,

jitter-free operation.

2) Connect all analog grounds to a separate solid

copper plane, which connects to the GND pin of

the Quick-PWM controller. This includes the V

CC

bypass capacitor, REF and GNDS bypass capaci-

tors, compensation (CC_) components, and the

resistive dividers connected to ILIM and OFS.

8)

Layout Procedure

Place the power components first, with ground termi-

nals adjacent (low-side MOSFET source, C

IN

, C

OUT

,

and D1 anode). If possible, make all these connections

on the top layer with wide, copper-filled areas:

1) Mount the controller IC adjacent to the low-side

MOSFET. The DL gate traces must be short and

wide (50 mils to 100 mils wide if the MOSFET is

1in from the controller IC).

______________________________________________________________________________________

37

prev next

MAX1545相关型号PDF文件下载

型号

版本

描述

厂商

下载
MAX100

英文版

250Msps, 8-Bit ADC with Track/Hold

MAX100
MAX100

英文版

250Msps, 8-Bit ADC with Track/Hold

MAXIM [Max...

MAX100
MAX101

英文版

500Msps, 8-Bit ADC with Track/Hold

MAX101
MAX101

英文版

500Msps, 8-Bit ADC with Track/Hold

MAXIM [Max...

MAX101
MAX101

英文版

500Msps, 8-Bit ADC with Track/Hold

MAXIM [Max...

MAX101
MAX104

英文版

【5V, 1Gsps, 8-Bit ADC with On-Chip 2.2GHz Track/Hold Amplif...

MAX104
MAX104

英文版

【5V, 1Gsps, 8-Bit ADC with On-Chip 2.2GHz Track/Hold Amplif...

MAXIM [Max...

MAX104
MAX105

英文版

Dual, 6-Bit, 800Msps ADC with On-Chip, Wideband Input Amplif...

MAX105
MAX105

英文版

Dual, 6-Bit, 800Msps ADC with On-Chip, Wideband Input Amplif...

MAXIM [Max...

MAX105
MAX106

英文版

【5V, 600Msps, 8-Bit ADC with On-Chip 2.2GHz Bandwidth Track...

MAX106
MAX106

英文版

【5V, 600Msps, 8-Bit ADC with On-Chip 2.2GHz Bandwidth Track...

MAXIM [Max...

MAX106
MAX107

英文版

Dual, 6-Bit, 400Msps ADC with On-Chip, Wideband Input Amplif...

MAX107
MAX107

英文版

Dual, 6-Bit, 400Msps ADC with On-Chip, Wideband Input Amplif...

MAXIM [Max...

MAX107
MAX108

英文版

【5V, 1.5Gsps, 8-Bit ADC with On-Chip 2.2GHz Track/Hold Ampl...

MAX108
MAX108

英文版

【5V, 1.5Gsps, 8-Bit ADC with On-Chip 2.2GHz Track/Hold Ampl...

MAXIM [Max...

MAX108
MAX109

英文版

8-Bit, 2.2Gsps ADC with Track/Hold Amplifier and 1:4 Demulti...

MAX109
MAX110

英文版

Low-Cost, 2-Channel, 【14-Bit Serial ADCs

MAX110
MAX110

英文版

Low-Cost, 2-Channel, 【14-Bit Serial ADCs

MAXIM [Max...

MAX110
MAX111

英文版

Low-Cost, 2-Channel, 【14-Bit Serial ADCs

MAX111
MAX111

英文版

Low-Cost, 2-Channel, 【14-Bit Serial ADCs

MAXIM [Max...

MAX111

MAX1545 Datasheet

PDF预览

MAX1545相关型号PDF文件下载

您可能感兴趣的PDF文件资料

热门IC型号推荐

MAX1545 Datasheet

PDF预览

MAX1545相关型号PDF文件下载

您可能感兴趣的PDF文件资料

热门IC型号推荐

建议反馈

PDF纠错X