Maxim MAX1714BEEE, MAX1714AEEP Datasheet

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General Description

The MAX1714 pulse-width modulation (PWM) controller
provides the high efficiency, excellent transient
response, and high DC output accuracy needed for
stepping down high-voltage batteries to generate low­voltage CPU core or chip-set/RAM supplies in notebook
computers.

Maxim’s proprietary Quick-PWM™ quick-response,
constant-on-time PWM control scheme handles wide
input/output voltage ratios with ease and provides
100ns “instant-on” response to load transients while
maintaining a relatively constant switching frequency.

The MAX1714 achieves high efficiency at a reduced
cost by eliminating the current-sense resistor found in
traditional current-mode PWMs. Efficiency is further
enhanced by an ability to drive very large synchronous­rectifier MOSFETs.

Single-stage buck conversion allows these devices to
directly step down high-voltage batteries for the highest
possible efficiency. Alternatively, two-stage conversion
(stepping down the +5V system supply instead of the
battery) at a higher switching frequency allows the mini­mum possible physical size.

The MAX1714 is intended for CPU core, chipset,
DRAM, or other low-voltage supplies as low as 1V. The
MAX1714A is available in a 20-pin QSOP package and
includes overvoltage protection. The MAX1714B is
available in a 16-pin QSOP package with no overvolt­age protection. For applications requiring VID compli­ance or DAC control of output voltage, refer to the
MAX1710/MAX1711 data sheet. For a dual output ver­sion, refer to the MAX1715†data sheet.

Applications

Notebook Computers

CPU Core Supply

Chipset/RAM Supply as Low as 1V

1.8V and 2.5V I/O Supply

Features

♦ Ultra-High Efficiency

♦ No Current-Sense Resistor (Lossless I

LIMIT

)

♦ Quick-PWM with 100ns Load-Step Response

♦ 1% V

OUT

Accuracy Over Line and Load

♦ 2.5V/3.3V Fixed or 1V to 5.5V Adjustable Output

Range

♦ 2V to 28V Battery Input Range

♦ 200/300/450/600kHz Switching Frequency

♦ Overvoltage Protection (MAX1714A)

♦ Undervoltage Protection

♦ 1.7ms Digital Soft-Start

♦ Drives Large Synchronous-Rectifier FETs

♦ 2V ±1% Reference Output

♦ Power-Good Indicator

MAX1714

High-Speed Step-Down Controller

for Notebook Computers

________________________________________________________________ Maxim Integrated Products 1

19-1536; Rev 1; 12/99

Pin Configurations appear at end of data sheet.

Quick-PWM is a trademark of Maxim Integrated Products.

†

Future product—contact factory for availability.

-40°C to +85°C

PART

MAX1714AEEP

TEMP. RANGE PIN-PACKAGE

20 QSOP

Ordering Information

EVALUATION KIT MANUALS

FOLLOW DATA SHEET

V

CC

+5V INPUT

BATTERY

4.5V TO 28V

OUTPUT

1.25V TO 2V

SHDN

ILIM

DL

LX

V+

BST

DH

PGND
(GND)

OUT

SKIP

V

DD

MAX1714

REF

PGOOD

FB

AGND
(GND)

( ) ARE FOR THE MAX1714B ONLY.

Minimal Operating Circuit

MAX1714BEEE -40°C to +85°C 16 QSOP

MAX1714

High-Speed Step-Down Controller
for Notebook Computers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

V+ to AGND (Note 1)..............................................-0.3V to +30V

V

DD

, VCCto AGND (Note 1).....................................-0.3V to +6V

PGND to AGND (Note 1) ................................................... ±0.3V

SHDN, PGOOD, OUT to AGND (Note 1)..................-0.3V to +6V

ILIM, FB, REF, SKIP,

TON to AGND (Notes 1, 2)....................-0.3V to (V

CC

+ 0.3V)

DL to PGND (Note 1)..................................-0.3V to (V

DD

+ 0.3V)

BST to AGND (Note 1) ...........................................-0.3V to +36V

DH to LX.....................................................-0.3V to (BST + 0.3V)

LX to BST..................................................................-6V to +0.3V

REF Short Circuit to AGND.........................................Continuous

Continuous Power Dissipation (T

A

= +70°C)

16-Pin QSOP (derate 8.3mW/°C above +70°C)..........667mW

20-Pin QSOP (derate 9.1mW/°C above +70°C)..........727mW

Operating Temperature Range ..........................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range ............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

V+ = 4.5V to 28V,
SKIP = V

CC

V

SHDN

= 0 , V+ = 28V, VCC= VDD= 0 or 5V

V

SHDN

= 0

V

CC,VDD

V

SHDN

= 0

Battery voltage, V+

FB forced above the regulation point

FB forced above the regulation point

Rising edge of SHDN to full I

LIM

(Note 4)

V+ = 24V,
V

OUT

= 2V

(Note 4)

I

LOAD

= 0 to 3A, SKIP = V

CC

VCC= 4.5V to 5.5V, V+ = 4.5V to 28V

CONDITIONS

µA<1 5Shutdown Supply Current (V+)

µA<1 5Shutdown Supply Current (VDD)

µA<1 5Shutdown Supply Current (VCC)

µA25 40Quiescent Supply Current (V+)

µA<1 5Quiescent Supply Current (VDD)

µA550 750Quiescent Supply Current (VCC)

ns400 500Minimum Off-Time

380 425 470

260 290 320

175 200 225

V

0.99 1.0 1.01

Error Comparator Threshold
(DC Output Voltage Accuracy)
(Note 3)

TON = REF (450kHz)

4.5 5.5

V

228

Input Voltage Range

TON = AGND (600kHz)

ns

140 160 180

On-Time

ms1.7Soft-Start Ramp Time

µA-0.1 0.1FB Input Bias Current

TON = unconnected (300kHz)

mV9Load Regulation Error

mV5Line Regulation Error

UNITSMIN TYP MAXPARAMETER

Falling edge, hysteresis = 40mV

REF in regulation

I

REF

= 0 to 50µA

VCC= 4.5V to 5.5V, no external REF load

V1.6REF Fault Lockout Voltage

µA10REF Sink Current

V0.01Reference Load Regulation

V1.98 2 2.02Reference Voltage

TON = VCC(200kHz)

Note 1: For the MAX1714B, AGND and PGND refer to a single pin designated GND.
Note 2: SKIP may be forced below -0.3V, temporarily exceeding the absolute maximum rating, disabling over/undervoltage fault

detection for the purpose of debugging prototypes (Figure 6). Limit the current drawn to 5mA maximum.

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 1, 4A components from Table 1, V+ = +15V, VCC= VDD= +5V, SKIP = AGND, TA= 0°C to +85°C, unless otherwise
noted.) (Note 1)

FB = AGND kΩ100 190 300OUT Input Resistance

FB = OUT

2.475 2.5 2.525FB = AGND

FB = V

CC

3.267 3.3 3.333

MAX1714

High-Speed Step-Down Controller

for Notebook Computers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 1, 4A components from Table 1, V+ = +15V, VCC= VDD= +5V, SKIP = AGND, TA= 0°C to +85°C, unless otherwise
noted.) (Note 1)

CONDITIONS UNITSMIN TYP MAXPARAMETER

PGND - LX

PGND - LX, I

LIM

= V

CC

From SHDN signal going high

mV

40 50 60

Current-Limit Threshold
(Positive Direction, Adjustable)

mV90 100 110

Current-Limit Threshold
(Positive Direction, Fixed)

ms10 30

Output Undervoltage Protection
Blanking Time

%65 70 75

Output Undervoltage Protection
Threshold

PGND - LX, SKIP = VCC, TA= +25°C,
with respect to positive current-limit threshold

%-90 -120 -140

Current-Limit Threshold
(Negative Direction)

V

ILIM

= 0.5V

V

ILIM

= 2.0V 170 200 230

Rising edge, hysteresis = 20mV,
PWM disabled below this level

V4.1 4.4

VCCUndervoltage Lockout
Threshold

BST - LX forced to 5V Ω1.5 5DH Gate-Driver On-Resistance

DL, high state Ω1.5 5

DL Gate-Driver On-Resistance
(Pull-Up)

DL, low state Ω0.5 1.7

DL Gate-Driver On-Resistance
(Pull-Down)

DH forced to 2.5V, BST - LX forced to 5V A1

DH Gate-Driver Source/Sink
Current

DL forced to 2.5V A1DL Gate-Driver Source Current

DL forced to 2.5V A3DL Gate-Driver Sink Current

FB forced 2% above trip threshold (MAX1714A only) µs1.5

Overvoltage Fault Propagation
Delay

%10.5 12.5 14.5Overvoltage Trip Threshold

FB forced 2% below PGOOD trip threshold, falling edge µs1.5PGOOD Propagation Delay

PGND - LX, SKIP = AGND

mV3

Current-Limit Threshold
(Zero Crossing)

I

SINK

= 1mA V0.4PGOOD Output Low Voltage

High state, forced to 5.5V µA1PGOOD Leakage Current

Hysteresis = 10°C °C150Thermal Shutdown Threshold

With respect to error comparator threshold (MAX1714A only)

With respect to error comparator threshold

DL rising

ns

35

Dead Time

DH rising 26

mA

SKIP Input Current Logic
Threshold

To disable overvoltage and undervoltage fault detection,
T

A

= +25°C

-1.5 -0.1

%PGOOD Trip Threshold

Measured at FB with respect to error comparator
threshold, falling edge

-8 -6 -4

VLogic Input High Voltage

SHDN, SKIP

2.4

VLogic Input Low Voltage

SHDN, SKIP

0.8

µALogic Input Current

SHDN, SKIP

-1 1

nAILIM Input Current

SHDN, SKIP

±

10

MAX1714

High-Speed Step-Down Controller
for Notebook Computers

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 1, 4A components from Table 1, V+ = 15V, V

CC

= VDD= +5V, SKIP = AGND, TA= -40°C to +85°C, unless other-

wise noted.) (Notes 1, 5)

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 1, 4A components from Table 1, V+ = +15V, VCC= VDD= +5V, SKIP = AGND, TA= 0°C to +85°C, unless otherwise
noted.) (Note 1)

CONDITIONS

VVCC- 0.4TON VCCLevel

V3.15 3.85TON Float Voltage

V1.65 2.35TON Reference Level

V0.5TON AGND Level

Forced to AGND or V

CC

µA-3 3TON Input Current

UNITSMIN TYP MAXPARAMETER

TON = VCC(200kHz)

Reference Voltage 1.98 2.02 VVCC= 4.5V to 5.5V, no external REF load

PARAMETER MIN TYP MAX UNITS

TON = unconnected (300kHz)

On-Time

140 180

ns

TON = AGND (600kHz)

Input Voltage Range

228

V

4.5 5.5

TON = REF (450kHz)

Error Comparator Threshold
(DC Output Voltage Accuracy)
(Note 3)

0.985 1.015

V

175 225

With respect to error comparator threshold
(MAX1714A only)

260 320

380 470

Minimum Off-Time

FB = AGND

500 ns

Quiescent Supply Current (VCC)

FB = OUT

750 µA

3.25 3.35

2.462 2.538

Logic Input Current -1 1 µA

SHDN, SKIP

Logic Input Low Voltage 0.8 V

SHDN, SKIP

Logic Input High Voltage

FB = V

DD

V

2.4 V

SHDN, SKIP

VCCUndervoltage Lockout
Threshold

4.1 4.4

Rising edge, hysteresis = 20mV, PWM disabled below
this level

Output Undervoltage
Protection Threshold

65 75

CONDITIONS

%

160 240

With respect to error comparator threshold

V

ILIM

= 2.0V

V

ILIM

= 0.5V

Current-Limit Threshold
(Positive Direction, Adjustable)

35 65

V+ = 24V,
V

OUT

= 2V

(Note 4)

(Note 4)

mV

Overvoltage Trip Threshold

FB forced above the regulation point

PGND - LX

Current-Limit Threshold (Positive
Direction, Fixed)

Battery voltage, V+

85 115

V

CC,VDD

mVPGND - LX, ILIM = V

CC

V+ = 4.5V to 28V,
SKIP = V

CC

10 15 %

MAX1714

High-Speed Step-Down Controller

for Notebook Computers

_______________________________________________________________________________________ 5

Note 1: For the MAX1714B, AGND and PGND refer to a single pin designated GND.
Note 2: SKIP may be forced below -0.3V, temporarily exceeding the absolute maximum rating, disabling over/undervoltage fault

detection for the purpose of debugging prototypes (Figure 6). Limit the current drawn to 5mA maximum.

Note 3: When the inductor is in continuous conduction, the output voltage will have a DC regulation level higher than the error-

comparator threshold by 50% of the ripple. In discontinuous conduction (SKIP = AGND, light-loaded), the output voltage
will have a DC regulation level higher than the trip level by approximately 1.5% due to slope compensation.

Note 4: On-time and off-time specifications are measured from 50% point to 50% point at the DH pin with LX = PGND, V

BST

= 5V,

and a 250pF capacitor connected from DH to LX. Actual in-circuit times may differ due to MOSFET switching speeds.

Note 5: Specifications to -40°C are guaranteed by design, not production tested.

__________________________________________Typical Operating Characteristics

(Circuit of Figure 1, components from Table 1, VIN= +15V, SKIP = AGND, TON = unconnected, TA= +25°C, unless otherwise noted.)

CONDITIONS

Measured at FB with respect to error comparator
threshold, falling edge

%-8 -4PGOOD Trip Threshold

I

SINK

= 1mA V0.4PGOOD Output Low Voltage

High state, forced to 5.5V µA1PGOOD Leakage Current

UNITMIN TYP MAXPARAMETER

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 1, 4A components from Table 1, V+ = +15V, V

CC

= VDD= +5V, SKIP = AGND, TA= -40°C to +85°C, unless other-

wise noted.) (Notes 1, 5)

EFFICIENCY vs. LOAD CURRENT

(4A COMPONENTS, V

100

VIN = 7V

90

= 2.5V, 300kHz)

OUT

MAX1714B-01

EFFICIENCY vs. LOAD CURRENT

(8A COMPONENTS, V

100

90

= 1.6V, 300kHz)

OUT

VIN = 7V

MAX1714B-02

EFFICIENCY vs. LOAD CURRENT

(1.5A COMPONENTS, V

TON = GND, 600kHz)

100

VIN = 5V

90

OUT

= 2.5V,

MAX1714B-03

80

EFFICIENCY (%)

70

60

0.01 1010.1

VIN = 12V

LOAD CURRENT (A)

VIN = 20V

80

EFFICIENCY (%)

70

60

0.01 1010.1

VIN = 12V

LOAD CURRENT (A)

VIN = 20V

80

EFFICIENCY (%)

70

60

0.01 1010.1
LOAD CURRENT (A)

MAX1714

High-Speed Step-Down Controller
for Notebook Computers

6 _______________________________________________________________________________________

_____________________________Typical Operating Characteristics (continued)

(Circuit of Figure 1, components from Table 1, VIN= +15V, SKIP = AGND, TON = unconnected, TA= +25°C, unless otherwise noted.)

0

2

1

3

4

5

6

7

8

9

0105 15202530

INDUCTOR CURRENT PEAKS AND VALLEYS

vs. INPUT VOLTAGE (4A COMPONENTS,

AT CURRENT-LIMIT TRIP POINT)

MAX1714B-09

INPUT VOLTAGE (V)

INDUCTOR CURRENT (A)

I

PEAK

I

VALLEY

0

200

400

600

800

0 10203051525

NO-LOAD SUPPLY CURRENT

(4A COMPONENTS, SKIP MODE, 300kHz)

MAX1714B-10

INPUT VOLTAGE (V)

SUPPLY CURRENT (µA)

I

CC

I

IN

I

DD

10

8

0

0 5 20 30

NO-LOAD SUPPLY CURRENT vs.

INPUT VOLTAGE

(4A COMPONENTS, PWM MODE, 300kHz)

4

6

2

MAX1714B-11

INPUT VOLTAGE (V)

SUPPLY CURRENT (mA)

10 15 25

I

CC

I

DD

I

IN

0

200

100

400

300

500

600

4.0 5.04.5 5.5 6.0

NO-LOAD SUPPLY CURRENT vs. INPUT

VOLTAGE (1.5A COMPONENTS,

SKIP MODE, V

OUT

= 2.5V, 600kHz)

MAX1714B-12

VCC, VDD, VIN INPUT VOLTAGE (V)

SUPPLY CURRENT (µA)

I

CC

I

DD

I

IN

0

12

10

2

4

8

6

I

OUT

AT CURRENT LIMIT vs.

TEMPERATURE

(4A COMPONENTS, V

OUT =

2.5V)

MAX1714B-07

TEMPERATURE (°C)

OUTPUT CURRENT (A)

-40

20 40-20 0 60 80

V

ILIM

= 1V

V

ILIM

= 0.5V

0

200

100

300

400

500

600

700

0105 15202530

CONTINUOUS TO DISCONTINUOUS INDUCTOR

CURRENT POINT vs. INPUT VOLTAGE

(4A COMPONENTS, V

OUT

= 2.5V)

MAX1714B-08

INPUT VOLTAGE (V)

LOAD CURRENT (mA)

300

0

0.01 1010.1

FREQUENCY vs. LOAD CURRENT
(4A COMPONENTS, V

OUT

= 2.5V)

100

50

250

200

350

150

MAX1714B-04

LOAD CURRENT (A)

FREQUENCY (kHz)

VIN = 7V, 15V, PWM MODE

VIN = 15V
SKIP MODE

VIN = 7V
SKIP MODE

280

290

300

310

320

FREQUENCY vs. INPUT VOLTAGE

(4A COMPONENTS, V

OUT

= 2.5V, I

OUT

= 1A)

MAX1714B-05

INPUT VOLTAGE (V)

FREQUENCY (kHz)

0

10 15520

3025

TEMPERATURE (°C)

FREQUENCY (kHz)

300

310

305

320

315

330

325

FREQUENCY vs. TEMPERATURE

(4A COMPONENTS, V

OUT

= 2.5V)

MAX1714B-06

-40

20 40-20 0 60 80

I

OUT

= 4A

I

OUT

= 1A

C

B

A

A = V

OUT

, AC-COUPLED, 100mV/div
B = INDUCTOR CURRENT, 2A/div
C = DL, 10V/div

10µs/div

LOAD-TRANSIENT RESPONSE

(4A COMPONENTS, V

OUT

= 2.5V, 300kHz)

MAX1714B-13

C

B

A

A = V

OUT

, AC-COUPLED, 100mV/div
B = INDUCTOR CURRENT, 5A/div
C = DL, 5V/div

10µs/div

LOAD-TRANSIENT RESPONSE

(8A COMPONENTS, V

OUT

= 1.6V, 300kHz)

MAX1714B-14

MAX1714

High-Speed Step-Down Controller

for Notebook Computers

_______________________________________________________________________________________ 7

_____________________________Typical Operating Characteristics (continued)

(Circuit of Figure 1, components from Table 1, VIN= +15V, SKIP = AGND, TON = unconnected, TA= +25°C, unless otherwise noted.)

C

B

A

A = V

OUT

, 1V/div
B = INDUCTOR CURRENT, 5A/div
C = DL, 5V/div

500µs/div

START-UP WAVEFORM

(4A COMPONENTS, I

OUT

= 4A, ACTIVE LOAD,

V

OUT

= 2.5V, 300kHz)

MAX1714B-16

C

B

A

A = V

OUT

, 1V/div
B = INDUCTOR CURRENT, 5A/div
C = DL, 5V/div

200µs/div

OUTPUT OVERLOAD WAVEFORM

(4A COMPONENTS, V

OUT

= 2.5V, 300kHz)

MAX1714B-17

OUTPUT
UNDERVOLTAGE
PROTECTION
THRESHOLD

C

B

A

A = V

OUT

, 1V/div
B = INDUCTOR CURRENT, 5A/div
C = DL, 5V/div

50µs/div

SHUTDOWN WAVEFORM

(4A COMPONENTS, V

OUT

= 2.5V, 300kHz)

MAX1714B-18

C

B

A

A = V

OUT

, AC-COUPLED, 100mV/div
B = INDUCTOR CURRENT, 1A/div
C = DL, 5V/div

5µs/div

LOAD-TRANSIENT RESPONSE

(1.5A COMPONENTS, V

IN

= 5V,

V

OUT

= 2.5V, 600kHz)

MAX1714B-15

PIN

MAX1714

High-Speed Step-Down Controller
for Notebook Computers

8 _______________________________________________________________________________________

Pin Description

Analog and Power Ground. AGND and PGND connect together internally.GND–

No Connection. These pins are not connected to any internal circuitry. Connect N.C. pins
to the ground plane to enhance thermal conductivity.

N.C.

2, 9,

11

Power-Good Open-Drain Output. PGOOD is low when the output voltage is more than 6%
below the normal regulation point or during soft-start. PGOOD is high impedance when
the output is in regulation and the soft-start circuit has terminated.

PGOOD10

High-Side Gate Driver Output. Swings from LX to BST.DH1

Current-Limit Threshold Adjustment. Connect ILIM to VCCfor 100mV current-limit threshold.
For an adjustable threshold, connect an external voltage source to ILIM, or use a two-resis­tor divider from REF to AGND. The external adjustment range of 0.5V to 2.0V corresponds to
a current-limit threshold of 50mV to 200mV.

ILIM6

+2.0V Reference Voltage Output. Bypass to AGND with 0.22µF (minimum) capacitor. Can
supply 50µA for external loads.

REF7

Analog Ground.AGND8

Shutdown Control Input. Drive SHDN to AGND to force the MAX1714 into shutdown. Drive
or connect to V

CC

for normal operation. A rising edge on SHDN clears the fault latch.

SHDN

3

Feedback Input. Connect to AGND for a +2.5V fixed output or to VCCfor a +3.3V fixed
output, or connect FB to a resistor divider from OUT for an adjustable output.

FB4

PIN

Output Voltage Connection. Connect directly to the junction of the external and output fil­ter capacitors. OUT senses the output voltage to determine the on-time and also serves
as the feedback input in fixed-output modes.

OUT5

FUNCTIONNAME

Low-Side Gate-Driver Output. Swings from PGND to VDD. DL13

Supply Input for the DL Gate Drive. Connect to the system supply voltage, +4.5V to +5.5V.
Bypass to PGND with a 1µF (min) ceramic capacitor.

V

DD

14

Analog-Supply Input. Connect to the system supply voltage, +4.5V to +5.5V, with a series
20Ω resistor. Bypass to AGND with a 1µF (min) ceramic capacitor.

V

CC

15

On-Time Selection-Control Input. This is a four-level input used to determine DH on-time.
Connect to AGND, REF, or VCC, or leave TON unconnected to set the following switching
frequencies: AGND = 600kHz, REF = 450kHz, floating = 300kHz, and VCC= 200kHz.

TON16

Battery Voltage Sense Connection. Connect to input power source. V+ is used only to set
the PWM one-shot timing.

V+17

Pulse-Skipping Control Input. Connect to VCCfor low-noise forced-PWM mode. Connect
to AGND to enable pulse-skipping operation.

SKIP

18

Boost Flying-Capacitor Connection. Connect to an external capacitor and diode according
to the Standard Application Circuit (Figure 1). See MOSFET Gate Drivers (DH, DL) section.

BST19

External Inductor Connection. Connect LX to the switched side of the inductor. LX serves
as the lower supply rail for the DH high-side gate driver. LX is also the positive input to the
current-limit comparator.

LX20

8

–

7

1

5

6

–

2

3

4

9

10

11

12

13

14

15

16

Power Ground. Connect directly to the low-side MOSFET’s source. Serves as the negative
input of the current-limit comparator.

PGND12 –

MAX1714A MAX1714B