MAX1972EEE+ Maxim Integrated Products, MAX1972EEE+ Datasheet

IC REG STP DWN 750MA 16-QSOP

MAX1972EEE+

Manufacturer Part Number
MAX1972EEE+
Description
IC REG STP DWN 750MA 16-QSOP
Manufacturer
Maxim Integrated Products
Type
Step-Down (Buck)r
Datasheet

Specifications of MAX1972EEE+

Internal Switch(s)
Yes
Synchronous Rectifier
Yes
Number Of Outputs
2
Voltage - Output
1.5V, 1.8V, 2.5V, 3.3V, Adj
Current - Output
750mA
Frequency - Switching
1.4MHz
Voltage - Input
2.6 ~ 5.5 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
16-QSOP
Power - Output
667mW
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
The MAX1970/MAX1971/MAX1972 dual-output current-
mode PWM buck regulators operate from 2.6V to 5.5V
input and deliver a minimum of 750mA on each output.
The MAX1970 and MAX1972 operate at a fixed 1.4MHz
(MAX1971 operates at 700kHz) to reduce output induc-
tor and capacitor size and cost. Switching the regula-
tors 180° out-of-phase also reduces the input capacitor
size and cost. Ceramic capacitors can be used for
input and output.
The output voltages are programmable from 1.2V to V
using external feedback resistors, or can be preset to
1.8V or 3.3V for output 1 and 1.5V or 2.5V for output 2.
When one output is higher than 1.2V, the second can
be configured down to sub-1V levels. Output accuracy
is better than ±1% over variations in load, line, and tem-
perature. Internal soft-start reduces inrush current dur-
ing startup.
All devices feature power-on reset (POR). The
MAX1971 includes a reset input (RSI), which forces
POR low for 175ms after RSI goes low. The MAX1970
and MAX1972 include an open-drain power-fail output
(PFO) that monitors input voltage and goes high when
the input falls below 3.94V. For USB-powered xDSL
modems, this output can be used to detect USB power
failure. A minimum switching frequency of 1.2MHz
ensures operation outside the xDSL band.
19-2297; Rev 1; 2/09
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
xDSL Modems
xDSL Routers
Copper Gigabit SFP
and GBIC Modules
Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step-
V
RSI
EN
IN
2.6V TO 5.5V
V
CC
Typical Operating Circuit
________________________________________________________________ Maxim Integrated Products
RSI
EN
COMP1
COMP2
FBSEL1
FBSEL2
Down Regulator with POR and RSI/PFO
REF
IN
General Description
MAX1971
USB-Powered Devices
Dual LDO Replacement
PGND
V
CC
POR
LX1
FB1
LX2
FB2
Applications
OUT1
1.8V
750mA
OUT2
2.5V
750mA
POR
IN
o Current-Mode, 1.4MHz Fixed-Frequency PWM
o 180° Out-of-Phase Operation Reduces Input
o ±1% Output Accuracy Over Load, Line, and
o 750mA Guaranteed Output Current
o 2.6V to 5.5V Input
o Power-On Reset Delay of 16.6ms (MAX1970) or
o Power-Fail Output (MAX1970 and MAX1972 Only)
o Power-On Reset Input (MAX1971 Only)
o Operation Outside xDSL Band
o Ultra-Compact Design with Smallest External
o Outputs Adjustable from 0.8V to V
o All-Ceramic Capacitor Application
o Soft-Start Reduces Inrush Current
MAX1970EEE
MAX1971EEE
MAX1972EEE
Operation
Capacitor
Temperature Ranges
175ms (MAX1971 and MAX1972)
Components
and 1.5V/2.5V Preset
TOP VIEW
PART
COMP1
COMP2
GND
LX1
V
FB1
FB2
REF
CC
1
2
3
4
5
6
7
8
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
Ordering Information
MAX1970
MAX1971
MAX1972
QSOP
Pin Configuration
16
15
14
13
12
11
10
9
PGND
LX2
IN
FBSEL1
FBSEL2
PF0 (MAX1970/MAX1972)
RSI (MAX1971)
EN
POR
IN
PIN-PACKAGE
16 QSOP
16 QSOP
16 QSOP
or 1.8V/3.3V
Features
1

Related parts for MAX1972EEE+

MAX1972EEE+ Summary of contents

Page 1

... FB2 FBSEL1 V CC FBSEL2 PGND REF ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. o Current-Mode, 1.4MHz Fixed-Frequency PWM Operation o 180° Out-of-Phase Operation Reduces Input Capacitor o ±1% Output Accuracy Over Load, Line, and ...

Page 2

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO ABSOLUTE MAXIMUM RATINGS IN, EN, FBSEL1, FBSEL2, PFO, POR, RSI GND ...................................................-0.3V to +6V CC COMP1, COMP2, FB1, FB2, REF to GND .............................................-0. LX1, ...

Page 3

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO ELECTRICAL CHARACTERISTICS (continued 5V 100kΩ to IN, R POR unconnected 0°C to +85°C, unless otherwise ...

Page 4

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO ELECTRICAL CHARACTERISTICS (continued 5V 100kΩ to IN, R POR unconnected 0°C to +85°C, unless otherwise ...

Page 5

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO ELECTRICAL CHARACTERISTICS (continued 5V 1.15V FB1 FB2 FBSEL1 = unconnected, FBSEL2 = unconnected, T ...

Page 6

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO ELECTRICAL CHARACTERISTICS (continued 5V 1.15V FB1 FB2 FBSEL1 = unconnected, FBSEL2 = unconnected, T ...

Page 7

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO (T = +25°C, unless otherwise noted.) A EFFICIENCY vs. LOAD CURRENT 100 V = 2.5V 90 OUT2 3.3V OUT1 1.8V 50 ...

Page 8

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO (T = +25°C, unless otherwise noted.) A LOAD-TRANSIENT RESPONSE V OUT1 I OUT1 40µs/div 3.3V, 100mV/div OUT1 I = 300mA TO 600mA ...

Page 9

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO (T = +25°C, unless otherwise noted.) A RSI AND POR TIMING 40ms/div 1.8V 2.5V OUT1 OUT2 I = 500mA, I ...

Page 10

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO (T = +25°C, unless otherwise noted.) A NAME PIN MAX1970/MAX1972 MAX1971 1 LX1 LX1 COMP1 COMP1 4 FB1 FB1 5 FB2 FB2 ...

Page 11

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO NAME PIN MAX1970/MAX1972 MAX1971 POR POR PFO — 11 — RSI 12 FBSEL2 FBSEL2 13 FBSEL1 FBSEL1 LX2 LX2 16 ...

Page 12

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO FB1 FB SELECT FBSEL1 COMP1 REF SOFT-START THERMAL SHUTDOWN EN VOK COMP2 FB2 FBSEL2 GND Figure 1. Functional Diagram turns off and the internal low-side ...

Page 13

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO the PWM comparator’s inverting input. The PWM com- parator turns off the internal high-side MOSFET when this sum exceeds the integrated feedback voltage. The internal MOSFET has a ...

Page 14

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO V OUT POR RSI 4.04V V IN PFO Figure 2. Timing Diagram Design Procedure Output Voltage Selection Both output voltages can be selected in three different ways as ...

Page 15

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO V 3.3V TO 5.5V PFO Figure 3. Typical Application Circuit 1 V 3.3V TO 5.5V PFO Figure 4. Typical Application Circuit 2 ______________________________________________________________________________________ IN 10Ω 10µF ...

Page 16

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO V IN 2.6V TO 5.5V RSI EN Figure 5. Setting the Output Voltage with External Resistors 3.6V RSI EN Figure 6. Setting an Output ...

Page 17

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO Table 1. Output Voltage Settings FBSEL1 OUTPUT 1 FBSEL2 V 3. GND 1.8V GND Open Ext Divider Open For most designs, a reasonable inductor value ...

Page 18

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO troller can respond, the output deviates further, depending on the inductor and output capacitor values. After a short time (see the Typical Operating Characteristics ), the controller responds ...

Page 19

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO As the load current decreases, the modulator pole also decreases; however, the modulator gain increases accordingly, and the closed-loop unity-gain frequency remains the same. Below is a numerical ...

Page 20

Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step- Down Regulator with POR and RSI/PFO Chip Information TRANSISTOR COUNT: 5428 PROCESS: BiCMOS 20 ______________________________________________________________________________________ Package Information For the latest package outline information and land patterns www.maxim-ic.com/packages. PACKAGE TYPE PACKAGE CODE 16 ...

Page 21

... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 21 © 2009 Maxim Integrated Products DESCRIPTION Maxim is a registered trademark of Maxim Integrated Products, Inc ...

Related keywords