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General Description

The MAX8515A/MAX8515 shunt regulators simplify the

design of voltage regulation and overvoltage protection

(OVP) functions in high-accuracy isolated DC-to-DC con-

verters with output voltages as low as 0.6V. The devices

have supply voltage and feedback inputs separated from

the output shunt stage, and can operate directly from the

DC-to-DC converter output stage when the output voltage

is 1.8V to 18V. Alternately, the MAX8515A/MAX8515 input

stage can be biased from an unregulated 1.7V to 28V

supply, independent of DC-to-DC converter output volt-

age. The MAX8515A/MAX8515 shunts 20mA when the

output voltage is as low as 0.2V.

The MAX8515A features an initial output accuracy of

0.5% at +25°C and 1% from -40°C to +85°C and provides

the output voltage regulation function for isolated DC-to-

DC converters. The MAX8515 features initial output

accuracy of 1% at +25°C and 1.8% from -40°C to +85°C

and can provide an output OVP function for isolated DC-

to-DC converters. High open-loop bandwidth allows

design of high-bandwidth DC-to-DC converters.

Low-cost, low-dropout linear regulators can be designed

with the MAX8515A/MAX8515 and an external NPN tran-

sistor for cost-conscious applications that do not require

overcurrent, short-circuit, or overtemperature protection.

The MAX8515/MAX8515A are available in space-saving

5-pin SC70 and SOT23 packages and are specified over

the -40°C to +85°C extended temperature range. An eval-

uation kit is available to speed designs.

Applications

Isolated DC-to-DC Converters

Network, Telecom, and Cellular Base Station

Power Supplies

Low-Dropout Linear Regulators

Shunt Regulator

Adjustable Voltage Reference

Features

♦ MAX8515A

0.6V ±0.5% Initial Accuracy at +25°C

0.6V ±1% Accuracy from -40°C to +85°C

♦ MAX8515

0.6V ±1% Initial Accuracy at +25°C

0.6V ±1.8% Accuracy from -40°C to +85°C

♦ Sinks 20mA at 0.2V to 18V

♦ Input Voltage Range from 1.7V to 28V

♦ Directly Drives Optocouplers

♦ 0.2Ω Dynamic Output Impedance

♦ Space-Saving 5-Pin SC70 or SOT23 Packages

MAX8515A/MAX8515

Wide-Input 0.6V Shunt Regulators for

Isolated DC-to-DC Converters

________________________________________________________________ Maxim Integrated Products 1

19-2528; Rev 1; 2/03

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX8515AEXK-T -40°C to +85°C 5 SC70-5

MAX8515AEZK-T -40°C to +85°C 5 Thin SOT23-5

MAX8515EXK-T -40°C to +85°C 5 SC70-5

MAX8515EZK-T -40°C to +85°C 5 Thin SOT23-5

GND

INOUT

15FBPGND

MAX8515A

MAX8515

SC7O/THIN SOT23

TOP VIEW

Pin Configuration

MAX8515A

MAX8515

PRIMARY SIDE

PWM CONVERTER

INPUT SUPPLY

1.7V TO 28V

INPUT

1.7V TO 18V

ISOLATED DC-DC

CONVERTER

OUTPUT

(DOWN TO 0.6V)

OUT

FBGND

PGND

CONTROL

VOLTAGE

Typical Operating Circuit

EVALUATION KIT

AVAILABLE

Functional Diagram appears at end of data sheet.

Selector Guide appears at end of data sheet.

Summary of content (10 pages)

PAGE 1
9-2528; Rev 1; 2/03 KIT ATION EVALU E L B A AVAIL Wide-Input 0.6V Shunt Regulators for Isolated DC-to-DC Converters Features ♦ MAX8515A 0.6V ±0.5% Initial Accuracy at +25°C 0.6V ±1% Accuracy from -40°C to +85°C The MAX8515A features an initial output accuracy of 0.5% at +25°C and 1% from -40°C to +85°C and provides the output voltage regulation function for isolated DC-toDC converters. The MAX8515 features initial output accuracy of 1% at +25°C and 1.
PAGE 2
MAX8515A/MAX8515 Wide-Input 0.6V Shunt Regulators for Isolated DC-to-DC Converters ABSOLUTE MAXIMUM RATINGS IN to GND ...............................................................-0.3V to +30V OUT to GND ...........................................................-0.3V to +20V FB to GND .................-0.3V to the lower of 5.5V and (VIN +0.3V) PGND to GND .......................................................-0.3V to +0.3V Continuous Power Dissipation (TA =+70°C) 5-Pin SC70 (derate 3.
PAGE 3
Wide-Input 0.6V Shunt Regulators for Isolated DC-to-DC Converters 35 OUT-LEAKAGE CURRENT (nA) VIN = 10V -15 -20 VIN = 28V -25 -30 30 10 40 20 15 10 35 60 20 -45 10 5 -10 0 -20 85 0 30 -90 0 -135 FIGURE 2 -30 -40 -15 TEMPERATURE (°C) 10 35 60 0.1 85 1 MAX8515 toc04 40 30 10 MAX8515 toc05 VOUT: 2V/div -45 0 -90 1 10 C2 = OPEN -180 1000 -30 0.1 0.66V 0.
PAGE 4
Typical Operating Characteristics (continued) (VIN = 3.3V, IOUT = 5mA, FB = OUT, circuit in Figure 1, C1 = 0.1µF, C2 = 1µF, TA = +25°C, unless otherwise specified.) OUTPUT VOLTAGE CHANGE vs. INPUT VOLTAGE OUTPUT VOLTAGE CHANGE vs. LOAD CURRENT 0.4 OUTPUT VOLTAGE CHANGE (%) 0.5 0.3 0.2 0.1 0 -0.1 MAX8515 toc09 0.05 MAX8515 toc08 0.6 OUTPUT VOLTAGE CHANGE (%) MAX8515A/MAX8515 Wide-Input 0.6V Shunt Regulators for Isolated DC-to-DC Converters 0.04 0.03 0.02 0.01 0 -0.2 -0.3 -0.
PAGE 5
Wide-Input 0.6V Shunt Regulators for Isolated DC-to-DC Converters MAX8515A/MAX8515 5.6V VIN 1.8V R3 IN C1 0.1µF 1kΩ R1 C2 1.0µF PGND FB R2 IN VIN (V) R3 (Ω) 135 3.3 470 10 1.33k 28 TEST 2.2nF VOUT = 0.6V TEST CIRCUIT R1 = SHORT R2 = OPEN OUT MAX8515A MAX8515 GND 3.3V VOUT 0.6V/20mA 1MΩ OUT 0.82µF 0.1µF MAX8515A MAX8515 50kΩ PGND GND NETWORK ANALYZER SOURCE FB 2.2nF REFERENCE 1MΩ Figure 1.
PAGE 6
MAX8515A/MAX8515 Wide-Input 0.6V Shunt Regulators for Isolated DC-to-DC Converters Overvoltage Protection VREG 1.8V INPUT SUPPLY V+ MAX5003 NDRV PGND CON R1 47kΩ C1 0.1µF V  R3 =  OVP - 1 × R4  VFB  OUT IN MAX8515A MAX8515 PGND GND R3 20kΩ 1% C2 0.1µF Figure 4 shows an isolated OVP circuit. R1 limits the current supplied to the photodiode. R2 limits the MAX8515A/MAX8515 input current. R3 and R4 set the trip threshold for the OVP. C1 is the input supply decoupling capacitor.
PAGE 7
Wide-Input 0.6V Shunt Regulators for Isolated DC-to-DC Converters VREG 1V OUT IN 0.6V REFERENCE R1 MAX8515A MAX8515 VIN IN C1 0.1µF OUT C2 1.0µF MAX8515A MAX8515 GND FB R2 6.65kΩ PGND GND FB Selector Guide R3 10kΩ VIN (V) 2.5 3.3 5 R1 (Ω) 22.1 40.2 82.5 Figure 5. MAX8515A/MAX8515 Typical Application Circuit, Linear Regulator PART INITIAL ACCURACY MAX8515AEXK-T 0.6V, 0.5% feedback TOP MARKS ADX MAX8515AEZK-T 0.6V, 0.5% feedback ADRK MAX8515EXK-T 0.6V, 1% feedback ADY MAX8515EZK-T 0.
PAGE 8
Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) SC70, 5L.EPS MAX8515A/MAX8515 Wide-Input 0.
PAGE 9
Wide-Input 0.6V Shunt Regulators for Isolated DC-to-DC Converters THIN SOT23.EPS _______________________________________________________________________________________ 9 MAX8515A/MAX8515 Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.
PAGE 10
MAX8515A/MAX8515 Wide-Input 0.6V Shunt Regulators for Isolated DC-to-DC Converters Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.