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AVAILABLE

EVALUATION KIT AVAILABLE

Functional Diagrams

Pin Configurations appear at end of data sheet.

Functional Diagrams continued at end of data sheet.

UCSP is a trademark of Maxim Integrated Products, Inc.

For pricing, delivery, and

ordering information, please contact Maxim Direct

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

General Description

The MAX15004A/B/MAX15005A/B high-performance,

current-mode PWM controllers operate at an automo-

tive input voltage range from 4.5V to 40V (load dump).

The input voltage can go down as low as 2.5V after

startup if V

is supplied by an external bias voltage.

The controllers integrate all the building blocks neces-

sary for implementing fixed-frequency isolated/noniso-

lated power supplies. The general-purpose boost,

flyback, forward, and SEPIC converters can be

designed with ease around the MAX15004/MAX15005.

The current-mode control architecture offers excellent

line-transient response and cycle-by-cycle current limit

while simplifying the frequency compensation.

Programmable slope compensation simplifies the

design further. A fast 60ns current-limit response time,

low 300mV current-limit threshold makes the controllers

suitable for high-efficiency, high-frequency DC-DC con-

verters. The devices include an internal error amplifier

and 1% accurate reference to facilitate the primary-side

regulated, single-ended flyback converter or nonisolat-

ed converters.

An external resistor and capacitor network programs

the switching frequency from 15kHz to 500kHz (1MHz for

the MAX15005A/B). The MAX15004A/B/MAX15005A/B

provide a SYNC input for synchronization to an external

clock. The maximum FET-driver duty cycle for the

MAX15004A/B is 50%. The maximum duty cycle can be

set on the MAX15005A/B by selecting the right combi-

nation of RT and CT.

The input undervoltage lockout (ON/OFF) programs the

input-supply startup voltage and can be used to shut-

down the converter to reduce the total shutdown cur-

rent down to 10µA. Protection features include

cycle-by-cycle and hiccup current limit, output overvolt-

age protection, and thermal shutdown.

The MAX15004A/B/MAX15005A/B are available in

space-saving 16-pin TSSOP and thermally enhanced

16-pin TSSOP-EP packages. All devices operate over

the -40°C to +125°C automotive temperature range.

Applications

Automotive

Vacuum Fluorescent Display (VFD) Power

Supply

Isolated Flyback, Forward, Nonisolated SEPIC,

Boost Converters

Features

♦ Wide 4.5V to 40V Operating Input Voltage Range

♦ Operates Down to 2.5V (with Bootstrapped V

Bias)

♦ Current-Mode Control

♦ Low 300mV, 5% Accurate Current-Limit Threshold

Voltage

♦ Internal Error Amplifier with 1% Accurate Reference

♦ RC Programmable 4% Accurate Switching

Frequency

♦ Switching Frequency Adjustable from 15kHz to

500kHz (1MHz for the MAX15005A/B)

♦ External Frequency Synchronization

♦ 50% (MAX15004) or Adjustable (MAX15005)

Maximum Duty Cycle

♦ Programmable Slope Compensation

♦ 10µA Shutdown Current

♦ Cycle-by-Cycle and Hiccup Current-Limit

Protection

♦ Overvoltage and Thermal Shutdown Protection

♦ -40°C to +125°C Automotive Temperature Range

♦ 16-Pin TSSOP or 16-Pin Thermally Enhanced

TSSOP-EP Packages

♦ AEC-Q100 Qualified

4.5V to 40V Input Automotive

Flyback/Boost/SEPIC Power-Supply Controllers

PART PIN-PACKAGE MAX DUTY CYCLE

MAX15004AAUE+ 16 TSSOP-EP* 50%

MAX15004AAUE/V+ 16 TSSOP-EP* 50%

MAX15004BAUE+ 16 TSSOP 50%

MAX15004BAUE/V+ 16 TSSOP 50%

MAX15005AAUE+ 16 TSSOP-EP* Programmable

MAX15005AAUE/V+ 16 TSSOP-EP* Programmable

MAX15005BAUE+ 16 TSSOP Programmable

MAX15005BAUE/V+ 16 TSSOP Programmable

Ordering Information

Note: All devices are specified over the -40°C to +125°C

temperature range.

Denotes a lead(Pb)-free/RoHS-compliant package.

/V denotes an automotive qualified part.

EP = Exposed pad.

Pin Configurations appear at end of data sheet.

MAX15004A/B/MAX15005A/B

19-0723; Rev 3; 1/11

Summary of content (27 pages)

PAGE 1
EVALUATION KIT AVAILABLE LE AVAILAB MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers General Description The MAX15004A/B/MAX15005A/B high-performance, current-mode PWM controllers operate at an automotive input voltage range from 4.5V to 40V (load dump). The input voltage can go down as low as 2.5V after startup if VCC is supplied by an external bias voltage.
PAGE 2
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers ABSOLUTE MAXIMUM RATINGS Continuous Power Dissipation* (TA = +70°C) 16-Pin TSSOP-EP (derate 21.3mW/°C above +70°C)..............................................................1702mW 16-Pin TSSOP (derate 9.4mW/°C above +70°C) ..........754mW Operating Junction Temperature Range ...........-40°C to +125°C Junction Temperature ......................................................
PAGE 3
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers ELECTRICAL CHARACTERISTICS (continued) (VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ, CT = 560pF, VSYNC = VOVI = VFB = VCS = 0V, COMP = unconnected, OUT = unconnected. TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to PGND, unless otherwise noted.
PAGE 4
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers ELECTRICAL CHARACTERISTICS (continued) (VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ, CT = 560pF, VSYNC = VOVI = VFB = VCS = 0V, COMP = unconnected, OUT = unconnected. TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to PGND, unless otherwise noted.
PAGE 5
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers ELECTRICAL CHARACTERISTICS (continued) (VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ, CT = 560pF, VSYNC = VOVI = VFB = VCS = 0V, COMP = unconnected, OUT = unconnected. TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to PGND, unless otherwise noted.
PAGE 6
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Typical Operating Characteristics (VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ, CT = 560pF. TA = +25°C, unless otherwise noted.) VIN SUPPLY CURRENT (ISUPPLY) vs. OSCILLATOR FREQUENCY (fOSC) 22 19 16 13 10 4 1 110 135 6.5 6.0 5.5 5.0 5 10 15 20 25 30 35 VIN SUPPLY VOLTAGE (V) 40 45 0.25 0.23 0.20 0.18 0.15 0.13 0.10 0.08 0.05 0.
PAGE 7
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Typical Operating Characteristics (continued) (VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ, CT = 560pF. TA = +25°C, unless otherwise noted.
PAGE 8
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Typical Operating Characteristics (continued) (VIN = 14V, CIN = 0.1μF, CVCC = 0.1μF // 1μF, CREG5 = 1μF, VON/OFF = 5V, CSS = 0.01μF, CSLOPE = 100pF, RT = 13.7kΩ, CT = 560pF. TA = +25°C, unless otherwise noted.
PAGE 9
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Pin Description PIN NAME FUNCTION 1 IN 2 ON/OFF 3 OVI 4 SLOPE 5 N.C. No Connection. Not internally connected. 6 RTCT Oscillator-Timing Network Input. Connect a resistor from RTCT to REG5 and a capacitor from RTCT to SGND to set the oscillator frequency (see the Oscillator Frequency/External Synchronization section). 7 SGND Signal Ground. Connect SGND to SGND plane.
PAGE 10
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Functional Diagram IN 1 MAX15004A/B MAX15005A/B PREREGULATOR 1.228V OFF OFF 16 VCC 7.4V LDO REG 10.5V 30mA CLAMP ON/OFF 2 ON/OFF COMP 3.5V UVLO REFERENCE UVB DRIVER 15 OUT 14 PGND VCC THERMAL SHUTDOWN SET RESET OV-COMP OVI 3 UVB ILIMIT COMP 5V LDO REG 13 REG5 50ns LEAD DELAY 12 CS 0.3V 1.
PAGE 11
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Detailed Description The MAX15004A/B/MAX15005A/B are high-performance, current-mode PWM controllers for wide inputvoltage range isolated/nonisolated power supplies. These controllers are for use as general-purpose boost, flyback, and SEPIC controllers. The input voltage range of 4.5V to 40V makes it ideal in automotive applications such as vacuum fluorescent display (VFD) power supplies.
PAGE 12
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers operation of the power supply; however, to reduce the power dissipation of the internal LDO, it can be disabled by applying an external voltage higher than 7.4V at VCC (LDO output). The LDO then stops drawing current from IN, thereby reducing the power dissipation in the IC. The VCC voltage is clamped to 10.4V with 30mA current sink in case there is a higher voltage at the bias winding.
PAGE 13
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers (tDISCHARGE). See Figures 3a and 3b for a coarse selection of capacitor values for a given switching frequency and maximum duty cycle and then use the following equations to calculate the resistor value to fine-tune the switching frequency and verify the worst-case maximum duty cycle.
PAGE 14
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers OSCILLATOR FREQUENCY (fOSC) vs. RT/CT MAX15005 MAXIMUM DUTY CYCLE vs.
PAGE 15
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers When the voltage produced by this current (through the current-sense resistor) exceeds the current-limit comparator threshold, the MOSFET driver (OUT) quickly terminates the on-cycle. In most cases, a short-time constant RC filter is required to filter out the leadingedge spike on the sense waveform.
PAGE 16
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers VIN DVIN CIN CREG5 0.1μF CVIN 1μF 1 13 REG5 RT IN L RVCC VOUT 18V D3 DVCC VCC 16 COUT CVCC 4.7μF 6 RTCT CT MAX15004A/B MAX15005A/B OUT CFF CS RF CF 11 10 COMP 15 Q RCS 12 RA CCS RS FB SLOPE SS PGND 9 4 CSLOPE RB CSS Figure 5.
PAGE 17
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Δ VESR ESR = IO I × D MAX C OUT = O Δ VQ × fOUT IO is the load current, ΔVQ is the portion of the ripple due to the capacitor discharge, and ΔVESR is the contribution due to the ESR of the capacitor. DMAX is the maximum duty cycle at the minimum input voltage. Use a combination of low-ESR ceramic and high-value, low-cost aluminum capacitors for lower output ripple and noise.
PAGE 18
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Selecting VCC Resistor (RVCC) The VCC external supply series resistor should be sized to provide enough average current from VOUT to drive the external MOSFET (IDRIVE) and ISUPPLY. The VCC is clamped internally to 10.4V and capable of sinking 30mA current. The VCC resistor must be high enough to limit the VCC sink current below 30mA at the highest output voltage.
PAGE 19
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Step 3) Calculate the secondary to primary turns ratio (NSP) and the bias winding to primary turns ratio (NBP) using the following equations: spike. The MOSFET’s absolute maximum VDS rating must be higher than the worst-case (maximum input voltage and output load) drain voltage. NS = NP ⎡N ⎤ VDSMAX = VINMAX + ⎢ P × (VOUT + VD ) ⎥ + VSPIKE N ⎢⎣ S ⎥⎦ N SP = LS LP and N BP = N BIAS 11 . 7 = NP VOUT + 0 .
PAGE 20
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers An additional small LC filter may be necessary to suppress the remaining low-energy high-frequency spikes. The LC filter also helps attenuate the switching frequency ripple. Care must be taken to avoid any compensation problems due to the insertion of the additional LC filter.
PAGE 21
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers MOSFET, Diode, and Series Capacitor Selection in a SEPIC Converter For the SEPIC configuration, choose an n-channel MOSFET with a VDS rating at least 20% higher than the sum of the output and input voltages. When operating at a high switching frequency, the gate charge and switching losses become significant. Use low gatecharge MOSFETs.
PAGE 22
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers VIN 2.5V TO 16V L1 L11 = L22 = 7.5μH C7 6.8μF VOUT (8V/2A) D2 STP745G D1 LL4148 VOUT R5 10Ω 1 IN VCC C4 22μF D3 BAT54C C1 6.8μF 16 C2 6.8μF C5 22μF C6 22μF C3 6.8μF CVCC 1μF C1 100nF MAX15005A/B 2 ON ON/OFF OFF OUT 3 REG5 REG5 RT 15kΩ 5 6 14 SLOPE CSLOPE 47pF REG5 STD20NF06L OVI PGND 4 RG 1Ω 15 13 C10 1μF N.C.
PAGE 23
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Layout Recommendations Typically, there are two sources of noise emission in a switching power supply: high di/dt loops and high dv/dt surfaces. For example, traces that carry the drain current often form high di/dt loops. Similarly, the heatsink of the MOSFET connected to the device drain presents a dv/dt source; therefore, minimize the surface area of the heatsink as much as possible.
PAGE 24
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Typical Operating Circuits R7 510Ω VIN (5.5V TO 16V) C1 330μF 50V C11 2200pF 100V R16 10Ω R17 100kΩ 1% C2 0.1μF 50V R8 100kΩ C3 1μF 16V R9 NU C14 NU 3 ON/OFF 15 C16 330μF 6.3V R15 100Ω R3 50Ω N FILAMENTC17 2.2μF 10V OVI PGND C4 100pF R10 36kΩ FILAMENT+ (3V/650mA) OUT 4 14 D5 REG5 SLOPE REG5 13 C10 1μF R1 8.45kΩ 1% 5 6 7 CS RTCT 12 C9 560pF R6 0.06Ω 1% SGND COMP 8 R5 1kΩ N.
PAGE 25
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Typical Operating Circuits (continued) VIN (4.5V TO 16V) C1 10μF 25V L1 10μH/IHLP5050 VISHAY 1 C11 0.1μF IN VCC C10 1μF/16V CERAMIC MAX15005A/B R11 301kΩ 2 D1 B340LB R8 153kΩ OUT 3 PGND C2 100pF Q Si736DP OVI R9 10kΩ 4 R1 5Ω 15 VOUT (18V/2A) C6 56μF/25V SVP-SANYO ON/OFF VOUT R10 100kΩ REG5 16 14 REG5 SLOPE REG5 13 C10 1μF 5 R2 13kΩ 6 CS RTCT 12 C4 100pF C3 180pF 7 R4 0.
PAGE 26
MAX15004A/B/MAX15005A/B 4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers Pin Configurations TOP VIEW + + IN 1 16 VCC IN 1 16 VCC ON/OFF 2 15 OUT ON/OFF 2 15 OUT OVI 3 SLOPE 4 N.C. 5 RTCT 6 SGND 7 SYNC 8 OVI 3 14 PGND MAX15004A MAX15005A EP 13 REG5 SLOPE 4 N.C. 5 12 CS 12 CS RTCT 6 11 COMP 10 FB SGND 7 10 FB 9 SS SYNC 8 9 SS TSSOP Package Information Chip Information For the latest package outline information and land patterns, go to www.maxim-ic.
PAGE 27
MAX15004A/B/MAX15005A/B 4.