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MAX16993 Step-Down Controller with

Dual 2.1MHz Step-Down DC-DC Converters

General Description

The MAX16993 power-management integrated cir-

cuit (PMIC) is a 2.1MHz, multichannel, DC-DC con-

verter designed for automotive applications. The device

integrates three supplies in a small footprint. The device

includes one high-voltage step-down controller (OUT1)

designed to run directly from a car battery and two low-

voltage step-down converters (OUT2/OUT3) cascaded from

OUT1. Under no-load conditions, the MAX16993 consumes

only 30µA of quiescent current, making it ideal for automotive

applications.

The high-voltage synchronous step-down DC-DC controller

(OUT1) operates from a voltage up to 36V continuous and

is protected from load-dump transients up to 42V. There is a

pin-selectable frequency option of either 2.1MHz or a factory-

set frequency for 1.05MHz, 525kHz, 420kHz, or 350kHz. The

low-voltage, synchronous step-down DC-DC converters run

directly from OUT1 and can supply output currents up to 3A.

The device provides a spread-spectrum enable input

(SSEN) to provide quick improvement in electromagnetic

interference when needed. There is also a SYNC input for

providing an input to synchronize to an external clock source

(see the Selector Guide). The device includes overtem-

perature shutdown and overcurrent limiting. The device also

includes individual RESET_ outputs and individual enable

inputs. The individual RESET_ outputs provide voltage

monitoring for all output channels.

The MAX16993 is available in a 32-pin TQFN/side-wettable

QFND-EP package and is specified for operation over the

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

Applications

● Automotive

● Industrial

Features

● High-Voltage DC-DC Controller

• 3.5V to 36V Operating Supply Voltage

• 42V Load-Dump Protection

• Output Voltage: Pin Selectable, Fixed or

Resistor-Divider Adjustable

• 350kHz to 2.1MHz Operation

• 30μAQuiescentCurrentwithDC-DC

Controller Enabled

● Dual High-Efficiency 2.1MHz DC-DC Converters

• Run Directly from OUT1

• 3A Integrated FETs

• 0.8V to 3.95V Output Voltage

• Fixed or Resistor-Divider-Adjustable Output Voltage

• 180° Out-of-Phase Operation

● Individual Enable Inputs

● Individual RESET_ Outputs

● Thermal-Warning Indication Output

● Forced-PWM and Skip Modes

● Overtemperature and Short-Circuit Protection

● 32-Pin TQFN-EP (5mm x 5mm x 0.75mm) and

Side-Wettable QFND-EP (5mm x 5mm x 0.8mm)

● -40°C to +125°C Operating Temperature Range

19-6684; Rev 9; 10/14

Ordering Information and Selector Guide appear at end of

data sheet.

EVALUATION KIT AVAILABLE

Summary of content (27 pages)

PAGE 1
EVALUATION KIT AVAILABLE MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters General Description The MAX16993 power-management integrated circuit (PMIC) is a 2.1MHz, multichannel, DC-DC converter designed for automotive applications. The device integrates three supplies in a small footprint. The device includes one high-voltage step-down controller (OUT1) designed to run directly from a car battery and two lowvoltage step-down converters (OUT2/OUT3) cascaded from OUT1.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Absolute Maximum Ratings VSUP, EN1 to GND................................................-0.3V to +45V PV_ to GND..........................................................-0.3V to +6.0V PV_ to GND..........................................................-0.3V to +6.0V PV2 to GND, PV2 to PGND2................................-0.3V to +6.0V PV3 to GND, PV3 to PGND3................................-0.3V to +6.0V PGND2–PGND3 to GND.......
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Electrical Characteristics (continued) (VSUP = 14V, VPV1 = VBIAS, VPV2 = VPV3 = VOUT1; TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C under normal conditions, unless otherwise noted.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Electrical Characteristics (continued) (VSUP = 14V, VPV1 = VBIAS, VPV2 = VPV3 = VOUT1; TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C under normal conditions, unless otherwise noted.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 5.5 V 5 µA OUT2 AND OUT3: LOW-VOLTAGE SYNCHRONOUS STEP-DOWN DC-DC CONVERTERS Supply Voltage Range VSUP 2.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Electrical Characteristics (continued) (VSUP = 14V, VPV1 = VBIAS, VPV2 = VPV3 = VOUT1; TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C under normal conditions, unless otherwise noted.) (Note 2) ERR PARAMETER Output Low Level SYMBOL CONDITIONS MIN ISINK = 3mA TYP MAX UNITS 0.1 0.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Typical Operating Characteristics (VSUP = 14V, TA = +25°C, unless otherwise noted) 40 30 PWM MODE 5.015 TA = +25ºC 5.010 5.005 4.990 0 1.00E-06 1.00E-04 1.00E-02 1.00E+00 0 1 2 3 TA = +25ºC 100.1 100.0 99.9 99.8 TA = -40ºC 99.7 15 20 25 30 35 100.0 99.8 99.6 99.0 40 IOUT1 = 3.75A 5.010 5.005 5.000 4.995 4.990 0 5 10 15 20 25 100.3 100.1 50 100 TEMPERATURE (ºC) www.maximintegrated.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Typical Operating Characteristics (continued) (VSUP = 14V, TA = +25°C, unless otherwise noted) 3.325 3.320 3.135 3.130 TA = +25ºC 99.6 99.4 3.315 1.5 2.0 2.5 3.0 3.5 IOUT2 (A) BUCK 3 EFFICIENCY 90 80 60 SKIP MODE PWM MODE 40 30 10 1.00E-02 VPV3 = 5.0V, IMAX = 1.5A, VOUT3 = 1.8V 1.82 TA = +25ºC 1.80 1.77 0.2 0.4 0.8 1.0 TA = +25ºC 99.8 1.224 1.222 1.220 1.2 1.4 1.6 0 0.5 1.0 1.810 TA = -40ºC 4.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Typical Operating Characteristics (continued) (VSUP = 14V, TA = +25°C, unless otherwise noted) MAX16993 toc18 120 SUPPLY CURRENT (µA) 5V/div 5V/div VOUT1 VRESET1 5V/div 5V/div VOUT2 VRESET2 80 40 TA = +25ºC 20 5V/div VRESET3 TA = +125ºC 60 5V/div VOUT3 VFB = VGND SKIP MODE ALL THREE BUCKS ENABLED MEASURED AT VSUP 100 5V/div VEN1 SUPPLY CURRENT vs.
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MAX16993 Step-Down Controller with Dual 2.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Pin Description (continued) PIN NAME FUNCTION 12 CS1 13 OUT1 14 EN2 Active-High Digital Enable Input for Buck 2. Driving EN2 high enables Buck 2. 15 EN3 Active-High Digital Enable Input for Buck 3. Driving EN3 high enables Buck 3. 16 OUT3 17 RESET3 18 PV3 Buck 3 Voltage Input. Connect a 2.2µF or larger ceramic capacitor from PV3 to PGND3. Connect PV3 to OUT1. 19 LX3 Buck 3 Switching Node.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Typical Operating Circuit BIAS GND LINEAR REGULATOR MAX16993 BIAS PV1 BST1 PV VSUP VBATP PV3 N VOUT1 DH1 P LX1 N STEP-DOWN PWM OUT3 DL1 GND CS1 STEP-DOWN CONTROLLER OUT1 OUT1 FB1 COMP1 PWM EN LX3 PGND3 OUT3 0.8V TO 3.95V 1.5A TO 3.0A PWM EN RESET1 VOUT1 P LX2 RESET2 STEP-DOWN PWM OUT2 RESET3 EN1 EN3 VOUT3 N PV2 EN2 VOUT1 POR GENERATION AND CONTROL 0.8V TO 3.95V 1.5A TO 3.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Detailed Description Enable Inputs (EN_) The 2.1MHz, high-voltage buck controller operates with a 3.5V to 36V input voltage range and is protected from load-dump transients up to 42V. The high-frequency operation eliminates AM band interference and reduces the solution footprint. It can provide an output voltage between 3.0V and 5.5V set at the factory or with external resistors.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters fSW + 6% INTERNAL OSCILLATOR FREQUENCY fSW t t + 250µs t + 500µs t + 750µs TIME Figure 1. Effect of Spread Spectrum on Internal Oscillator Spread-Spectrum Enable (SSEN) The device features a spread-spectrum enable (SSEN) input that can quickly enable spread-spectrum operation to reduce radiated emissions. Connect SSEN to BIAS to enable the spread-spectrum oscillator. Connect SSEN to GND for standard oscillator operation.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Soft-Start The device includes a 4ms fixed soft-start time on OUT1 and 2.5ms fixed soft-start time on OUT2/OUT3. Soft-start time limits startup inrush current by forcing the output voltage to ramp up towards its regulation point. If OUT1 is prebiased above 1.25V, all three buck converters do not start up until the prebias has been removed. Once the prebias has been removed, OUT1 self-discharges to GND and then goes into soft-start.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Current-Sense Measurement For the best current-sense accuracy and overcurrent protection, use a 1% tolerance current-sense resistor between the inductor and output, as shown in Figure 2. This configuration constantly monitors the inductor current, allowing accurate current-limit protection. Use low-inductance current-sense resistors for accurate measurement.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Skip mode helps improve efficiency in light-load applications by allowing the converters to turn on the highside switch only when the output voltage falls below a set threshold. As such, the converter does not switch MOSFETs on and off as often as is the case in the FPWM mode. Consequently, the gate charge and switching losses are much lower in skip mode.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters the following formulas to determine the minimum inductor value:   VOUT 1 ( VSUPMAX − VOUT 1 ) ×    VSUPMAX L MIN 1 [ H =] 1.3 ×   1 ×     f   SW 1 × I OUTMAX × K INDMAX         where fSW1 is the operating frequency and 1.3 is a coefficient that accounts for inductance initial precision. or L MIN 2 [ µH ] = 1.3 × × A V_CS × VOUT1 0.8 × R CS age, maximum current, and load regulation accuracy.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Gate-charge losses are dissipated by the driver and do not heat the MOSFET. Therefore, the power dissipation in the device due to drive losses must be checked.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters A dominant pole (fdpEA) is set by the compensation capacitor (CC) and the amplifier output resistance (ROUT,EA). A zero (fZEA) is set by the compensation resistor (RC) and the compensation capacitor (CC). There is an optional pole (fPEA) set by CF and RC to cancel the output capacitor ESR zero if it occurs near the crossover frequency (fC, where the loop gain equals 1 (0dB)).
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters OUT2/OUT3 Adjustable Output-Voltage Option The device’s adjustable output-voltage version (see the Selector Guide for details) allows the customer to set the outputs to any voltage between 0.8V and 3.95V. Connect a resistive divider from the buck converter output (VOUT_(BUCK)) to OUT_ to GND to set the output voltage (Figure 5). Select R4 (OUT_ to GND resistor) less than or equal to 100kΩ.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Table 2. Inductor Values vs. (VPV_, VOUT) VPV2/3 = 5.5V, VOUT2/3 = 3.3V VPV2/3 = 5.5V, VOUT2/3 = 2.5V VPV2/3 = 5.5V, VOUT2/3 = 1.5V VPV2/3 = 3.0V, VOUT2/3 = 0.8V INDUCTOR (µH), ILOAD = 1.5A 2.2 1.5 1.0 0.56 INDUCTOR (µH), ILOAD = 3.0A 1.0 0.68 0.56 0.33 VPV_ TO VOUT (V) Table 3. Output Capacitor Values vs. VOUT VOUT (V) 3.3 2.5 1.5 0.8 COUT (µF), IMAX = 1.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters PCB Layout Guidelines of input capacitor, high-side FET, inductor, and the output capacitor should be as short as possible. Careful PCB layout is critical to achieve low switching losses and clean, stable operation. Use a multilayer board whenever possible for better noise immunity and power dissipation. Follow these guidelines for good PCB layout: 4) Keep the power traces and load connections short.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Typical Application Circuit BIAS BIAS BIAS D2 VBATP 0.1µF D1 0.1µF VOUT1 (5V, 5A) 47µF 47µF 0.1µF BST1 FB1 PV VSUP 0.1µF 22mΩ 47µF PV1 2.2µF 220µF 2.2µH 0.1µF 10Ω 1µF 1µF VOUT1 DH1 N1 LX1 PV3 47µF 10µF DL1 N2 GND BIAS LX3 47µF PGND3 47µF MAX16993 20pF 10kΩ FB1 COMP1 40kΩ 4.7nF CS1 OUT1 VOUT3 (1.2V, 3A) 0.6µH OUT3 47pF 20kΩ VOUT1 VOUT1 5.
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MAX16993 Step-Down Controller with Dual 2.1MHz Step-Down DC-DC Converters Selector Guide BUCK 1 BUCK 2 fSW1 FIXED ACTIVE DIVIDE OPTION OUTPUT TIMEOUT RATIO VOLTAGE PERIOD FROM fSW (V) (ms) BUCK 3 FIXED MAX OUTPUT OUTPUT VOLTAGE CURRENT (V) (A) ACTIVE TIMEOUT PERIOD (ms) FIXED MAX OUTPUT OUTPUT VOLTAGE CURRENT (V) (A) ACTIVE TIMEOUT PERIOD (SAME AS BUCK 2) (ms) SYNC A 3.3/5.0 ÷5 3.9 ADJ 3.0 3.9 ADJ 3.0 3.9 Input B 3.3/5.0 ÷5 3.9 3.15 1.5 3.9 1.8 1.5 3.9 Input C 3.3/5.
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MAX16993 Step-Down Controller with Dual 2.
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MAX16993 www.maximintegrated.com Step-Down Controller with Dual 2.
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MAX16993 www.maximintegrated.com Step-Down Controller with Dual 2.