A6861 Automotive 3-Phase Isolator MOSFET Driver FEATURES AND BENEFITS • • • • • • • 3 floating N-channel MOSFET drives Maintains VGS with 100 kΩ gate-source resistors Integrated charge pump controller 4.5 V-50 V Supply voltage operating range Independent TTL input for each phase 150°C ambient (165°C junction) continuous A2-SILTM Product – device features for safety critical systems APPLICATIONS • • • • 3-phase safety disconnect systems Electric power steering (EPS) Electric braking 3-phase Solid State Relay driver Package: 16-Lead TSSOP with exposed thermal pad (suffix LP) Not to scale. DESCRIPTION The A6861 is an N-channel power MOSFET driver capable of controlling MOSFETs connected as a 3-phase solid state relay in phase-isolation applications. The A6861 is intended for automotive systems that must meet ASIL requirements. In safety critical applications motor isolation is a critical safety requirement which is currently addressed with discrete circuitry or relays. Allegro A2-SILTM products include specific features that compliment proper system design, allowing users to achieve up to ASIL-D system rating. The A6861 has three independent floating gate drive outputs to maintain the power MOSFETs in the on state over the full supply range with high phase-voltage slew rates. An integrated charge pump regulator provides the above battery supply voltage necessary to maintain the power MOSFETs in the on state continuously when the phase voltage is equal to the battery voltage. The charge pump will maintain sufficient gate drive (>7.5 V) for battery voltages down to 4.5 V with 100 kΩ gate-source resistors. The three gate drives can be independently controlled by a logic level control input. In typical applications the MOSFETs will be switched on within 8 µs and will switch off within 1 µs. An undervoltage monitor checks that the pumped supply voltage is high enough to ensure that the MOSFETs are maintained in a safe conducting state. Continued on the next page… Typical Application Diagram 6861-DS, Rev. 2 A6861 Automotive 3-Phase Isolator MOSFET Driver Description (continued) The A6861 is supplied in a 16-lead TSSOP (LP), with exposed pad for enhanced thermal dissipation. They are lead (Pb) free, with 100% matte tin leadframe plating. Selection Guide Part Number Packing A6861KLPTR-T 13-in. reel, 4000 pieces/reel Package 16-Lead TSSOPwith exposed thermal pad, 4.4 X 5 mm case SPECIFICATIONS Absolute Maximum Ratings1 Characteristic Symbol Rating Units VBB –0.3 to 50 V Terminal VCP VCP VBB – 0.3 to VBB + 12 V Terminal CP1 VCP1 VBB – 12 to VBB + 0.3 V Terminal CP2 VCP2 VBB – 0.3 to VCP4 + 0.3 V Terminal CP3 VCP3 VBB – 12 to VBB + 0.3 V Terminal CP4 VCP4 VCP2 – 0.3 to VCP + 0.3 V VI –0.3 to 50 V Terminal GU, GV, GW VGX VSX – 0.3 to VSX + 12 V Terminal SU, SV, SW VSX – 6 to VBB + 5 V –40 to 150 ºC 165 ºC 175 ºC –55 to 150 ºC Load Voltage Supply Terminal ENU, ENV, ENW Operating Ambient Temperature TA Maximum ContinuousJunction Temperature Limited by power dissipation TJ(max) Transient Junction Temperature TJt Storage Temperature Tstg 1With Notes Over temperature event not exceeding 10s, lifetime duration not exceeding 10hours, guaranteed by design characterization. respect to GND. Ratings apply when no other circuit operating constraints are present. THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol Package Thermal Resistance (Junction to Ambient) RθJA Package Thermal Resistance (Junction to Pad) RθJP Test Conditions* Value Units 4-layer PCB based on JEDEC standard 34 ºC/W 1-layer PCB with copper limited to solder pads 43 ºC/W 2 ºC/W *Additional thermal data available on the Allegro Web site. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 A6861 Automotive 3-Phase Isolator MOSFET Driver Pin-out Diagram and Terminal List Table VBB 1 16 VCP CP4 2 15 GU CP3 3 14 SU CP2 4 13 GV CP1 5 12 SV ENU 6 11 GW ENV 7 10 SW ENW 8 9 GND Package LP, 16-Pin TSSOP Pin-out Diagram Terminal List Table Name Number Description VBB 1 Main Power Supply CP4 2 Pump Capacitor Connection CP3 3 Pump Capacitor Connection CP2 4 Pump Capacitor Connection CP1 5 Pump Capacitor Connection ENU 6 U phase Enable Input ENV 7 V phase Enable Input ENW 8 W phase Enable Input GND 9 Ground SW 10 W Phase MOSFET Source Reference GW 11 W Phase MOSFET Gate Drive SV 12 V Phase MOSFET Source Reference GV 13 V Phase MOSFET Gate Drive SU 14 U Phase MOSFET Source Reference GU 15 U Phase MOSFET Gate Drive VCP 16 Pump Supply Tab Exposed Tab - Connect to GND Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 A6861 Automotive 3-Phase Isolator MOSFET Driver Battery VCP Optional Reverse Protected Supply Network Bridge VCP C VCP VCP Floating Gate-Drive VBB GU R GPD CP4 SU CCP2 CP3 CP2 Protected Supply Motor Charge Pump Bridge VCP CCP1 Floating Gate-Drive CP1 GV GND R GPD SV Motor Level Shift ENU R PD Level Shift ENV R PD Floating Gate-Drive Level Shift ENW Bridge VCP R PD GW R GPD SW Motor GND Functional Block Diagram Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 4 A6861 Automotive 3-Phase Isolator MOSFET Driver ELECTRICAL CHARACTERISTICS at TJ = -40 to +150°C, VBB 6 V to 50 V (unless noted otherwise) Characteristics Symbol Test Conditions Min. Typ. Max. Units Supply Operating. Outputs active. VBB Functional Operating Range1 VBB Quiescent Current 4.5 – 50 V Operating. Outputs disabled 4 – 50 V No unsafe states. 0 – 50 V IBBQ Gate drive active, VBB = 12 V, Sx = GND. – 10 13.5 mA IBBS Gate drive disabled, VBB = 12 V – 5.5 8 mA 9 10 11 V 8 10 11 V 4.5 V < VBB ≤ 6 V, IVCP > - 800 µA[2] 7.5 9.5 – V Between VCP and VBB 100 – – kΩ CLOAD = 10 nF, 20% to 80% CLOAD = 10 nF, 80% to 20% – – 5 0.5 – – µs µs µs VBB VBB > 9V, IVCP > -1 VCP Output voltage w.r.t. VBB VCP Static Load Resistance VCP RCP mA[2] 6 V < VBB ≤ 9 V, IVCP > -1 mA[2] Gate Output Drive Turn-on Time Turn-off Time tr tr Propagation Delay – Turn On3 tPON CLOAD = 10 nF, ENx high to Gx 20% – – 3 Propagation Delay – Turn Off3 tPOFF CLOAD = 10 nF, ENx low to Gx 80% – – 1.5 µs Turn-on Pulse Current IGXP – 14 – mA Turn-on Pulse Time tGXP – 12.5 – µs On Hold Current IGXH – 400 – μA Pull-down On Resistance RDS(on)DN TJ = 25°C, IGx= 10 mA – 5 – Ω TJ = 150°C, IGx = 10 mA – 10 – Ω 8.5 10 12 V VBB > 9 V Gx Output high voltage w.r.t. SX, or VBB if SX>VBB VGH Gate Drive Static Load Resistance Gx Output Voltage Low Gx Passive Pull-down RGPD 6 V < VBB ≤ 9 V 8 10 12 V 4.5 V < VBB ≤ 6 V 7.5 9.5 – V RGS Between Gx and Sx 100 – – kΩ VGL -10 µA < IGx < 10 µA – – VSX +0.3 V VGx - VSx < 0.3 V – 950 – kΩ V Logic Inputs & Outputs Input Low Voltage VIL – – 0.8 Input High Voltage VIH 2.0 – – V Input Hysteresis VIhys 150 300 – mV Input Pull-down Resistor RPD 30 50 70 kΩ tCPON – 100 – µs Diagnostics & Protection VCP Undervoltage Start-up Blank Timer VCP Undervoltage Lockout VCPON VCP w.r.t. VBB. VCP rising 6.2 6.7 7.2 V VCPOFF VCP w.r.t. VBB. VCP falling 6.0 6.5 7.0 V Function is correct but parameters are not guaranteed below the general limits (6-50V). 2 For input and output current specifications, negative current is defined as coming out of (sourcing) the specified device terminal. 3 Refer to Figure 1. 1 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 A6861 Automotive 3-Phase Isolator MOSFET Driver FUNCTIONAL DESCRIPTION The A6861 is an N-channel power MOSFET driver capable of controlling MOSFETs connected as a 3-phase solid state relay in phase-isolation applications. It has three independent floating gate drive outputs to maintain the power MOSFETs in the ON state over the full supply range when the phase outputs are PWM switched with high phase-voltage slew rates. A charge pump regulator provides the above battery supply voltage necessary to maintain the power MOSFETs in the ON state continuously when the phase voltage is equal to the battery voltage. Voltage regulation is based on the difference between VBB and VCP. The charge pump will maintain sufficient gate drive (>7.5 V) for battery voltages down to 4.5 V. It is also able to provide the current taken by gate-source resistors as low as 100 kΩ should they be required, between the source and gate of the power MOSFETS. The voltage generated by the charge pump can also be used to power circuitry to control the gate-source voltage for a MOSFET connected to the main supply to provide reverse battery protection. The three gate drives can be controlled independently by three logic level enable inputs. In typical applications the MOSFETs will be switched on within 8 µs and will switch off within 1 µs. An undervoltage monitor checks that the pumped supply voltage is high enough to ensure that the MOSFETs are maintained in a safe conducting state Input & Output Terminal Functions VBB: Main power supply. The main power supply should be connected to VBB through a reverse voltage protection circuit. GND: Main power supply return. Connect to supply ground. VCP: Pumped gate drive voltage. Can be used to turn on a MOSFET connected to the main supply to provide reverse battery protection. Connect a 1 µF ceramic capacitor between VCP and VBB. CP1, CP2: Pump capacitor connections. Connect a 330 nF ceramic capacitor between CP1 and CP2. CP3, CP4: Pump capacitor connections. Connect a 330 nF ceramic capacitor between CP3 and CP4. ENU, ENV, ENW: Logic level enable inputs to control the gate drive outputs. GU, GV, GW: Floating, gate-drive outputs for external n-channel MOSFETs. SU, SV, SW: Load phase connections. These terminals are the reference connections for the floating gate-drive outputs. ENx t POFF t PON V GSx 80% 80% 20% 20% tf tR Figure 1: Enable Inputs to VGS Timing Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 6 A6861 Automotive 3-Phase Isolator MOSFET Driver Power Supplies A single reverse polarity protected power supply voltage is required. It is recommended that the VBB supply is decoupled to GND by ceramic capacitors mounted close to the device pins. Decoupling capacitors are not required for correct operation but will assist in reducing switching noise conducted to the supply from the charge pump switching circuits. The A6861 will operate within specified parameters with VBB from 6 V to 50 V and will function correctly with a supply down to 4.5 V. This provides a very rugged solution for use in the harsh automotive environment and permits use in start-stop systems. There are no unsafe device states, even at low supply voltage. As the supply voltage rises from 0 V, the gate drive outputs are maintained in the off state until the gate voltage is sufficiently high to ensure conduction and the outputs are enabled. Pump Regulator The gate drivers are powered by a regulated charge pump, which provides the voltage above VBB to ensure that the MOSFETs are fully enhanced with low on-resistance when the source of the MOSFET is at the same voltage as VBB. Voltage regulation is based on the difference between the VBB and VCP pins. The pumped voltage, VCP, is available at the VCP terminal and is limited to 12 V maximum with respect to VBB. This removes the need for external clamp diodes on the power MOSFETs to limit the gate source voltage. It also allows the VCP terminal to be used to power circuitry to control a MOSFET connected to the main supply to provide reverse battery protection. To provide the continuous low level current required when gatesource resistors are connected to the external MOSFETs, a pump storage capacitor, typically 1 µF, has to be connected between the VCP and VBB terminals. Pump capacitors, typically 330 nF, have to be connected between the CP1 and CP2 terminals and between the CP3 and CP4 terminals to provide sufficient charge transfer, especially at low supply voltage. Gate Drives The A6861 is designed to drive external, low on-resistance, power N-channel MOSFETs when used in a phase isolation application. The gate drive outputs and the VCP supply will turn the MOSFETs on in typically 8 µs and will maintain the on-state during transients on the source of the MOSFETs. The gate drive outputs will turn the MOSFETs off in typically 1 µs and will hold them in the off-state during transients on the source. An internal resistor, RGPD, between the Gx and Sx pins plus an integrated hold-off circuit, will ensure that the gate-source voltage of the MOSFET is held close to 0 V even with the power disconnected. This can remove the need for additional gate-source resistors on the isolation MOSFETs. In any case, if gate-source resistors are mandatory for the application then the pump regulator can provide sufficient current to maintain the MOSFET in the on state with a gate-source resistor of as low as 100 kΩ. The floating gate-drive outputs for external N-channel MOSFETs are provided on pins GU, GV, and GW. Gx=1 (or “high”) means that the upper half of the driver is turned on and current will be sourced to the gate of the MOSFET in the phase isolation circuit, turning it on. Gx=0 (or “low”) means that the lower half of the driver is turned on and will sink current from the external MOSFET’s gate to the respective Sx terminal, turning it off. The reference points for the floating drives are the load phase connections, SU, SV, and SW. The discharge current from the floating MOSFET gate capacitance flows through these connections. In some applications it may be necessary to provide a current recirculation path when the motor load is isolated. This will be necessary in situations where the motor driver does not reduce the load current to zero before the isolation MOSFETs are turned off. The recirculation path can be provided by connecting a suitably rated power diode to the “motor” side of the isolation MOSFETs and GND. See the Functional Block Diagram for more details. Only three diodes are required since the source to drain diodes in the isolation and bridge MOSFETs provide a recirculation path to the Battery connection. Logic Control Inputs Three TTL level digital inputs, ENU, ENV, & ENW, provide independent control for each gate drive. The three enable inputs directly control their respective gate drive outputs. When an enable input is high the corresponding gate drive output will be on. These inputs have nominal hysteresis of 300 mV to improve noise performance and can be shorted to VBB without damage. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 7 A6861 Automotive 3-Phase Isolator MOSFET Driver Supply Monitor The A6861 includes undervoltage detection on the charge pump output. If the voltage at the charge pump output, VCP , drops below the falling undervoltage threshold, VCPOFF , then the gate drive outputs will be held in the off state. They will remain in that state until VCP rises above the rising undervoltage threshold VCPON. Input and Output Structures VCP VESD ENU ENV ENW GU GV GW 200 k R GPD VESD 50 k 11 V 4V SU SV SW 6V Figure 3: Drive Outputs Figure 2: ENU, ENV, ENW Inputs VBB 12 V VCP VESD 12 V 12 V 16 V 16 V 20 V CP1 CP3 CP2 CP4 Figure 4: Supplies Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 A6861 Automotive 3-Phase Isolator MOSFET Driver Battery Voltage Reversal Protection The charge pump output voltage may be used to drive a reverseconnected battery protection circuit as illustrated in Figure 5. Battery VCP R1 When the battery voltage is reversed the voltage between VBB and VCP is zero, the gate source voltage on Q1 is zero and its source to drain diode becomes reverse biased. In this condition Q1 blocks current flow to VBB and the voltage between VBB and GND remains at Zero. Transistor Q2 is a normally connected p channel, small signal MOSFET used to control the gate of Q1 in the normal and reversed battery voltage condition. Both Q1 and Q2 must be correctly rated for the full peak reversed battery voltage. Q2 Q1 Transistor Q1 is an n-channel power MOSFET selected to create a low voltage drop at the full current rated for the motor drive system. It is connected with source and drain pins reversed from the normal biased condition. During power up the initial system current is supplied to VBB through the forward biased parasitic source to drain diode until VCP has exceeded the threshold voltage of Q1 and turned it on. Protected VBB Resistor R1 is used to control the gate to source voltage of Q1 and is powered from the VCP supply. To reduce the current drain from VCP the value of R1 should be a minimum defined for RCP, 100 k. Figure 5: Indicative Reverse Voltage Protection Scheme Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 9 A6861 Automotive 3-Phase Isolator MOSFET Driver PACKAGE OUTLINE DRAWING For Reference Only – Not for Tooling Use (Reference MO-153 ABT) Dimensions in millimeters. NOT TO SCALE Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown 0.65 0.45 8º 0º 5.00 ±0.10 16 16 0.20 0.09 1.70 B 3 (NOM) 4.40 ±0.10 3.00 (NOM) 6.40 ±0.20 A 6.10 0.60 ±0.15 1.00 (REF) 1 2 3 (NOM) 1 0.29 (BSC) 2 Branded Face 3.00 SEATING PLANE C 16X 0.10 C GAUGE PLANE C SEATING PLANE 0.30 0.19 1.20 (MAX) 0.65 (BSC) NNNNNNN YYWW LLLL 0.15 0.00 A Terminal #1 mark area B Exposed thermal pad (bottom surface); dimensions may vary with device C Reference land pattern layout (reference IPC7351 SOP65P640X110-17M); All pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances; when mounting on a multilayer PCB, thermal vias at the exposed thermal pad land can improve thermal dissipation (reference EIA/JEDEC Standard JESD51-5) D PCB Layout Reference View 1 D Standard Branding Reference View N = Device part number = Supplier emblem Y = Last two digits of year of manufacture W = Week of manufacture L = Characters 5-8 of lot number Branding scale and appearance at supplier discretion Figure 6: LP Package, 16-Lead TSSOP with Exposed Pad Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 10 A6861 Automotive 3-Phase Isolator MOSFET Driver Revision Date – February 26, 2014 1 August 25, 2014 2 May 28, 2015 Change Initial Release Various text edits throughout; reformatted document Corrected typo on Package Outline Drawing Copyright ©2014-15, Allegro MicroSystems, LLC Allegro MicroSystems, LLC (“Allegro”) products may, in certain cases, be promoted to assist with applications related to safety. Allegro’s objective is to provide an opportunity for customers to design and develop their own end-products that meet functional safety standards and requirements. However, Allegro’s products are not to be used in any devices or systems in which a failure of Allegro’s product can reasonably be expected to cause bodily harm. Customer agrees that it has sole responsibility for compliance with all applicable laws, regulations, and safety-related requirements regarding its products. Customer shall indemnify Allegro and its representatives against any damages arising out of the use of any Allegro products in safety-critical applications. Allegro assumes no responsibility for the intended use of its products, nor for any infringement of patents or other rights of third parties which may result from their use. Allegro reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, customer is cautioned to verify the detailed specifications. For the latest version of this document, visit our website: www.allegromicro.com Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 11