Value The Customer™ VM3500 4, 6 or 8-CHANNEL, 5-VOLT, THIN-FILM HEAD, READ/WRITE PREAMPLIFIER with MULTIPLE SERVO WRITE CAPABILITY 980624 FEATURES June 24, 1998 BLOCK DIAGRAM V ,M3 4 6 , 500 or 8 -C ha nn el, PE CL or T T L WD I, S ervo W rite , Ve ry H igh Pe rfo rm an ce • General • High Performance Reader - Read Gain = 300 V/V Typical - Input Noise = 0.5nV/ÐHz Typical - Low Input Capacitance = 8 pF Typical VCC R/W CS GND Mode Select H0X Read Buffer H0Y Read Preamp H1X RDX H1Y RDY H2X WDI WDI Write Current Switch Multiplexer - Single Power Supply (5 V ± 10%) - Power Up/Down Data Protect Circuitry - Very Low Power Dissipation (3 mW Typical in Sleep Mode) - Reduced Write-to-Read Recovery Time - Head Inductance Range = 0.2 – 1 µH (0.54 µH Typical) - Write Unsafe Detection - Available in 4, 6 or 8 Channels H2Y H3X H3Y H4X WC Write Current Source H4Y H5X • High Speed Writer - Write Current Range 5 - 25 mA - IW Rise/Fall Times = 3.3 ns (LH = 0.54 µH, IW = 10 mA b-p) - PECL or TTL Write Data Inputs - Multi-Channel Servo Write - Write Current Range (Servo) 5 - 20 mA - Optional Write Data Flip-Flop DESCRIPTION The VM3500 is a high-performance read/write preamplifier designed for use in high-end disk drives. It provides write current control, data protection circuitry, and a low-noise read preamplifier for up to eight channels. Fault protection is provided so that during power supply sequencing the write current generator is disabled. System write-to-read recovery time is minimized by maintaining the read channel common-mode output voltage in write mode. Very low-power dissipation from the +5V supply is achieved through use of high-speed bipolar processing and innovative circuit design techniques. When unselected, the device enters a sleep mode, with power dissipation reduced to less than 3mW. In multi-channel servo write mode, all heads are written simultaneously. The servo mode is activated via the WUS line. The VM3500 is available in several different packages. Please contact VTC for package availability. HS0 HS1 Head Select DIS HS2 WUS H5Y S0 S1 H6X SWA H7X Servo Write H6Y H7Y ABSOLUTE MAXIMUM RATINGS Power Supply: V CC ……………………………………………………… -0.3V to +7V 30mA Write Current, IW Input Voltages: Digital Input Voltage, VIN ………………… -0.3V to (VCC + 0.3)V Head Port Voltage, VH …………………… -0.3V to (VCC + 0.3)V WUS Pin Voltage Range, VWUS ……………………… -0.3V to +6V Output Current: RDX, RDY: lO ……………………………………………… -10mA WUS: lWUS ………………………………………………… +12mA Junction Temperature ……………………………………… 150°C Storage Temperature, Tstg ………………………… -65° to 150°C Thermal Characteristics, ΘJA: 20-lead SOIC ……………………………………………… 90°C/W 20-lead SSOP …………………………………………… 110°C/W 24-lead SSOP …………………………………………… 100°C/W 32-lead VSOP …………………………………………… 100°C/W RECOMMENDED OPERATING CONDITIONS Power Supply Voltage: V CC ……………………………………………………… +5V ± 10% Write current, IW …………………………………………… 5 to 25mA Head Inductance, LH …………………………………… 0.2 to 1µH Junction Temperature, TJ …………………………… 25°C to 125°C VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 2-1 2 - TERMINAL 5V/12V PREAMPS VTC Inc. VM3500 980624 selected. CIRCUIT OPERATION 2 - TERMINAL 5V/12V PREAMPS The VM3500 addresses up to eight two-terminal thin-film heads, providing write drive or read amplification. Mode control is accomplished with pins CS and R/W as shown in Table 1. Head selection is accomplished with pins HS0, HS1 and HS2 as shown in Table 2. Internal pull-up resistors provided on pins CS and R/W force the device into a non-writing condition if either control line is opened accidentally. Write Mode The write mode configures the VM3500 as a write current switch with the write current toggled between the X and Y side of the selected head in response to transitions on the WDI/WDI PECL inputs. The write unsafe (WUS) detection circuitry is also activated at this time to drive the output to a low (Safe) condition. VM3500: Write current is toggled on each low to high transition of WDI/WDI. A preceding read operation initializes the write data flip flop (WDFF) so that upon entering the write mode current flows into the “X” port. VM3500F: For the VM3500F (without the WDFF), the write current polarity is defined by the levels of WDI/WDI. For WDI > WDI, current flows into the “X” port; for WDI < WDI, current flows into the “Y” port. An internally-generated 2.5 V reference voltage is present at the WC pin. The write current magnitude is determined by an external resistor connected between the WC pin and ground and is defined by the equation: KW 50 I W = ------------ + 0.3mA = ------------ + 0.3mA R WC R WC (eq. 1) To return to normal operations: 1. Enter read mode (bring R/W high). 2. Drop the WUS pin (remove the 10 mA current) and return to normal read mode. Read Mode The read mode configures the VM3500 as a low-noise differential amplifier. The write current reference remains active to minimize the write/read recovery time. The RDX and RDY outputs are emitter followers and are in phase with the “X” and “Y” head ports. These outputs should be AC-coupled to the load. The RDX, RDY common-mode voltage is maintained in the write mode, minimizing the transient between the write mode and the read mode, thereby substantially reducing the recovery time delay to the subsequent pulse detection circuitry. Sleep Mode In sleep mode (CS high), most of the circuit is idle and power dissipation is reduced to 3mW typical. Table 1 Mode Select R/W CS MODE 0 0 Write 0 0 Servo* 1 0 Read X 1 Idle * See (Multi-Channel Servo Write Mode on page 2) for additional detail. (0-peak ±10%) Power supply fault protection improves data security by disabling the write current generator during a voltage fault or power-up. Additionally, the write unsafe circuitry will flag any of the conditions below as a high level on the open collector output pin WUS: • No write current • WDI frequency too low • Device in read or sleep mode Two transitions on pin WDI, after the fault is corrected, may be required to clear the WUS flag. Multi-Channel Servo Write Mode In servo write mode, the operation is the same as described above except that all channels are written simultaneously. Servo mode is controlled using the WUS pin. Table 2 Head Selection HS2 HS1 HS0 HEAD 0 0 0 0 0 0 1 1 0 1 0 2 0 1 1 3 1 0 0 4 1 0 1 5 1 1 0 6 1 1 1 7 To initiate servo mode: 1. Enter read mode (bring R/W high). 2. Select Head 1 (bring HS0 high). 3. Supply 10mA source current into the WUS pin. 4. Enter servo mode (drop the R/W line low). Note: If any other head is selected during servo, the part will exit servo mode and write only the selected head. Unless servo is “formally” exited by removing the 10mA current, servo mode will return whenever head 1 is 2-2 VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 VM3500 980624 NAME I/O HS0 - HS2 I1 Head Selects: Selects one of up to eight heads. H0X - H7X H0Y - H7Y I/O X, Y Head Terminals I1 Write Data Inputs: PECL input signal; a rising edge toggles direction of head current. (Each transition toggles the direction of head current on the “F” option without the write data flip flop.) WDI, WDI DESCRIPTION I R/W I1 Read/Write select: A high level selects read mode. A low-level selects write mode O1 Write Unsafe/Servo Enable: (open collector output) A high level indicates a writes unsafe condition. Note: The WUS pin is also used to enter servo mode. See (Multi-Channel Servo Write Mode on page 2). Head 345Ω Write Amp Write Current Adjust: A resistor adjusts level of write current. WC RDX-RDY Read Amp Chip Select: A high level signal puts chip in sleep mode; a low level awakens chip. CS WUS/SE Damping Resistor Unless otherwise indicated, the VM3500 has damping resistors isolated by Schottky diodes. The diodes effectively remove the resistor from the circuit during the read mode, however during the write mode with the higher level input signal, the resistor provides damping for the write current waveform. 2 - TERMINAL 5V/12V PREAMPS PIN DESCRIPTIONS O Read Data Output: Differential output data. VCC +5 volt supply GND Ground 1. May be wire-OR’ed for multi-chip usage. VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 2-3 VM3500 980624 DC CHARACTERISTICS Recommended operating conditions apply unless otherwise specified. PARAMETER Power Supply Voltage SYM Power Supply Power Dissipation MIN TYP MAX UNITS 4.5 5.0 5.5 V Read Mode 34 + 0.05IW 50 Write Mode, Normal, IW = 10mA 34 + 1.05IW 60 Write Mode, Servo, IW = 10mA (4-Channel) 55 + 4.3IW 125 Write Mode, Servo, IW = 10mA (6-Channel) 100 + 8.6IW 225 Write Mode, Servo, IW = 10mA (8-Channel) 100 + 8.6IW 225 Sleep Mode 0.5 3 Read Mode 175 275 Write Mode, Normal, IW = 10mA 225 330 Write Mode, Servo, IW = 10mA (4-Channel) 490 688 VCC 2 - TERMINAL 5V/12V PREAMPS VCC Supply Current CONDITIONS ICC mA PD mW Write Mode, Servo, IW = 10mA (6-Channel) 930 1240 Write Mode, Servo, IW = 10mA (8-Channel) 930 1240 3 16.5 Sleep Mode Input High Voltage VIH 2 VCC +0.3 V Input Low Voltage VIL -0.3 0.8 V Input High Current IIH VIH = 2.7V 80 µA Input Low Current IIL VIL = 0.4V WDI, WDI Input High Voltage VIH Pseudo ECL VCC - 1.5 VCC - 0.1 V WDI, WDI Input Low Voltage VIL Pseudo ECL VIH - 1.5 VIH - 0.25 V WDI, WDI Input High Current IIH VIH = VCC - 0.7V 100 µA WDI, WDI Input Low Current IIL VIH = VCC - 1.6V 80 µA -160 µA WUS Output Low Voltage VOL IOL = 4.0mA 0.35 0.5 V WUS Output High Current IOH VOH = 5.0V 13 100 µA 3.3 3.6 4.0 V 10 1 20 mA VCC Value for Write Current Turn Off WUS Servo Enable IH < 0.2mA ISE 1. The typical value for servo activation is 6 mA. The minimum value at which servo activation is guaranteed is 10 mA. 2-4 VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 VM3500 980624 WRITE CHARACTERISTICS Recommended operating conditions apply unless otherwise specified; LH = 0.54µH, RH = 20¾, IW = 10mA, fDATA = 5MHz. PARAMETER WC Pin Voltage 2 - TERMINAL 5V/12V PREAMPS 1. SYM CONDITIONS MIN TYP 1 MAX UNITS VWC 2.5 V IWC to Head Current Gain AI 20 mA/mA Write Current Constant KW VCC = 5V ±10% 45 Write Current Range IW 10.64k¾ > RWC > 2k¾ 50 55 V 5 25 mA Write Current Tolerance ∆IW VCC ±10% -10 +10 % Write Current Tolerance Servo ∆IW VCC ±10% -14 +14 % Differential Head Voltage Swing VDH Open head @ VCC = 4.5V 5.4 WDI Transition Frequency for Safe Condition fDATA WUS = low Differential Output Capacitance COUT Differential Output Resistance ROUT Unselected Head Current IUH RDX, RDY Common Mode Output Voltage VCM 6.0 Vp-p 1 MHz 10 3.2 IW = 25mA pF k¾ 0.15 0.5 VCC - 2.7 mA(pk) V Typical values are given at VCC = 5V and TA = 25°C. SERVO WRITE PARAMETER Write Current Matching Between Channels Duty Cycle (20mA/head) SYM ∆IW CONDITIONS MIN TYP MAX UNITS 5mA < IW < 20mA 10 % TA = 25°C, t s-on < 50ns 1 50 % 1. The ambient temperature (TA) and servo-on time (ts-on) limitations are consistent with keeping the peak junction temperature under 125°C. 2-5 VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 VM3500 980624 READ CHARACTERISTICS Recommended operating conditions apply unless otherwise specified; CL (RDX, RDY) < 20pF, RL (RDX, RDY) = 1k¾. PARAMETER 2 - TERMINAL 5V/12V PREAMPS Differential Voltage Gain AV Bandwidth BW TYP 1 MAX UNITS VIN = 1mVrms, 1MHz 250 300 350 V/V -1dB |Zs| < 5¾, VIN = 1mVp-p 50 55 -3dB |Zs| < 5¾, VIN = 1mVp-p 90 100 CONDITIONS MHz Input Noise Voltage ein BW = 20MHz, LH = 0, RH = 0 Differential Input Capacitance CIN VIN = 1mVp-p, f = 5MHz Differential Input Resistance RIN VIN = 1mVp-p, f = 5MHz Dynamic Range DR AC input where AV is 90% of gain at 0.2mVrms input 2 mV P-P 300 0.5 0.65 nV/ÐHz 8 12 pF 750 ¾ Common Mode Rejection Ratio CMRR VIN = 100mVp-p @ 5MHz 50 dB Power Supply Rejection Ratio PSRR 100mVp-p @ 5MHz on VCC 45 dB 45 dB Channel Separation CS Unselected channels: VIN = 20mVp-p @ 5MHz VIN = 0 on selected head Output Offset Voltage VOS Steady state read RDX, RDY Common Mode Output Voltage VOCM Read/Write Mode RDX, RDY Common Mode Output Voltage Difference Between Modes ∆VOCM Single-Ended Output Resistance Output Current 1. MIN SYM RSEO IO -300 +300 mV +350 mV 35 ¾ VCC - 2.0 -350 f = 5 MHz AC-coupled load, RDX to RDY ±1 mA Typical values are given at VCC = 5V and TA = 25°C. 2-6 VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 VM3500 980624 SWITCHING CHARACTERISTICS Recommended operating conditions apply unless otherwise specified; IW = 10mA, fDATA = 5MHz, LH = 0.54µH, RH = 20¾, CL (RDX, RDY) ð 20pF (see Figures 1 and 2). SYM CONDITIONS TYP 1 MAX UNITS R/W Read to Write Delay tRW R/W to 90% IW 0.06 0.15 µs R/W Write to Read Delay tWR R/W to 90% of 100mV, 10 MHz read signal envelope 0.2 0.4 µs CS Unselect to Select Delay tIR CS to 90% I W or 90% of 100mV, 10MHz read signal envelope 0.6 µs CS Select to Unselect Delay tRI CS to 10% of IW 0.6 µs HS0 - HS3 any Head Delay tHS HS0 - HS3 to 90% of 100mV, 10MHz read signal envelope 0.6 µs WUS Safe to Unsafe Delay tD1 3.6 µs WUS Unsafe to Safe Delay tD2 IW = 10mA 1.0 µs Head Current Propagation tD3 LH = 0, RH = 0, from 50% points 30 ns Head Current Asymmetry ASYM 50% duty cycle on WDI, 1ns rise/fall time; LH = 0, RH = 0 0.5 ns 0.6 10% to 90% points, LH = 0, RH = 0, IW = 10mA Head Current Rise/Fall Time 1.0 2.0 tr/tf ns 10% to 90% points, LH = 540nH, IW = 10mA, RH = 20¾ 1. MIN 2 - TERMINAL 5V/12V PREAMPS PARAMETER 3.3 5.0 Typical values are given at VCC = 5V and TA = 25°C. VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 2-7 VM3500 980624 WDI - WDI tD2 tD1 2 - TERMINAL 5V/12V PREAMPS WUS tD3 HEAD CURRENT (IW) Figure 1 Write Mode Timing Diagram for VM3500 WDI-WDI tD2 tD1 WUS tD3 HEAD CURRENT (IW) Figure 2 Write Mode Timing Diagram for VM3500F (without write data flip flop) 2-8 VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 VM3500 980624 LIST OF SPECIFIC PART VARIATIONS (described on the following pages) VM357830 Page Location 1 VM355830 11 VM355830 (28-lead package) VM356630 10 2 - TERMINAL 5V/12V PREAMPS PART VARIATION 12 1 13 VM355635 14 VM355630 15 VM355435 16 VM355430 17 1. This part is non-conventional. See the specific page for details. VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 2-9 VM3500 980624 VM357830 8-Channel Connection Diagram 2 - TERMINAL 5V/12V PREAMPS H0X H0Y H1X H1Y H2X H2Y H3X H3Y H4X H4Y H5X H5Y H6X H6Y H7X H7Y 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 GND R/W WC RDX RDY HS0 HS1 HS2 WDI WDI WUS/SE CS NC NC NC VCC 8-Channel 32-lead VSOP VM357830FVSM Note: This part is non-conventional in the following aspects: • It has an alternate pin-out (CS is in a different location). • It has a bank servo mode where 4 heads are written at a time based on the head selected. (See below.) • It has a nominal damping resistor value of 250 Ω (Schottky isolated). Specific Characteristics See the general data sheet for common specification information. Multi-Channel Servo Write Mode In servo write mode, the operation is the same as described in the general datasheet except that four channels are written simultaneously as shown in the table below. 2-10 HEAD SELECTED HEADS WRITTEN 0 or 1 none 2 odd (1,3,5 and7) 3 even (0,2,4 and 6) VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 VM3500 980624 VM355830 8-Channel Connection Diagram 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 NC NC GND CS R/W WC RDY RDX HS0 HS1 HS2 VCC WDI WDI WUS/SE NC 2 - TERMINAL 5V/12V PREAMPS H0X H0Y H1X H1Y H2X H2Y H3X H3Y H4X H4Y H5X H5Y H6X H6Y H7X H7Y 8-Channel 32-lead VSOP VM355830(F)VSL Specific Characteristics See the general data sheet for common specification information. VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 2-11 VM3500 980624 VM355830 (28-lead package) 8-Channel Connection Diagram 2 - TERMINAL 5V/12V PREAMPS H0X H0Y H1X H1Y H2X H2Y H3X H3Y H4X H4Y H5X H5Y H6X H6Y 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 GND R/W WC RDY RDX HS0 HS1 HS2 WDI WDI WUS/ SE VCC H7Y 8-Channel 28-lead SSOP VM355830FSS28L Specific Characteristics See the general data sheet for common specification information. 2-12 VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 VM3500 980624 VM356630 6-Channel Connection Diagram 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 GND CS R/W WC RDY RDX HS0 HS1 HS2 VCC WDI WUS/SE 2 - TERMINAL 5V/12V PREAMPS H0X H0Y H1X H1Y H2X H2Y H3X H3Y H4X H4Y H5X H5Y 6-Channel 24-lead SSOP VM356630SSL Note: This part is non-conventional in one aspect: • It has TTL single-ended write data input. Write current is toggled on each high-to-low transition of WDI. Specific Characteristics See the general data sheet for common specification information. VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 2-13 VM3500 980624 VM355635 6-Channel Connection Diagram 2 - TERMINAL 5V/12V PREAMPS H0X H0Y H1X H1Y H2X H2Y H3X H3Y H4X H4Y H5X H5Y 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 GND R/W WC RDY RDX HS0 HS1 HS2 WDI WDI WUS/SE VCC 6-Channel 24-lead SSOP VM355635FSSP Specific Characteristics See the general data sheet for common specification information. • 350 V/V read gain. PARAMETER SYM CONDITIONS Differential Voltage Gain AV VIN = 1mVrms, 1MHz Differential Input Capacitance CIN VIN = 1mVp-p, f = 5MHz Single-Ended Output Resistance 2-14 RSEO f = 5 MHz MIN TYP MAX UNITS 292 350 408 V/V 10 14 pF 50 ¾ VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 VM3500 980624 VM355630 6-Channel Connection Diagram 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 GND R/W WC RDY RDX HS0 HS1 HS2 WDI WDI WUS/SE VCC 2 - TERMINAL 5V/12V PREAMPS H0X H0Y H1X H1Y H2X H2Y H3X H3Y H4X H4Y H5X H5Y 6-Channel 24-lead SSOP VM355630FSSL Specific Characteristics See the general data sheet for common specification information. VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 2-15 VM3500 980624 VM355435 4-Channel Connection Diagram 2 - TERMINAL 5V/12V PREAMPS GND H0X H0Y H1X H1Y H2X H2Y H3X H3Y VCC 20 19 18 17 16 15 14 13 12 11 1 2 3 4 5 6 7 8 9 10 CS R/W WC RDY RDX HS0 HS1 WDI WDI WUS/SE 4-Channel 20-lead SSOP VM355435FSSP Specific Characteristics See the general data sheet for common specification information. • 350 V/V read gain. PARAMETER SYM CONDITIONS Differential Voltage Gain AV VIN = 1mVrms, 1MHz Differential Input Capacitance CIN VIN = 1mVp-p, f = 5MHz Single-Ended Output Resistance 2-16 RSEO f = 5 MHz MIN TYP MAX UNITS 292 350 408 V/V 10 14 pF 50 ¾ VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 VM3500 980624 VM355430 4-Channel Connection Diagram 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 CS R/W WC RDY RDX HS0 HS1 WDI WDI WUS/SE 2 - TERMINAL 5V/12V PREAMPS GND H0X H0Y H1X H1Y H2X H2Y H3X H3Y VCC 4-Channel 20-lead SOIC, SSOP, VSOP VM355430SSL Specific Characteristics See the general data sheet for common specification information. VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100 2-17