ADDITIONAL CONNECTION DIACRAMS

H2X H2Y H3X H3Y H4X H4Y H5X H5Y HOX HOY H7X H7Y HBX HBY HOX HOY

14-Channel 64-lead TQFP

VEE H53 NC5 ANW AWC ADY ADX NC HSO H51 H52 vee

WDIN WOI WU5 VDD

VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100

H14X H14Y H15X H15Y H16X H16Y H17X H17Y H18X H18Y H19X H19Y NC NC NC NC

20-Channel 64-lead TQFP

17181920212223242526272829303132

H5Y H5X H4Y H4X H3Y H3X H2Y H2X H1Y H1X HOY HOX NC NC NC NC

2-59

2-60 VTC Inc., 2800 Easl Old Shakopee Road, Bloominglon, MN 55425, 612-853-5100

FEATURES

• High Performance

- Rise/Fall Times

=

6.5 ns Typical into 1 I1H Head

• Power Supply Fault Protection

• Options Available

- WDFF on the Write Data Inputs Connected or Disconnected

DESCRIPTION

The VM5200M is a high-performance, integrated read/write preamplifier designed for use with two-terminal, thin-film record-ing heads. The circuit contains read amplifiers and write drivers to address up to 20-channels. Internal damping resistors pro-vide different values of damping resistance between the read mode and write modes. When deselected, the circuit enters a low-power sleep mode. Current gain in the write mode is 20 and it is DAC or resistor-controllable. The power supply fault detect circuit shuts off write current in the event the power supply level drops below a unsafe threshold, thus protecting the data on the disk from any potential transients. If a line should open up, the mode select lines (CS and R/W) have internal pullup resistors to ensure the select lines will be forced into a high state to prevent the device from affecting data on the disk.

The VM5200M is available in a variety package options.

Please consult VTC for package availability.

VTC Inc., 2800 East Old Shakopee Road, Bloomingion, MN 55425, 612-853-5100

VMS200M

10 OR 20-CHANNEL,

HIGH-PERFORMANCE, THIN-FILM HEAD, READIWRITE PREAMPLIFIER

PRELIMINARY

~

~, _~:~#

.. ~.~ VM5200M

'Option available with no WOFF

ABSOLUTE MAXIMUM RATINGS Power Supply Voltages:

HOX Junction Temperature, ... 150°C Storage Temperature Range ... -65° to 150°C Thermal Characteristics, 0JA:

36-lead SOIC ... ... ... 80°CIW 48-lead TQFP ... ... .... ... 80°CIW 64-lead TQFP ... ... 60°CIW

RECOMMENDED OPERATING CONDITIONS DC Power Supply Voltage:

Voo ... 12V ± 10%

Vee ... 5V± 10%

Junction Temperature ... O°C to 125°C

2-62

CIRCUIT OPERATION

The VM5200M addresses up to 20 two-terminal thin film heads, providing write drive or read amplification. Head selec-tion and mode control are accomplished with pins HSn, CS and

RJW

as shown in Table 1. Internal resistor pull ups provided on pins CS and RiW will force the device into a non-writing condi-tion if either control line is opened accidentally.

Write Mode

Write mode configures the VM5200M as a current switch and activates the write unsafe (WUS) detection Circuitry. Write cur-rent is toggled between the X and Y direction of the selected head on each high-to-Iow transition on pins WDI- WDI (differen-tial write data inputs).

A preceding read operation initializes the Write Data Flip-Flop (WDFF) so that upon entering the write mode current flows into the "X" head port.

The part is also available without the write data flip-flop. In this option the write current direction is controlled by the WDI and WDI pins. When WDI > WDI current flows into the "X" head port. Current flows in the opposite direction when the write data voltages are reversed.

The write current magnitude is determined by an external resistor connected between the WC pin and ground. An inter-nally generated 2.5V reference voltage is present at the WC pin.

The magnitude of the write current (O-pk, ± 8%) is:

Iw= 50/Rwe

Typically, an adjustment to the calculated head current is required to account for current shunted by the damping resistor.

This complication is avoided in the VM5200M because the inter-nal 380n damping resistors are series-connected with Schottky diode pairs.

In multiple-device applications, a single RWC resistor may be made common to all devices.

Power supply fault protection improves data security by dis-abling the write current generator during a voltage fault or power supply sequencing. Additionally, the write unsafe detection cir-cuitry will flag any of the conditions listed below with a high level on the open collector output pin, WUS.

• No write current

• WDI frequency too low

• Open head

• Device in read mode

• Device not selected

Two negative write data transitions, after the fault is corrected, may be required to clear the WUS flag.

Read Mode

Read mode configures the VM5200M as a low-noise differen-tial amplifier and deactivates the write current generator and write unsafe detection circuitry. The RDX and ROY outputs are emitter followers and are in phase with the "X" and "Y" head ports. These outputs should be AC coupled to the load.

VTe Inc:, 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100

There is also a mask option to make RDX and RDY open col-lector outputs. The RDX, RDY common-mode voltage is maintained in the write mode, minimizing the transient between write mode and read mode, substantially reducing the recovery time delay to the subsequent Pulse Detection circuitry.

Idle Mode

When ~ is high, virtually the entire circuit is shut down so that power dissipation is reduced to less than 35mW for a sleep mode. Multiple devices may have their read outputs wire OR'ed together and the write current programming resistor common to all devices.

Table 1: Mode Select

RlW CS

MODE

0 0 Write

.1 0 Read

0 1 Idle

1 1 Idle

VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853·5100

Table 2: Head Select

HSO HS1

0 0

1 0

0 1

1 1

0 0

1 0

0 1

1 1

0 0

1 0

0 1

1 1

0 0

1 0

0 1

1 1

0 0

1 0

0 1

1 1

HS2 HS3 HS4 HEAD

0 0 0 0

0 0 0 1

0 0 0 2

0 0 0 3

1 0 0 4

1 0 0 5

1 0 0 6

1 0 0 7

0 1 0 8

0 1 0 9

0 1 0 10

0 1 0 11

1 1 0 12

1 1 0 13

1 1 0 14

1 1 0 15

0 0 1 16

0 0 1 17

0 0 1 18

0 0 1 19

2-63

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_~~,

VM5200M

DC CHARACTERISTICS Unless otherwise specified, recommended operating conditions apply.

PARAMETER SYM CONDITIONS MIN

Read Mode

VCC Supply Current lee Write Mode

Idle Mode Read Mode

VDD Supply Current 100 Write Mode

Idle Mode Read Mode

Power Dissipation (T J = 125°C) Po Write Mode: Iw=20mA Idle Mode

Input Low Voltage VIL TTL -0.3

Input High Voltage VIH TTL 2.0

Input Low Current IlL VIL = 0.8V, TTL -200

Input High Current IIH VIH = 2.0V, TTL

WDI,

wm

Input High Voltage VIH Pseudo ECL Vee- 1.O

WDI, WDI Input Low Voltage VIL Pseudo ECL Vee -1.9

WDI,

wm

Input High Current IIH VIH = Vee - 0.7V WDI,

WDf

Input Low Current IlL VIL = Vee -1.6V WUS Output Low Voltage VOL IOL= 4mA

VCC Fault Voltage VOOF 9.5

VCC Fault Voltage VeeF 3.8

Write Mode, 0 < Vee 3.8V,

-200 0< Voo<9V

Head Current (HnX, HnY) IH

Write Mode, 0 < Vee 5.5V,

-200 0< Voo < 13.2V

TYP MAX UNITS

47 50

30· 32 mA

1.3 1.5

0.8 1.2

20+lw 22+lw mA

0.83 1

270 291

660 730 mW

18 22

0.8 V

Vcc+0.3 V

I!A

100

I!A

Vee- 0.7 V Vee -1;6 V

100

I!A

80

I!A

0.35 0.5 V

10 10.5 V

4 4.3 V

+200

I!A

+200

2-64 ^VTC Inc., 2800 East Old Shakopee Road, Bloomington. MN 55425, 612-853-5100

READ CHARACTERISTICS Unless otherwise specified, recommended operating conditions apply, CL (RDX, ROY) < 20pF and RL (RDX, ROY) = 1kn.

PARAMETER SYM CONDITIONS MIN TYP MAX UNITS

Differential Voltage Gain Av VIN = 1mVp-p @300kHz 120 1 SO' 180 VN

-1dB, IZsl < SO, VIN = 1mVp-p

40 SO"

@300kHz

Bandwidth BW MHz

-3dB, IZsl < SO, VIN = 1 mVp-p

SO 7S"

@300kHz

Input Noise Voltage ein BW = 1SMHz, LH

=

0, RH = 0 0.S2 0.6S nV/-#lZ

Differential Input Capacitance CIN VIN = 1 mVp-p, f = SMHz 10 14 pF

Differential Input Resistance RIN VIN

=

1 mVp-p, f = SMHz,

260 SSO 0

(2S0C < TA < 12S°C)

AC input voltage where the gain

Dynamic Range DR falls to 90% of the gain @ 2 S mVrms

0.2mVrms input, f

=

^SMHz

Common Mode Rejection Ratio CMRR VeM = 100mVp-p @SMHz SO 60 dB

Power Supply Rejection Ratio PSRR 100mVp-p @SMHzon Voo or Vee 4S SO dB

Unselected channels driven with

Channel Separation CS 100mVp-p @SMHz, Selected 4S SO dB

Channels VIN = OmVp-p

Output Offset Voltage I Vas I VIN = 0 on selected head, 1S0 mV

Av = 1S0

RDX, ROY Common Mode Output Read Mode Vee - 3.0 Vee - 2.8 Vee - 2.2

Voltage VOeM V

Write Mode Vee - 3.0 Vee - 2.8 Vee - 2.2

Single-Ended Output Resistance RSEO f= SMHz 17 3S 0

Output Current 10 AC coupled load, RDX to ROY 1.S mA

,

Nommal gam - other options available

" The bandwidth is head dependent due to the capacitive cancellation circuitry. When the preamplifier is used with a head the band-width is dominated by the inductance of the head and the input capacitance of the preamplifier even if the LC pole is beyond the amplifier bandwidth as given above.

WRITE CHARACTERISTICS Unless otherwise specified, recommended operating conditions apply, Iw = 20mA, LH = 1.0j.lH, RH = 300 and fOATA = SMHz.

PARAMETER SYM CONDITIONS MIN TYP MAX UNITS

WC Pin Voltage Vwe 2.S V

Write Current Voltage VOH Iwe=3SmA 9 9.S 10 Vp-p

Unselected Head Current IUH 0.3 1.0 mA (pk)

Differential Output Capacitance COUT 18 22 pF

Without damping resistor 3.2 kn

Differential Output Resistance ROUT

With damping resistor 400 0

WDI Transition Frequency fOATA WUS = low 1.0 MHz

Write Current Range Iw 14300< Rwe < Skn 10 3S mA

Write Current Tolerance Alw Iw range 10mA to 3SmA -8 +8 %

VTe Inc .. 2800 East Old Shakopee Road. Bloomington. MN 55425. 612-853-5100 2-6S

SWITCHING CHARACTERISTICS (see Figure 1) Unless otherwise specified, recommended operating conditions apply, Iw = 20mA, LH = 1.0J.1H, RH = 30n and fOATA = 5MHz.

PARAMETER

Am

to Write Mode

RiW to Read Mode

CS to Select

CS to Unselect HSO - HS3 to Any Head Safe to Unsafe Unsafe to Safe Propagation Delay Asymmetry Rise/Fall Time Rise/Fall Time

WUS

HEAD CURRENT(lw)

SYM tRW

tWR

tlR

tlW tHS tOl t02 t03 ASYM

t,lt, t,lt,

Figure 1: Write Mode Timing Diagram

CONDITIONS MIN TYP MAX

Delay to 90% of write current 0.6

Delay to 90% of 100mV, 10MHz

read signal envelope or to 90% 0.6

decay of write current Delay to 90% of write current or

to 90% of 100mV, 10MHz read 0.6

signal envelope

Delay to 10% of write current 0.6

Delay to 90% of 100mV, 10MHz read signal envelope 0.4

50% WDI to 50% WUS 0.6 3.6

50% WDI to 50% WUS 1

From 50% points, LH = 0, RH = 0 30

WDI has 50% duty cycle and 1 ns

0.2 0.5

riselfall time, LH = 0, RH = 0

(LH = 1J.1H) 6.5 9

(LH =OJ.1H) 2 5

UNITS

J.1S J.1S

J.1S J.1S J.1S J.1S J.1S ns ns ns ns

2-66 VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100

~:~

~~

~~.~

..

~~

VTC Inc.

,:.:~ Value the Customer'"

FEATURES

• High Performance

- Rise/Fall Times

=

4 ns Typical into 600 nH Head - Input Capacitance

=

10 pF Typical

- Input Noise

=

0.65 nV/-{RZ Typical - Head Inductance Range = 400 - 800 nH - Voltage Gain

=

^{150 VN}

• PECl Write Data Lines

• Write Current Range 5 - 25 mA

• Operates From +5v/+12V

• Power Supply Fault Protection

• 4000 Schottky Damping Resistor DESCRIPTION

The VM522015C is a high-performance, integrated read/write preamplifier designed for use with two-terminal, thin-film record-ing heads. The circuit contains read amplifiers and write drivers to address 20-channels. Internal damping resistors provide dif-ferent values of damping resistance between the read mode and write modes. When deselected, the circuit enters a low-power sleep mode. Current gain in the write mode is 20 and it is DAC or resistor-controllable. The power supply fault detect circuit shuts off write current in the event the power supply level drops below a unsafe threshold, thus protecting the data on the disk from any potential transients. If a line should open up, the mode select lines (CS and Am) have internal pullup resistors to ensure the select lines will be forced into a high state to prevent the device from affecting data on the disk.

The VM522015C is available in a variety package options.

Please consult VTC for package availability.

VTC Inc., 2800 East Old Shakopee Road, Bloomington, MN 55425, 612-853-5100

VM522015C

20-CHANNEL, HIGH-PERFORMANCE,

Dans le document Gain of ~ (Page 124-132)