Philips Semiconductors
QIC read-write amplifier
Preliminary specification
TZA1000
FEATURES
• 3-wire serial interface for programming
• On-chip Digital-to-Analog Converters (DAC) for:
– MR (Magneto Resistive) sense bias current
– MR DC bias current
– Write current
• Low noise differential input stage: typically 0.65 nV/√Hz
(Zi = 0 Ω)
• Magnetic feedback circuit to handle large output signals
• MR DC bias current circuit
• Very fast write current rise and fall times with near
rail-to-rail voltage swing
• Maximum write current of 100 mA: ready for high
coercivity tape
• Low noise read amplifier for reading track height servo
signals with the write coil
• Very few external components required
• On board registers for easy format or bit rate selection
• Fast read-after-write recovery time
• Test circuit for yoke-type heads
• Switchable differentiator for yoke-type heads, with
programmable cut-off frequencies
• Anti-aliasing low-pass filter, with programmable cut-off
frequencies
• AGC (Automatic Gain Control) options: internally
(digitally) controlled, externally controlled or fixed gain
• Hold input for fast AGC freeze
• Input for fast reader/writer (track height servo) signal
selection
• Power fail detection on both 5 and 12 V lines (status can
be read from the read register)
• Write unsafe detection
• Provides an accurate reference voltage (for AD
conversion)
• Very simple interconnection with the SZA1000 QIC
digital equalizer
• +5 V ±10% and +12 V ±10% supply voltages
• Low power standby, active and test modes.
RELATED DOCUMENTS
• SZA1000 QIC digital equalizer data sheet
• Application notes for TZA1000 and SZA1000.
Both are available from Philips Semiconductors.
GENERAL DESCRIPTION
The TZA1000 is a single-chip read-write amplifier for
single-channel QIC (Quarter Inch Cartridge) systems with
MR heads. It can be used with both SIG (Sensor in Gap)-
and yoke-type MR heads and is designed to be used in
conjunction with the Philips SZA1000 digital equalizer IC
(although it can also function as a stand alone unit). This
combination is flexible enough to be used with all popular
tape backup formats including QIC 80, QIC 3010,
QIC 3020, QIC 3080, QIC 5010, Travan 1, Travan 2,
Travan 3 and Travan 4 and to be forward compatible with
their single channel successors.
QUICK REFERENCE DATA
SYMBOL
VDD1
VDD2
VDD3
IDD1; IDD2
IDD3
Vn(i)(eq)
fclk
Tamb
Tj
Rth(j-a)
PARAMETER
read circuit supply voltage
FB and write circuit supply voltage
sense current circuit supply voltage
read/FB and write circuit supply current
Read mode
Write mode
sense current circuit supply current
equivalent input noise voltage
clock frequency
recommended operating temperature
recommended junction temperature
thermal resistance from junction to ambient
CONDITIONS
Iwrite = 30 mA
Isense = 16 mA
Zsource = 0 Ω
in free air
MIN.
4.5
4.5
10.8
−
−
15.0
−
−
0
0
−
TYP.
5
5
12
69
105
16.2
0.65
−
−
−
66
MAX.
5.5
5.5
13.2
UNIT
V
V
V
−
mA
−
mA
19.0 mA
0.8
nV/√Hz
24
MHz
70
°C
125
°C
−
K/W
1998 Mar 17
2