LTC1263
12V, 60mA Flash Memory
Programming Supply
FEATURES
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DESCRIPTION
The LTC
®
1263 is a regulated 12V, 60mA output DC/DC
converter. It provides the 12V
±5%
output necessary to
program double byte-wide flash memories. The output
provides 60mA from input voltages as low as 4.75V
without using any inductors. Only four external capacitors
are required to complete an extremely small, surface
mountable circuit. The output can be momentarily shorted
to ground without damaging the part.
The active high TTL compatible Shutdown pin can be
directly connected to a microprocessor. In the shutdown
mode, the supply current typically drops to 0.5µA.
The LTC1263 is available in an 8-pin SO package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Guaranteed 60mA Output
Regulated 12V
±
5% Output Voltage
No Inductors
Supply Voltage Range: 4.75V to 5.5V
I
CC
0.5µA Typ in Shutdown
Low Power: I
CC
= 300µA
8-Pin SO Package
Same Pinout as LTC1262 and MAX662
APPLICATIONS
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12V Flash Memory Programming Supplies
Compact 12V Op Amp Supplies
Battery-Powered Systems
TYPICAL APPLICATION
Flash Memory Programming Supply
V
CC
4.75V TO 5.5V
13.0
12.8
12.6
OUTPUT VOLTAGE (V)
10µF
SHDN
C1
–
0.47µF
C1
+
12.4
12.2
12.0
11.8
11.6
11.4
11.2
V
CC
SHDN
ON
µP
LTC1263
C2
–
0.47µF
C2
+
V
OUT
GND
12V
5V
FLASH
MEMORY
VPP
10µF
LTC1263 • TA01
11.0
0
20
40
60
80
LOAD CURRENT (mA)
100
LTC1263 • TA02
U
U
U
Output Voltage vs Load
1
LTC1263
ABSOLUTE
MAXIMUM
RATINGS
(Note 1)
PACKAGE/ORDER INFORMATION
TOP VIEW
C1
–
1
C1
+
2
C2
–
3
C2
+
4
8 SHDN
7 GND
6 V
OUT
5 V
CC
Supply Voltage (V
DD
) ................................................. 6V
Input Voltage (SHDN) ..................... – 0.3V to V
CC
+ 0.3V
I
OUT
Continuous.................................................... 90mA
Operating Temperature Range ..................... 0°C to 70°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC1263CS8
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 125°C,
θ
JA
= 150°C/ W
Consult factory for Industrial and Military grade parts and TSSOP package
option.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
V
OUT
I
CC
I
SHDN
f
OSC
Output Voltage
Supply Current
Shutdown Supply Current
Oscillator Frequency
Power Efficiency
R
SW
V
IH
V
IL
V
CC
to V
OUT
Switch Impedance
SHDN Input High Voltage
SHDN Input Low Voltage
SHDN Input Current
CONDITIONS
4.75V
≤
V
CC
≤
5.5V, T
A
= 0°C to 70°C (Notes 2, 3).
MIN
q
q
q
TYP
MAX
12.6
UNITS
V
mA
µA
kHz
%
0mA
≤
I
OUT
≤
60mA, V
SHDN
= 0V
No Load, V
SHDN
= 0V
No Load, V
SHDN
= V
CC
V
CC
= 5V, I
OUT
= 60mA
V
CC
= 5V, I
OUT
= 60mA
V
CC
= V
SHDN
= 5V, I
OUT
= 0mA
11.4
0.32
0.5
300
76
1.0
10
q
q
q
0.3
2.4
1
0.8
– 40
– 10
– 20
0
600
10
–5
10
V
CC
= 5V, V
SHDN
= 0V
V
CC
= 5V, V
SHDN
= 5V
q
q
t
ON
t
OFF
Turn-On Time
Turn-Off Time
C1 = C2 = 0.47µF, C3 = C4 = 10µF (Note 4) (Figures 1, 2)
C1 = C2 = 0.47µF, C3 = C4 = 10µF (Figures 1, 2)
The
q
denotes specifications which apply over the full operating
temperature range.
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified.
Note 3:
All typicals are given at V
CC
= 5V, T
A
= 25°C.
Note 4:
A higher value output capacitor can be used but the “turn-on” and
“turn-off” time will increase proportionally.
2
U
W
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W W
W
kΩ
V
V
µA
µA
µs
ms
LTC1263
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current
328
326
I
OUT
= 0
12.8
12.6
V
CC
= 5V
SUPPLY CURRENT (mA)
SUPPLY CURRENT (µA)
OUTPUT VOLTAGE (V)
324
322
320
318
316
314
312
–55 –35 –15 5 25 45 65
TEMPERATURE (°C)
85 105
LTC1263 • TPC01
V
CC
= 5V
Output Voltage
12.8
12.6
T
A
= 25°C
460
420
380
I
OUT
= 0mA, 60mA
OUTPUT VOLTAGE (V)
12.4
FREQUENCY (kHz)
12.2
12.0
11.8
11.6
11.4
11.2
4.7
4.8
I
OUT
= 90mA
4.9 5.0 5.1 5.2 5.3
SUPPLY VOLTAGE (V)
PIN FUNCTIONS
C1
–
(Pin 1):
First Charge Capacitor Negative Input. Connect
a 0.47µF capacitor (C1) between C1
+
and C1
–
.
C1
+
(Pin 2):
First Charge Capacitor Positive Input. Connect
a 0.47µF capacitor (C1) between C1
+
and C1
–
.
C2
–
(Pin 3):
Second Charge Capacitor Negative Input.
Connect a 0.47µF capacitor (C2) between C2
+
and C2
–
.
C2
+
(Pin 4):
Second Charge Capacitor Positive Input.
Connect a 0.47µF capacitor (C2) between C2
+
and C2
–
.
V
CC
(Pin 5):
Positive Supply Input. 4.75V
≤
V
CC
≤
5.5V.
Requires a 10µF bypass capacitor to ground (C4).
V
OUT
(Pin 6):
12V Output. Requires a 10µF or a higher
value bypass capacitor to ground (C3). V
OUT
= V
CC
when
in the shutdown mode.
GND (Pin 7):
Ground.
SHDN (Pin 8):
Active-High TTL Logic Level Shutdown Pin.
SHDN is internally pulled up to V
CC
. Connect to GND for
normal operation. In shutdown mode, the charge pump is
turned off and V
OUT
= V
CC
.
U W
Output Voltage
220
215
210
205
200
195
Supply Current
I
OUT
= 60mA
12.4
12.2
I
OUT
= 60mA
12.0
11.8
11.6
11.4
11.2
–55 –35 –15 5 25 45 65
TEMPERATURE (°C)
85 105
LTC1263 • TPC02
V
CC
= 4.75V
V
CC
= 5V
V
CC
= 5.5V
I
OUT
= 0mA
I
OUT
= 90mA
190
185
180
–55 –35 –15 5 25 45 65
TEMPERATURE (°C)
85 105
LTC1263 • TPC03
Oscillator Frequency
340
300
260
220
180
5.4 5.5
140
–55 –35 –15 5 25 45 65
TEMPERATURE (°C)
85 105
LTC1263 • TPC05
LTC1263 • TPC04
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LTC1263
BLOCK DIAGRAM
W
V
CC
S3A
S3C
S4A
C1
–
S4C
S3B
C2
+
R2
S1
R1
SHDN
V
OUT
C
OUT
C
IN
S4B
CLK
S2
S3D
CHARGE PUMP
LTC1263 • BD
C1
+
C1
C2
C2
–
S1 AND S2 SHOWN WITH SHDN PIN LOW. S3A, S3B, S3C, S3D, S4A, S4B AND S4C SHOWN CHARGING C1 AND C2
WITH OSCILLATOR OUTPUT LOW AND V
DIV
< V
BGAP
– V
HYST
. AT OSCILLATOR OUTPUT HIGH, S3A, S3B, S3C AND S3D
OPEN WHILE S4A, S4B AND S4C CLOSE TO CHARGE V
OUT
. COMPARATOR HYSTERESIS IS
±V
HYST
TIMING DIAGRAMS
t
OFF
t
ON
12V
V
OUT
5.1V
V
CC
V
CC
V
SHDN
1.4V
1.4V
0V
V
OUT
Figure 1. Timing Diagram
1
C1 = 0.47µF
2
3
C2 = 0.47µF
4
C1
–
C1
+
SHDN
GND
LTC1263
V
OUT
V
CC
8
7
6
5
C3 = 10µF
C2
–
C2
+
Figure 2. Timing Circuit
4
–
V
BGAP
BANDGAP
REFERENCE
V
DIV
R3
+
OSCILLATOR
GND
W
UW
LTC1263 • F01
V
SHDN
V
OUT
C4 = 10µF
V
CC
4.75V TO 5.5V
LTC1263 • F02
LTC1263
OPERATION
The LTC1263 uses a charge pump tripler to generate 12V
from a V
CC
of 5V. The charge pump is clocked by an
internal oscillator. The oscillator frequency is not critical
and may vary from the typical value of 300kHz. When the
oscillator output is low, C1 and C2 are each connected
between V
CC
and GND, charging them to V
CC
(see Figure
3). When the oscillator output goes high, C1 and C2 are
stacked in series with the bottom plate of C1 pulled to V
CC
(see Figure 4). The top plate of C2 is switched to charge
C
OUT
, which enables V
OUT
to rise.
V
OUT
is regulated to within 5% of 12V by an oscillator pulse
gating scheme that turns the charge pump on and off
based on the comparator results of V
OUT
and a reference
voltage. First, a resistor divider senses V
OUT
; if the output
of the divider (V
DIV
) is less than the output of a bandgap
(V
BGAP
) by the hysteresis voltage (V
HYST
) of the compara-
tor, then oscillator pulses are applied to the charge pump
to raise V
OUT
. When V
DIV
is above V
BGAP
by V
HYST
, the
V
CC
V
OUT
C
OUT
Figure 3. C1 and C2 Charge to V
CC
APPLICATIONS INFORMATION
Choice of Capacitors
The LTC1263 is tested with the capacitors shown in Figure
2. C1 and C2 are 0.47µF ceramic capacitors and C
IN
and
C
OUT
are 10µF tantalum capacitors. Refer to Table 1 if
other choices are desired.
Table 1. Recommended Capacitor Types and Values
CAPACITOR
C1, C2
C
OUT
C
IN
CERAMIC
0.47µF to 1µF
10µF (Min)
10µF (Min)
TANTALUM
10µF (Min)
10µF (Min)
ALUMINUM
10µF (Min)
10µF (Min)
Not Recommended Not Recommended
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oscillator pulses are prevented from clocking the charge
pump. As a result, V
OUT
drops until V
DIV
is below V
BGAP
by
V
HYST
again.
To ensure proper start-up when V
OUT
is lower than V
CC
and maintain proper operation when V
OUT
is higher than
V
CC
, the gates of all internal switches are driven between
GND and the higher of either V
OUT
or V
CC
.
To reduce supply current, the LTC1263 may be put into
shutdown mode by “floating” the SHDN pin or connecting
it to V
CC
. In this mode, the bandgap, comparator, oscilla-
tor and resistor divider are switched off to reduce the
supply current to typically 0.5µA. At the same time an
internal switch shorts V
OUT
to V
CC
; V
OUT
takes 10ms (typ)
to reach 5.1V (see t
OFF
in Figure 1). When the SHDN pin
is low, the LTC1263 exits shutdown and the charge pump
operates to raise V
OUT
to 12V. V
OUT
takes 600µs (typ) to
reach the lower regulation limit of 11.4V (see t
ON
in Figure 1).
+
C1
+
C2
V
CC
+
C2
+
C1
LTC1263 • F04
LTC1263 • F03
Figure 4. C1 and C2 Stacked in Series with C1
–
Tied to V
CC
C1 and C2 should be ceramic capacitors with values in the
range of 0.47µF to 1µF. Higher values provide better load
regulation. Tantalum capacitors are not recommended as
the higher ESR of these capacitors degrades performance
at high load currents and V
CC
= 4.75V.
C
IN
and C
OUT
can be ceramic, tantalum or electrolytic
capacitors. The ESR of C
OUT
introduces steps in the V
OUT
waveform whenever the charge pump charges C
OUT
. This
tends to increase V
OUT
ripple. Ceramic or tantalum capaci-
tors are recommended for C
OUT
if minimum ripple is
5
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