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Microchip Technology |
TC1235
TC1236
TC1237
Inverting Dual (–VIN, –2VIN) Charge Pump Voltage Converters with Shutdown
FEATURES
s 10-Pin MSOP Package
s Operates from 1.8V to 5.5V
s Up to 5mA Output Current at –VIN Pin
s Up to 1mA Output Current at –2VIN Pin
s Power-Saving Shutdown Mode
s –VIN and –2VIN Outputs Available
s Low Active Supply Current
.......................................... 120µA (MAX) for TC1235
.......................................... 360µA (MAX) for TC1236
.......................................... 1.5mA (MAX) for TC1237
s Fully Compatible with 1.8V Logic Systems
TYPICAL APPLICATIONS
s LCD Panel Bias
s Cellular Phones PA Bias
s Pagers
s PDAs, Portable Dataloggers
s Battery Powered Devices
GENERAL DESCRIPTION
The TC1235/1236/1237 are CMOS dual inverting
charge pump voltage converters with a low power shutdown
mode in MSOP 10-Pin packages. Only four external capaci-
tors are required for full circuit implementation. Switching
frequencies are 12kHz for the TC1235, 35kHz for the
TC1236 and 125kHz for the TC1237. When the shutdown
pin is held at a logic low, the device goes into a very low
power mode of operation, consuming less than 1µA of
supply current.
These devices provide both a negative voltage inver-
sion (available at the –VIN output), and a negative doubling
voltage inversion (available at the –2 VIN output) with a low
output impedance capable of providing output currents up to
5mA for the –VIN output and 1mA for the –2VIN output. The
input voltage can range from +1.8V to +5.5V.
ORDERING INFORMATION
Part No. Package Osc Freq (KHz) Temp Range
TC1235EUN 10-Pin MSOP
TC1236EUN 10-Pin MSOP
TC1237EUN 10-Pin MSOP
12
35
125
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
PIN CONFIGURATION
10-Pin MSOP
C1– 1
C2+ 2
NC 3
C2– 4
TC1235
TC1236
TC1237
10 –VIN
9 C1+
8 SHDN
7 VIN
–2 VIN 5
6 GND
Notes:
1) C1 and COUT1 must have a voltage rating greater
than or equal to VIN
2) C2 and COUT2 must have a voltage rating greater
than or equal to 2VIN
© 2001 Microchip Technology Inc. DS21371A
TYPICAL OPERATING CIRCUIT
+ C1+
C1
INPUT
VIN
OUTPUT 1
C1– –VIN
C2+ + COUT1
+
C2
TC1235
C2–
TC1236
TC1237
SHDN
ON
OFF
GND
NC
–2 VIN
OUTPUT 2
+ COUT2
TC1235/6/7-1 3/24/00
TC1235
TC1236
TC1237
Inverting Dual (–VIN, –2VIN)
Charge Pump Voltage Converters
with Shutdown
ABSOLUTE MAXIMUM RATINGS*
Input Voltage (VIN to GND) ......................... +6.0V, – 0.3V
Output Voltage (–VIN, –2VIN to GND) ........ –12.0V, + 0.3V
Current at –VIN, –2VIN Pins ...................................... 10mA
Short-Circuit Duration –VIN, –2VIN to GND ........ Indefinite
Operating Temperature Range ............... – 40°C to +85°C
Power Dissipation (TA ≤ 70°C) MSOP-10 ............. 320mW
Storage Temperature (Unbiased) ......... – 65°C to +150°C
Lead Temperature (Soldering, 10sec) .................. +260°C
*This is a stress rating only and functional operation of the device at these
or any other conditions above those indicated in the operational sections
of the specifications is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS: TA = –40°C to +85°C, VIN = +5V, C1 = 3.3µF, C2 = 1µF (TC1235); C1 = 1µF, C2
= 0.33µF (TC1236); C1 = 0.33µF, C2 = 0.1µF (TC1237), SHDN = VIN, unless otherwise noted. Typical values are at TA = +25°C.
Symbol Parameter
Device Test Conditions
Min Typ Max Unit
IDD
ISHDN
VMIN
VMAX
FOSC
Supply Current
TC1235
TC1236
TC1237
Shutdown Supply Current All
Minimum Supply Voltage All
Maximum Supply Voltage All
Oscillator Frequency
TC1235
TC1236
TC1237
SHDN = VIN
SHDN = VIN
SHDN = VIN
SHDN = GND, VIN = +5V
RLOAD = 1kΩ for –VIN output
RLOAD = 10kΩ for –2VIN output
RLOAD = 1kΩ for –VIN output
RLOAD = 10kΩ for –2VIN output
— 75
— 200
— 625
— 0.1
1.8 —
——
8.4 12
24.5 35
65 125
VIH Shutdown Input All VIN = VMIN to VMAX
Logic High
1.4 —
VIL
VEFF1
VEFF2
ROUT1
ROUT2
TWK1
Shutdown Input
Logic low
Voltage Conversion
Efficiency (Stage 1)
Voltage Conversion
Efficiency (Stage 2)
Output Resistance
for –VIN output (Note 1)
Output Resistance
for –2VIN output (Note 1)
Wake-Up Time
From Shutdown Mode
Stage 1
All
All
All
All
All
TC1235
TC1236
TC1237
VIN = VMIN to VMAX
RLOAD = ∞ for –VIN output
RLOAD = ∞ for –2VIN output
RLOAD = ∞ for –VIN output
RLOAD = ∞ for –2VIN output
ILOAD = 0.5mA to 5mA
No Load at -VIN Output
ILOAD = 0.1mA to 1mA
No Load at -2VIN Output
RLOAD = 1kΩ for -VIN Output
RLOAD = 10kΩ for -2VIN Output
——
96 99.5
94 99
— 45
— 135
— 650
— 250
— 100
TWK2
Wake-Up Time
From Shutdown Mode
Stage 2
TC1235
TC1236
TC1237
RLOAD = 1kΩ for -VIN Output
RLOAD = 10kΩ for -2VIN Output
— 750
— 280
— 120
NOTES: 1. Capacitor contribution is approximately 20% of the output impedance [ESR = 1 / pump frequency x capacitance)].
120
360
1500
1
—
5.5
15.6
45.5
170
—
0.4
—
—
80
420
—
—
—
—
—
µA
µA
V
V
kHz
V
V
%
%
Ω
Ω
µsec
µsec
PIN DESCRIPTION
Pin Number
1
2
3
4
5
6
7
8
9
10
Name
C1–
C2+
NC
C2–
–2VIN
GND
VIN
SHDN
C1+
–VIN
Description
C1 Commutation Capacitor Negative Terminal.
C2 Commutation Capacitor Positive Terminal.
No Connection.
C2 Commutation Capacitor Negative Terminal.
Doubling Inverting Charge Pump Output (–2 x VIN).
Ground.
Positive Power Supply Input.
Shutdown Input (Active Low).
C1 Commutation Capacitor Positive Terminal.
Inverting Charge Pump Output (–1 x VIN).
TC1235/6/7-1 3/24/00
2 © 2001 Microchip Technology Inc. DS21371A
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