TC1235 Datasheet, PDF (1/10 Pages) Microchip Technology – Inverting Dual (-VIN, -2VIN) Charge Pump Voltage Converters with Shutdown

TC1235
TC1236
TC1237
Inverting Dual (–V_IN, –2V_IN) 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 –V_IN Pin
s Up to 1mA Output Current at –2V_IN Pin
s Power-Saving Shutdown Mode
s –V_IN and –2V_IN 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 –V_IN output), and a negative doubling
voltage inversion (available at the –2 V_IN output) with a low
output impedance capable of providing output currents up to
5mA for the –V_IN output and 1mA for the –2V_IN 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 12
TC1236EUN 10-Pin MSOP 35
TC1237EUN 10-Pin MSOP 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 –V_IN
9 C1+
8 _SHDN
7 V_IN
–2 V_IN 5
6 GND
Notes:
1) C1 and C_OUT1 must have a voltage rating greater
than or equal to V_IN
2) C2 and C_OUT2 must have a voltage rating greater
than or equal to 2V_IN
© 2001 Microchip Technology Inc. DS21371A
TYPICAL OPERATING CIRCUIT
+
C1+
C1
INPUT
V_IN
OUTPUT 1
C1–
–V_IN
C2+
+ ^COUT1
+
C2
TC1235
C2–
TC1236
TC1237
SHDN
ON
OFF
GND
NC
–2 V_IN
OUTPUT 2
+ ^COUT2
TC1235/6/7-1 3/24/00