MAX840 Maxim, MAX840 Datasheet - Page 7

• Manufacturer Part Number: MAX840
• Description: Low-Noise / Regulated / -2V GaAsFET Bias
• Manufacturer: Maxim

Dual Mode is a trademark of Maxim Integrated Products.
Figure 1a. MAX840 Block Diagram
______________________________________________________________Pin Description
MAX840
—
1
2
3
4
5
6
7
8
NEGOUT
SHDN
PIN
C1+
C1-
MAX843
MAX844
—
1
2
3
4
5
6
7
8
Low-Noise, Regulated, -2V GaAsFET Bias
_______________________________________________________________________________________
-0.5V
REF
CHARGE
PUMP
N
NEGOUT
NAME
SHDN
CONT
GND
OUT
C1+
C1-
FB
IN
MAX840
GND
Positive Terminal for C1
Negative Terminal for C1
Negative Output Voltage (unregulated)
Active-Low, TTL Logic-Level Shutdown Input
Dual Mode™ Feedback Input. When FB is grounded, the output is preset to -2V. To
select other output voltages, connect FB to an external resistor divider (Figure 2b).
Control Voltage Input. To set V
positive control voltage between 0V and 10V (Figure 2c).
Regulated Negative Output Voltage
Ground
Positive Power-Supply Input
IN
OUT
FB
CONNECT TO
GND TO SET
V
OUT
= -2V
Figure 1b. MAX843/MAX844 Block Diagram
OUT
SHDN
, connect a resistor divider between OUT and a
NEGOUT
C1+
C1-
FUNCTION
CHARGE
PUMP
N
GND
MAX843
MAX844
IN
OUT
CONT
CONTROL
VOLTAGE
R2
R1
7