Rainbow Electronics MAX608 - Manual (Page 6)

MAX608
5V or Adjustable, Low-Voltage,
Step-Up DC-DC Controller
6 _______________________________________________________________________________________
______________________________________________________________Pin Description
PIN NAME FUNCTION
1 EXT Gate Drive for External N-Channel Power Transistor
2 OUT
3 FB
4 SHDN
5 REF
6 AGND Analog Ground
7 GND High-Current Ground Return for the Output Driver
8 CS
Power-Supply and Voltage-Sense Input. Always connect OUT to circuit output.
Feedback Input for Adjustable-Output Operation. Connect to ground for fixed-output operation.
Use a resistor divider network to adjust the output voltage. See
Setting the Output Voltage section.
Active-High TTL/CMOS Logic-Level Shutdown Input. In shutdown mode, V OUT is a diode drop
below the input voltage (due to the DC path from the input voltage to the output). Connect to
ground for normal operation.
1.5V Reference Output that can source 100 µ A for external loads. Bypass to GND with 0.1 µ F.
The reference is disabled in shutdown.
Positive Input to the Current-Sense Amplifier. Connect the current-sense resistor between CS
and AGND.
1.5V
REFERENCE
Q TRIG
Q S
F/F
R
Q TRIG
LOW-VOLTAGE
OSCILLATOR
2.5V
0.1V
MAX ON-TIME
ONE-SHOT
MIN OFF-TIME
ONE-SHOT
CURRENT-SENSE
AMPLIFIER
DUAL-MODE
COMPARATOR
FB REF
50mV
ERROR
COMPARATOR
SHDN
OUT
LOW-VOLTAGE
START-UP
COMPARATOR
EXT
CS
BIAS
CIRCUITRY
N
MAX608
2.3 µ s
16 µ s
Figure 1. Functional Diagram