MAX3320A General Description
The MAX3320 combines a microprocessor (µP) supervisory circuit with an RS-232 transceiver. The power-on reset performs a single function: it asserts a reset signal whenever the VCC supply voltage declines below a preset th-reshold, staying asserted for at least 100ms after VCC rises above the reset threshold. The MAX3320 has an active-low RESET output, which is guaranteed to be in the correct state for VCC down to 1V. The reset comparator is de-signed to ignore fast transients on VCC. Reset thresholds suitable for operation with a variety of supply voltages are available.
The MAX3320 transceivers have a proprietary lowdropout transmitter output stage, enabling true RS-232 perfor-mance with a dual charge pump powered from a +3V to +5.5V supply. The device requires only four small 0.1µF external charge-pump capacitors, and is guaranteed to run at data rates of up to 250kbps. It comes in the space-saving 20-pin SSOP package.
MAX3320A Maximum Ratings
VCC .............................................................................-0.3V to 6V
V+ (Note 1) .................................................................-0.3V to 7V
V- (Note 1)...................................................................0.3V to -7V
V+ + |V-| (Note 1) ..................................................................13V
Input Voltages
T_IN, FORCEOFF, FORCEON.........................................-0.3V to 6V
R_IN.....................................................................................±25V
Output Voltages
T_OUT ..............................................................................±13.2V
R_OUT, INVALID, RESET..............................-0.3V to (VCC + 0.3V)
Short-Circuit Duration
T_OUT........................................................................Continuous
Continuous Power Dissipation (TA = +70°C)
SSOP (derate 8.00mW/°C above +70°C) .....................640mW
Operating Temperature Ranges
MAX3320_CAP.....................................................0°C to +70°C
MAX3320_EAP .................................................-40°C to +85°C
Storage Temperature Range .........................-65°C to +160°C
Lead Temperature (soldering, 10sec) ...........................+300°C
MAX3320A Features
Precise Monitoring of 5V and 3.3V PowerSupply Voltages:
- 100ms (min) Power-On RESET Pulse Width
- Power-Supply Transient Immunity
- Guaranteed RESET Valid to VCC = 1V
4µA Supply Current Achieved with AutoShutdown Plus
Receivers Always Active
Power-On Reset Always Active
4µA Low-Power Shutdown
250kbps Guaranteed Data Rate
MAX3320A Typical Application
Palmtop Computers
Portable/Battery-Powered Equipment
Hand-Held Equipment
Peripherals
Printers
MAX3320A Connection Diagram
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