Methods, systems, and devices for wireless communication are described. A wireless device configured for carrier aggregation may communicate using transport blocks (TBs) mapped according to a wideband configuration that includes resources of multiple component carriers (CCs) within a single, low latency transmission time interval (TTI)—e.g., a TTI that has a shorter duration relative to other TTIs used in the same system. The number of CCs, and thus bandwidth, available for mapping each TB may change dynamically based on the configuration of the CCs. For a CC configured with a control region during a given low latency TTI, a TB sent during that low latency TTI may not be mapped to resources of that CC. In other cases, portions of a CC configured with a control region may be used for wideband configurations. Wideband low latency communications may be used on the uplink or downlink communications, or both.